High-tenacity cellulose diacetate composite and method for producing the same
By introducing antioxidants and grafting mesoporous silica into cellulose diacetate, the problems of poor bridging and dispersibility of cellulose diacetate materials during processing are solved, improving the thermal stability and toughness of the material, making it suitable for eyeglass frames, packaging and 3D printing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIMEI (DONGGUAN) NEW MATERIAL CO LTD
- Filing Date
- 2026-03-11
- Publication Date
- 2026-05-29
AI Technical Summary
Existing cellulose diacetate materials suffer from problems such as bridging and poor dispersibility of additives during processing, resulting in low production efficiency and unstable material properties. Furthermore, their high brittleness and insufficient toughness limit their application range.
A high-toughness composite material was formed by grafting antioxidants onto mesoporous silica and cellulose diacetate, and by grafting antioxidants onto the surface of mesoporous silica through sol-gel preparation and self-assembly reaction, combined with plasticizers, and then mixing and extruding granulation.
It achieves uniform dispersion of additives, improves the thermal stability and toughness of materials, reduces the risk of yellowing during processing, enhances powder flowability and processing stability, and is suitable for industrial production.
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Figure CN122103700A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials technology, specifically to a high-toughness cellulose diacetate composite material and its preparation method. Background Technology
[0002] Cellulose diacetate is a cellulose derivative, also known as cellulose acetate. It is a thermoplastic resin obtained by esterification of cellulose with acetic acid or anhydride under the action of a catalyst. Based on the degree of substitution of the acetyl group for the hydroxyl group, cellulose acetate is classified into cellulose monoacetate (CMA), cellulose diacetate (CDA), and cellulose triacetate (CTA). Among them, cellulose diacetate has the characteristics of lower esterification degree and good dyeing properties, and has been widely used in plastics, coatings, textiles and clothing, cigarette filters, and other fields.
[0003] Processing technology is crucial for cellulose diacetate, especially the mixing process, which directly affects the material's properties. Traditional mixing involves adding cellulose diacetate powder and plasticizer to a mixing hopper. This process leads to problems such as powder adhering to the mixing equipment and bridging in the hopper, causing feeding difficulties and significantly reducing production efficiency. After curing, antioxidants are added, but poor antioxidant dispersibility causes unstable yellowness values, making it unsuitable for modern industrial production and limiting its potential applications. Furthermore, the inherent brittleness and lack of toughness of cellulose diacetate make it prone to cracking and breakage during use. Therefore, adding fillers and additives can improve processing performance and enhance material properties.
[0004] For example, Chinese patent CN105218866A discloses a cellulose diacetate material that uses camphor and epoxy resin to improve the toughness of the cellulose diacetate material. Camphor and epoxy resin have high viscosity and poor dispersibility in cellulose diacetate powder. Furthermore, the use of large doses of camphor will cause harm to the environment and threaten human health. In addition, the addition of epoxy resin will reduce the degradation performance of cellulose diacetate. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a high-toughness cellulose diacetate composite material and its preparation method. Addressing the processing and material performance problems caused by poor bridging of raw materials and poor dispersibility of additives in cellulose diacetate, this invention relies on introducing antioxidants to graft mesoporous silica to modify the material, thereby solving the problems mentioned in the background art.
[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-toughness cellulose diacetate composite material, comprising the following parts by weight: Cellulose diacetate, 45–84.9 parts; Plasticizer, 0.1–3 parts; Antioxidant grafted mesoporous silica, 15–50 parts; The plasticizer is a phthalic acid plasticizer or an environmentally friendly non-phthalic acid ester plasticizer.
[0007] To further optimize this technical solution, the cellulose diacetate is prepared from wood pulp or cotton pulp as raw material, and the bound acid of the cellulose diacetate is 52.0%–56.0%.
[0008] To further optimize this technical solution, when the plasticizer is a phthalic acid plasticizer, the phthalic acid plasticizer is one or more of diethyl phthalate, dioctyl phthalate, or dibutyl phthalate.
