Preparation method of high-filling polymer composite material
By using dynamic network design and nano-inorganic particle modification technology, the problems of poor flowability and high cost of PCL-based composite materials have been solved, achieving high strength, easy processing and recyclability of highly filled polymer composite materials, thus expanding their application range.
Patent Information
- Application Number
- CN202511885201.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-02-13
AI Technical Summary
PCL-based composite materials suffer from poor flowability after the addition of high-concentration fillers, leading to processing difficulties and high costs, which limits their industrialization process. At the same time, traditional cross-linked polymers are difficult to recycle.
By employing dynamic network design technology and nano-inorganic particle-modified polymer technology, a dynamic reversible network is constructed by chemically grafted modified nano-inorganic particles and branched polymers undergoing a DA reaction, thereby forming a highly filled polymer composite material.
It significantly improves the mechanical properties and processability of composite materials, enhances the tensile strength and elastic modulus of the materials, and the materials exhibit thermal reversibility under different temperature environments, making them easy to recycle.
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Figure CN121517892A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials technology, and in particular to a method for preparing a highly filled polymer composite material. Background Technology
[0002] Against the backdrop of increasingly severe global environmental problems, the massive accumulation of plastic waste has become a serious ecological threat. Traditional plastics are difficult to degrade naturally and are also difficult to recycle, resulting in numerous negative impacts on ecosystem balance, biodiversity, and human health. With increasing environmental awareness and increasingly stringent environmental regulations, finding alternatives to traditional plastics has become an urgent priority.
[0003] Among numerous fields of materials research, biodegradable polymer composites have emerged. PCL-based composites, in particular, have demonstrated enormous application potential due to their unique degradability and biocompatibility. In the medical field, their biocompatibility helps avoid immune rejection in the human body, thus enabling their widespread application in drug delivery carriers and tissue engineering scaffolds. In the packaging industry, their degradability makes them an ideal choice for disposable packaging materials, gradually decomposing under natural conditions or composting, reducing waste accumulation.
[0004] However, in practical applications, PCL-based composites face the dual challenges of cost and processability. From a cost perspective, the high price of raw materials and the complexity of the production process contribute to their high cost, raising concerns about their economic feasibility for large-scale application. Regarding processing, while the addition of high-concentration fillers can help reduce costs to some extent, it introduces challenges related to material flowability. This is because high-concentration fillers increase internal friction and steric hindrance, hindering the movement of polymer molecular chains and making it difficult to form the material smoothly during traditional melt processing, severely limiting its industrialization process.
[0005] Previous studies have shown that the rheological behavior of highly filled polymers is influenced by a variety of factors, including the filler volume fraction, filler size distribution, filler shape characteristics, filler-matrix interaction, and matrix viscosity. Among these, the viscosity of the polymer matrix directly affects the viscosity of the composite material; lower matrix viscosity results in lower composite viscosity. While adding low-molecular-weight flow modifiers can reduce the viscosity of the polymer system, this practice can easily lead to surface overflow, product defects, and even negatively impact material properties.
[0006] In recent years, research on reversible covalent bonds in the field of new materials has deepened, and their significant advantages have attracted widespread attention. Traditional cross-linked polymers have inherent defects such as non-reprocessability and non-recyclability, while the introduction of reversible covalent bonds has brought new opportunities to solve these problems. It has successfully endowed new materials with a series of unique and valuable functions. In terms of processing performance optimization, it effectively improves the fluidity of materials during processing, thereby improving processing efficiency and molding quality. In terms of self-healing properties, when materials are damaged, reversible covalent bonds can promote self-repair, extending the service life of materials. In terms of mechanical property regulation, through the ingenious design and control of reversible covalent bonds, the mechanical properties of materials can be flexibly adjusted to meet the needs of different application scenarios. In terms of solid-state recyclability, it provides the possibility of material recycling, greatly improving resource utilization.
