Microfibrillated cellulose from non-wood plant biomass

Abstract

The present disclosure relates to methods of processing non-wood plant biomass to produce microfibrillated cellulose. The present disclosure also relates to microfibrillated cellulose produced by those methods, and their uses.

Description

[0001] Microfibrillated cellulose from non-wood plant biomass RELATED APPLICATION

[0002] [1] This application claims priority from Australian provisional patent application number 2024902880, the contents of which are incorporated herein by reference in their entirety.

[0003] FIELD

[0004] [2] The present disclosure relates to methods of processing non-wood plant biomass to produce microfibrillated cellulose. The present disclosure also relates to microfibrillated cellulose produced by those methods, and their uses.

[0005] BACKGROUND

[0006] [3] In view of a global shift away from the use of petrochemical resources, there has been increased interest in the development of sustainable materials. These include cellulose-based materials produced from lignocellulosic biomass.

[0007] [4] Lignocellulosic biomass can be obtained from a wide range of sources and transformed into a variety of products ranging from biofuels, biochemicals, cosmetics, paper and packaging materials, biomedical materials, and electronic device components. A key contributor to the advancement of biomass-based products for these applications is the conversion of lignocellulosic biomass into nanostructured cellulosic materials such as microfibrillated cellulose (MFC) and cellulose nanofibers (CNF). MFC contain bundles of microfibrils typically having a lateral dimension in the order of 10-100 nm with a length in the micrometre scale. CNF, also known as cellulose nanofibrils, typically have a diameter of around 5-30 nm and an aspect ratio of greater than 50. Among the nanocellulosic materials, MFC is of particular interest because it is easier to prepare in high yield and has properties that enable a wide range of potential applications.

[0008] [5] However, conventional methods for processing lignocellulosic biomass, for example kraft pulping treatment and refining, require highly energy and water intensive multistep processes which can make the nanocellulosic materials expensive and less sustainable to produce. These factors can hinder the hinder the production and adoption of nanocellulosic materials.

[0009] [6] Accordingly, there remains need for alternative methods of processing lignocellulosic materials to produce nanocellulosic materials such as MFC, which may advantageously address one or more of the above identified problems.

[0010] [7] Any reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.

[0011] SUMMARY

[0012] [8] The present inventors have developed a low cost method of producing microfibrillated cellulose (MFC) from lignocellulosic biomass, in particular non-wood plant biomass. Advantageously, the method of the present disclosure can reduce or avoid the use of water and high energy processes typically required by conventional processing methods.

[0013] [9] In one aspect, the present disclosure provides a method of processing a non-wood plant biomass, the method comprising: (i) presoaking the non-wood plant biomass in a solution comprising a polyol at a temperature of about 20°C to about 75°C, wherein the solution comprises no more than about 10 vol% water based on the total volume of the solution; and

[0014] (ii) subjecting the presoaked non-wood plant biomass to mechanical shearing to produce MFC.

[0015]

[0010] In some embodiments, the solution comprises substantially no water. In some embodiments, the solution comprises or is a polyol selected from glycerol, ethylene glycol and propylene glycol, preferably ethylene glycol and propylene glycol, more preferably propylene glycol.

[0016]

[0011] In some embodiments, the solution comprises a base, preferably an alkali metal hydroxide, more preferably potassium hydroxide or sodium hydroxide, even more preferably potassium hydroxide. In some embodiments, the solution comprises or consists of a polyol and an alkali metal hydroxide.

[0017]

[0012] In some embodiments, the non-wood plant biomass is presoaked in up to about 50 wt% solution, based on the total weight of the non-wood plant biomass and the solution.

[0018]

[0013] In some embodiments, the mechanical shearing comprises one or both of extrusion and homogenisation. In some embodiments, the mechanical shearing comprises, or is, extrusion. In some embodiments, the mechanical shearing is performed using a twin screw extruder.

[0019]

[0014] In some embodiments, the produced MFC contains lignin. In another aspect, the present disclosure provides MFC produced by the method described herein.

[0020]

[0015] In another aspect, the present disclosure provides an agricultural film composition comprising the MFC described herein, or produced by the method described herein; optionally a binder, preferably guar gum; and optionally a resin or wax, preferably gum rosin.

[0021]

[0016] In another aspect, the present disclosure provides the use of the MFC described herein, or produced by the method described herein, in an agricultural film composition, which may be an agricultural biodegradable polymer film.

[0022]

[0017] In another aspect, the present disclosure provides the use of the MFC described herein, or produced by the method described herein, in any one or more of the following applications: composite materials including compostable and / or biodegradable composite materials, barrier films, packaging including thermoformed packaging, paints, coatings including carbon fibre coatings, resins, adhesives, printing inks, plant protection, personal care products, home care products, micropaper and nanopaper, gels including aerogels, hydrogels and biogels, nanocomposite materials, construction materials, papermaking, electronic device components, electrodes, biomedical materials and medicine.

[0023]

[0018] In another aspect, the present disclosure provides a composite material comprising the MFC described herein, or produced by the method described herein.

[0024]

[0019] In another aspect, the present disclosure provides the use of the MFC described herein, or produced by the method described herein, for producing cellulose nanofiber (CNF).

[0025]

[0020] In another aspect, the present disclosure provides a method of processing MFC, the method comprising: diluting the MFC described herein, or produced by the method described herein; and subjecting the diluted MFC to mechanical shearing to produce CNF.

[0026]

[0021] In some embodiments, the produced CNF contains lignin.

[0027]

[0022] In another aspect, the present disclosure provides CNF produced by the method described herein.

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029]

[0023] Figure 1. Photographs of A) sorghum biomass samples presoaked with 50 wt% water, glycerol or propylene glycol as the solution and subsequently subjected to 1, 2 or 3 passes of extrusion, and B) the extruded samples compared to an 2% NaOH sample.

[0030]

[0024] Figure 2. Thermal gravimetric analysis of A) glycerol and propylene glycol, B) extruded biomass (100 wt%) and 50 wt% biomass in water (W, B50W50-Ext), glycerol (G, B50G50-Ext), and propylene glycol (P, B50P50-Ext), and C) B50P50-Ext after washing compared to cellulose pulp after washing.

[0031]

[0025] Figure 3. Spectroscopic analysis of B50P50-Ext sample A) before, and B) after washing.

[0032]

[0026] Figure 4. Transmission electron microscopy (TEM) images at i) low magnification and ii) high magnification, of lignin dispersion by propylene glycol solution showing A) lignin (darker particles) dispersed after being dislodged from the nanofibers, and B) lignin bound in the biomass particles (large agglomerate) dispersed into fractals by the solution.

[0033]

[0027] Figure 5. A) Polarised microscopy images indicating the effect of increased dislodging of lignin with increased PG solution content: i) 30wt% PG, ii) 50 wt% PG, and ill) 70wt% PG. Thermal gravimetric analysis of extruded biomass / PG samples at 30 wt%, 50wt% and 70 wt% biomass loading B) before washing and C) after washing.

[0034]

[0028] Figure 6. Comparison of i) polarised microscopy images and ii) low magnification TEM images of biomass A) after soaking in 50wt% PG followed by no mechanical treatment, B) after soaking in 50wt% PG followed by extrusion, and C) after soaking in 50wt% PG followed by hand-held shear homogenization.

[0035]

[0029] Figure 7. Thermal gravimetric analysis of 50 wt% PG solution-treated biomass without subsequent mechanical treatment, after extrusion and after shear homogenisation.

[0036]

[0030] Figure 8. TEM images at i) low magnification and ii) high magnification, of lignin-containing cellulose nanofibers after A) soaking biomass in 50% PG solution followed by extrusion then high-pressure homogenization, and B) soaking biomass in 50% PG solution followed by mechanical treatment by hand-held shear homogenizer.

[0037]

[0031] Figure 9. Photograph of barley biomass in powder form: a) untreated biomass, b) polyol treated biomass with one time extrusion, c) polyol treated biomass with two times extrusion, d) alkaline polyol treated biomass with one time extrusion, and e) alkaline polyol treated biomass with two times extrusion.

[0038]

[0032] Figure 10. Photograph of barley biomass powder in water: a) untreated biomass, b) polyol treated biomass with one time extrusion, c) polyol treated biomass with two times extrusion, d) alkaline polyol treated biomass with one time extrusion, and e) alkaline polyol treated biomass with two times extrusion.

[0039]

[0033] Figure 11 . Optical microscopy images of a) untreated biomass, c) polyol treated biomass with one time extrusion, e) polyol treated biomass with two times extrusion, g) polyol-potassium hydroxide treated biomass with one time extrusion, and i,k) biomass with two times extrusion; and polarized optical microscopy images of b) untreated biomass d) polyol treated biomass with one time extrusion, f) polyol treated biomass with two times extrusion, h) polyol-potassium hydroxide treated biomass with one time extrusion, and j,l) biomass with two times extrusion.

[0040]

[0034] Figure 12. Photographs of mulch compositions: a) microfibrillated lignocellulose (MFC), guar gum and water; b) MFC, guar gum, gum rosin and water; c) MFC, guar gum, sprayable biodegradable polyurethane mulch (15%) and glycerol; and d) MFC, sprayable polyurethane mulch composition (15%).

[0041]

[0035] Figure 13. Graph showing results of water contact angle (WCA tests) of mulch films: MFC solvated with glycerol + guar gum (MFC(G) + Gu); MFC solvated with glycerol + guar gum + gum rosin (MFC(G) + Gu + R); MFC solvated with propylene glycol + guar gum MFC(PG) + Gu; and MFC solvated with propylene glycol + guar gum + gum rosin (MFC(PG) + Gu + R).

[0042] DETAILED DESCRIPTION

[0043]

[0036] The present disclosure relates to methods of processing lignocellulosic biomass to produce microfibrillated cellulose (MFC).

[0044]

[0037] Conventionally, fibrillation of lignocellulosic biomass into nanocellulosic materials is most commonly achieved through a range of enzymatic, chemical, catalysed and mechanical treatments, or combinations thereof. Mechanical treatment methods are highly energy-consuming and typically require multiple passes to reach adequate fibrillation degrees. Therefore, chemical, enzymatic or catalytic pretreatment is usually performed prior to mechanical treatment to reduce energy consumption and facilitate the release of the fibrils. One such example is conventional kraft pulping treatment, a multistep method which produces wet pulp that is then further refined to produce nanocellulosic materials such as MFC and cellulose nanofiber (CNF). A typical mild kraft pulping process can involve: presoaking lignocellulosic biomass in water (2 litres per 100g of biomass) at 50 °C with stirring; pretreating the presoaked biomass with aqueous sodium hydroxide at 80 °C with stirring to provide solid pulp; and washing the pulp using up to 8 litres of water per 100 grams of biomass, to provide wet pulp at about 40% yield and black liquor waste. The wet pulp can be diluted and then subjected to mechanical treatment such as high-pressure homogenisation, shear homogenisation, or milling to produce CNF. Alternatively, the water can be squeezed out of the wet pulp and then subjected to extrusion to produce MFC.

