Method for preparing a thermoplastic composition

Abstract

A method for preparing a thermoplastic composition comprising grafted cellulose and optionally grafted hemicellulose is disclosed, which includes providing a composition comprising cellulose and optionally hemicellulose, at least partially dissolving the cellulose and optionally hemicellulose of the composition, thereby obtaining a solution comprising solubilized cellulose and optionally solubilized hemicellulose, adding a cyclic ester monomer to the solution, such that the cyclic ester monomer reacts with the solubilized cellulose and optionally solubilized hemicellulose, thereby at least partially grafting the solubilized cellulose and optionally solubilized hemicellulose with the cyclic ester monomer, and coagulating the grafted cellulose and optionally grafted hemicellulose, thereby obtaining a thermoplastic composition.

Description

[Technical field]

[0001] The present disclosure relates to methods of preparing thermoplastic compositions, thermoplastic compositions, and products obtainable therefrom. [Background technology]

[0002] Cellulose and hemicellulose are renewable raw materials well suited for the production of thermoplastic materials.

[0003] Thermoplastic cellulose and hemicellulose derivatives that can be processed using conventionally used thermoplastic processing equipment such as extrusion and molding are of great interest as replacements for fossil-based thermoplastic materials. Moreover, based on general considerations regarding the correlation between molecular structure, degree of substitution and biodegradability, such derivatives may enable both thermoplastic processing and post-consumer waste management via biological degradation.

[0004] However, balancing biodegradability, thermoplasticity and material properties can be difficult. Summary of the Invention

[0005] A method for preparing a thermoplastic composition comprising grafted cellulose and optionally grafted hemicellulose is disclosed. The method may include providing a composition comprising cellulose and optionally hemicellulose, at least partially dissolving the cellulose and optionally hemicellulose of the composition, thereby obtaining a solution comprising solubilized cellulose and optionally solubilized hemicellulose, adding a cyclic ester monomer to the solution, such that the cyclic ester monomer reacts with the solubilized cellulose and optionally solubilized hemicellulose, thereby at least partially grafting the solubilized cellulose and optionally solubilized hemicellulose with the cyclic ester monomer, and coagulating the grafted cellulose and optionally grafted hemicellulose, thereby obtaining a thermoplastic composition.

[0006] The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification, illustrate various embodiments. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 illustrates one embodiment of a method for preparing a thermoplastic composition. [Diagram 2] 1 is a graph showing Fourier transform infrared spectroscopy (FTIR) spectra of the cellulose starting material and the resulting caprolactone-grafted cellulose. [Diagram 3] 1 is a graph showing the biodegradability of lactone grafted cellulose samples with different degrees of substitution. Ref. = Reference, MCC = Microcrystalline Cellulose, 20-02831-007 = Grafted cellulose with degree of substitution of 1.72 and 20-02831-012 = Grafted cellulose with degree of substitution of 0.61 (Example 1). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A method for preparing a thermoplastic composition is disclosed.

[0009] The thermoplastic composition may include grafted cellulose and optionally grafted hemicellulose.

[0010] This method is Providing a composition comprising cellulose and optionally hemicellulose; at least partially dissolving the cellulose and optionally hemicellulose of the composition, thereby obtaining a solution comprising solubilized cellulose and optionally solubilized hemicellulose; adding a cyclic ester monomer to the solution such that the cyclic ester monomer reacts with the solubilized cellulose and optionally the solubilized hemicellulose, thereby at least partially grafting the solubilized cellulose and optionally the solubilized hemicellulose with the cyclic ester monomer; coagulating the grafted cellulose and optionally the grafted hemicellulose, thereby obtaining a thermoplastic composition; may include.

[0011] The reaction of cyclic ester monomer with solubilized cellulose and optionally solubilized hemicellulose produces solubilized cellulose and optionally solubilized hemicellulose with cyclic ester monomer, oligomer and / or polymer grafted thereon. The cyclic ester bonds to the OH group of hemicellulose and optionally cellulose. Thus, the cyclic ester esterifies cellulose and optionally hemicellulose. This reaction can be considered as a ring-opening polymerization reaction of the cyclic ester monomer.

[0012] Thus, the grafted cellulose and optionally the grafted hemicellulose are the polymerization products of cellulose and optionally hemicellulose with cyclic ester monomers.