[0009] To further optimize this technical solution, when the plasticizer is an environmentally friendly non-phthalate plasticizer, the environmentally friendly non-phthalate plasticizer is one or more of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, cyclohexane-1,2-dicarboxylic acid diisononyl ester, glycerol ester or citrate derivative.
[0010] To further optimize this technical solution, the antioxidant grafted onto the mesoporous silica is a hindered phenolic antioxidant and a phosphite antioxidant.
[0011] A method for preparing a high-toughness cellulose diacetate composite material, based on the above-mentioned cellulose diacetate composite material, includes the following specific preparation steps: S1. Prepare mesoporous silica sol-gel; S2. Antioxidants are grafted onto the surface of mesoporous silica via a self-assembly reaction; S3. Pre-dry cellulose diacetate; S4. Perform premixing and curing treatment of plasticizers; S5. Add antioxidants and graft mesoporous silica; S6. Twin-screw extrusion granulation and drying yield cellulose diacetate composite material.
[0012] To further optimize this technical solution, in step S1, the preparation includes: Hexadecyltrimethylammonium bromide was dissolved in deionized water and stirred continuously at 30°C; then ethanol and alkaline catalyst were added and kept under stirring for 10 min. Add tetraethyl orthosilicate, then pour the reaction mixture into deionized water and keep it magnetically stirred. After dilution, hydrochloric acid solution was added dropwise to neutralize the system, resulting in a mesoporous silica suspension. After high-speed centrifugation and filtration, the solid was placed in a muffle furnace at 550–600℃ to calcine and remove the template agent, yielding mesoporous silica powder.
[0013] To further optimize this technical solution, in step S2, the mesoporous silica powder obtained in step S1 is added to a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed to obtain a mesoporous silica-zinc solution. A hindered phenolic antioxidant and a phosphite antioxidant, along with a 50% zinc sulfate aqueous solution, were separately prepared and ultrasonically dispersed. Then, they were added dropwise to the mesoporous silica-zinc solution and stirred for 24 hours. Subsequently, the mixture was centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain antioxidant-grafted mesoporous silica.
[0014] To further optimize this technical solution, when the cellulose diacetate is a rubber powder, in the order of steps S4 and S5, the cellulose diacetate is first mixed with the plasticizer and cured, and then the antioxidant grafted mesoporous silica is added and mixed evenly.
[0015] To further optimize this technical solution, when the cellulose diacetate is in the form of granules, steps S4 and S5 are adjusted so that cellulose diacetate, plasticizer, and antioxidant grafted mesoporous silica are directly mixed and then subjected to aging treatment.
[0016] Compared with the prior art, the present invention provides a high-toughness cellulose diacetate composite material and its preparation method, which has the following beneficial effects: This high-toughness cellulose diacetate composite material and its preparation method involve a one-step process of mixing antioxidant-grafted mesoporous silica with raw materials and plasticizers, followed by extrusion to obtain granules, facilitating industrial production. Furthermore, the preparation process is simple, the required materials are environmentally friendly, and easily meet the requirements of industrial production. Moreover, this invention can effectively improve the antioxidant effect of cellulose diacetate materials while ensuring the dispersion and compatibility of additives, without affecting other excellent properties. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic flowchart of a method for preparing a high-toughness cellulose diacetate composite material proposed in this invention. Detailed Implementation
[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0020] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0021] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.
[0022] A high-toughness cellulose diacetate composite material, comprising the following parts by weight: Cellulose diacetate, 45–84.9 parts; plasticizer, 0.1–3 parts; antioxidant grafted mesoporous silica, 15–50 parts.