[0045]

[0038] The conventional pulping and refining processes have several drawbacks. For example, the presoaking and pretreatment steps are highly energy and water intensive and use toxic chemicals. The washing step also uses large quantities of water and the waste liquid is highly basic or acidic and toxic. The drying and mechanical treatment steps are highly energy consuming. Further, the products are typically low solid content (e.g., 2-3%) dispersions which can be challenging and uneconomic to transport in large quantities.

[0046]

[0039] The present inventors have developed a low-cost method of producing MFC from non-wood plant biomass. As described herein and shown in the Examples, the processing method of the present disclosure advantageously reduces or avoids the use of water and high energy processes typically required by conventional processing methods and is a more sustainable method. The method of the present disclosure involves presoaking the biomass in a polyol solution, and subsequently subjecting the presoaked biomass to mechanical shearing to produce MFC. The present inventors have surprisingly found that the method described herein can produce MFC having adequate fibrillation without requiring a conventional chemical or enzymatic pretreatment step prior to mechanical shearing. That is, the method described herein only requires a presoaking step before mechanical shearing. Advantageously, this avoids the need for multistep processing and allows for higher throughput processing. It also advantageously avoids the need for toxic chemicals and allows for safer processing. Additionally, the method described herein avoids the need for high temperatures and / or stirring during the presoaking step. The inventors have further surprisingly found the method can produce MFC having a high solid content in high yield and with minimal waste.

[0047]

[0040] The present inventors have further surprisingly found that the method described herein can produce MFC which contains residual lignin. The presence of lignin may advantageously make the MFC of the present disclosure more suitable for use in applications that require one or more of the following: increased mechanical properties, ultraviolet absorption, hydrophobicity, low viscosity at zero shears, and reduced anti-degradation (into sugars) properties.

[0048]

[0041] Reference will now be made in detail to certain embodiments of the present disclosure. While the present disclosure will be described in conjunction with the embodiments, it will be understood that the intention is not to limit the present disclosure to those embodiments. On the contrary, the present disclosure is intended to cover all alternatives, modifications, and equivalents, which may be included within the scope of the present disclosure as defined by the claims.

[0049]

[0042] One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practice of the present disclosure. The present disclosure is in no way limited to the methods and materials described. It will be understood that the present disclosure extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the present disclosure.

[0050]

[0043] For the purposes of interpreting this specification, terms used in the singular will also include the plural and vice versa. As used herein, singular forms “a”, “an” and “the” include plural aspects, unless the context clearly indicates otherwise. As used herein, the term “and / or”, e.g., “X and / or Y” will be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

[0051]

[0044] Various features of the present disclosure are described with reference to a certain value, or range of values. These values are intended to relate to the results of the various appropriate measurement techniques, and therefore should be interpreted as including a margin of error inherent in any particular measurement technique. Some of the values referred to herein are denoted by the term “about’ to at least in part account for this variability. The term “about’, when used to describe a value, may mean an amount within ±10%, ±5%, ±1% or ±0.1% of that value.

[0052]

[0045] As used herein, except where the context requires otherwise, the term “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0046] Any methods provided herein can be combined with one or more of any of the other methods provided herein.

[0053] Processing method

[0054]

[0047] The present disclosure provides methods of producing MFC from non-wood plant biomass.

[0055]

[0048] In one aspect, there is provided a method of processing a non-wood plant biomass, the method comprising:

[0056] (i) presoaking the non-wood plant biomass in a solution comprising a polyol at a temperature of about 20°C to about 75°C, wherein the solution comprises no more than about 10 vol% water based on the total volume of the solution; and

[0057] (ii) subjecting the presoaked non-wood plant biomass to mechanical shearing to produce MFC.

[0058]

[0049] In another aspect, there is provided a method of producing MFC from a non-wood plant biomass, the process comprising:

[0059] (i) presoaking the non-wood plant biomass in a solution comprising a polyol at a temperature of about 20°C to about 75°C, wherein the solution comprises no more than about 10 vol% water based on the total volume of the solution; and

[0060] (ii) subjecting the presoaked non-wood plant biomass to mechanical shearing to produce microfibrillated cellulose.

[0061] Non-wood plant biomass

[0062]

[0050] The present disclosure provides methods of processing non-wood plant biomass. It will be appreciated that non-wood plant biomass is lignocellulosic biomass which contains lignocellulose, hemicellulose and cellulose. Non-wood plant biomass typically contains a lower proportion of lignin than woody biomass, and is suitable for producing MFC according to the method described herein. In the context of the present disclosure, “non-wood plant biomass” refers to non-woody organic material that comes from plants, and includes by-products of crops harvested primarily for food, animal feed, biofuel, or biochemical production. Beneficially, the method provided herein can allow a low value waste material to be converted into a useful product.

[0063]

[0051] Any suitable non-wood plant biomass may be used. The non-wood plant biomass may include one or more sources of non-wood plant biomass. Examples of suitable sources include sorghum, especially forage sweet sorghum; sugarcane; cotton; bamboo; rice; wheat; barley; banana; palm tree; pineapple; jute; kenaf; sisal; maize; hemp; flax; sunflower; canola; soybean; mung bean; chickpea; faba bean; peanut; cassava; chia; Dhaincha; eggplant; mulberry; mustard; okra; red lentil; oat; and spinifex. The non-wood plant biomass may be derived from any suitable part of a plant including: bagasse, stalk, husk, hull, straw, stem, leaf, peduncle, empty fruit bunch, fibre, and stick.

[0064]

[0052] Examples of suitable non-wood plant biomass sources include: sorghum, especially forage sweet sorghum; sugarcane including sugarcane bagasse; cotton including cotton stalk; bamboo; rice including rice husk and straw; wheat including wheat straw; barley including barley straw; banana including banana pseudo stem, leaf and peduncle; palm tree including empty fruit bunch; pineapple including pineapple leaf; jute including jute fibre and stick; kenaf; sisal; maize including maize stalk; hemp; flax; sunflower including sunflower stem and hull; canola including canola stalk; soybean; mung bean; chickpea; faba bean; peanut including peanut hull; cassava including cassava stalk; chia including chia stalk; Dhaincha including Dhaincha stalk; eggplant including eggplant stalk; mulberry including mulberry stalk; mustard including mustard stalk; okra including okra stalk; red lentil including red lentil stalk; oat; and spinifex.

[0065]

[0053] In some embodiments, the non-wood plant biomass is sorghum, preferably forage sweet sorghum. In some embodiments, the non-wood plant biomass is sugarcane, preferably sugarcane bagasse. Beneficially, sorghum and sugarcane can provide sustainable sources of non-woody plant biomass. In some embodiments, the non-wood plant biomass is barley.

[0066]

[0054] The non-wood plant biomass may optionally be subjected to a reduction in size, prior to the presoaking step. Beneficially, reducing the size can increase the surface area of biomass, which may advantageously increase fibrillation efficiency of during the presoaking and / or mechanical shearing steps. In addition, this can be used to control the size of the biomass and may advantageously provide the non-wood plant biomass in a substantially uniform size. Further, reducing the size can beneficially prevent or reduce clogging of apparatuses which may be used in subsequent steps, such as the mechanical shearing step.

[0067]

[0055] Accordingly, the method described herein may optionally further comprise a step of reduce the size of the non-wood plant biomass, before the presoaking step. Any suitable methods for reducing biomass size known in the art may be used to reduce the non-wood plant biomass to a desired size. Examples of suitable methods for reducing biomass size include shredding, milling and grinding. The methods for reducing biomass size may be performed using any suitable apparatus known in the art. The step of reducing biomass size may comprise one method, or a combination of two or more methods for reducing biomass size. Beneficially, combining two or more methods can be used to sequentially reduce the biomass size. In some embodiments, reducing the size of the non-wood plant biomass comprises one or both of shredding and milling.

[0068]

[0056] In some embodiments, the step of reducing the size of the non-wood plant biomass comprises, or is, shredding. The shredding may be performed using, for example, an industrial shredder such as a Brentwood Shredder (Brentwood, Australia). In embodiments where the non-wood biomass comprises long fibres (e.g. bagasse, stalk, straw, leaf, fibre, and stick), the shredding may reduce the biomass to a length of no more than about 10 cm, about 9 cm, about 8 cm, about 7 cm, about 6 cm, about 5 cm, about 4 cm, about 3 cm, about 2 cm, or about 1 cm. In some embodiments, the length is reduced to from about 1 cm to about 10 cm, and all combinations and sub combinations of ranges therein. The length may be reduced to about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, or about 10 cm. Any minimum and maximum amount may be combined to form a range, provided the range is between 1 cm to 10 cm, for example from about 2 cm to about 4 cm.

[0069]

[0057] In some embodiments, the step of reducing the size of the non-wood plant biomass comprises, or is, milling. The milling may be performed using, for example, a cutting mill such as a Cutting Mill SM 300 (Retsch, Germany). The milling may reduce the biomass to a particle size of no more than about 1000 pm, about 950 pm, about 900 pm, about 850 pm, about 800 pm, about 750 pm, about 700 pm, about 650 pm, about 600 pm, about 550 pm, about 500 pm, about 450 pm, about 400 pm, about 350 pm, about 300 pm, about 250 pm, about 200 pm, about 150 pm, or about 100 pm. In some embodiments, the particle size is reduced to from about 100 pm to about 1000 pm, and all combinations and sub combinations of ranges therein. The particle size may be reduced to about 100 pm, about 150 pm, about 200 pm, about 250 pm, about 350 pm, about 400 pm, about 450 pm, about 500 pm, about 550 pm, about 600 pm, about 650 pm, about 700 pm, about 750 pm, about 800 pm, about 850 pm, about 900 pm, about 950 pm, or about 1000 pm. Any minimum and maximum amount may be combined to form a range, provided the range is between 100 pm to 1000 pm, for example from about 500 pm to about 1000 pm, or from about 250 pm to about 500 pm, or from about 100 pm to about 500 pm, or from about 100 pm to about 250 pm. The milled biomass may optionally be sieved, for example using a mesh screen, which can beneficially separate the milled biomass based on particle size.

[0070] Presoaking step

[0071]

[0058] The method described herein comprises a step of presoaking the non-wood plant biomass in a solution. Presoaking may also be referred to herein as swelling.