[0013] Because the cellulose and optionally hemicellulose are solubilized, their OH groups may be more accessible and the cellulose and optionally hemicellulose may be grafted more efficiently and uniformly compared to, for example, cellulose and optionally hemicellulose that are not solubilized but may have a fibrous structure.

[0014] The cellulose and optionally hemicellulose may be at least partially grafted with cyclic ester monomers, in the sense that at least a portion of the cellulose and optionally hemicellulose molecules may be grafted.

[0015] The cellulose and optionally hemicellulose may be at least partially grafted with cyclic ester monomers such that the cyclic ester monomers, oligomers and / or polymers (polyesters) are essentially uniformly or homogeneously distributed within the cellulose and optionally hemicellulose molecules.

[0016] Polyesters (such as polylactones), i.e., polyesters that are not grafted to cellulose or hemicellulose, may be obtained as by-products. The polyesters may be at least partially removed if desired, for example if a particular purity level of the thermoplastic composition is desired. The free acid content of the thermoplastic composition may be, for example, less than 2% (w / w) as determined by ASTM standard D871-96. The polyesters, such as polylactones, may be at least partially removed after the reaction, for example by extraction with acetic acid. However, in at least some embodiments, a certain amount of polyester may remain in the thermoplastic composition. This may also have a role in the material properties, such as the melting temperature, of the thermoplastic composition.

[0017] An example of a grafting reaction with ε-caprolactone as the cyclic ester monomer (lactone) is shown in Scheme 1 below. [ka]

[0018] Scheme 1. Reaction mechanism of the base-catalyzed ring-opening polymerization with ε-caprolactone in the grafting of ε-caprolactone onto cellulose and the modification of the cellulose surface.

[0019] The resulting thermoplastic composition may be biodegradable.

[0020] In general, the biodegradation and biodegradability of a polymeric material or composition may depend on the environmental conditions and the time required for degradation. For example, the environmental conditions may be aggressive or less aggressive. The following environmental conditions may be considered in order of increasing aggressiveness: marine environment, fresh water, wastewater treatment plant, soil, home compost, and industrial compost. Biodegradability does not necessarily mean that a product, such as a thermoplastic composition, is biodegradable in any one of these conditions or in any one of these conditions within any given time. For example, less aggressive conditions may require significantly longer periods of time for biodegradation.

[0021] The thermoplastic composition may be biodegradable as determined by OECD Standard 301 F for the testing of chemicals.

[0022] The term "biodegradable", at least in some embodiments, can refer to readily biodegradable as determined by OECD Standard 301 F for the Testing of Chemical Substances (Manometer Breath Test). A readily biodegradable thermoplastic composition or thermoplastic polymeric material can be a thermoplastic composition or thermoplastic polymeric material that reaches at least 60% biodegradability within 28 days as determined by OECD Standard 301 F for the Testing of Chemical Substances.

[0023] It may be possible to adjust and / or control the extent to which the cellulose and optionally hemicellulose are grafted. For example, if the cellulose and optionally hemicellulose are efficiently solubilized, they may be grafted relatively uniformly and the resulting thermoplastic composition may have different properties than a thermoplastic composition in which the cellulose and optionally hemicellulose are grafted only, for example, at the surface of the fiber.

[0024] The extent to which the cellulose and optionally hemicellulose are grafted may also affect the barrier properties of the thermoplastic composition: if the hemicellulose and optionally cellulose are essentially grafted throughout, the thermoplastic composition may have better barrier properties than, for example, a thermoplastic composition in which the hemicellulose and optionally cellulose are primarily or only surface grafted.

[0025] Thus, the degree and / or type of grafting can be adjusted and / or controlled depending on the intended purpose, the environmental impact, the energy efficiency of the material and / or other factors, e.g., the use of toxic solvents can be minimized, the number of processing steps can be minimized, atomic economy can be maximized, and / or waste can be minimized.

[0026] In the context of this specification, the term "a cyclic ester monomer" or "the cyclic ester monomer" may be understood to refer to one or more cyclic ester monomers, and / or mixtures or combinations thereof.

[0027] The cyclic ester monomer may include or be a lactone or a mixture of one or more lactones.