[0023] Antioxidant-grafted mesoporous silica exhibits good compatibility with cellulose diacetate. The antioxidant-grafted mesoporous silica is uniformly dispersed in the matrix, acting as a dispersant and flow-resistant anti-caking agent, preventing the cellulose diacetate powder from agglomerating and maintaining its loose or free-flowing state, thus improving feedability. The antioxidants and mesoporous structure in the antioxidant-grafted mesoporous silica contribute to the strong thermal stability of cellulose diacetate. The mesoporous surface of the antioxidant-grafted mesoporous silica provides numerous interfacial interaction points, which is beneficial for improving the material's impact strength. The cellulose diacetate composite material made from antioxidant-grafted mesoporous silica possesses good thermal stability and high toughness. This material can be used in eyeglass frames, packaging, and 3D printing as eyeglass frame materials, packaging materials, and 3D printing consumables.
[0024] The plasticizer is a phthalic acid plasticizer or an environmentally friendly non-phthalic acid ester plasticizer.
[0025] The cellulose diacetate is prepared from wood pulp or cotton pulp as raw material, and the bound acid of the cellulose diacetate is 52.0%–56.0%.
[0026] When the plasticizer is a phthalic acid plasticizer, the phthalic acid plasticizer is one or more of diethyl phthalate, dioctyl phthalate, or dibutyl phthalate.
[0027] When the plasticizer is an environmentally friendly non-phthalate plasticizer, the environmentally friendly non-phthalate plasticizer is one or more of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, cyclohexane-1,2-dicarboxylic acid diisononyl ester, glycerol ester or citrate derivative.
[0028] The antioxidants grafted onto the mesoporous silica are hindered phenolic antioxidants and phosphite antioxidants.
[0029] Reference Figure 1 A method for preparing a high-toughness cellulose diacetate composite material, based on the above-mentioned cellulose diacetate composite material, includes the following specific preparation steps: S1. Prepare mesoporous silica sol-gel.
[0030] Specifically, 10g of hexadecyltrimethylammonium bromide was dissolved in 200ml of deionized water and stirred continuously at 30°C. Then, 20ml of ethanol and 40ml of alkaline catalyst were added, and the mixture was stirred for 10min. 20ml of tetraethyl orthosilicate was added, and after 50s, the reaction mixture was poured into 600ml of deionized water while maintaining magnetic stirring. After dilution, 2mol / L hydrochloric acid solution was added dropwise to neutralize the system for 180s until the pH value decreased from 11 to 9.5, yielding a mesoporous silica suspension. After high-speed centrifugation and filtration, the solid was calcined in a muffle furnace at 550–600°C for 6h to remove the template agent, yielding mesoporous silica powder.
[0031] S2. Antioxidants are grafted onto the surface of mesoporous silica via a self-assembly reaction.
[0032] The mesoporous silica powder obtained in step S1 was added to a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed to obtain a mesoporous silica-zinc solution. A hindered phenolic antioxidant and a phosphite antioxidant (i.e., primary and secondary antioxidants) and a 50% zinc sulfate aqueous solution were separately prepared and ultrasonically dispersed evenly. These were then added dropwise to the mesoporous silica-zinc solution and stirred for 24 hours. Subsequently, the mixture was centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain antioxidant-grafted mesoporous silica (i.e., stabilizer).
[0033] S3. Pre-dry cellulose diacetate.
[0034] The cellulose diacetate powder was dried at 80°C for 12 hours.
[0035] S4. Perform premixing and curing treatment of plasticizers.
[0036] Mix cellulose diacetate and plasticizer according to the formula ratio and allow to stand for curing; curing time is 12–36 hours.
[0037] S5. Add antioxidants and graft mesoporous silica.
[0038] After the curing process is complete, the antioxidant grafted mesoporous silica obtained in steps S1 and S2 is added and stirred to obtain a mixture of adhesive powders.
[0039] S6. Twin-screw extrusion granulation and drying yield cellulose diacetate composite material.
[0040] The above-mentioned rubber powder mixture is fed into the hopper of a twin-screw extruder, extruded and granulated within a temperature range of 150℃–240℃, and then dried to obtain composite material granules. The temperature zones are set as follows: 150–160℃, 160–170℃, 170–180℃, 180–190℃, 190–200℃, 200–210℃, 210–220℃, 220–230℃, and 230–240℃, with a die head temperature of 235–240℃.