[0072]

[0059] The solution comprises no more than about 10 vol% water, based on the total volume of the solution. In some embodiments, the solution comprises no more than about 10 vol%, about 9 vol%, about 8 vol%, about 7, vol%, about 6 vo l%, about 5 vol%, about 4 vol%, about 3 vol%, about 2 vol% or about 1 vol% water. In some embodiments, the solution comprises about 0 vol% to about 10 vol% water, and all combinations and sub combinations of ranges therein. The solution may comprise about 0 vol%, about 1 vol%, about 2 vol%, about 3 vol%, about 4 vol%, about 5 vol%, about 6 vol%, about 7 vol%, about 8 vol%, about 9 vol%, or about 10 vol% water. Any minimum and maximum amount may be combined to form a range, provided the range is between 0 vol% to 10 vol%, for example from about 0 vol% to about 5 vo l%, or from about 0 vol% to about 3 vol%.

[0073]

[0060] In some embodiments, the solution comprises substantially no water. In the context of the present disclosure, “substantially no water” means the solution does not comprise water or the solution comprises a negligible amountof water which does not require removal from the presoaked biomass (e.g. by filtration or drying) before the biomass is subjected to mechanical shearing. In some embodiments, the solution does not comprise water. Advantageously, the method described herein does not require the use of water for presoaking, pretreatment or washing steps required for conventional pulping processes.

[0074]

[0061] The solution comprises a polyol. In the context of the present disclosure, “polyol” refers to an aliphatic compound containing two or more hydroxyl groups. Examples of suitable polyols include polymeric polyols, for example polyether, polyester, polybutadiene, polycarbonate and polyacrylate polyols; and low molecular weight polyols, including sugar alcohols and monomeric polyols useful for preparing polymeric polyols. The solution may include one or more species of polyol.

[0075]

[0062] In some embodiments, the polyol is a diol. In some embodiments, the polyol is a low molecular weight polyol. In the context of the present disclosure, “low molecular weight polyol” refers to a polyol having a molecular weight no more than about 500 g / mol. Examples of suitable low molecular weight polyols include glycerol, ethylene glycol (EG), diethylene glycol, triethylene glycol, 1,4-butanediol and propylene glycol (PG). In some embodiments, the low molecular weight polyol is selected from glycerol, ethylene glycol and propylene glycol, preferably ethylene glycol and propylene glycol, more preferably propylene glycol.

[0063] In some embodiments, the solution comprises a base. Examples of suitable bases include hydroxides, such as metal hydroxides and ammonium hydroxide, and alkali / urea solutions. The metal hydroxide may be an alkali metal hydroxide. The alkali / urea solution may be a NaOH / urea solution.

[0076]

[0064] The base may be present in the solution in any suitable amount. In some embodiments, the solution comprises up to about 16 wt% base, based on the total weight of the solution. In some embodiments, the solution comprises up to about 16 wt%, about 15 wt%, about 14 wt%, about 13 wt%, about 12 wt%, about 11 wt%, about 10 wt%, about 9 wt%, about 8 wt%, about 7 wt%, about 6 wt%, about 5 wt%, about 4 wt%, about 3 wt%, about 2 wt%, or about 1 wt% base. In some embodiments, the solution comprises about 1 wt% to about 16 wt% base, and all combinations and sub combinations of ranges therein. The solution may comprise about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, or about 16 wt% base. Any minimum and maximum amount may be combined to form a range, provided the range is between 1 wt% to 16 wt%, for example from about 1 wt% to about 10 wt%, or from about 5 wt% to about 10 wt%, or from about 1 wt% to about 5 wt%. The amount of base may be suitably selected depending on the solution, for example depending on the solubility of the base in the solution. In embodiments where the solution comprises water, the base may be present in an amount up to about 16 wt%, for example present in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, or about 16 wt%, based on the total weight of the solution.

[0077]

[0065] In some embodiments, the base is an alkali metal hydroxide. Examples of suitable alkali metal hydroxides include potassium hydroxide, sodium hydroxide and lithium hydroxide. The alkali metal hydroxide preferably is substantially soluble in the solution, and more preferably is substantially soluble in the polyol. In some embodiments, the alkali metal hydroxide is potassium hydroxide or sodium hydroxide, preferably potassium hydroxide. Beneficially, the residual potassium provided by potassium hydroxide may be advantageous in agricultural applications, for example in sprayable biodegradable polymer films, by acting as a potassium nutrient.

[0078]

[0066] In some embodiments, the solution essentially consists of a polyol and an alkali metal hydroxide, and substantially no water. That is, the solution is a polyol-alkali metal hydroxide solution. Accordingly, in some embodiments of the method described herein, step (i) comprises presoaking the non-wood plant biomass in a polyol-alkali metal hydroxide solution. The polyol and the alkali metal hydroxide may be any polyol or alkali metal hydroxide described herein. In some embodiments, the polyol-alkali metal hydroxide solution is a propylene glycol-potassium hydroxide solution or a propylene glycol-sodium hydroxide solution, preferably a propylene glycol-potassium hydroxide solution. Advantageously, as shown in the Examples, soaking non-wood plant biomass in a polyol-alkali metal hydroxide solution can extract more lignin from the biomass, compared to soaking non-wood plant biomass in a polyol solution.

[0079]

[0067] The alkali metal hydroxide may be present in the solution in any suitable amount. In some embodiments, the solution comprises up to about 16 wt% alkali metal hydroxide, based on the total weight of the solution. In some embodiments, the solution comprises up to about 16 wt%, about 15 wt%, about 14 wt%, about 13 wt%, about 12 wt%, about 11 wt%, about 10 wt%, about 9 wt%, about 8 wt%, about 7 wt%, about 6 wt%, about 5 wt%, about 4 wt%, about 3 wt%, about 2 wt%, or about 1 wt% alkali metal hydroxide. In some embodiments, the solution comprises about 1 wt% to about 16 wt% alkali metal hydroxide, and all combinations and sub combinations of ranges therein. The solution may comprise about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, or about 16 wt% alkali metal hydroxide. Any minimum and maximum amount may be combined to form a range, provided the range is between 1 wt% to 16 wt%, for example from about 1 wt% to about 10 wt%, or from about 5 wt% to about 10 wt%, or from about 1 wt% to about 5 wt%. The amount of alkali metal hydroxide may be suitably selected depending on the solution, for example depending on the solubility of the alkali metal hydroxide in the solution. In embodiments where the polyol is propylene glycol and the alkali metal hydroxide is potassium hydroxide, the potassium hydroxide may be present in an amount up to about 10 wt%, for example present in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, or about 10 wt%, based on the total weight of the propylene glycol. In embodiments where the polyol is propylene glycol and the alkali metal hydroxide is sodium hydroxide, the sodium hydroxide may be present in an amount up to about 5 wt%, for example present in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, or about 5 wt%, based on the total weight of the propylene glycol. In embodiments where the solution comprises water, the alkali metal hydroxide may be present in an amount up to about 16 wt%, for example present in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, or about 16 wt%, based on the total weight of the solution.

[0080]

[0068] In some embodiments, the solution is a polyol. That is, the polyol is the only solution that the non-wood plant biomass is presoaked in. Accordingly, in some embodiments of the method described herein, step (i) comprises presoaking the non-wood plant biomass in a polyol.

[0081]

[0069] In some embodiments, the solution is a low molecular weight polyol. The low molecular weight polyol is preferably glycerol, ethylene glycol or propylene glycol, more preferably ethylene glycol or propylene glycol, still more preferably propylene glycol. Beneficially, glycerol, ethylene glycol and propylene glycol can provide sustainable, non-toxic and inexpensive solutions.

[0082]

[0070] The non-wood plant biomass may be presoaked in from about 20 wt% to about 70 wt% solution, based on the total weight of the non-wood plant biomass and the solution, and all combinations and sub combinations of ranges therein. The solution may be at least about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt% or about 45 wt%. The solution may be no more than about 70 wt%, about 65 wt%, about 60 wt%, about 55 wt% or about 50 wt%. Any minimum and maximum amount may be combined to form a range, provided the range is between 20 wt% and 70 wt%, for example from about 30 wt% to about 50 wt%. In some embodiments, the non-wood plant biomass is presoaked in up to about 70 wt%, about 65 wt%, about 60 wt%, about 55 wt%, about 50 wt%, about 45 wt%, about 40 wt%, about 35 wt%, about 30 wt%, about 25 wt%, or about 20 wt% solution, based on the total weight of the non-wood plant biomass and the solution. Advantageously, as shown in the Examples, the non-wood plant biomass may be presoaked in a relatively low amount of polyol while still producing a high yield of MFC product.

[0083]

[0071] The mass ratio of the non-wood plant biomass to the solution may be from about 1 :4 to about 1 :1, and all combinations and sub combinations of ranges therein. The mass ratio may be at least about 1 :4, about 1 :3 or about 1 :2. The mass ratio may be no more than about 1:1, about 5:6 or about 2:3. Any minimum and maximum amount may be combined to form a range, provided the range is between 1 :4 and 1 :1, for example from about 1 :3 to about 1 :1.

[0084]

[0072] The presoaking step of the method described herein may be performed over any suitable duration. For example, the presoaking step may be performed for about 1 to about 48 hours, and all combinations and sub combinations of ranges thereof. The presoaking step may be at least about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, or about 24 hours. The presoaking step may be no more than about 48 hours, about 47 hours, about 46 hours, about 45 hours, about 44 hours, about 43 hours, about 42 hours, about 41 hours, about 40 hours, about 39 hours, about 38 hours, about 37 hours, about 36 hours, about 35 hours, about 34 hours, about 33 hours, about 32 hours, about 31 hours, about 30 hours, about 29 hours, about 28 hours, about 27 hours, about 26 hours, about 25 hours, about 24 hours, about 23 hours, about 22 hours, about 21 hours, about 20 hours, about 19 hours, about 18 hours, about 17 hours, about 16 hours, about 15 hours, about 14 hours, about 13 hours, or about 12 hours. The presoaking step may be performed for about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 25 hours, about 26 hours, about 27 hours, about 28 hours, about 29 hours, about 30 hours, about 31 hours, about 32 hours, about 33 hours, about 34 hours, about 35 hours, about 36 hours, about 37 hours, about 38 hours, about 39 hours, about 40 hours, about 41 hours, about 42 hours, about 43 hours, about 44 hours, about 45 hours, about 46 hours, about 47 hours, or about 48 hours. Any minimum and maximum duration may be combined to form a range, provided the range is between 1 to 48 hours, for example from about 1 hour to about 12 hours. The presoaking duration may be suitably selected based on the amount of biomass to be pretreated. In some embodiments, step (i) is performed for about 1 hour to about 8 hours, preferably for about 2 to about 6 hours. In some embodiments, step (i) is performed over 4 hours. In some embodiments, step (i) is performed for about 6 hours to about 18 hours.