[0028] The cyclic ester monomers are represented by formula (I) and / or (II): [ka] [ka] (In the formula, R 1 and R 2 are each independently selected from the group consisting of H, methyl, ethyl, and propyl; R 3 and R 4 are each independently selected from the group consisting of H, methyl, ethyl, and propyl; A is selected from O and N; R 5 is selected from the group consisting of H, methyl, ethyl and propyl when A is N; R 5 is non-existent if A is O, m is an integer ranging from 1 to 5. The lactone may be selected from lactones represented by

[0029] In one embodiment, in Formula I and / or II, R 1 and R 2 One of them is H and the other is R 1 and R 2the other is selected from the group consisting of H, methyl, ethyl and propyl; R 3 and R 4 One of them is H and the other is R 3 and R 4 the other is selected from the group consisting of H, methyl, ethyl, and propyl; A is selected from O or N; R 5 is selected from the group consisting of H, methyl, ethyl and propyl when A is N; R 5 is non-existent if A is O, m is an integer ranging from 1 to 5.

[0030] In one embodiment, in Formula I and / or II, R 1 and R 2 One of them is H and the other is R 1 and R 2 the other is selected from the group consisting of H, methyl, ethyl and propyl; R 3 and R 4 One of them is H and the other is R 3 and R 4 the other is selected from the group consisting of H, methyl, ethyl, and propyl; A is selected from O or N; R 5 is H if A is N, and R 5 is non-existent if A is O, m is an integer ranging from 1 to 5.

[0031] m can be 1, 2, 3, 4 or 5.

[0032] The cyclic ester monomer may be a lactone such as ε-caprolactone, γ-valerolactone, δ-valerolactone, or any mixture or combination of lactones, or any mixture or combination thereof.

[0033] The composition comprising cellulose and optionally hemicellulose may be a mixture of cellulose and hemicellulose. In other words, the cellulose and hemicellulose may be provided as a mixture comprising cellulose and hemicellulose. Thus, any reference herein to cellulose and optionally hemicellulose may also be understood to refer to a mixture comprising cellulose and hemicellulose.

[0034] Such mixtures, as well as compositions comprising cellulose and optionally hemicellulose, may comprise or be a pulp, such as, for example, a chemical pulp.

[0035] Compositions comprising cellulose and optionally hemicellulose, such as pulp, can be alkali soluble, such as alkali soluble pulp.

[0036] The pulp may include or be, for example, a wood pulp (e.g., hardwood and / or softwood pulp), a non-wood pulp, and / or an agropulp. The pulp may be a chemical pulp, such as a kraft pulp. The pulp may additionally or alternatively be a never-dried pulp, such as a never-dried kraft pulp.

[0037] Many cellulose sources may further contain a certain amount of hemicellulose. For example, pulp may contain a mixture of cellulose and hemicellulose. The mixture may contain, for example, at least 3% by weight, or at least 5% by weight, or at least 10% by weight of hemicellulose, based on the total dry weight of cellulose and hemicellulose.

[0038] Cellulose is a polysaccharide containing linear chains of several thousand to ten thousand linked D-glucose units.

[0039] Hemicellulose is a heteropolymer, i.e., the term "hemicellulose" may be understood to refer to several heteropolymers (matrix polysaccharides), such as arabinoxylan. Hemicellulose is present in the cell walls of almost all land plants, together with cellulose. While cellulose is crystalline, strong, and resistant to hydrolysis, hemicellulose has a random amorphous structure and has little strength. In other words, the term "hemicellulose" may be understood to refer to one or more hemicellulose molecules and mixtures thereof. Hemicellulose is composed of a variety of sugars and may include xylose, arabinose, glucose, mannose, galactose, and / or rhamnose. Hemicellulose may contain primarily D-pentose sugars, and occasionally small amounts of L-sugars. Xylose is the sugar monomer most often present in the greatest amount, although in conifers, mannose may be the most abundant sugar. In hemicellulose, not only regular sugars but also their acidified forms, such as glucuronic acid and galacturonic acid, can be found.

[0040] Cellulose can be present as cellulose fibers, macrofibrils and / or microfibrils.

[0041] The composition comprising cellulose and optionally hemicellulose may be dissolved in an alkaline solution. The alkaline solution may include an alkaline agent such as NaOH, LiOH, KOH, Mg(OH)2, Ca(OH)2, NH4OH, and / or any mixture or combination thereof. Additional organic hydroxides such as tetrabutylammonium hydroxide may also be included in the alkaline solution. The alkaline solution may be an aqueous alkaline solution.