[0041] When the cellulose diacetate is in the form of a gel powder, in the order of steps S4 and S5, the cellulose diacetate and plasticizer are first mixed and cured, and then the antioxidant grafted mesoporous silica is added and mixed evenly.
[0042] When the cellulose diacetate is in the form of granules, steps S4 and S5 are adjusted so that cellulose diacetate, plasticizer, and antioxidant grafted mesoporous silica are directly mixed and then subjected to aging treatment.
[0043] Mesoporous silica, with its adjustable pore size and high specific surface area, is an excellent carrier for additives. By grafting hindered phenolic antioxidants and phosphite antioxidants onto mesoporous silica, the activity and stability of the antioxidants can be improved, resulting in a more efficient antioxidant effect. This reduces the initial yellowing of cellulose diacetate and minimizes changes in yellowing after repeated high-temperature processing. Regarding dispersion compatibility, mesoporous silica exhibits good flowability and easy dispersibility, reducing powder agglomeration and facilitating dispersion in cellulose diacetate powder, preventing bridging in the hopper and hindering transport. Furthermore, its abundant hydroxyl functional groups on its surface allow it to interact with the hydroxyl functional groups on the cellulose diacetate molecular chains, enhancing its compatibility.
[0044] Meanwhile, a method for preparing antioxidant-grafted mesoporous silica in the preparation method of high-toughness cellulose diacetate materials is provided. The other methods are completely consistent, as detailed in the following examples: Example 1: 10 g of hexadecyltrimethylammonium bromide was dissolved in 200 ml of deionized water and stirred continuously at 30 °C. Then, 200 ml of ethanol and 40 ml of alkaline catalyst were added, and the mixture was stirred for 10 minutes. Next, 20 ml of tetraethyl orthosilicate was added, and after 50 seconds, the mixture was poured into 600 ml of deionized water and magnetically stirred. After dilution, 2 mol / L HCl solution was added dropwise to neutralize the system for 180 seconds until the pH value decreased from 11 to 9.5, yielding a mesoporous silica suspension. After high-speed centrifugation and filtration, the suspension was calcined in a muffle furnace at 550-600 °C for 6 hours to remove the template agent, yielding mesoporous silica powder.
[0045] Mesoporous silica powder was poured into a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed for 2 hours to obtain a mesoporous silica-zinc solution. Separately, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris(2,4-di-tert-butyl)phosphite, and a 50% zinc sulfate aqueous solution were prepared, ultrasonically dispersed evenly, and then added dropwise to the above mesoporous silica solution. The mixture was stirred for 24 hours, centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain an antioxidant-grafted mesoporous silica stabilizer.
[0046] Cellulose diacetate powder is dried at 80℃ for 12 hours. Then, cellulose diacetate powder and plasticizer are mixed in a specific ratio and allowed to stand for 12-36 hours. Antioxidant-grafted mesoporous silica is then added and stirred until homogeneous, resulting in a powder mixture. Finally, the mixture is extruded through a twin-screw extruder at 150℃-240℃ and dried to obtain granules. The temperatures of each zone of the twin-screw extruder are set to 150-160℃, 160-170℃, 170-180℃, 180-190℃, 190-200℃, 200-210℃, 210-220℃, 220-230℃, and 230-240℃, with the die head temperature at 235-240℃.
[0047] Example 2: 10 g of hexadecyltrimethylammonium bromide was dissolved in 200 ml of deionized water and stirred continuously at 30 °C. Then, 200 ml of ethanol and 40 ml of alkaline catalyst were added, and the mixture was stirred for 10 minutes. Next, 20 ml of tetraethyl orthosilicate was added, and after 50 seconds, the mixture was poured into 600 ml of deionized water and magnetically stirred. After dilution, 2 mol / L HCl solution was added dropwise to neutralize the system for 180 seconds until the pH value decreased from 11 to 9.5, yielding a mesoporous silica suspension. After high-speed centrifugation and filtration, the suspension was calcined in a muffle furnace at 550-600 °C for 6 hours to remove the template agent, yielding mesoporous silica powder.