[0085]

[0073] Advantageously, in contrast to methods such as those described in LU, H. et al. (Cellulose. 2018, Vol. 25, pp. 7043-7051), LU. H. et al. (Carbohydrate Polymers. 2022, Vol. 277, No. 118897, pp. 1-9), YAN, M. et al. (Industrial Crops and Products. 2022, Vol. 185, No. 115126, pp. 1 -10) and YAN, M. et al. (Journal of Applied Polymer Science. 2002, Vol. 139, No. 43, e53054, pp. 1 -11), the presoaking step of the present disclosure is not required to be performed at high temperatures. The presoaking step of the method described herein may be performed at a temperature of about 20 °C to about 75 °C, and all combinations and sub combinations of ranges thereof. The presoaking step may be performed at a temperature of at least about 20 °C, about 25 °C, about 30 °C, about 35 °C, about 40 °C, about 45 °C, or about 50 °C. The presoaking step may be performed at a temperature of no more than about 75 °C, about 70 °C, about 65 °C, about 60 °C, or about 55 °C. The presoaking step may be performed at a temperature of about 20 °C, about 25 °C, about 30 °C, about 35 °C, about 40 °C, about 45 °C, about 50 °C, about 55 °C, about 60 °C, about 65 °C, about 70 °C, or about 75 °C. Any minimum and maximum duration may be combined to form a range, provided the range is between 20 °C to about 75 °C, for example about 20 °C to about 60 °C or about 60 °C to about 75 °C. The presoaking temperature may be suitably selected based on the solvent. In some embodiments, step (i) is performed at about 20 °C to about 25 °C, or at about 25 °C. In some embodiments, step (i) is performed at about 60 °C. In some embodiments, step (i) is performed at about 75 °C.

[0086]

[0074] To improve fibrillation efficiency and provide sufficient product yield, conventional processing methods such as pulping typically require presoaking and pretreatment under certain conditions. These can include heating, stirring, pressure, chemical treatment, and treatments with exogenous enzymes and catalysts that promote the fibrillation of the biomass. These additional treatments and physiochemical conditions can significantly inflate the costs associated with the processing of non-wood plant biomasses to produce useful MFC. In particular, the use of additional exogenous components at any pretreatment / presoaking stage can also have the disadvantage of the components eventually needing to be removed or inactivated. Advantageously, as shown in the Examples, such conditions are not required in the presoaking step of the method described herein, and no pretreatment is required before mechanical shearing, while still providing high product yield. Beneficially, this can provide a more energy efficient processing method with fewer steps and at lower cost.

[0087]

[0075] Accordingly, in some embodiments, one or more of the following apply: step (i) is performed at room temperature (about 20 to 25 °C); step (i) is performed without mechanical agitation, for example by stirring, mixing or shaking; step (i) is performed at atmospheric pressure; step (i) is performed in the absence of chemical treatment, for example a chemical treatment using sodium hydroxide, sodium sulfate, sodium carbonate, or combinations thereof; step (i) is performed in the absence of an exogenous enzyme; step (i) is performed in the absence of an exogenous catalyst, for example an acid catalyst.

[0088] Mechanical shearing step

[0089]

[0076] After the presoaking step, the method described herein comprises a step of subjecting the presoaked non-wood plant biomass to mechanical shearing. Mechanical shearing may also be referred to herein as mechanical fibrillation or mechanical disintegration. The mechanical shearing promotes disintegration of cellulose bundles in the presoaked biomass into cellulose fibres (fibrillation) to provide MFC.

[0090]

[0077] Any suitable mechanical shearing method(s) may be used, including those known in the art. Examples of suitable mechanical shearing methods include homogenisation, for example high pressure homogenisation and low pressure homogenisation; milling, for example ball milling; microfluidisation; disk refining; ultrafine grinding (also referred to herein as microgrinding); ultrasonication, for example high-intensity ultrasonication; extrusion, for example using a twin screw extruder; cryocrushing; blending (also referred to herein as high shear mixing); steam explosion; and aqueous counter collision. The mechanical shearing methods may be performed using any suitable apparatus known in the art. The step of mechanical shearing may comprise one mechanical shearing method, or a combination of two or more mechanical shearing methods. In some embodiments, the mechanical shearing comprises one or both of extrusion and homogenisation.

[0091]

[0078] In some embodiments, in step (ii) the mechanical shearing comprises, or is, extrusion. The extrusion may be performed using, for example, a twin screw extruder. In some embodiments, in step (ii) the mechanical shearing is performed using a twin screw extruder. Advantageously, as shown in the Examples, twin screw extrusion is capable of producing a high yield of MFC. Beneficially, compared to other conventionally used mechanical shearing methods such as high-pressure homogenisation and bead milling, using a twin screw extruder can allow for processing of larger quantities of material, for example up to kilogram amounts. Further, twin screw extrusion can process and produce material with higher solid content. Twin screw extrusion can also provide a more energy efficient processing method.

[0092]

[0079] In some embodiments, in step (ii) the mechanical shearing comprises, or is, homogenisation. The homogenisation may be performed using, for example, a high-pressure homogeniser (e.g., Silverson mixer homogeniser) or a hand-held shear homogeniser.

[0093]

[0080] The presoaked non-wood plant biomass may be subjected to one or more passes of mechanical shearing. For example, the biomass may be subjected to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more passes of mechanical shearing. In some embodiments, in step (ii) the presoaked non-wood plant biomass is subjected to 1, 2, 3 or 4 passes of mechanical shearing. In some embodiments, in step (ii) the presoaked non-wood plant biomass is subjected to 1 or 2 passes of mechanical shearing. In some embodiments, in step (ii) the presoaked non-wood plant biomass is subjected to 1 pass of mechanical shearing. Advantageously, as shown in the Examples, the methods described herein can produce MFC having adequate fibrillation with a relatively low number of passes. Beneficially, a lower number of passes can provide a more energy efficient method.

[0094] Microfibrillated cellulose

[0095]

[0081] The method described herein produces MFC. Accordingly, in one aspect, the present disclosure provides MFC produced by the method described herein.

[0096]

[0082] As shown in the Examples, the methods of the present disclosure can produce MFC which contains residual lignin. Accordingly, in some embodiments, the produced MFC contains lignin. Advantageously, lignin containing MFC may be more suitable for use in applications that require one or more of the following: increased mechanical properties, ultraviolet absorption, hydrophobicity, low viscosity at zero shears, and reduced antidegradation (into sugars) properties.

[0097]

[0083] Further, the methods of the present disclosure may be capable of extracting lignin present in the non- wood plant biomass. Advantageously, unlike conventional alkaline pretreatment methods which destroy and remove lignin, the methods of the present disclosure can retain and gradually disperse the bound lignin into the solution, as shown in the Examples. The intact lignin may be characterised by methods known in the art, for example Fourier transform infrared (FTIR) spectroscopy and electron microscopy (TEM). Accordingly, in some embodiments, the produced MFC contains intact lignin. Further, in some embodiments of the method of the present disclosure, in the presoaking step lignin present in the non-wood biomass may be extracted and dispersed into the solution. The present disclosure also provides a method of extracting lignin from a non-wood plant biomass, the method comprising soaking the non-wood plant biomass in a solution comprising a polyol, wherein the solution comprises no more than 10 vol% water based on the total volume of the solution, or wherein the solution comprises substantially no water; whereby lignin present in the non-wood biomass is extracted and dispersed into the solution. In some embodiments, the solution comprises substantially no water. In some embodiments, the solution comprises an alkali metal hydroxide. Advantageously, as described herein and shown in the Examples, the presence of alkali metal hydroxide in the solution can increase lignin extraction, compared to in the absence of alkali metal hydroxide. The dispersed lignin may be precipitated from the solution by methods known in the art.

[0098]

[0084] The method described herein may produce MFC having a solid content from about 30 wt% to about 80 wt%, based on the total weight of the product produced by the method (e.g., the MFC and any residual solution), and all combinations and sub combinations of ranges therein. The solid content may be at least about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, or about 50 wt%. The solid content may be no more than about 80 wt%, about 75 wt%, about 70 wt%, about 65 wt%, about 60 wt%, or about 55 wt%. Any minimum and maximum amount may be combined to form a range, provided the range is between 30 wt% and 80 wt%, for example from about 50 wt% to about 80 wt%. In some embodiments, MFC has a solid content of up to at least about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, or about 70 wt%, based on the total weight of the product. The solid content of the produced MFC may be suitably adjusted, for example to provide a concentration suitable for a desired application of the MFC. The MFC may have a solid content from about 5 wt% to about 95 wt%, and all combinations and sub combinations of ranges therein. The solid content may be at least about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, or about 70 wt%. The solid content may be up to about 95 wt%, about 90 wt%, about 85 wt%, about 80 wt%, or about 75 wt%. Any minimum and maximum amount may be combined to form a range, provided the range is between 5 wt% and 95 wt%, for example from about 30 wt% to about 80 wt% or from about 50 wt% to about 80 wt%. The solid content can be measured by methods conventionally used in the art, for example by removing the solution and measuring the dry content. Advantageously, as shown in the Examples, the method described herein can directly produce MFC having a relatively high solid content, with minimal waste. Beneficially, the product may be used directly without further processing such as drying or removal of solution. This is in contrast to conventional processes such as pulping, which typically produce low solid content microfibrillated cellulose, for example as a 2-3 wt% solution, where further processing of the product can be required and transport of such materials can be challenging.

[0099]

[0085] The MFC may be produced in a yield of at least about 80 wt%, for example at least about 85 wt%, about 90 wt% or about 95 wt%, relative to the total weight of the non-wood plant biomass. Advantageously, as shown in the Examples, the method described herein can produce MFC in relatively high yield. In contrast, the presoaking and pretreatment steps of conventional processes such as pulping can result in comparatively low yield of pulp.

[0100]

[0086] The produced MFC can be characterised by methods known in the art including those described herein, for example thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. In some embodiments, thermal analysis of the produced MFC shows a decomposition peak at about 270 °C to about 300 °C, which may indicate presence of hemicellulose. In some embodiments, thermal analysis of the produced MFC shows a decomposition peak at about 340 °C to about 360 °C, which may indicate presence of lignin and / or cellulose. Additional methods for characterising the produced MFC may include one or more of the following: atomic force microscopy, optical microscopy, X-ray diffraction, transmission electron microscopy, and rheology.

[0101] Additional steps

[0102]

[0087] The processing methods of the present disclosure may optionally comprise further steps.

[0103]

[0088] In some embodiments, the method described herein further comprises a step of washing the presoaked non-wood plant biomass, before subjecting the pre-soaked biomass to mechanical shearing. Preferably, the washing step comprises washing the presoaked non-wood plant biomass sparingly with water. The washing step may advantageously remove some or all of the polyol solution from the presoaked biomass to produce MFC containing little to no polyol, which can be beneficial for some applications of MFC.

[0104]

[0089] The MFC of the present disclosure may optionally be further processed, for example to produce cellulose nanofiber (CNF).