[0007] Of particular note is that the polymers incorporating reversible covalent bonds exhibit excellent mechanical properties and solvent resistance similar to those of irreversibly crosslinked materials at room temperature, enabling them to maintain stable and reliable mechanical properties under normal operating conditions. At high temperatures, the exchange or dissociation of these dynamic reversible bonds significantly enhances the polymer's flowability, effectively improving its processing performance and providing greater convenience and flexibility in molding and processing, thus expanding its application range and potential.
[0008] The preparation of nano-inorganic particle / polymer composites using chemical grafting modification of nano-inorganic particles can significantly increase the content of nano-inorganic particles, thereby improving the mechanical properties of the polymer composites. Furthermore, the construction of a dynamic reversible network significantly enhances the recyclability of the composites, offering considerable practical value compared to the low filler content and difficulty in recycling of nano-inorganic particles. Simultaneously, the construction of the dynamic reversible network can improve the dispersion of inorganic particles in the matrix material. Therefore, the preparation of self-reinforced materials using nano-inorganic particle / polymer composites has become a new research hotspot.
[0009] Obtaining high-performance, recyclable polymer composites through different modification designs and the construction of dynamic reversible networks is one of the research challenges, while successfully applying high-performance, dynamic reversible materials to final products is also a research hotspot. Summary of the Invention
[0010] To address the aforementioned technical problems, this invention provides a method for preparing polymer composite materials by combining dynamic network design technology with polymer modification technology using nano-inorganic particles. This method significantly improves the strength and modulus of the composite material. First, nano-inorganic particles are chemically grafted and then functionalized with furan via esterification. Simultaneously, a branched polymer is used as a raw material, and a hydroxy-isocyanate addition reaction is performed using the activity difference at both ends of isophorone diisocyanate (IPDI). This is followed by a further reaction with furfurylamine to graft furan groups, obtaining a furanized polymer. A cross-linked polymer network is then successfully prepared via a DA reaction using bismaleimide (BMI). Finally, the modified nano-inorganic particles are chemically linked to the cross-linked polymer network via the DA reaction to obtain the final composite material.
[0011] Functional modification of nano-inorganic particles, shifting from traditional polymer blending to chemical bonding, allows for better dispersion of these particles within the polymer network. This, in turn, increases the amount of nano-inorganic particles added, thereby enhancing the mechanical properties of the composite material system. Branching the polymer and introducing dynamic bonds to form a network cross-linked structure further improves the mechanical properties of the composite material system. Furthermore, it endows the material with dynamic thermal reversibility under different temperature conditions, further enhancing the processability and recyclability of the composite material system.
[0012] The objective of this invention can be achieved through the following technical solutions: This invention provides a method for preparing highly filled polymer composite materials, which involves a reversible dynamic chemical reaction between a modified filler and a modified polymer to prepare the highly filled polymer composite material.
[0013] Furthermore, highly filled polymer composite materials were prepared by melt blending modified fillers and modified polymers, and by constructing a dynamic reversible network through the design of diene synthesis reactions.
[0014] Furthermore, the modified filler is a DA bond-functionalized nano-inorganic particle.
[0015] Furthermore, the method for preparing the DA bond-functionalized inorganic nanoparticles is as follows: the inorganic nanoparticles are reacted successively with carbodiimide and furfurylamine to obtain furan-functionalized inorganic nanoparticles, and then reacted with bismaleimide to obtain DA bond-functionalized inorganic nanoparticles.
[0016] Furthermore, the nano-inorganic particles are at least one of nano-calcium carbonate, nano-silica, or nano-microcrystalline cellulose.
[0017] Furthermore, the nano-silica particles are precipitated nano-silica or fumed nano-silica, with an average particle size of 7–50 nm and a specific surface area of 150–640 m². 2 / g.
[0018] Furthermore, the modified polymer is a branched polymer with DA bond functionalization.