[0042] The composition comprising cellulose and optionally hemicellulose and the alkaline solution may be mixed, for example by feeding into a continuous reactor or a high consistency dissolution unit, in which partial or complete dissolution of the cellulose and optionally hemicellulose can be achieved.

[0043] The alkaline solution may be an aqueous alkaline solution. For example, the alkaline solution may include an alkali metal hydroxide (e.g., sodium hydroxide, NaOH) and optionally a zinc salt (e.g., zinc oxide, ZnO). The alkaline solution may include an alkaline agent such as NaOH at a concentration of about 5-15% (w / w). The alkaline solution may further include a zinc salt at about 0-3% (w / w) or 0.1-2.5% (w / w).

[0044] The concentration of solubilized cellulose and optionally hemicellulose in the solution, ie in the mixture containing solubilized cellulose and optionally solubilized hemicellulose, may be, for example, about 1-12% (w / w).

[0045] The alkaline solution may be a low-temperature alkaline solution. The temperature of the low-temperature alkaline solution may be within a range of -5°C to 5°C, for example.

[0046] At least partial dissolution of the cellulose, and optionally the hemicellulose, of the composition may be achieved using methods (and / or reagents) that are not sensitive to the presence of hemicellulose.

[0047] The consistency of the mixture containing solubilized cellulose and optionally solubilized hemicellulose, i.e., solubilized cellulose and optionally solubilized hemicellulose, can be adjusted as desired for extrusion, for example. The consistency of the mixture containing solubilized cellulose and optionally solubilized hemicellulose, i.e., solubilized cellulose and optionally solubilized hemicellulose, can be, for example, in the range of about 5-12% (w / w).

[0048] The solubilized cellulose and optionally solubilized hemicellulose, ie the mixture containing solubilized cellulose and optionally solubilized hemicellulose, may have a viscosity value, for example, in the range of 150 ml / g to 500 ml / g.

[0049] The cyclic ester monomers may be added and / or mixed with the solubilized cellulose and optionally solubilized hemicellulose, ie, the mixture containing the solubilized cellulose and optionally solubilized hemicellulose.

[0050] The cyclic ester monomers can be reacted with the solubilized cellulose and optionally the solubilized hemicellulose in the presence of a suitable catalyst.

[0051] The cyclic ester monomers can be reacted with the solubilized cellulose and optionally the solubilized hemicellulose in the presence of a basic catalyst.

[0052] Such a basic catalyst may be or may include, for example, a strong base such as LiOH, NaOH, KOH, Ca(OH)2, RbOH, Sr(OH)2, CsOH, Ba(OH)2, or any mixture or combination thereof, a superbase catalyst such as ethoxide ion (C2H5ONa), sodium amide (NaNH2), sodium hydride (NaH), CH5N3 (guanidine), or any mixture of combinations thereof, or any mixture or combination thereof.

[0053] The alkaline agent of the alkaline solution, such as NaOH, may also function as the basic catalyst. However, additional basic catalyst may be added to the solution containing solubilized cellulose and, optionally, solubilized hemicellulose.

[0054] The cyclic ester monomer can be reacted with the solubilized hemicellulose and optionally the solubilized cellulose at a temperature in the range of about 0-100°C, or in the range of about 0-50°C, or in the range of 1-45°C.

[0055] The cyclic ester monomer can be reacted with the solubilized cellulose and optionally the solubilized hemicellulose for at least 5 minutes, or at least 30 minutes, or at least 1 hour, or at least 5 hours, or about 1-5 hours, or about 1-3 hours.

[0056] The solution comprising solubilized and / or grafted cellulose and optionally solubilized and / or grafted hemicellulose may be considered to be a cellulose spinning solution (cellulose spinning dope), especially if the solution is an alkaline solution.

[0057] However, the chemistry used to dissolve the cellulose and optionally hemicellulose is not particularly limited, so long as it is capable of solubilizing, grafting, and subsequently solidifying the cellulose and optionally hemicellulose into a solid form.

[0058] The grafted cellulose and optionally the grafted hemicellulose may be extruded, for example, through a die or nozzle.

