Method for preparing a thermoplastic composition

Abstract

A method for preparing a thermoplastic composition comprising grafted cellulose and optionally grafted hemicellulose is disclosed. The method includes providing a composition comprising cellulose and optionally hemicellulose, dissolving the cellulose and optionally hemicellulose of the composition at least partially, thereby obtaining a solution comprising solubilized cellulose and optionally solubilized hemicellulose, extruding the cellulose and optionally hemicellulose into a shape, such as a filament, a bead, a 3D object, or a molded article, and treating the shape with cyclic ester monomer, such that the cyclic ester monomer reacts with the cellulose and optionally hemicellulose contained in the shape, thereby at least partially grafting the cellulose and optionally hemicellulose with the cyclic ester monomer, thereby obtaining a thermoplastic composition.

Description

[Technical field]

[0001] The present disclosure relates to a method for preparing a thermoplastic composition, the thermoplastic composition, and products obtainable from the composition. [Background technology]

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

[0003] Thermoplastic cellulose and hemicellulose derivatives that can be processed using conventional 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, extruding the cellulose and optionally hemicellulose into a shape, and treating the shape with a cyclic ester monomer, such that the cyclic ester monomer reacts with the cellulose and optionally hemicellulose contained in the shape, thereby at least partially grafting the cellulose and optionally hemicellulose with the cyclic ester monomer, 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 an embodiment of a method for preparing a thermoplastic composition. [Diagram 2] FIG. 2 shows Fourier transform infrared spectroscopy (FTIR) spectra of the cellulose starting material and the produced caprolactone-grafted cellulose. [Diagram 3] FIG. 1 shows the biodegradability of lactone grafted cellulose samples. Ref. = Reference, MCC = Microcrystalline Cellulose, 20-02831-009 = Grafted cellulose filaments prepared according to Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A method for preparing a thermoplastic composition is disclosed. The thermoplastic composition may include grafted cellulose and optionally grafted hemicellulose. The method 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; extruding the solubilized cellulose and optionally the solubilized hemicellulose into a shape; treating the shape with the cyclic ester monomer such that the cyclic ester monomer reacts with the cellulose and optionally hemicellulose contained in the shape, thereby at least partially grafting the cellulose and optionally hemicellulose with the cyclic ester monomer, thereby obtaining a thermoplastic composition; may include.

[0009] The reaction of cyclic ester monomer with cellulose and optionally hemicellulose contained in the form produces a form containing cellulose and optionally hemicellulose with cyclic ester monomer, oligomer and / or polymer grafted thereon. The cyclic ester bonds to the OH group of cellulose and optionally hemicellulose. 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.

[0010] Thus, the grafted cellulose and optionally grafted hemicellulose are the polymerization products of cellulose and optionally hemicellulose and cyclic ester monomers.

[0011] However, the cellulose and optionally hemicellulose may be at least partially grafted with the cyclic ester monomer, in the sense that at least a portion of the cellulose molecules and optionally hemicellulose molecules contained in the shape, the fibers and / or fiber bundles may be grafted. The resulting thermoplastic composition, i.e. the shape or the product obtainable from the shape, may be a hybrid type product, i.e. a composite.

[0012] 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 certain 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 standard ASTM 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. The polyesters may also have a role in the material properties, such as the melting temperature, of the thermoplastic composition.

[0013] An example of a grafting reaction with ε-caprolactone as the cyclic ester monomer (lactone) is shown in Scheme 1 below. [ka]

[0014] Scheme 1. Reaction mechanism of a) grafting of ε-caprolactone onto cellulose and b) acid-catalyzed ring-opening polymerization with ε-caprolactone in the modification of cellulose surface.

[0015] The resulting thermoplastic composition may be biodegradable.

[0016] In general, the biodegradation and biodegradability of a polymeric material or composition may depend on the environmental conditions and 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 at any given time. For example, in less aggressive conditions, biodegradation may require a significantly longer period of time.

[0017] The thermoplastic composition may be biodegradable as determined by Standard OECD 301 F for the Testing of Chemical Substances.

[0018] The term "biodegradable", at least in some embodiments, may refer to being readily biodegradable as determined by standard OECD 301 F for the testing of chemicals (pressure measurement respiration test). A readily biodegradable thermoplastic composition or thermoplastic polymer material may be a thermoplastic composition or thermoplastic polymer material that reaches at least 60% biodegradability within 28 days as determined by standard OECD 301 F for the testing of chemicals.