[0019] Furthermore, the method for preparing the DA bond-functionalized branched polymer is as follows: the branched polymer is reacted successively with isophorone diisocyanate and furfurylamine to obtain a furan-functionalized branched polymer, and then reacted with bismaleimide to obtain a DA bond-functionalized branched polymer.
[0020] Furthermore, the monomer of the branched polymer is at least one of polycaprolactone monomer and polyethylene glycol monomer.
[0021] Furthermore, the polycaprolactone monomer is ε-caprolactone.
[0022] The beneficial effects of this application are as follows: This invention employs a combination of dynamic network design technology and inorganic particle-filled modified polymer composite materials. During stretching, the nanoparticles disperse within the matrix, promoting aggregate dispersion and resulting in a well-reinforced material. Furthermore, the nanoparticles also enhance the tensile properties of the material during stretching. The addition of inorganic particles does not affect the compatibility and recyclability of the self-reinforcing material layers. Therefore, combining these two technologies yields high-performance polymer composite materials. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the dynamic reversible cross-linked network structure of the present invention.
[0024] Figure 2 The image shows the 1H NMR spectrum of PCL-OH in CDCl3.
[0025] Figure 3 The image shows the 1H NMR spectrum of PCL-furan in CDCl3.
[0026] Figure 4 The second-order kinetic curves for the DA and retro-DA conversions of PCL-furan and BM are shown.
[0027] Figure 5The image shows a comparison of the kinetic curves of the DA reaction and the retro-DA reaction involved in PCL-DA by in-situ 1H NMR (equal molar amounts of furan and maleimide in PCL-furan and BM were dissolved in DMSO-d6 and sealed in an NMR tube, and the 1H NMR spectra were measured after heating at 65 °C for different times).
[0028] Figure 6 Typical stress-strain curves for CaCO3-DA / PCLDA and CaCO3-DA / PCLRef with different filler loading amounts.
[0029] Figure 7 Typical stress-strain curves for CaCO3-DA / PCLDA after initial and three-stage recycling with different filler loading amounts. Detailed Implementation
[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0031] Example First, ε-caprolactone was ring-opening polymerized using pentaerythritol as an initiator and stannous octoate as a catalyst at 120°C under an argon atmosphere for 24 h to synthesize a four-armed star-shaped polycaprolactone (PCL-OH). The molar ratio of ε-caprolactone to pentaerythritol was 50 / 1, and the mass ratio of stannous octoate to monomer was 5 / 10000. Next, 50 mmol of IPDI and 0.1 g of dibutyltin dilaurate (DBTDL) were dissolved in ultra-dry tetrahydrofuran (THF), and 50 g of PCL-OH (33.3 mmol of hydroxyl groups) was added. The reaction was carried out at 60°C under an argon atmosphere for 12 h, followed by the addition of 100 mmol of 2-furfurylamine and the reaction at 40°C for 6 h to obtain PCL-furan. Its molecular weight and furan content were determined. Then, 30 g of CaCO3 was suspended in 400 mL of dimethylformamide (DMF), and 30 g of... Carbodiimide (CDI) was reacted at 60°C under an argon atmosphere for 4 h, followed by the addition of 35.90 g of 2-furfurylamine, and the reaction was continued for another 6 h to obtain CaCO3-F. CaCO3-F was then reacted with excess BMI at 65°C under an argon atmosphere for 48 h to obtain DA-functionalized calcium carbonate (CaCO3-DA). The reaction was verified by FTIR and elemental analysis to determine the grafting amount. PCL-furan (10.0 g, 1.39 mmol) and BMI (1.00 g, 2.78 mmol) were then dissolved in 40 mL of DMF, poured into a silicone mold, and cured in a 65°C oven for 24 h. Curing was then continued under vacuum and at 65°C for another 24 h to obtain DA-crosslinked polycaprolactone (PCLDA). Simultaneously, PCLRef was prepared by solvent evaporation. For comparison, the raw materials were dried and premixed in proportion, and CaCO3-DA / PCLDA and CaCO3-DA / PCLRef composites were prepared by melt blending, injection molding and post-treatment. The CaCO3-DA / PCLDA composite material also needs to be placed in a 65 ℃ oven to allow the furan groups and maleimide groups to fully undergo the DA reaction. The whole process uses a variety of chemical synthesis and treatment methods, and strictly controls the raw materials, reagents and reaction conditions to introduce DA bonds, so that the composite material has thermal reversibility, improves the filling amount and mechanical properties, etc.