[0059] The grafted cellulose and optionally the grafted hemicellulose can be considered to be regenerated when they are solidified, for example by extruding them into a shape. The cellulose is not necessarily actually regenerated cellulose in the sense of having undergone viscose treatment and subsequent regeneration. In this case, the terms "solidified" and "regenerated" can refer to cellulose that has been precipitated and / or crystallized from a solubilized state. It can be crystallized at least partially into cellulose I, or at least partially into cellulose II, or partially into cellulose I and partially into cellulose II.

[0060] The grafted cellulose and optionally the grafted hemicellulose may be solidified by extrusion, and may be solidified into fibers or a shape, such as filaments, beads, films, 3D objects or molded products. The shape is not particularly limited. Various shapes can be extruded or molded from the grafted cellulose and optionally the grafted hemicellulose.

[0061] The grafted cellulose and optionally grafted hemicellulose, for example in the form of an extruded shape, such as a filament or any other shape, can be washed after coagulation and / or extrusion. For example, the method can include immersing the grafted cellulose and optionally grafted hemicellulose, for example an extruded shape, in a washing bath. The washing bath can include an acidic washing solution, such as a sulfuric acid solution, which can then assist in coagulating the cellulose. The coagulated cellulose and optionally hemicellulose, for example in the form of an extruded shape, can be immersed in one or more washing baths. For example, after a washing bath including an acidic washing solution, the coagulated cellulose and optionally hemicellulose can be immersed in a second washing bath. Such a second washing bath can include, for example, water or another neutral solution.

[0062] Thus, the thermoplastic composition may be in the form of solidified cellulose and optionally hemicellulose.

[0063] However, the thermoplastic composition may additionally or alternatively be further processed. The method may further include, for example, washing the thermoplastic composition. The method may further include, for example, removing unreacted cyclic ester monomer.

[0064] Thus, the thermoplastic composition may be in the form of a solidified shape comprising grafted cellulose and optionally grafted hemicellulose. In other words, the shape comprising grafted cellulose and optionally grafted hemicellulose may be the desired end product. Alternatively or additionally, it may be further processed. For example, it may be possible to form other shapes or products from the shape comprising grafted cellulose and optionally grafted hemicellulose. Thus, the resulting thermoplastic composition comprising grafted cellulose and optionally grafted hemicellulose may be in the form of, for example, pellets or powder.

[0065] The method may further include pelletizing the thermoplastic composition (i.e., forming pellets) or forming a powder. The method may further include forming a film, filament, melt, and / or 3D shape of the thermoplastic composition. Such products may be formed, for example, by extrusion, extrusion molding, and / or injection molding. In principle, the thermoplastic composition and the thermoplastic polymeric material may be further processed as other thermoplastic materials.

[0066] A thermoplastic composition is also disclosed.

[0067] Any of the embodiments and features described above or below may also be understood to relate to the methods, thermoplastic compositions, thermoplastic polymeric materials, and / or articles according to one or more embodiments described herein.

[0068] The thermoplastic composition can be biodegradable.

[0069] The thermoplastic composition may comprise cellulose and optionally hemicellulose grafted with a polyester, such as a polylactone. The grafted polyester chains may be formed, for example, from at least 10 cyclic ester monomers. In other words, the grafted polyester chains may, for example, each comprise at least 10 ester groups. In an embodiment in which the cellulose and optionally hemicellulose are grafted with a polylactone, the grafted polylactone chains may, for example, be formed from at least 10 lactone monomers.

[0070] The thermoplastic composition may be obtained or be obtainable by a method according to one or more embodiments described herein.

[0071] The degree of substitution of the grafted hemicellulose and optionally the grafted cellulose in the thermoplastic composition may be in the range of 0.1 to 3.0, or in the range of 0.1 to 2.0, or in the range of 0.5 to 1.5.

[0072] The melting temperature of the thermoplastic composition may be in the range of 40 to 200°C, or in the range of 40 to 180°C, or in the range of 40 to 160°C.

[0073] The lactone content of the thermoplastic composition may be in the range of 5 to 210, or in the range of 10 to 100, or in the range of 50 to 100 (wt % pulp). In this context, the term "lactone content" may be understood to refer to the (relative) amount in the thermoplastic composition of units derived from lactone.