[0048] Mesoporous silica powder was poured into a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed for 2 hours to obtain a mesoporous silica-zinc solution. Separately, pentaerythritol tetra(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), tris(2,4-di-tert-butyl)phosphite phenyl ester, and a 50% zinc sulfate aqueous solution were prepared, ultrasonically dispersed evenly, and then added dropwise to the above mesoporous silica solution. The mixture was stirred for 24 hours, centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain an antioxidant-grafted mesoporous silica stabilizer.
[0049] Cellulose diacetate powder is dried at 80℃ for 12 hours. Then, cellulose diacetate powder and plasticizer are mixed in a specific ratio and allowed to stand for 12-36 hours. Antioxidant-grafted mesoporous silica is then added and stirred until homogeneous, resulting in a powder mixture. Finally, the mixture is extruded through a twin-screw extruder at 150℃-240℃ and dried to obtain granules. The temperatures of each zone of the twin-screw extruder are set to 150-160℃, 160-170℃, 170-180℃, 180-190℃, 190-200℃, 200-210℃, 210-220℃, 220-230℃, and 230-240℃, with the die head temperature at 235-240℃.
[0050] Example 3: 10 g of hexadecyltrimethylammonium bromide was dissolved in 200 ml of deionized water and stirred continuously at 30 °C. Then, 200 ml of ethanol and 40 ml of alkaline catalyst were added, and the mixture was stirred for 10 minutes. Next, 20 ml of tetraethyl orthosilicate was added, and after 50 seconds, the mixture was poured into 600 ml of deionized water and magnetically stirred. After dilution, 2 mol / L HCl solution was added dropwise to neutralize the system for 180 seconds until the pH value decreased from 11 to 9.5, yielding a mesoporous silica suspension. After high-speed centrifugation and filtration, the suspension was calcined in a muffle furnace at 550-600 °C for 6 hours to remove the template agent, yielding mesoporous silica powder.
[0051] Mesoporous silica powder was poured into a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed for 2 hours to obtain a mesoporous silica-zinc solution. Separately, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol diphosphite bis(2,4-di-tert-butylphenol) and a 50% zinc sulfate aqueous solution were prepared, ultrasonically dispersed evenly, and then added dropwise to the above mesoporous silica solution. The mixture was stirred for 24 hours, centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain an antioxidant-grafted mesoporous silica stabilizer.
[0052] Cellulose diacetate powder is dried at 80℃ for 12 hours. Then, cellulose diacetate powder and plasticizer are mixed in a specific ratio and allowed to stand for 12-36 hours. Antioxidant-grafted mesoporous silica is then added and stirred until homogeneous, resulting in a powder mixture. Finally, the mixture is extruded through a twin-screw extruder at 150℃-240℃ and dried to obtain granules. The temperatures of each zone of the twin-screw extruder are set to 150-160℃, 160-170℃, 170-180℃, 180-190℃, 190-200℃, 200-210℃, 210-220℃, 220-230℃, and 230-240℃, with the die head temperature at 235-240℃.
[0053] Example 4: 10 g of hexadecyltrimethylammonium bromide was dissolved in 200 ml of deionized water and stirred continuously at 30 °C. Then, 200 ml of ethanol and 40 ml of alkaline catalyst were added, and the mixture was stirred for 10 minutes. Next, 20 ml of tetraethyl orthosilicate was added, and after 50 seconds, the mixture was poured into 600 ml of deionized water and magnetically stirred. After dilution, 2 mol / L HCl solution was added dropwise to neutralize the system for 180 seconds until the pH value decreased from 11 to 9.5, yielding a mesoporous silica suspension. After high-speed centrifugation and filtration, the suspension was calcined in a muffle furnace at 550-600 °C for 6 hours to remove the template agent, yielding mesoporous silica powder.