[0105]

[0090] Accordingly, in some embodiments of the method described herein, the method further comprises:

[0106] (iii) diluting the MFC; and

[0107] (iv) subjecting the diluted MFC to mechanical shearing to produce CNF.

[0108]

[0091] The present disclosure also provides a method of producing CNF, the method comprising: diluting the MFC described herein, or produced by the method described herein; and subjecting the diluted MFC to mechanical shearing to produce CNF.

[0109]

[0092] The additional diluting and mechanical shearing steps can be performed using methods conventionally used in the art to produce CNF.

[0110]

[0093] The mechanical shearing to produce CNF may be any mechanical shearing method known in the art, including those described herein. In some embodiments, the mechanical shearing is selected from high pressure homogenisation and milling.

[0111]

[0094] It will be appreciated that in embodiments where the further processed MFC contains lignin, the produced CNF may also contain lignin. Accordingly, in some embodiments, the produced CNF contains lignin.

[0112]

[0095] The present disclosure also provides CNF produced by the methods described herein.

[0113] Applications

[0114]

[0096] The MFC of the present disclosure may be useful in various applications, including those known in the art for MFC. As described herein, the methods of the present disclosure may produce MFC which contains residual lignin. Advantageously, lignin containing MFC of the present disclosure may be particularly useful in applications that require one or more of the following: increased mechanical properties, ultraviolet absorption, hydrophobicity, low viscosity at zero shears, and reduced anti-degradation (into sugars) properties.

[0115]

[0097] Beneficially, the MFC of the present disclosure may be useful as a substitute for nonrenewables such as plastics, metals and chemicals. One such application is as an additive in plastic-based agricultural films. Preformed plastic mulch film has been used in agricultural cropping systems to increase crop yields by modifying the soil thermal environment, suppressing weeds, and reducing soil water evaporation, particularly in areas where decreasing arable land limits the growth of crops. However, due to long-term environmental concerns regarding the persistence of polyethylene-based mulch films in the environment and the use of heavy metals, (e.g., Co) in oxo-degradable films, there is a growing interest in biodegradable, biobased and compostable plastics as more environmentally friendly alternatives. Sprayable biodegradable polymer films have been developed for use on soils due to their easy application and versatility. However, the high cost of such sprayable films can make them commercially non-viable. The MFC of the present disclosure may be useful as an additive for bulking out such agricultural films, which can beneficially reduce the cost of the films and make them economically viable.

[0116]

[0098] Accordingly, in one aspect, the present disclosure provides the use of the MFC described herein, or produced by the method described herein, in an agricultural film composition, which may be an agricultural biodegradable polymer film composition. The agricultural film composition may be a sprayable polymer film composition. The agricultural film composition may be a polyurethane polymer film composition. The agricultural film composition may be a mulch film composition. The present disclosure also provides an agricultural film composition, which may be an agricultural biodegradable film composition, comprising the MFC described herein, or produced by the method described herein. The agricultural film composition may be a sprayable film composition. The agricultural film composition may be a polyurethane film composition. The agricultural film composition may be a mulch film composition.

[0117]

[0099] The MFC may be present in the of agricultural film composition in an amount of from about 0.1 wt% to about 99.9 wt%, based on the total weight of the components present in the composition (excluding the vehicle, if present), and all combinations and sub combinations of ranges therein. The composition may comprise at least about 0.1 wt%, about 0.2 wt%, about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 1.0 wt%, about 1.5 wt%, about 2.0 wt%, about 2.5 wt%, about 3.0 wt%, about 3.5 wt%, about 4.0 wt%, about 4.5 wt%, about 5.0 wt%, about 5.5 wt%, about 6.0 wt%, about 6.5 wt%, about 7.0 wt%, about 7.5 wt%, about 8.0 wt%, about 8.5 wt%, about 9.0 wt%, about 9.5 wt%, about 10.0 wt%, about 11.0 wt%, about 12.0 wt%, about 13.0 wt%, about 14.0 wt%, about 15.0 wt%, about 16.0 wt%, about 17.0 wt%, about 18.0 wt%, about 19.0 wt%, about 20.0 wt%, about 25.0 wt%, about 30.0 wt%, about 35.0 wt%, about 40.0 wt%, about 45.0 wt% or about 50.0 wt% of the MFC. The composition may comprise no more than about 99.9 wt%, about 99.8 wt%, about 99.7 wt%, about 99.6 wt%, about 99.5 wt%, about 99.0 wt%, about 98.5 wt%, about 98.0 wt%, about 97.5 wt%, about 97.0 wt%, about 96.5 wt%, about 96.0 wt%, about 95.5 wt%, about 95.0 wt%, about 94.5 wt%, about 94.0 wt%, about 93.5 wt%, about 93.0 wt%, about 92.5 wt%, about 92.0 wt%, about 91 .5 wt%, about 91 .0 wt%, about 90.5 wt%, about 90.0 wt%, about 89.0 wt%, about 88.0 wt%, about 87.0 wt%, about 86.0 wt%, about 85.0 wt%, about 84.0 wt%, about 83.0 wt%, about 82.0 wt%, about 81 .0 wt%, about 80.0 wt%, about 75.0 wt%, about 70.0 wt%, about 65.0 wt%, about 60.0 wt%, or about 55.0 wt%. Any minimum and maximum amount may be combined to form a range, provided the range is between 0.1 wt% and 99 wt%, for example from about 50 wt% to about 99 wt%, from about 70 wt% to about 95 wt%, or from about 1 wt% to about 30 wt%. The MFC may be present in an amount of about 0.1 wt%, about 0.2 wt%, about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 1 .0 wt%, about 1 .5 wt%, about 2.0 wt%, about 2.5 wt%, about 3.0 wt%, about 3.5 wt%, about 4.0 wt%, about 4.5 wt%, about 5.0 wt%, about 5.5 wt%, about 6.0 wt%, about 6.5 wt%, about 7.0 wt%, about 7.5 wt%, about 8.0 wt%, about 8.5 wt%, about 9.0 wt%, about 9.5 wt%, about 10.0 wt%, about 11.0 wt%, about 12.0 wt%, about 13.0 wt%, about 14.0 wt%, about 15.0 wt%, about 16.0 wt%, about 17.0 wt%, about 18.0 wt%, about 19.0 wt%, about 20.0 wt%, about 25.0 wt%, about 30.0 wt%, about 35.0 wt%, about 40.0 wt%, about 45.0 wt%, about 50.0 wt%, about 55.0 wt%, about 60.0 wt%, about 65.0 wt%, about 70.0 wt%, about 75.0 wt%, about 80.0 wt%, about 81 .0 wt%, about 82.0 wt%, about 83.0 wt%, about 84.0 wt%, about 85.0 wt%, about 86.0 wt%, about 87.0 wt%, about 88.0 wt%, about 89.0 wt%, about 90.0 wt%, about 90.5 wt%, about 91 .0 wt%, about 91 .5 wt%, about 92.0 wt%, about 92.5 wt%, about 93.0 wt%, about 93.5 wt%, about 94.0 wt%, about 94.5 wt%, about 95.0 wt%, about 95.5 wt%, about 96.0 wt%, about 96.5 wt%, about 97.0 wt%, about 97.5 wt%, about 98.0 wt%, about 98.5 wt%, about 99.0 wt%, about 99.5 wt%, about 99.6 wt%, about 99.7 wt%, about 99.8 wt% or about 99.9 wt%.

[0118]

[0100] The agricultural film composition may optionally comprise a binder, which may be a biodegradable binder. The binder may act to hold the MFC together and can optionally be plasticized or crosslinked, for example to provide flexibility and strength to the film. Examples of suitable binders include polysaccharides, including guar gum, starch, alginate, pectin, xanthan gum and cellulose derivatives. In some embodiments, the agricultural film composition comprises guar gum.

[0119]

[0101] The binder (e.g. guar gum) may be present in the of agricultural film composition in an amount of from about 0.1 wt% to about 7 wt%, based on the total weight of the components present in the composition (excluding the vehicle, if present), and all combinations and sub combinations of ranges therein. The composition may comprise at least about 0.1 wt%, about 0.5 wt%, about 1 wt%, about 1 .5 wt%, about 2 wt%, about 2.5 wt%, about 3 wt% or about 3.5 wt% of the binder. The composition may comprise no more than about 7 wt%, about 6.5 wt%, about 6 wt%, about 5.5 wt%, about 5.0 wt%, about 4.5 wt% or about 4 wt% of the binder. Any minimum and maximum amount may be combined to form a range, provided the range is between 0.1 wt% and 7 wt%, for example from about 2 wt% to about 6 wt% or from about 3 wt% to about 5 wt%. The binder may be present in an amount of about 0.1 wt%, about 0.5 wt%, about 1 wt%, about 1 .5 wt%, about 2 wt%, about 2.5 wt%, about 3 wt% about 3.5 wt%, about 4 wt%, about 4.5 wt%, about 5 wt%, about 5.5 wt%, about 6 wt%, about 6.5 wt% or about 7 wt%.

[0120]

[0102] The agricultural film composition may optionally comprise a resin or wax, which may be a bio-based (natural) resin or wax. The resin or wax may provide one or more of the following properties to the film when blended or chemically modified with other polymers: enhanced water resistance, hydrophobicity, toughness, adhesion and / or durability. Examples of suitable resins and waxes include gum rosin, shellac, lignin, natural waxes and or modified plant oils. The resin or wax may form part of the agricultural film composition or may be applied to a surface of a formed film. The resin or wax may be dissolved or dispersed in a solvent, for example to aid handling. The solvent may be suitably selected depending on the application of the composition. In some embodiments, the agricultural film composition comprises gum rosin. Gum rosin may be provided in a solvent such as ethanol, isopropanol, acetone or alkaline aqueous solutions (e.g. sodium carbonate solutions). For coatings, gum rosin is typically dissolved in ethanol or isopropanol at about 10-30 wt% for spray or dip applications. In papermaking, rosin soaps are typically prepared in alkaline solutions at about 5-15 wt% for sizing. Roisin may be emulsified with oleic acid (oleate salts) and stabilised with alum (aluminium sulfate) as a fixing agent. In such “rosin-alum sizing” systems, the rosin is converted to a soap (rosin-oleate), typically prepared at 5- 15 wt% concentration. The alum then precipitates the rosin onto the cellulose fibres, anchoring it within the paper matrix and improving water resistance.