[0074] The lactone content of the thermoplastic composition may be measured as the total lactone content of the thermoplastic composition. The lactone content may include only lactones grafted to cellulose and optionally hemicellulose (polylactones). In some embodiments, it may include the polymerization product of lactones alone (polylactones) that are not grafted to cellulose and optionally hemicellulose. The ungrafted polylactones may be at least partially removed from the thermoplastic composition before measuring the lactone content.

[0075] The cellulose may be present in the extrudate, in a subsequent form obtainable from the extrudate, and / or in the thermoplastic composition at least partially as cellulose II, i.e., as cellulose having the crystalline structure of cellulose II. For example, at least 10% (w / w), i.e., 10-100% (w / w), of the cellulose in the thermoplastic composition may have the crystalline structure of cellulose II.

[0076] The whiteness of the thermoplastic composition can be very good. The whiteness of the thermoplastic composition can be similar to that of pulp.

[0077] Also disclosed are thermoplastic polymeric materials that include or are formed from a thermoplastic composition according to one or more embodiments described herein.

[0078] The thermoplastic polymeric material may further include a biocomposite and / or a plastic.

[0079] Also disclosed are articles obtainable from or formed from the thermoplastic compositions according to one or more embodiments described herein and / or thermoplastic polymer materials according to one or more embodiments described herein.

[0080] The article may be, for example, a pellet, powder, film, filament, melt, 3D shape, coating, hot melt adhesive, container, casing, packaging article, film label, paper, medical device, plastic or composite profile, and / or 3D printing filament.

[0081] The thermoplastic compositions, thermoplastic polymeric materials, and / or articles may be recyclable, for example, they may be recyclable in paper and cardboard recycling systems and / or other recycling systems.

[0082] The thermoplastic polymeric materials and / or articles may be biodegradable. EXAMPLES

[0083] Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings.

[0084] The following description discloses some embodiments based on the present disclosure in detail so that those skilled in the art can utilize those embodiments. Not all steps or features of the embodiments are described in detail because many of the steps or features will be apparent to those skilled in the art based on the present specification.

[0085] For brevity, item numbers are maintained in the following exemplary embodiment where elements are repeated.

[0086] Figure 1 shows an exemplary embodiment of the method. In this embodiment, the method operates as a semi-continuous process. An alkali-soluble pulp 1 or other suitable composition, comprising cellulose and optionally hemicellulose, is mixed with an alkaline solution 2 in a suitable vessel, such as a reactor 3. The alkaline solution dissolves the pulp, resulting in a solution comprising solubilized cellulose and optionally solubilized hemicellulose.

[0087] To this solution, cyclic ester monomer 4 is added. Reactor 3 may provide suitable conditions, such as temperature, for the grafting reaction. After the grafting reaction has taken place, the solubilized mixture, including grafted cellulose and optionally hemicellulose, is forced through die 7 by screw 5 driven by motor 6. At die 7, the mixture is extruded into filaments 8. However, the mixture may alternatively be extruded into various other shapes or profiles, such as films. The wet filaments 8 may then be immersed in a coagulation bath 9, including, for example, a sulfuric acid solution. In the coagulation bath 9, the grafted cellulose and hemicellulose solubilized in the solution are coagulated. The coagulated filaments may then enter a washing bath 10, including a washing solution, such as water. This neutralizes and washes the filaments exiting washing bath 10. The resulting dry thermoplastic composition, i.e., filaments, may then be processed, for example, by pelletizer 11. The resulting pelletized thermoplastic material 12 may then be collected. If desired, it may be ground, for example, into a powder, or otherwise further processed.

[0088] Example 1 140 g of ε-caprolactone and 24 g of citric acid as catalyst were added to the Juccheim reactor, and mixing was set to about 8 Hz. The mixture was refluxed at 120° C. for 30 minutes to dissolve the citric acid. The reactor was then cooled to 70° C., and 10 g of birch pulp dried in a hot and cold mixer was added to the reactor. The temperature of the batch reactor was increased to 120° C., mixing was set to 11 Hz, and the reaction started. The reactor was held at this temperature for 5 hours and then worked up as follows: The reactor was first cooled at 40° C., and after cooling, the citric acid catalyst was neutralized using 30 g of 20 wt.% NaOH. The non-immobilized polycaprolactone and citric acid were then extracted from the sample using 300 g of acetic acid at 65° C. for about 60 minutes. The product was then filtered from the liquid, slurried with 2 liters of deionized water, and the procedure repeated until washing yielded a neutral pH suspension. The water was removed as much as possible by filtration and then removed in an oven at 105°C. Differential scanning calorimetry (DSC) results for the product are shown in Table 1. The FTIR spectrum of the product is shown in Figure 2.