[0054] Mesoporous silica powder was poured into a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed for 2 hours to obtain a mesoporous silica-zinc solution. Separately, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, and a 50% zinc sulfate aqueous solution were prepared, ultrasonically dispersed evenly, and then added dropwise to the above mesoporous silica solution. The mixture was stirred for 24 hours, centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain an antioxidant-grafted mesoporous silica stabilizer.
[0055] Cellulose diacetate powder is dried at 80℃ for 12 hours. Then, cellulose diacetate powder and plasticizer are mixed in a specific ratio and allowed to stand for 12-36 hours. Antioxidant-grafted mesoporous silica is then added and stirred until homogeneous, resulting in a powder mixture. Finally, the mixture is extruded through a twin-screw extruder at 150℃-240℃ and dried to obtain granules. The temperatures of each zone of the twin-screw extruder are set to 150-160℃, 160-170℃, 170-180℃, 180-190℃, 190-200℃, 200-210℃, 210-220℃, 220-230℃, and 230-240℃, with the die head temperature at 235-240℃.
[0056] Example 5: Cellulose diacetate powder is dried at 80℃ for 12 hours. Then, cellulose diacetate powder and plasticizer are mixed in a specific ratio and allowed to stand for 12-36 hours. Next, antioxidants pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and bis(2,4-dicumylphenyl)pentaerythritol diphosphite are added and stirred until homogeneous to obtain a powder mixture. Finally, the mixture is extruded through a twin-screw extruder at 150℃-240℃ and dried to obtain granules. The temperatures of each zone of the twin-screw extruder are set to 150-160℃, 160-170℃, 170-180℃, 180-190℃, 190-200℃, 200-210℃, 210-220℃, 220-230℃, and 230-240℃, with the die head temperature at 235-240℃.
[0057] Example 6: 15g of hexadecyltrimethylammonium bromide was dissolved in 200ml of deionized water and stirred continuously at 30℃. Then, 200ml of ethanol and 40ml of alkaline catalyst were added, and the mixture was stirred for 10 minutes. Next, 20ml of tetraethyl orthosilicate was added, and after 50s, the mixture was poured into 600ml of deionized water and magnetically stirred. After dilution, 2mol / L HCl solution was added dropwise to neutralize the system for 180s until the pH value decreased from 11 to 9.5, yielding a mesoporous silica suspension. After high-speed centrifugation and filtration, the suspension was calcined in a muffle furnace at 550-600℃ for 6 hours to remove the template agent, yielding mesoporous silica powder.
[0058] Mesoporous silica powder was poured into a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed for 2 hours to obtain a mesoporous silica-zinc solution. Separately, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], pentaerythritol distearate diphosphite, and a 50% zinc sulfate aqueous solution were prepared, ultrasonically dispersed evenly, and then added dropwise to the above mesoporous silica solution. The mixture was stirred for 24 hours, centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain an antioxidant-grafted mesoporous silica stabilizer.
[0059] Cellulose diacetate powder is dried at 80℃ for 12 hours. Then, cellulose diacetate powder and plasticizer are mixed in a specific ratio and allowed to stand for 12-36 hours. Antioxidant-grafted mesoporous silica is then added and stirred until homogeneous, resulting in a powder mixture. Finally, the mixture is extruded through a twin-screw extruder at 150℃-240℃ and dried to obtain granules. The temperatures of each zone of the twin-screw extruder are set to 150-160℃, 160-170℃, 170-180℃, 180-190℃, 190-200℃, 200-210℃, 210-220℃, 220-230℃, and 230-240℃, with the die head temperature at 235-240℃.
[0060] Based on Examples 1-6, the performance parameters of cellulose diacetate are shown in Table 1.