[0019] It may be possible to adjust and / or control how much cellulose and optionally hemicellulose are grafted.For example, when cellulose and optionally hemicellulose are mainly or only surface grafted (e.g., when hemicellulose and optionally cellulose-containing fiber bundles are mainly or only surface grafted), the resulting thermoplastic composition may be more economical to manufacture and / or more easily recyclable.When hemicellulose and optionally cellulose are essentially grafted throughout, the thermoplastic composition may be more difficult to recycle.

[0020] When primarily or only the surface of the shape is treated such that the cellulose and optionally hemicellulose present primarily or only on the surface of the shape is grafted, the resulting thermoplastic composition may be more economical to manufacture and / or more easily recyclable.

[0021] The extent to which the cellulose and optionally hemicellulose are grafted may also affect the barrier properties of the thermoplastic composition: if the cellulose and optionally hemicellulose are grafted essentially throughout, the thermoplastic composition may have better barrier properties than, for example, a thermoplastic composition in which the cellulose and optionally hemicellulose are primarily or only surface grafted.

[0022] 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 process steps can be minimized, atom economy can be maximized, and / or waste can be minimized.

[0023] 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.

[0024] The cyclic ester monomer may include or be a lactone or a mixture of one or more lactones.

[0025] The lactone may be represented by formula (I) and / or formula (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; If A is N, then R 5 is selected from the group consisting of H, methyl, ethyl, and propyl; when A is O, R 5 is non-existent, m is an integer ranging from 1 to 5. The lactone may be selected from lactones represented by

[0026] In one embodiment, in Formula I and / or Formula 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 R4 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; If A is N, then R 5 is selected from the group consisting of H, methyl, ethyl, and propyl; when A is O, R 5 is non-existent, m is an integer ranging from 1 to 5.

[0027] In one embodiment, in Formula I and / or Formula 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; If A is N, then R 5 is H, and if A is O, then R 5 is non-existent, m is an integer ranging from 1 to 5.

[0028] m can be 1, 2, 3, 4, or 5.

[0029] The cyclic ester monomer can be a lactone such as ε-caprolactone, γ-valerolactone, δ-valerolactone, or any mixture or combination of lactones, or any mixture or combination thereof.

[0030] The composition comprising cellulose and optionally hemicellulose may be a mixture of cellulose and hemicellulose. In other words, 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.

[0031] Such mixtures and compositions comprising cellulose and optionally hemicellulose may comprise or be a pulp, such as a chemical pulp.

[0032] A composition comprising cellulose and optionally hemicellulose, such as pulp, can be alkali soluble, such as an alkali soluble pulp.

[0033] 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.

[0034] 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.

[0035] Cellulose is a polysaccharide containing linear chains of several thousand to ten thousand linked D-glucose units.

[0036] 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 along with cellulose in almost all land plant cell walls. 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, but in conifers, mannose may be the most abundant sugar. Not only regular sugars can be found in hemicellulose, but also their acidified forms, such as glucuronic acid and galacturonic acid.

[0037] Cellulose can be present as cellulose fibers, macrofibrils and / or microfibrils.

[0038] The composition comprising cellulose and optionally hemicellulose can be dissolved in an alkaline solution. The alkaline solution can include an alkaline agent such as NaOH, LiOH, KOH, Mg(OH)2, Ca(OH)2, NH4OH, and / or any mixture or combination thereof. An additional organic hydroxide such as tetrabutylammonium hydroxide can also be included in the alkaline solution. The alkaline solution can be an aqueous alkaline solution.

[0039] The composition comprising cellulose and optionally hemicellulose and an alkaline solution can be mixed, for example, by feeding into a continuous reactor or a high consistency dissolution unit where partial or complete dissolution of the cellulose and optionally hemicellulose can be achieved.

[0040] The alkaline solution may be an alkaline aqueous 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 0-2.5% (w / w), or about 0-3% (w / w), or about 0.1-2.5% (w / w).

[0041] The concentration of solubilized cellulose and optionally hemicellulose in the solution may be, for example, about 1-12% (w / w).

[0042] The alkaline solution may be a cold alkaline solution. The temperature of the cold alkaline solution may be within the range of -5°C to 5°C, for example.

[0043] The consistency of the solubilized cellulose and optionally solubilized hemicellulose can be adjusted as desired, for example for extrusion. The consistency of the solubilized cellulose and optionally solubilized hemicellulose can be, for example, in the range of 5-12% by weight.