[0121]

[0103] The resin or wax (e.g. gum rosin) may be present in of agricultural film composition in an amount of from about 0.1 wt% to about 5 wt%, based on the total weight of the components present in the composition (excluding the vehicle, if present), and all combinations and sub combinations of ranges therein. The composition may comprise at least about 0.1 wt%, about 0.2 wt%, about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 0.7 wt%, about 0.8 wt%, about 0.9 wt% or about 1 wt% of the resin or wax. The composition may comprise no more than about 5 wt%, about 4.5 wt%, about 4 wt%, about 3.5 wt%, about 3 wt%, about 2.5 wt%, about 2 wt%, about 1 .9 wt%, about 1 .8 wt%, about 1 .7 wt%, about 1 .6 wt%, about 1 .5 wt%, about 1.4 wt%, about 1 .3 wt%, about 1 .2 wt% or about 1 .1 wt% of the resin or wax. Any minimum and maximum amount may be combined to form a range, provided the range is between 0.1 wt% and 5 wt%, for example from about 0.1 wt% to about 3 wt% or from about 0.1 wt% to about 1 wt%. The resin or wax may be present in an amount of about 0.1 wt%, about 0.2 wt%, about 0.3 wt%, about 0.4 wt%, about 0.5 wt%, about 0.7 wt%, about 0.8 wt%, about 0.9 wt%, about 1 wt%, about 1.1 wt%, about 1 .2 wt%, about 1 .3 wt%, about 1 .4 wt%, about 1 .5 wt%, about 1 .6 wt%, about 1 .7 wt%, about 1.8 wt%, about 1 .9 wt%, about 2 wt%, about 2.5 wt%, about 3 wt%, about 3.5 wt%, about 4 wt%, about 4.5 wt% or about 5 wt%.

[0122]

[0104] An agricultural film composition of the present disclosure may comprise the MFC described herein, or produced by the method described herein; optionally a binder, which may be a biodegradable binder, preferably guar gum; and optionally a resin or wax, which may be a bio-based resin or wax, preferably gum rosin. In some embodiments, the agricultural film composition comprises the MFC described herein, or produced by the method described herein; a binder, which may be a biodegradable binder, preferably guar gum; and optionally a resin or wax, which may be a bio-based resin or wax, preferably gum rosin. The binder (e.g. guar gum) may be present in an amount of from about 0.1 wt% to about 7 wt%, for example from about 2 wt% to about 6 wt% or from about 3 wt% to about 5 wt%. The resin or wax (e.g. gum rosin) may be present in an amount of 0.1 wt% and 5 wt%, for example from about 0.1 wt% to about 3 wt% or from about 0.1 wt% to about 1 wt%.

[0123]

[0105] The agricultural film composition may further optionally comprise a polymer composition, optionally a biodegradable polymer composition, such as those used in sprayable biodegradable polymer film compositions. The polymer composition may be a polyurethane-based polymer composition. The polymer composition may be provided in any suitable form, for example as a solution, dispersion or solid.

[0106] The polymer composition (e.g. sprayable polyurethane-based composition) may be present in the agricultural film composition an amount of from about 1 wt% to about 99 wt%, based on the total weight of the components present in the composition (excluding the vehicle, if present), and all combinations and sub combinations of ranges therein. The composition may comprise at least about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 40 wt%, about 45 wt% or about 50 wt% of the polymer composition. The composition may comprise no more than about 99 wt%, about 98 wt%, about 97 wt%, about 96 wt%, about 95 wt%, about 94 wt%, about 93 wt%, about 92 wt%, about 91 wt%, about 90 wt%, about 85 wt%, about 80 wt%, about 75 wt%, about 70 wt%, about 65 wt%, about 60 wt% or about 55 wt% of the polymer composition. Any minimum and maximum amount may be combined to form a range, provided the range is between 1 wt% to 99 wt%, for example from about 1 wt% to about 30 wt% or from about 50 to about 99 wt%. The polymer composition may be present in an amount of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 85 wt%, about 90 wt%, about 91 wt%, about 92 wt%, about 93 wt%, about 94 wt%, about 95 wt%, about 96 wt%, about 97 wt%, about 98 wt% or about 99 wt%.

[0124]

[0107] The agricultural film composition may further optionally comprise a vehicle, for example water or a polyol such as glycerol. In some embodiments, the vehicle is water. The vehicle and / or the concentration of the agricultural film composition in the vehicle may be suitably selected depending on the application and / or desired viscosity of the composition. For spraying, the vehicle may be water at a concentration of about 95 wt%, based on the total weight of the vehicle and the agricultural film composition.

[0125]

[0108] The vehicle may be present at a concentration of from about 1 wt% to about 99 wt%, based on the total weight of the vehicle and the agricultural film composition, and all combinations and sub combinations of ranges therein. The vehicle may be present at a concentration of at least about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 40 wt%, about 45 wt% or about 50 wt%. The vehicle may be present at a concentration of no more than about 99 wt%, about 98 wt%, about 97 wt%, about 96 wt%, about 95 wt%, about 94 wt%, about 93 wt%, about 92 wt%, about 91 wt%, about 90 wt%, about 85 wt%, about 80 wt%, about 75 wt%, about 70 wt%, about 65 wt%, about 60 wt% or about 55 wt%. Any minimum and maximum amount may be combined to form a range, provided the range is between 1 wt% to 99 wt%, for example from about 1 wt% to about 10 wt% or from about 80 to about 99 wt%. The vehicle may be present at a concentration of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 85 wt%, about 90 wt%, about 91 wt%, about 92 wt%, about 93 wt%, about 94 wt%, about 95 wt%, about 96 wt%, about 97 wt%, about 98 wt% or about 99 wt%.

[0109] The agricultural film composition may be present at a concentration of from about 1 wt% to about 99 wt%, based on the total weight of the vehicle and the agricultural film composition, and all combinations and sub combinations of ranges therein. The agricultural film composition may be present at a concentration of at least about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 40 wt%, about 45 wt% or about 50 wt%. The agricultural film composition may be present at a concentration of no more than about 99 wt%, about 98 wt%, about 97 wt%, about 96 wt%, about 95 wt%, about 94 wt%, about 93 wt%, about 92 wt%, about 91 wt%, about 90 wt%, about 85 wt%, about 80 wt%, about 75 wt%, about 70 wt%, about 65 wt%, about 60 wt% or about 55 wt%. Any minimum and maximum amount may be combined to form a range, provided the range is between 1 wt% to 99 wt%, for example from about 1 wt% to about 10 wt%, from about 80 to about 99 wt%, or from about 95 wt% to about 99 wt%. The agricultural film composition may be present at a concentration of about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 85 wt%, about 90 wt%, about 91 wt%, about 92 wt%, about 93 wt%, about 94 wt%, about 95 wt%, about 96 wt%, about 97 wt%, about 98 wt% or about 99 wt%

[0126]

[0110] The present disclosure also provides a method of forming an agricultural film, the method comprising: providing an agricultural film composition comprising the MFC described herein, or produced by the method described herein, optionally a binder, and optionally a polymer composition; and forming a film from the agricultural film composition.

[0127]

[0111] In some embodiments, the agricultural film composition optionally comprises a resin or wax. In some embodiments, the method comprises a further step of applying a resin or wax to a surface of the formed film. In some embodiments, the agricultural film composition optionally comprises a vehicle.

[0128]

[0112] Additional examples of suitable applications include, but are not limited to: composite materials including compostable and / or biodegradable composite materials, barrier films, packaging including thermoformed packaging, paints, coatings including carbon fibre coatings, resins, adhesives, printing inks, plant protection, personal care products, home care products, micropaper and nanopaper, gels including aerogels, hydrogels and biogels, nanocomposite materials, construction materials, papermaking, electronic device components, electrodes, biomedical materials and medicine. Accordingly, the present disclosure also provides the use of the MFC described herein, or produced by the method described herein, in any one or more of these applications.

[0129]

[0113] As described herein, the MFC may be further processed to produce CNF. Accordingly, in one aspect, the present disclosure provides the use of MFC described herein, or produced by the method described herein, for producing CNF. The CNF may be useful in various applications, including those known in the art for CNF.

[0130]

[0114] The MFC and / or the CNF of the present disclosure may be suitable for use in a composite material, for example as a filler or an additive. Accordingly, in one aspect, the present disclosure provides a composite material comprising the MFC described herein or produced by the method described herein, and / or the CNF described herein or produced by the method described herein.

[0131]

[0115] It will be appreciated by persons skilled in the art that numerous variations and / or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

[0132] EXAMPLES

[0133] Example 1

[0134]

[0116] The study herein investigates the method of processing non-wood biomass to produce m icrofibril lated cellulose (MFC) according to the present disclosure.

[0135] Materials and methods

[0136] Materials

[0137]

[0117] Sorghum biomass of the Yemen variety was grown from seeds provided by the Department of Agriculture and Fisheries (DAF), Queensland, Australia. 1,2- propaneglycol (PG), with OHv of 1474.6 mg KOH / g, Mw of 76.1 g / mol, and a f of 2 was obtained from Era Polymers. Glycerol (G), from Sigma Aldrich, has a f of 3, a Mw of 92.09, and an OHv of 1800 mg (KOH) / g).

[0138] Preparation of the mixture and mechanical treatment

[0139]

[0118] The biomass (B) samples were soaked for 4 hours at room temperature at different loadings (30 wt%, 50 wt%, and 70 wt%) in different solutions including water (W), glycerol (G), and propylene glycol (PG or P). The samples were further mechanically treated using an extruder (Ext) or high-pressure homogenizer (HPH) or handheld shear homogenizer (HH) to produce lignin-containing microfibres or lignin-containing nanofibres.

[0140]

[0119] Control samples were prepared using traditional mild alkaline pretreatment. Ground biomass was dispersed and stirred overnight at -350 rpm in deionised water at a solid ratio of 1 :20 (20 g of water for every 1 g of ground biomass). Chemical pretreatment was performed using a 2% NaOH or KOH solution (w / v) at 80°C for 2 h, stirred at -350 rpm. The treated (delignified) material was separated from the waste liquor through a fine mesh sieve (53 pm aperture) and rinsed extensively until the filtrate pH was below 8. The delignified grass suspension was diluted to -0.5% (w / v) using a Halogen Moisture Analyzer HC103 (Mettler Toledo, United States) prior to mechanical treatment.

[0141]

[0120] Twin-screw extrusion (TSE) was performed with a HAAKE Rheomex PTW 16 OS Extruder connected to a PolyLab OS Drive Unit (Thermo Scientific, United States). Samples were passed through the co-rotating intermeshing twin-screw extruder with a screw diameter of 16 mm and a barrel length to diameter ratio (L / D) of 40:1 . The screw configuration used was based on the optimised profile established by Rol et al. (ACS Sustainable Chem. Eng. 2020, 8, 1, 50-59).

[0142]

[0121] High pressure homogenisation (HPH) was performed with a benchtop Panda 2 K NS1001 L (GEA Niro Soavi S.p.A, Italy) at a solids content of -0.4%. Extensive stirring of the delignified pulp feedstock suspension was required to reduce the likelihood of clogging. Samples were collected at three sequential energy levels without sample temperature control (1 pass x 300 bar, 1 pass x 600 bar, 3 pass x 850 bar). All HPH passes were conducted within the same session for each biomass sample, to ensure temperature effects imparted from the homogenisation process were kept relatively constant across different samples.