[0061] Table 1. Performance parameters of stabilizers prepared with different types of antioxidants and the cellulose diacetate to which they are added. Examples 1 to 4 represent typical implementation paths of the core technical solution of this invention. All four examples employ a sol-gel method to prepare mesoporous silica, and further graft hindered phenolic antioxidants and phosphite antioxidants onto the surface of the mesoporous silica via a self-assembly reaction to form an antioxidant-grafted mesoporous silica stabilizer. Subsequently, cellulose diacetate powder is dried, mixed with a plasticizer, and cured. The stabilizer is then added for further compounding, and finally, high-toughness composite granules are obtained through twin-screw extrusion granulation. The differences between the above examples mainly lie in the different combinations of antioxidant systems: Example 1 uses a pentaerythritol ester-type hindered phenolic antioxidant and tris(2,4-di-tert-butyl)phosphite synergistic system; Example 2 uses a different pentaerythritol-structured hindered phenolic antioxidant; Example 3 uses a pentaerythritol diphosphite structure in the phosphite antioxidant; and Example 4 further adjusts the substituent structure of the phosphite antioxidant. This type of differentiated antioxidant system design allows us to verify the influence of different antioxidant structures on the dispersion performance and resistance to thermo-oxidative aging of stabilizers. Overall results show that grafted mesoporous silica, when uniformly dispersed in the matrix, significantly improves the thermal stability and impact toughness of cellulose diacetate, while reducing the risk of yellowing during processing and improving powder flowability and processing stability.
[0062] Example 5 is a comparative verification scheme for the necessity of the stabilizer structure. This example does not use an antioxidant-grafted mesoporous silica stabilizer; instead, it directly adds a hindered phenolic antioxidant and a phosphite antioxidant to the cellulose diacetate system in a conventional manner for mixing and granulation. While this scheme can improve the material's antioxidant properties to some extent, the lack of an effective carrier structure for the antioxidant in the matrix significantly reduces its dispersibility and stability, easily leading to additive agglomeration and uneven processing. Furthermore, it fails to utilize the interfacial bonding and stress transfer functions provided by the mesoporous structure, resulting in lower toughness, thermal stability, and long-term processing stability compared to the composite structure systems formed in Examples 1-4. This example serves to demonstrate that the antioxidant-grafted mesoporous silica stabilizer is a key technical feature of this invention.
[0063] Example 6 pertains to the verification scheme for adjusting the structural parameters of the stabilizer. In this example, the amount of the template agent, hexadecyltrimethylammonium bromide, is increased during the stabilizer preparation stage, thereby altering the pore structure parameters of the mesoporous silica. Simultaneously, phosphite antioxidants with different structures are selected for graft modification. This example verifies the influence of mesoporous structure regulation on the performance of the stabilizer carrier and the stability of the antioxidant system. Experimental results show that appropriately adjusting the template agent content can regulate the pore size distribution and specific surface area of the mesoporous silica, thereby affecting the antioxidant loading efficiency and interfacial compatibility, further improving the thermal stability and mechanical toughness of the composite material. This demonstrates that the stabilizer structure of this invention has controllability and potential for expanded applications.
[0064] Based on Examples 1-6, the following technical conclusions can be drawn: First, the antioxidant-grafted mesoporous silica stabilizer plays multiple roles in the composite system, acting as an additive carrier, dispersant, and structural reinforcing phase, significantly improving the poor dispersibility and easy migration problems of traditional antioxidant systems. Second, the mesoporous structure of the stabilizer provides high specific surface area and interfacial binding sites, improving the antioxidant activity and thermal stability, while also enhancing the material's impact toughness. Third, by changing the type of antioxidant or adjusting the mesoporous structure parameters, the material properties can be controllably adjusted. Finally, compared with the comparative scheme without grafted stabilizer, the composite material of the present invention shows significant advantages in processing stability, thermal stability, and mechanical toughness, verifying the effectiveness and advancement of the technical route of the present invention.