[0044] 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.

[0045] At least partially dissolving the cellulose and optionally hemicellulose of the composition may be accomplished using methods (and / or reagents) that are not sensitive to the presence of hemicellulose.

[0046] The solution containing solubilized cellulose and optionally solubilized hemicellulose may be considered to be a cellulose spinning solution (cellulose spinning dope), especially when the solution is an alkaline solution.

[0047] However, the chemistry used to dissolve the cellulose and optionally the hemicellulose is not particularly limited, so long as it is capable of solubilizing them and extruding them into shapes.

[0048] The solubilized cellulose and optionally the solubilized hemicellulose may be extruded, for example, through a die or nozzle.

[0049] When the solubilized cellulose and optionally solubilized hemicellulose are extruded into a shape, they may be considered to be coagulated and / or regenerated. The cellulose is not necessarily actually regenerated cellulose in the sense that it may have undergone a viscose process and subsequent regeneration. In this case, the terms "coagulated" and "regenerated" may refer to cellulose that has precipitated and / or crystallized from a solubilized state, and the cellulose may be at least partially crystallized into cellulose I, or at least partially crystallized into cellulose II, or partially crystallized into cellulose I and partially into cellulose II.

[0050] The shape can be, for example, a filament, a bead (pearl), a film, a 3D object, or a molded article. The shape is not particularly limited. Various shapes can be extruded or molded from the solubilized cellulose and optionally the solubilized hemicellulose.

[0051] The extruded shape, such as a filament or any other shape, may be washed after extrusion. For example, the method may include immersing the extruded shape in a washing bath. The washing bath may contain an acidic washing solution, such as a sulfuric acid solution, which may then aid in the coagulation of the cellulose contained in the shape. The extruded shape may be immersed in one or more washing baths. For example, after a washing bath containing an acidic washing solution, the extruded shape may be immersed in a second washing bath. Such a second washing bath could, for example, contain water or another neutral solution.

[0052] Grafting may then be carried out during or after the solidification process, for example immediately after the solidification process.

[0053] For example, the shape can be treated with the cyclic ester monomer by immersing the shape in a bath containing the cyclic ester monomer and allowing the cyclic ester monomer to react at elevated temperature with the cellulose and optionally hemicellulose contained in the shape. This can be done, for example, immediately after a wash bath. This can be done, for example, by transferring the shape from the bath to an oven, dryer, or other object or device capable of providing elevated temperature.

[0054] The cyclic ester monomers can be reacted with the cellulose and optionally hemicellulose contained in the form in the presence of a suitable catalyst.

[0055] The cyclic ester monomers can be reacted with the cellulose and optionally hemicellulose contained in the form in the presence of an acidic or basic catalyst.

[0056] 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.

[0057] The acid catalyst may include or be an organic acid such as citric acid, tartaric acid, acetic acid, and / or any mixture or combination thereof. The acid catalyst may include or be citric acid.

[0058] The cyclic ester monomer can be reacted with the cellulose and optionally hemicellulose contained in the form at a temperature within the range of about 50-200°C, or within the range of about 100-160°C, or within the range of about 110-140°C.

[0059] The cyclic ester monomer can be allowed to react with the cellulose and optionally hemicellulose contained in the form 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.

[0060] The thermoplastic composition may 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.

[0061] The thermoplastic composition may be in the form of a 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.

[0062] The method may further include pelletizing (i.e., forming pellets) and / or forming a powder of a shape comprising the grafted cellulose and optionally the grafted hemicellulose. 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.

[0063] A thermoplastic composition is also disclosed.

[0064] The thermoplastic composition may include 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 contain at least 10 ester groups. In an embodiment in which the cellulose and / or hemicellulose are grafted with a polylactone, the grafted polylactone chains may, for example, be formed from at least 10 lactone monomers.

[0065] Any 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.

[0066] The thermoplastic composition can be biodegradable.

[0067] The thermoplastic composition may be biodegradable as determined by Standard OECD 301 F for the Testing of Chemical Substances.

[0068] The thermoplastic composition can be in the form of shapes such as filaments, beads, 3D objects, or molded articles.

[0069] The cellulose and optionally hemicellulose on the surface of the shape may be grafted to a greater extent than the cellulose and optionally hemicellulose on the interior of the shape. Thus, the shape may be considered to be coated with grafted cellulose and optionally grafted hemicellulose. In other words, the degree of substitution of the grafted cellulose and optionally grafted hemicellulose may be higher on the surface of the shape than on the interior of the shape.