[0089] Example 2 500g of ε-caprolactone and 100g of catalytic citric acid are added to a 3L high consistency batch reactor and the mixing is set to about 40 RRM. The mixture is refluxed at 120°C for 30 minutes. The reactor is then cooled to 70°C and 100g of birch pulp dried in a hot and cold mixer is added to the reactor.

[0090] The temperature of the batch reactor is raised to 120° C. and the reaction begins. The reactor is held at this temperature for 3 hours and then worked up as follows.

[0091] The reactor is first cooled at 60°C, and after cooling, 120g of 20wt% NaOH is used to neutralize the citric acid catalyst. The non-immobilized polycaprolactone and citric acid are then extracted from the sample using 1.2kg of acetic acid at 65°C for approximately 60 minutes. The product is then filtered from the liquid, slurried with 2l of deionized water, and the procedure is repeated until a neutral pH suspension is obtained by washing. The water is removed as much as possible by filtration and then removed in a 40°C oven.

[0092] Example 3 40 g of alkaline doping (7.8 wt. % NaOH / 1.3 wt. % ZnO / 90.9 wt. % water) is carried out by using pretreated softwood kraft pulp (DP abt. 300) with a dry matter content of 5%.

[0093] 16 g of ε-caprolactone are added dropwise to the cellulose solution (in a 250 ml plastic beaker equipped with an overhead stirrer and a cooling bath) over a period of 20 minutes at a temperature of 0° C. The cooling bath is prepared for this purpose by making 2 L of a 5 wt % NaCl aqueous solution (freezing point −3° C.) and storing this solution in a freezer for at least 2 hours prior to the reaction to bring the temperature of the cooling solution to the desired level.

[0094] The mixture is stirred at room temperature for 6 hours. The reaction solution is then regenerated with 12% sulfuric acid to give a precipitated product. The contents are filtered, washed with water until pH neutral, and dried in an oven at 40°C.

[0095] Example 4 Caprolactone grafting was carried out by reacting caprolactone with birch pulp on a laboratory scale using different reactors and catalysts as shown in Table 2. The resulting thermoplastic compositions were found to have different degrees of substitution and different melting temperatures.

[0096] Table 2 shows the reaction parameters and properties of the resulting thermoplastic compositions. The compositions shown as "homogeneous reactions" were prepared as in Example 3.

[0097] The lactone grafted cellulose compositions were moldable by extrusion and injection molding, for example, they could be melt processed. [Table 1]

[0098] Example 5 - Biodegradability of lactone-grafted cellulose The lactone-grafted cellulose composition samples prepared as above with different degrees of substitution (Example 2 with DS of 1.72 and Example 1 with DS of 0.61) were tested for biodegradability using OECD Standard 301 F for the testing of chemicals (pressure gauge breath test). The references used were microcrystalline cellulose (MCC) and CH3COONa.

[0099] The results are shown in Figure 3. The lactone grafted cellulose composition samples were at least 60% biodegradable within 28 days.

[0100] It is obvious to those skilled in the art that with the advancement of technology, the basic concept can be implemented in various ways. Therefore, the embodiments are not limited to the above examples. Instead, the embodiments can vary within the scope of the claims.

[0101] The above-mentioned embodiments may be used in any combination with each other. Some of the embodiments may be combined to form further embodiments. The method, product or use disclosed herein may include at least one of the embodiments described herein above. It will be understood that the benefits and advantages described above may relate to one embodiment or to several embodiments. The embodiments are not limited to those that solve any or all of the problems described or those that have any or all of the benefits and advantages described. It will be further understood that a reference to "an" item refers to one or more of the items. The term "comprising" is used herein to mean including one or more of the preceding features or operations without excluding the presence of one or more additional features or operations.