[0065] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A high-toughness cellulose diacetate composite material, characterized in that, The formula includes the following mass fractions: Cellulose diacetate, 45–84.9 parts; Plasticizer, 0.1–3 parts; Antioxidant grafted mesoporous silica, 15–50 parts; The plasticizer is a phthalic acid plasticizer or an environmentally friendly non-phthalic acid ester plasticizer.
2. The high-toughness cellulose diacetate composite material according to claim 1, characterized in that, The cellulose diacetate is prepared from wood pulp or cotton pulp as raw material, and the bound acid of the cellulose diacetate is 52.0%–56.0%.
3. The high-toughness cellulose diacetate composite material according to claim 1, characterized in that, When the plasticizer is a phthalic acid plasticizer, the phthalic acid plasticizer is one or more of diethyl phthalate, dioctyl phthalate, or dibutyl phthalate.
4. The high-toughness cellulose diacetate composite material according to claim 1, characterized in that, When the plasticizer is an environmentally friendly non-phthalate plasticizer, the environmentally friendly non-phthalate plasticizer is one or more of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, cyclohexane-1,2-dicarboxylic acid diisononyl ester, glycerol ester or citrate derivative.
5. The high-toughness cellulose diacetate composite material according to claim 1, characterized in that, The antioxidants grafted onto the mesoporous silica are hindered phenolic antioxidants and phosphite antioxidants.
6. A method for preparing a high-toughness cellulose diacetate composite material, comprising preparing the cellulose diacetate composite material according to any one of claims 1-5, characterized in that, The specific preparation steps include the following: S1. Prepare mesoporous silica sol-gel; S2. Antioxidants are grafted onto the surface of mesoporous silica via a self-assembly reaction; S3. Pre-dry cellulose diacetate; S4. Perform premixing and curing treatment of plasticizers; S5. Add antioxidants and graft mesoporous silica; S6. Twin-screw extrusion granulation and drying yield cellulose diacetate composite material.
7. The method for preparing a high-toughness cellulose diacetate composite material according to claim 6, characterized in that, In step S1, the preparation includes: Hexadecyltrimethylammonium bromide was dissolved in deionized water and stirred continuously at 30°C; then ethanol and alkaline catalyst were added and kept under stirring for 10 min. Add tetraethyl orthosilicate, then pour the reaction mixture into deionized water and keep it magnetically stirred. After dilution, hydrochloric acid solution was added dropwise to neutralize the system, resulting in a mesoporous silica suspension. After high-speed centrifugation and filtration, the solid was placed in a muffle furnace at 550–600℃ to calcine and remove the template agent, yielding mesoporous silica powder.
8. The method for preparing a high-toughness cellulose diacetate composite material according to claim 6, characterized in that, In step S2, the mesoporous silica powder obtained in step S1 is added to a 0.3% zinc sulfate aqueous solution and ultrasonically dispersed to obtain a mesoporous silica-zinc solution. A hindered phenolic antioxidant and a phosphite antioxidant, along with a 50% zinc sulfate aqueous solution, were separately prepared and ultrasonically dispersed. Then, they were added dropwise to the mesoporous silica-zinc solution and stirred for 24 hours. Subsequently, the mixture was centrifuged, washed several times with deionized water, and vacuum dried at 80°C for 48 hours to obtain antioxidant-grafted mesoporous silica.
9. The method for preparing a high-toughness cellulose diacetate composite material according to claim 6, characterized in that, When the cellulose diacetate is in the form of a gel powder, in the order of steps S4 and S5, the cellulose diacetate and plasticizer are first mixed and cured, and then the antioxidant grafted mesoporous silica is added and mixed evenly.
10. The method for preparing a high-toughness cellulose diacetate composite material according to claim 6, characterized in that, When the cellulose diacetate is in the form of granules, steps S4 and S5 are adjusted so that cellulose diacetate, plasticizer, and antioxidant grafted mesoporous silica are directly mixed and then subjected to aging treatment.