[0032] The preparation flow chart of the composite material of the present invention is as follows: Figure 1 As shown.
[0033] The preparation process is the same in all embodiments of the present invention. The specific steps are as follows: the nano-inorganic particles are first chemically grafted via an esterification reaction, with furfurylamine as the grafting monomer, and the dosage ratio is shown in Table 1. Simultaneously, a furanization reaction is performed using four-armed star-shaped polycaprolactone as the raw material, followed by a DA reaction via BMI to successfully prepare a cross-linked polymer network (PCL). DA Grafted modified nanoparticles with PCL DA The masterbatch was prepared by melt blending in a Hakke torque rheometer, with the dosage ratios shown in Table 2. The composite material was then prepared into test specimens according to ASTM 3039 standard.
[0034] The comparative examples had the same component ratios as the examples, but different molding processes. The preparation processes for each comparative example were identical. The specific preparation steps for the comparative examples were as follows: First, the nano-inorganic particles were chemically grafted via an esterification reaction. The grafting monomer was furfurylamine, and the ratios are shown in Table 1. The grafted and modified nanoparticles were then melt-blended with linear polycaprolactone prepared by a solvent method in the mixer of a Hakke torque rheometer to prepare a masterbatch, with the ratios shown in Table 3. The composite material with the required ratio was directly injected into standard specimens using an injection molding machine without solid-state stretching treatment.
[0035] Given the close intrinsic relationship between the final material's melt processing rate and reversible reaction kinetics, in-situ 1H NMR spectroscopy was employed to investigate the kinetics of the DA adduct and retro-DA reactions. The specific procedure was as follows: Equimolar amounts of PCL-furan and N-methylmaleimide (BM) containing furan and maleimide were dissolved in DMSO-d6 and sealed in an NMR tube. The mixture was then heated at 65 °C for different durations, and the corresponding 1H NMR spectra were measured. To effectively avoid polymer gelation, BM was used instead of BMI in the reaction. Spectral data were collected at 10, 20, and 30 min intervals to monitor the formation of the DA adduct in the 65 °C mixed solution in real time. Subsequently, the samples that had undergone the DA reaction were transferred to 110 °C and incubated for 10, 20, and 30 min, respectively, and the 1H NMR spectra were collected again to further analyze the dynamic changes of the retro-DA reaction. The contents of DA adduct and unreacted raw materials can be accurately obtained by integrating the peaks 1' and 1'.
[0036] Therefore, the reaction conversion rate x of the DA adduct can be calculated using the following formula.
[0037] The DA reaction follows a second-order kinetic model, which can be expressed as: Where k represents the rate constant.
[0038] according to Figure 3 Quantitative analysis shows that the retro-DA reaction proceeds faster than the DA reaction, which aligns with the requirement for the DA crosslinking network to break down rapidly to impart suitable flowability to the material. This confirms that the construction of the DA crosslinking network in this invention can reduce the melt viscosity of the system during composite injection molding, thereby improving the processing performance of the material.
[0039] In addition, to understand whether the DA reaction can occur in PCL DA The study was conducted in the solid phase, and FTIR was used to investigate PCL containing equimolar furan and maleimide groups. DA Thermal reversibility in the solvent-free state, according to Figure 5 The curves can verify the thermal activation, decrosslinking, and recrosslinking characteristics of the DA bond crosslinking network of this material at different temperatures. Stress-strain curves for multiple repairs of different filler loadings and different control samples were also tested. Figure 6 and Figure 7 ).