[0143]

[0122] Handheld shear homogenisation (HH) was performed using Omni tissue Homogeniser TH (PerkinElmer Inc., United States). Samples were allowed to pass through speeds varying from 5,000 - 35,000 rpm for 5 mins. Washing for better characterisation

[0144]

[0123] The characterization of the micro-lignocellulose (MLC) samples was difficult due to the lignin solvation in the process. To characterize these samples better and remove residual materials such as lignin, hemicellulose, and other extractives, the samples were washed using water. These samples are marked as ‘after wash’ samples herein. N.b. This washing may not be necessary commercially for certain applications, for example in agriculture or biocomposites, rather it has been done herein to demonstrate the effect of the solution on lignin solvation.

[0145] Characterisation techniques

[0146]

[0124] The FTIR spectra of control polyols and the samples were recorded using a Thermo-Nicolet 5700 with a diamond attenuated total reflection (ATR) attachment (Thermo electron Corp., USA) in absorbance mode, in the wavelength range between 500 and 4000 cm1as an average from 64 scans at 4 cm1. The recorded raw spectra were smoothened and normalized.

[0147]

[0125] The morphology of the dispersions was examined by compressing 10 pL between microscopic slide and coverslips and viewed on Olympus BX61 optical microscope under a polariser using a DP controller and DP manager software. The dispersions (0.01 mg / mL, diluted from samples with deionized water) were further dropped on a copper grid and air-dried at 60 °C, further examined by using a Hitachi HT7700 transmission electron microscopy (TEM) operating at 80 kV.

[0148]

[0126] Thermogravimetric analysis of the control polyols and the samples was conducted using a Mettler Toledo TGA (LabStar, Australia) operated by STA-Re version 9.10 software. The samples were heated in a nitrogen atmosphere using aluminium pans of a standard size of 40 pL. The temperature was initially ramped from room temperature to 40 °C before heating to 480 °C at a constant heating rate of 10 °C / min.

[0149]

[0127] The total energy consumption for mechanical treatment was obtained from a FLUKE 1736 Three-Phase Power Quality Logger (FLUKE, Australia). The energy consumption (kW) of each pass was recorded and transformed into total energy (kWh) based on the time to pass.

[0150]

[0128] FloWire software (LEWI, Australia) was used to evaluate the overall cost-benefit analysis and the total cost reduction. The unwashed B50P50-Ext sample analysed. For each process, plantwide models were developed to perform the full quantification of material, energy, and cost requirements for at-scale production. The cost modelling undertaken is in accordance with the Association for the Advancement of Cost Estimating International (AACE International) class 5 estimate. This means that the accuracy is typically around ±30-50% accuracy, which is appropriate for this stage of project assessment. The primary aim of this costing was to assess the economic feasibility of the proposed processes. The following assumptions were made to conduct the analysis. The cost database from Sinnott and Towler (2012) was used to estimate the equipment costing, using the factorial methodology. Equipment sizings were calculated as in Woods (Woods, 2007), using material balances for each unit; sizing and applying the costing factors as per Sinnott and Towler. Factors were used to add installed capital costs including equipment erection, piping, instrumentation and control, electrical, civil, structures and buildings, lagging and painting. Further factors were used for offsite cost, design and engineering, and contingency. Finally, a working capital cost of 20% was added to account for the investment expenses. Further assumptions were: grinding was not included in scope; water usage was only quantified for direct process usage (not auxiliary plant usage such as equipment washdown); Old treatment will require 1 more shift position for labour due to size of plant and number of operation units. Chemical costs used: Propylene glycol: 1506 USD / Metric Tonne; KOH: 900 USD / Metric Tonne.

[0151] Results and discussion

[0152] A. Effect of solution

[0153]

[0129] Figure 1A is a photograph of sorghum biomass samples presoaked with 50 wt% water, glycerol or propylene glycol as the solution and subsequently subjected to 1, 2 or 3 passes of extrusion. The colour differences signify the degree of delignification, with a lighter colour denoting a higher degree of delignification. Figure 1 B is a photograph of the extruded samples compared to the 2% NaOH sample as the gold standard. The propylene glycol sample showed better results in lignin fibrillation compared to the water and glycerol samples, and more closely matched the 2% NaOH sample.

[0154]

[0130] The thermal analysis of selected polyols, namely P and G, showed degradation at 192°C and 294°C respectively (Figure 2A). Figure 2B shows that the secondary control ‘biomass extruded’ (biomass-Ext) broadly degraded at 290°C (possibly hemicellulose and other extractives) and around 340°C (lignin and cellulose). The biomass-water (B50W50-Ext) sample degraded similarly to extruded biomass, yet the degradation occurred relatively sharply. This could be due to the extruder dislocating the soaked fibres effectively over the dry material. The biomass-glycerol (B50G50-Ext) sample also behaved similarly; however, a strong degradation was observed at 276°C, indicating the solution’s potential to extract hemicellulose over lignin. The biomass-PG sample (B50P50-Ext) showed a strong and sharp degradation peak at 183°C, which is the PG present in the sample. The sample further degrades at 287°C and 344°C, which indicates that the sample is still inherently ‘lignocellulose’ after the processing.

[0155]

[0131] Figure 2C shows that after washing the B50P50-Ext sample, the degradation of lignin and cellulose shifted towards 361 °C. This indicates better thermal stability which is higher than that of mildly alkaline treated pulp of the same biomass (349°C) pulp and is a positive result. Furthermore, the strong thermal signature at 183°C disappeared, indicating that PG can be washed away to a substantive degree. This is supported by the spectroscopic analysis (Figure 3A), where the OH stretching (3000-3600 cm1) and CH stretching (2800-2990 cm1) decreased after washing. However, the samples retain the peak of CO stretching (1000-1150 cm1) even after washing (Figure 3B), which was less intense for raw biomass, but much stronger for PG, possibly due to solution trapped inside the biomass particles.

[0156]

[0132] It is interesting to note that the PG solution appeared to extract the lignin present in the lignocellulose material effectively. Figure 4 shows evidence of solution-dispersed lignin dislodged from lignin-containing nanofibres. The high magnification image of the same (Figure 4A) shows ‘lignin fractals’, which appear to be similar to the Cryo-TEM image of a fractal cluster of pre-treated and extracted kraft lignin reported by Norgren et al (Current Opinion in Colloid & Interface Science, Volume 19, Issue 5, October 2014, Pages 409-416). Figure 4B shows evidence of lignin bound in the biomass particles (large agglomerate) dispersed into fractals by the solution. These images may indicate that the process described herein could also be used for effectively extracting lignin, specifically nano lignin.

[0157] B. Effect of the amount of solution

[0158]

[0133] The effect of biomass:solution ratio on delignification was investigated. The polarised microscopy images in Figure 5A show the effects of increasing PG solution concentration in samples containing 30wt%, 50wt% and 70wt% PG. These images show that the samples contained cellulose materials (brighter due to its crystallinity) and lignin, hemicellulose etc. (brown, darker due to its amorphous nature). They also show that more crystalline material (herein, cellulose) was generated with the increased solution (%) in the sample, followed by mechanical treatment (herein; extrusion).

[0159]

[0134] The thermal gravimetric analysis of extruded biomass / PG samples at 30 wt%, 50wt% and 70 wt% biomass loading before washing and after washing (Figure 5B and 5C) showed that the initial degradation of PG shifted with the concentration of solution in the sample. For example, B70P30 with 30wt% PG degraded at 172°C whereas B30P70 with 70 wt% PG degraded at 195°C (which is closer to the degradation temperature of control PG). Regardless of the effect of solution, this peak disappeared after washing and all samples further degraded at ~302°C and -361 °C.

[0160] C. Effect of mechanical treatment

[0161]

[0135] Figure 6 compares polarised microscopy images and low magnification TEM images of biomass after soaking in 50% PG without extrusion, after extrusion, and alternatively, after hand-held shear homogenization. The polarised microscopy image of biomass after soaking (sample A) in Figure 6 shows that the cellulose particles were quite amorphous without mechanical treatment. However, the samples after extrusion and shear homogenization had a large amount of cellulose (crystalline bright microparticles and fibres) compared to the merely soaked samples. This could indicate that soaking alone may not be sufficient to dislodge lignin from the biomass, and mechanical treatment may be necessary for the process in this study to be effective.

[0162]

[0136] The thermal properties of samples soaked and further mechanically treated (and washed for better characterization) are shown in Figure 7. It was observed that regardless of the mechanical treatment applied, the micro lignocellulosic material degraded around ~360°C. However, extruded samples degraded hemicellulose more intensively (stronger degradation at 297°C) than the shear homogenized samples.

[0163]

[0137] TEM images of lignin-containing cellulose nanofibres after soaking in 50% PG, followed by extrusion and high-pressure homogenization (4 pass), and alternatively, followed by a hand-held shear homogenizer, are shown in Figure 8. In particular, the sample in Figure 8A was soaked in 50% PG solution followed by extrusion (1 pass) then high-pressure homogenization (1 pass x 300 bar, 1 pass x 600 bar, 3 pass x 850 bar), and the sample in Figure 8B was soaked in 50% PG solution followed by hand-held homogenizer (medium-high speed, 5 min). The images show that mechanical treatment provides lignin-containing cellulose nanofibres after these mechanical treatments. The large blobs in the TEM images indicate that lignin was retained during the processing, whereas the fibres appear to be more “cellulosic” in composition and appearance. Advantageously, the pre- treatment method described herein could be useful in the manufacture of lignocellulosic micro and nanofibers (MFC and CNF) using all established refining methodologies (e.g., shredding, grinding, bead milling, shear homogenization, disc milling, Silverson mixer, etc).

[0164] Techno-economic analysis

[0165]

[0138] In traditional pre-treatment processes, the delignification of biomass is driven by the addition of potassium hydroxide or sodium hydroxide. This process additionally relies on a soaking step upstream of delignification and a dewatering step downstream of delignification, which increase the capital cost of the process resulting from additional unit operations as well as increasing the volume (and therefore unit sizing) through the processing infrastructure. Additionally, the pre-treatment must occur at a higher temperature which increases the operational cost associated with pre-treatment.

[0166]

[0139] In contrast, the alternative pre-treatment process in this study uses propylene glycol and other polyols, followed by mechanical treatment, and is advantageously a more sustainable process. Further, the differences in water, chemical, and energy consumption beneficially provided a 41 % reduction in total annual cost per tonne per day. The results of the techno-economic analysis of the process in this study compared to the traditional alkaline pulping process are provided in Table 1.

[0167] Table 1. Techno-economic analysis

[0168] Example 2

[0169]

[0140] The study herein investigates the method of processing non-wood biomass to produce microfibrillated cellulose (MFC) according to the present disclosure.