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

[0071] The degree of substitution of the grafted cellulose and optionally the grafted hemicellulose in the thermoplastic composition may be in the range of 0.01 to 2.5, 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 230° C. The melting temperature may be in the range of 40 to 130° C. or in the range of 40 to 110° C.

[0073] The lactone content of the thermoplastic composition may be in the range of 1 to 140, or in the range of 5 to 140, or in the range of 10 to 100 (% of pulp weight). In this context, the term "lactone content" may be understood to refer to the (relative) amount of units derived from lactone in the thermoplastic composition.

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

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

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

[0077] Also disclosed are thermoplastic polymeric materials comprising or formed from the thermoplastic compositions according to one or more embodiments described herein. The thermoplastic polymeric materials may optionally further comprise biocomposites and / or plastics.

[0078] Further disclosed are articles obtainable from or formed from the thermoplastic compositions according to one or more embodiments described herein and / or the thermoplastic polymeric materials according to one or more embodiments described herein.

[0079] The article can be, for example, a pellet, a powder, a film, a filament, a melt, a 3D shape, a coating, a hot melt adhesive, a container, a casing, a packaging article, a film label, paper, a medical device, a plastic or composite profile, and / or a 3D printing filament.

[0080] 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.

[0081] The thermoplastic polymeric materials and / or articles may be biodegradable. EXAMPLES

[0082] Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings.

[0083] The following description discloses some embodiments in detail so that those skilled in the art can utilize some embodiments based on the present disclosure. Not all steps or features of the embodiments are described in detail, and many of the steps or features will be apparent to those skilled in the art based on this specification.

[0084] For brevity, item numbers are maintained in the following exemplary embodiment where elements are repeated.

[0085] FIG. 1 shows an exemplary embodiment of the method. In this embodiment, the method is operated as a semi-continuous process. An alkali-soluble pulp 1 or other suitable composition containing cellulose and optionally hemicellulose is mixed with an alkali solution 2. The alkali solution dissolves the pulp, and the solubilized mixture is driven by a screw 3 operated by a motor 4 through a die 5. In the die 5, the mixture is extruded into filaments 6, although the mixture may alternatively be extruded into various other shapes or profiles, such as films. The wet filaments 6 can then be immersed in a washing bath 7, for example, containing a sulfuric acid solution. In the washing bath 7, the solubilized cellulose and hemicellulose from the pulp coagulate. The washed and coagulated filaments can then enter a monomer bath 8, which contains a cyclic ester monomer, for example any of the lactones described herein. Thus, the filaments exiting the monomer bath 8 are coated with the cyclic ester monomer. The filaments can then enter an oven 9 or other suitable device that can provide the appropriate conditions, such as temperature, for the grafting reaction. After the grafting reaction has taken place in the oven 9, the resulting dry thermoplastic composition, i.e., the filaments, can be processed, for example, by a pelletizer 10. The resulting pelletized thermoplastic material 11 can then be recovered. If desired, it can be ground, for example, to a powder, or otherwise further processed.

[0086] Example 1 140 g of ε-caprolactone and 24 g of citric acid as a catalyst were added to a Juccheim reactor with mixing set at 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 hot-cold mixer dried birch pulp was inserted into the reactor. The temperature of the batch reactor was raised to 120° C. and mixing was set to 11 Hz, after which the reaction started. The reactor was maintained 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 and slurried with 2 liters of deionized water, and the procedure was repeated until a neutral pH suspension was obtained by washing. Water was removed as much as possible by filtration and then in an oven at 105° C. Differential scanning calorimetry (DSC) results of the product are shown in Table 1. The FTIR spectrum of the product is shown in FIG.

[0087] Example 2 400 g of spin dope was prepared from hydrolyzed softwood kraft pulp with a dry matter content of 7% and a total alkalinity of 7.8%, which was then regenerated (coagulated) in a spin bath containing 12% sulfuric acid to obtain precipitated noodles.

[0088] 140 g of ε-caprolactone and 24 g of catalytic citric acid were added to a Juccheim reactor with mixing set at approximately 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 the precipitated noodles were inserted into the reactor. The temperature of the batch reactor was increased to 120° C. and mixing was set to 11 Hz, at which point the reaction began. The reactor was maintained at this temperature for 4 hours and then worked up as follows:

[0089] The reactor was first cooled at 40°C and after cooling, 30g of 20wt% NaOH was used to neutralize the citric acid catalyst. The non-immobilized polycaprolactone and citric acid were then extracted from the sample using 300g of acetic acid at 65°C for approximately 60 minutes. The product was then filtered from the liquid and slurried with 2l of deionized water, and the procedure repeated until a neutral pH suspension was obtained by washing. Water was removed as much as possible by filtration and then in an oven at 105°C.