[0040] Tables 4 and 5 compare the properties of the composite materials prepared in the embodiments of the present invention with those of the comparative example composite materials. As can be seen from Tables 4 and 5: 1. The tensile strength of the embodiments of the present invention is significantly improved compared with that of the comparative examples. The tensile strength of Example 3 is 6.6 times that of Comparative Example 1, indicating that the performance of the composite material prepared by the process of the present invention is greatly improved.
[0041] 2. The elastic modulus of the samples in Examples 1, 2, and 3 of this invention is higher than that of Comparative Examples 1, 2, and 3, indicating that the dynamic network crosslinking technology of nano-inorganic particles and polymers used in this invention can oriented the molecular chains and enhance the mechanical properties of the composite material.
[0042] 3. The elastic modulus of the recovered samples was close to that before recovery, and some were even better than the elastic modulus before recovery. This shows that the dynamic network crosslinking technology of nano-inorganic particles and polymers used in this invention can significantly improve the processability and recyclability of the materials.
[0043] This invention utilizes the principle of dynamically crosslinking and modifying nano-inorganic particles and polymers using dynamic reversible chemical bonds, resulting in composite materials with significantly improved mechanical properties and processability. This invention can also be applied to nanoparticle composite materials such as nano-silica particles or nano-microcrystalline cellulose.
[0044] Table 1 Table 2 Note: The chemical grafting modification of nano-calcium carbonate is followed by DA functionalization. The four-armed star-shaped polycaprolactone is furanized and then cross-linked with BMI to form a cross-linked structure. The modified nano-inorganic particles and the DA-cross-linked polycaprolactone are further reacted with DA to form a composite material.
[0045] Table 3 Note: The chemical grafting modification of nano-calcium carbonate was followed by DA functionalization. After preparing linear polycaprolactone by solvent method, the modified nano-inorganic particles and linear polycaprolactone were further reacted with DA to form a composite material.
[0046] Table 4 Table 5 Note: The tensile strength and modulus of elasticity of the comparative example were determined according to ASTM D638-1998, and the tensile strength and modulus of elasticity of the example were determined according to ASTM 3039.
[0047] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.
Claims
1. A method for preparing a highly filled polymer composite material, characterized in that, Highly filled polymer composites were prepared by designing modified fillers to undergo reversible dynamic chemical reactions with modified polymers.
2. The method for preparing a highly filled polymer composite material according to claim 1, characterized in that, Highly filled polymer composites were prepared by melt blending modified fillers and modified polymers, and by constructing a dynamic reversible network through the design of diene synthesis reactions.
3. The method for preparing a highly filled polymer composite material according to claim 1 or 2, characterized in that, The modified filler is a nano-inorganic particle functionalized with DA bonds.
4. The method for preparing a highly filled polymer composite material according to claim 3, characterized in that, The method for preparing the DA bond-functionalized inorganic nanoparticles is as follows: the inorganic nanoparticles are reacted with carbodiimide and furfurylamine successively to obtain furan-functionalized inorganic nanoparticles, and then reacted with bismaleimide to obtain DA bond-functionalized inorganic nanoparticles.
5. The method for preparing a highly filled polymer composite material according to claim 4, characterized in that, The nano-inorganic particles are at least one of nano-calcium carbonate, nano-silica, or nano-microcrystalline cellulose.
6. A method for preparing a highly filled polymer composite material according to claim 1 or 2, characterized in that, The modified polymer is a branched polymer with DA bond functionalization.
7. The method for preparing a highly filled polymer composite material according to claim 6, characterized in that, The method for preparing the DA bond-functionalized branched polymer is as follows: the branched polymer is reacted with isophorone diisocyanate and furfurylamine successively to obtain a furan-functionalized branched polymer, and then reacted with bismaleimide to obtain a DA bond-functionalized branched polymer.
8. The method for preparing a highly filled polymer composite material according to claim 6, characterized in that, The branched polymer's monomer is at least one of polycaprolactone monomer and polyethylene glycol monomer.