Claims

1. 1. A method for preparing a thermoplastic composition comprising grafted cellulose and optionally grafted hemicellulose, comprising: providing a composition comprising cellulose and optionally hemicellulose; at least partially dissolving the cellulose and optionally the hemicellulose of the composition, thereby obtaining a solution comprising solubilized cellulose and optionally solubilized hemicellulose; adding a cyclic ester monomer to the solution, such that the cyclic ester monomer reacts with the solubilized cellulose and optionally the solubilized hemicellulose, thereby at least partially grafting the solubilized cellulose and optionally the solubilized hemicellulose with the cyclic ester monomer; coagulating said grafted cellulose and optionally said grafted hemicellulose, thereby obtaining said thermoplastic composition; A method comprising:

2. 10. The method of claim 1, wherein the thermoplastic composition is biodegradable as determined by OECD Standard 301 F for the testing of chemicals.

3. 2. The method of claim 1, wherein the cyclic ester monomer is a lactone such as ε-caprolactone, γ-valerolactone, δ-valerolactone, or any mixture or combination of lactones, or any mixture or combination thereof.

4. The cyclic ester monomer is represented by formula (I) or (II): 【Chemistry 1】 【Chemistry 2】 (In the formula, R １ and R ２ are each independently selected from the group consisting of H, methyl, ethyl, and propyl; R ３ and R ４ are each independently selected from the group consisting of H, methyl, ethyl, and propyl; A is selected from O and N; R ５ is selected from the group consisting of H, methyl, ethyl and propyl when A is N; R ５ is non-existent if A is O, m is an integer ranging from 1 to 5.

2. The method of claim 1, wherein the lactone is selected from lactones represented by

5. 2. The method of claim 1, wherein the composition comprising the cellulose and optionally the hemicellulose comprises or is a pulp, such as a chemical pulp.

6. The method of claim 1 , wherein the composition comprising the cellulose and optionally the hemicellulose is dissolved in an alkaline solution.

7. The alkaline solution may be NaOH, LiOH, KOH, Mg(OH) ２ , Ca(OH) ２ , N.H. ４ 7. The method of claim 6, further comprising an alkaline agent such as OH, and / or any mixture or combination thereof.

8. 10. The method of claim 1, wherein the cyclic ester monomer is reacted with the solubilized cellulose and optionally the solubilized hemicellulose in the presence of a basic catalyst.

9. 10. The method of claim 1, wherein the cyclic ester monomer is reacted with the solubilized hemicellulose and optionally the solubilized cellulose at a temperature in the range of about 0 to 100°C, or in the range of about 0 to 50°C.

10. 10. The method of claim 1, wherein the cyclic ester monomer is reacted with the solubilized cellulose and optionally the solubilized hemicellulose for at least 5 minutes, or at least 30 minutes, or at least 1 hour, or at least 5 hours, or about 1 to 5 hours, or about 1 to 3 hours.

11. 2. The method of claim 1, wherein the solution has a viscosity value in the range of 120 to 500 ml / g, or in the range of 150 to 300 ml / g, or in the range of 160 to 200 ml / g.

12. 2. The method of claim 1, wherein the grafted cellulose and optionally the grafted hemicellulose are solidified by extruding into fibers or a shape, such as filaments, beads, 3D objects or molded products, and solidifying.

13. The method of claim 1 further comprising pelletizing the thermoplastic composition or forming a powder of the thermoplastic composition.

14. A thermoplastic composition that is biodegradable and comprises cellulose and optionally hemicellulose grafted with a polyester such as a polylactone.

15. The thermoplastic composition of claim 14, obtainable by the method of claim 1.

16. 15. The method of claim 1, or the thermoplastic composition of claim 14, wherein the degree of substitution of the grafted hemicellulose and optionally the grafted cellulose in the thermoplastic composition is in the range of 0.1 to 3.0, or in the range of 0.1 to 2.0, or in the range of 0.5 to 1.

5.

17. The method of claim 1 or the thermoplastic composition of claim 14, wherein the melting temperature of the thermoplastic composition is in the range of 40 to 200°C.

18. A thermoplastic polymer material comprising or formed from the thermoplastic composition of claim 14, optionally further comprising a biocomposite and / or a plastic.

19. An article obtainable from or formed from the thermoplastic composition of claim 14 and / or the thermoplastic polymer material of claim 18.

20. 20. The article of claim 19, which is a pellet, powder, film, filament, melt, 3D shape, coating, hot melt adhesive, container, casing, packaging article, film label, paper, medical device, plastic or composite profile, and / or 3D printing filament.

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