[0170] Preparation of mixtures and mechanical treatment

[0171]

[0141] Barley biomass was milled via Cutting Mill SM 300 (Retsch, Germany). The milled biomass was sieved through fine mesh strainer with a mesh size of 60. The biomass was treated (soaked) in polypropylene glycol (polyol) or in propylene glycol-potassium hydroxide (alkaline polyol) solution, at a ratio of 1:1 by weight at room temperature overnight without mixing. The alkaline polyol solution was prepared by dissolving 5.0 wt% potassium hydroxide in polypropylene glycol. An untreated (unsoaked) biomass was used as a comparator. Each mixture was then extruded via a Polylab twin screw extruder one or two times. Results and discussion

[0172]

[0142] Figure 9 is a photograph of powder samples of (a) untreated biomass, (b,c) polyol treated biomass, and (d,e) alkaline polyol treated biomass which has been extruded one or two times. The treated biomass mixtures were darker compared to the untreated mixture. Further, the alkaline polyol treated biomass mixtures were darker compared to the polyol treated biomass mixtures. The darker colour may be attributed to a higher dissolution of lignin in the mixture. Thus, the results provide an indication that treating biomass with a polyol can increase lignin extraction from biomass, and the presence of alkali can further increase lignin extraction.

[0173]

[0143] Figure 10 is a photograph of the powder samples of (a) untreated biomass, (b,c) polyol treated biomass, and (d,e) alkaline polyol treated biomass which has been extruded one or two times, which have been added into water. The colour of the water samples for the alkali polyol treated biomass significantly changed to brown, indicating the presence of free lignin chains. This result also provides an indication that delignification of biomass is increased in the presence of alkali.

[0174]

[0144] In Figure 11, the image of samples was taken by optical microscopy (OM) and polarized optical microscopy (POM). Figures 11a and 11 b shows the OM and POM image of the untreated sample. The POM image is dark because the crystalline structure of cellulose could not be seen due to the presence of the lignin. Treatment with polyol resulted in dissolution of lignin (Figures 11c and 11 e), however; the crystalline structure of cellulose still could not be seen in Figures 11 d and 11f. Introducing alkali in the solution resulted in increased removal of lignin, shown by the appearance of crystalline structure of cellulose in Figures 11 h, 11j and 111.

[0175]

[0145] The above results may provide an indication that the presence of base in the polyol solution can improve green solvolysis of lignocellulose by increasing delignification.

[0176] Example 3

[0177]

[0146] The study herein investigates mulch compositions comprising microfibrillated lignocellulose (MFC) produced by methods according to the present disclosure. The MFC was prepared by grinding wheat straw biomass (approximately 2-5 cm in length) to approximately 1 mm size using a cutting mill (SM 300, Retsch) operated at 2500 rpm with a 1mm trapezoidal mesh screen, presoaking the ground biomass (50 wt%) in glycerol (50 wt%), followed by twin-screw extrusion at room temperature at 60 rpm, yielding a partially defibrillated lignocellulosic fraction (MFC(g)).

[0178]

[0147] Mulch compositions according to Table 2 were prepared by mixing all components except gum rosin (where present). The sprayable biodegradable mulch (SBM) used in MFC(g)_G_SBM and MFC(g)_SBM was polyurethane-based. Up to 5 wt% water was added to the compositions to facilitate mixing. The compositions were then hot-pressed at 1 kN using a Rondol sample press and air dried to provide the film samples. For MFC(g)_G_R, a gum rosin top coat was applied by preparing a rosin-ethanol solution (50 % w / w). Rosin pellets were dissolved in ethanol under mechanical stirring at 200 rpm until a homogeneous solution was obtained. The solution was then applied onto pressed films as a surface coating and allowed to dry under ambient conditions, leaving a thin hydrophobic layer. Images of the samples in Figures 12 a-d show that the mulch compositions formed homogenous, cohesive films without cracking, illustrating that the compositions are capable of forming films. These results may provide an indication that the compositions may be useful for forming flexible mulch films for agricultural applications, for agricultural applications.

[0179] Table 2. Mulch compositions

[0180] Example 4

[0181]

[0148] The study herein investigates mulch film comprising microfibrillated lignocellulose (MFC) produced by methods according to the present disclosure. The MFC was prepared as described in Example 3, with the ground wheat straw biomass (50 wt%) being presoaked in either glycerol (g) or propylene glycol (pg) at 50 wt% to provide MFC(g) and MFC(pg), respectively.

[0182]

[0149] Mulch compositions according to Table 3 were prepared, and films were formed following the method described in Example 3. For MFC(g)_G_R and MFC(pg)_G_R, a gum rosin top coat was applied onto pressed films as described in Example 3. Results of water contact angle (WCA) tests using the compositions are shown in Figure 13. All samples exhibited a low contact angle (under 90 degrees), indicating a hydrophilic surface.

[0183] Table 3. Mulch film compositions

[0184] Example 5

[0185]

[0150] The study herein investigates mechanical properties of mulch film comprising microfibrillated lignocellulose (MFC) produced by methods according to the present disclosure. The following samples from Example 3 were assessed: MFG(g)_G, MFG(g)_G_R, MFC(g)_G_SBM.

[0186]

[0151] Mechanical testing was performed using an Instron 5543 under 500N load cell at length and breadth set at 20mm x22mm, though thickness and mass were varied to account for differences between the samples. The following properties were measured: tensile stress, tensile index, strain at break, energy at break, volumetric toughness, and specific toughness. The results are summarised in Table 4. MFC(g)_G achieved the best overall performance, combining high tensile stress (336 kPa) and tensile index (244 Nm / g) with ductility (strain -10%) and toughness (416 MJ / m3). The addition of rosin in MFC(g)_G_R reduced tensile stress to 205 kPa and tensile index to 138 Nm / g, while ductility was maintained (strain -10%). The lower toughness (-251 MJ / m3) may suggest that ethanol used in rosin incorporation weakened bonding within the fibre network, consistent with previous observations in resin-coated biodegradable films. MFC(g)_G_SBM retained relatively high tensile stress (313 kPa) but decreased ductility (8.6%) and toughness (277 MJ / m3), indicating that the sprayable biodegradable polyurethane mulch (SBM) contributed stiffness but at the cost of flexibility. Taken together, the results highlight MFC(g)_G as the most balanced system tested, with the addition of rosin and SBM introducing trade-offs between hydrophobicity, strength, and flexibility.

[0187] Table 4. Mechanical properties of mulch films

Claims

1. CLAIMS:1 . A method of processing a non-wood plant biomass, the method comprising:(i) presoaking the non-wood plant biomass in a solution comprising a polyol at a temperature of about 20°C to about 75°C, wherein the solution comprises no more than about 10 vol% water based on the total volume of the solution; and(ii) subjecting the presoaked non-wood plant biomass to mechanical shearing to produce microfibrillated cellulose (MFC).

2. The method according to claim 1, wherein the non-wood plant biomass is derived from a source selected from sorghum; sugarcane; cotton; bamboo; rice; wheat; barley; banana; palm tree; pineapple;jute; kenaf; sisal; maize; hemp; flax; sunflower; canola; soybean; mung bean; chickpea; faba bean; peanut; cassava; chia; Dhaincha; eggplant; mulberry; mustard; okra; red lentil; oat; and spinifex; preferably wherein the non-wood plant biomass is sorghum, more preferably forage sweet sorghum.

3. The method according to claim 1 or claim 2, wherein the solution comprises substantially no water.

4. The method according to any one of claims 1 to 3, wherein the polyol is a low molecular weight polyol, preferably selected from glycerol, propylene glycol and ethylene glycol, more preferably propylene glycol and ethylene glycol.

5. The method according to any one of claims 1 to 4, wherein the solution comprises a base, preferably an alkali metal hydroxide, more preferably potassium hydroxide or sodium hydroxide, even more preferably potassium hydroxide.

6. The method according to any one of claims 1 to 5, wherein in step (i) the non-wood plant biomass is presoaked in up to about 70 wt% solution, based on the total weight of the non-wood plant biomass and the solution, wherein the solution comprises substantially no water.

7. The method according to any one of claims 1 to 6, wherein one or more of the following apply: step (i) is performed at a temperature of about 20°C to about 60°C, or about 20°C to about 25°C; step (i) is performed without mechanical agitation; step (i) is performed in the absence of chemical treatment; step (i) is performed in the absence of an exogenous enzyme; step (i) is performed in the absence of an exogenous catalyst.

8. The method according to any one of claims 1 to 7, wherein one or both of the following apply: in step (ii) the mechanical shearing comprises one or both of extrusion and homogenisation; in step (ii) the mechanical shearing is performed using a twin screw extruder.

9. The method according to any one of claims 1 to 8, wherein in step (ii) the presoaked non-wood plant biomass is subjected to one, two, three or four passes of mechanical shearing, preferably one pass of mechanical shearing.

10. The method according to any one of claims 1 to 9, wherein the method further comprises a step of washing the presoaked non-wood plant biomass before subjecting the presoaked biomass to mechanical shearing.11 . The method according to any one of claims 1 to 10, wherein the produced MFC contains lignin.

12. The method according to any one of claims 1 to 11, wherein the produced MFC has a solid content from about 30 wt% to about 80 wt%.

13. The method according to any one of claims 1 to 12, wherein the MFC is produced in a yield of at least about 80 wt%, relative to the total weight of the non-wood plant biomass.

14. MFC produced by the method according to any one of claims 1 to 13.

15. An agricultural film composition comprising:MFC produced by the method according to any one of claims 1 to 13, or according to claim 14; optionally a binder, preferably guar gum; and optionally a resin or wax, preferably gum rosin.

16. Use of MFC produced by the method according to any one of claims 1 to 13, or according to claim 14, in an agricultural film composition, preferably an agricultural biodegradable polymer film composition.

17. Use of MFC produced by the method according to any one of claims 1 to 13, or according to claim 14, in any one or more of the following applications: composite materials including compostable and / or biodegradable composite materials, barrier films, packaging including thermoformed packaging, paints, coatings including carbon fibre coatings, resins, adhesives, printing inks, plant protection, personal care products, home care products, micropaper and nanopaper, gels including aerogels, hydrogels and biogels, nanocomposite materials, construction materials, papermaking, electronic device components, electrodes, biomedical materials and medicine.

18. A method of processing MFC, the method comprising: diluting MFC produced by the method according to any one of claims 1 to 13, or according to claim 14; and subjecting the diluted MFC to mechanical shearing to produce CNF, optionally wherein the produced CNF contains lignin.

19. CNF produced by the method according to claim 18.

20. A composite material comprising the MFC produced by the method according to any one of claims 1 to 13 or according to claim 14, or the CNF produced by the method according to claim 18 or according to claim 19.

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