[0090] The results of differential scanning calorimetry (DSC) of the products obtained in Examples 1 and 2 are shown in Table 1. [Table 1]

[0091] The FTIR spectrum of the product obtained in Example 1 is shown in FIG.

[0092] Example 3 500g of ε-caprolactone and 100g of catalytic citric acid are added to a 3L high consistency batch reactor with mixing set at approximately 40 RPM. The mixture is refluxed at 120°C for 30 minutes. The reactor is then cooled to 70°C and 100g of hot cold mixer dried birch pulp is inserted into the reactor.

[0093] The reaction begins when the temperature of the batch reactor is raised to 120° C. The reactor is maintained at this temperature for 3 hours and then worked up as follows.

[0094] 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 repeated until a neutral pH suspension is obtained by washing. Water is removed as much as possible by filtration and then in a 40°C oven.

[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. [Table 2]

[0096] The lactone grafted cellulose compositions were extrusion and injection moldable, for example, and could be melt processed.

[0097] Example 5 - Biodegradability of lactone-grafted cellulose The caprolactone grafted cellulose composition samples prepared as described above in Example 2 were tested for their biodegradability using standard OECD 301 F for testing of chemicals (pressure measurement respiration test). The references used were microcrystalline cellulose (MCC) and CH3COONa.

[0098] The results are shown in Figure 3. The lactone grafted cellulose composition samples were at least 60% biodegradable within 28 days.

[0099] 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.

[0100] 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 subsequent 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 the solubilized cellulose and optionally the solubilized hemicellulose; extruding the cellulose and optionally the hemicellulose into shapes such as filaments, beads, 3D objects, or molded articles; treating said shape with said cyclic ester monomer so that said cyclic ester monomer reacts with said cellulose and optionally said hemicellulose contained in said shape, thereby at least partially grafting said cellulose and optionally said hemicellulose with said cyclic ester monomer, 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 301 F standard 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 formula (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 When A is O, R ５ is non-existent, 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. 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. 10. The method of claim 1, wherein the cyclic ester monomer is reacted with the cellulose and optionally the hemicellulose contained in the form in the presence of an acidic or basic catalyst.

8. 10. The method of claim 1, wherein the cyclic ester monomer is reacted with the cellulose and optionally the hemicellulose contained in the form at a temperature in the range of about 50 to 200°C, or in the range of about 100 to 160°C, or in the range of about 110 to 140°C.

9. 10. The method of claim 1, wherein the cyclic ester monomer is reacted with the cellulose and optionally the hemicellulose contained in the shape 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.

10. 2. The method of claim 1, wherein the shape is treated with the cyclic ester monomer by immersing the shape in a bath containing the cyclic ester monomer and reacting the cyclic ester monomer with the cellulose and optionally the hemicellulose contained in the shape at an elevated temperature.

11. 10. The method of claim 1, further comprising pelletizing or forming a powder of said shape comprising said grafted cellulose and optionally said grafted hemicellulose.

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

13. 13. The thermoplastic composition of claim 12 in the form of a shape such as a filament, a bead, a 3D object, or a molded article.

14. The thermoplastic composition of claim 12, obtainable by the method of claim 1.

15. 13. The method of claim 1 or the thermoplastic composition of claim 12, wherein the degree of substitution of the grafted cellulose and optionally the grafted hemicellulose in the thermoplastic composition is in the range of 0.01 to 2.5, or in the range of 0.1 to 2.0, or in the range of 0.5 to 1.

5.

16. The method of claim 1 or the thermoplastic composition of claim 12, wherein the melting temperature of the thermoplastic composition is in the range of 40 to 230°C.

17. 13. The method of claim 1 or the thermoplastic composition of claim 12, wherein the lactone content of the thermoplastic composition is in the range of 1 to 140, or 5 to 140, or 10 to 100 (% of pulp weight).

18. A thermoplastic polymer material comprising or formed from the thermoplastic composition of claim 12, optionally further comprising a biocomposite and / or a plastic.

19. An article obtainable from or formed from the thermoplastic composition of claim 12 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.

Images