Titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material and preparation method thereof

Abstract

Brittleness and low fracture toughness (especially at low temperature) are two main limiting factors for limiting application of hard PVC composite materials in extreme environments. In the invention, a method capable of realizing large-scale production is provided, and the challenge is dealt with by combining mechanochemically modified attapulgite (mATP) and nitrile butadiene rubber (NBR) for synergistic enhancement. The properties of the optimized composite material are remarkably improved, and the tensile strength, the elongation and the impact are respectively improved by 23.9%, 250.5% and 83.7% compared with those of original PVC (polyvinyl chloride). According to the invention, not only is the high-performance thermoplastic resin composite material produced, but also the influence mechanism of the relationship between the structure and the performance on the thermomechanical response of the thermoplastic plastic is disclosed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material preparation, and particularly relates to a titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material and a preparation method. BACKGROUND

[0002] Polyvinyl chloride (PVC) is one of the most widely used plastics in the world due to its high mechanical strength, good flame resistance, corrosion resistance, low cost and other advantages. It is widely used in building (such as door and window profiles, pipes), electronic appliances, automobile parts and other fields. Among them, hard PVC products occupy a large market share due to their excellent rigidity and dimensional stability. However, traditional hard PVC materials still have a series of inherent defects in actual production and application. First, PVC resin is extremely sensitive to heat, and its molecules are prone to decomposition at processing temperature, resulting in discoloration, performance degradation, and even release of hydrogen chloride (HCl) gas, which seriously corrodes the processing equipment. Therefore, a large amount of heat stabilizer must be added, which not only increases the cost, but also causes environmental and health concerns (such as the gradual elimination of lead-containing stabilizers). Second, hard PVC has poor impact toughness, especially at low temperatures, which is brittle and easily broken by external impact, which greatly limits its application in key structural parts that require high reliability. To solve this problem, toughening modifiers (such as CPE, ACR, etc.) are usually added, but this often comes at the expense of the rigidity, strength and Vicat softening temperature of the material. In addition, hard PVC has low melt strength and poor processing rheology, resulting in uneven filling and poor surface finish during extrusion or injection molding of complex section profiles, affecting the quality of the final product. Therefore, developing a new hard PVC material that can simultaneously balance high thermal stability, high impact resistance, good processability and good rigidity and toughness has become a key technical problem for those skilled in the art. SUMMARY

[0003] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0004] In view of the above problems of the prior art, the present application is proposed.

[0005] Therefore, the application aims to provide a titanium acid ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material and a preparation method, which are suitable for solving the poor impact toughness of hard PVC, especially the significant brittleness in low temperature environment, and the easy breakage due to external impact. Secondly, the material is extremely sensitive to heat, and the molecules are prone to decomposition reaction at the processing temperature, resulting in discoloration, performance degradation, and even release of hydrogen chloride (HCl) gas, which seriously corrodes the processing equipment. Therefore, a large amount of heat stabilizer must be added, which not only increases the cost, but also causes environmental and health concerns (such as the gradual elimination of lead-containing stabilizers). To solve the above technical problems, the application provides the following technical scheme: a reinforced polyvinyl chloride composite material, the composite material comprises:

[0006] As a titanium acid ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to the application, the composite material comprises:

[0007] The polyvinyl chloride, attapulgite, nitrile rubber, titanium acid ester coupling agent and other PVC processing aids are fully mixed and then dried at 80℃ for 4 hours;

[0008] Among them, the attapulgite is surface treated with different concentrations of titanium acid ester coupling agent;

[0009] The polyvinyl chloride, attapulgite, nitrile rubber, titanium acid ester coupling agent and other PVC processing aids are fully mixed, and the mixed material is melted, extruded and granulated to obtain the composite material.

[0010] As a titanium acid ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to the application, the attapulgite treated with the titanium acid ester coupling agent refers to the attapulgite modified with a mass concentration of 1wt%, 1.5wt%, 2wt%, 3wt% or 4wt% (the concentration is based on the mass fraction of the attapulgite) titanium acid ester coupling agent.

[0011] As a titanium acid ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to the application, the temperature of the constant temperature is 80℃, and the drying time is 4h.

[0012] As a titanium acid ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to the application, the polyvinyl chloride, attapulgite, nitrile rubber, attapulgite treated with the titanium acid ester coupling agent and other PVC processing aids are melted, extruded and granulated at a temperature range of 170℃ to 180℃, and the granules are dried at 80℃ for 4 hours.

[0013] The titanium ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material has the characteristics that the compatibility between the attapulgite and the polyvinyl chloride matrix is increased, the internal structure of the material is more compact, and the mechanical properties of the composite material are improved.

[0014] The titanium ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material has the characteristics that the incorporation of the attapulgite treated by the titanium ester coupling agent enhances the loss modulus and storage modulus of the composite material.

[0015] The titanium ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material has the characteristics that the incorporation of the attapulgite treated by the titanium ester coupling agent enhances the rheological properties of the composite material, and the processing time of the material is significantly shortened.

[0016] The titanium ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material has the characteristics that the interfacial adhesion between the attapulgite treated by the titanium ester coupling agent and the matrix is enhanced, the roughness and viscosity of the internal and surface of the composite material are increased, the heat transfer path of the material in the melting process is complicated, and the heat resistance of the composite material is improved.

[0017] The titanium ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material has the characteristics that the incorporation of the attapulgite treated by the titanium ester coupling agent and the nitrile rubber enhances the impact resistance of the composite material at low temperature.

[0018] A preparation method of a titanium ester coupling agent modified attapulgite reinforced polyvinyl chloride composite material has the characteristics that the preparation method is suitable for any one of the above composite materials, and the preparation method comprises the following steps:

[0019] S1: material drying: the polyvinyl chloride, attapulgite, nitrile rubber, titanium ester coupling agent and other PVC processing aids are fully mixed and then dried at 80°C for 4 hours;

[0020] S2: the titanium ester coupling agent of different concentrations is dropped into the attapulgite, then transferred to a small high-speed mixer for sufficient stirring, and then the surface treated attapulgite is placed in an oven at 120°C for 3 hours;

[0021] S3: the components of the composite material are fully mixed, the uniformly mixed material is melted, extruded and granulated at a temperature of 170°C to 180°C, the granules are dried at 80°C for 4 hours, and finally injection molded at a temperature of 180°C to 190°C.

[0022] The application has the beneficial effects that: the application successfully grafts TCA to the surface of ATP through a dry modification process, and enhances the interfacial compatibility and dispersion stability between ATP and PVC. In addition, the superior interfacial effect between nitrile rubber and PVC significantly improves the toughness and low-temperature ductility of the PVC composite material, thereby opening up a new way to develop advanced PVC-based composite materials. The performance of the modified composite material is significantly improved. Compared with pure PVC, the PVC-based composite material containing 2wt% TCA modified ATP and NBR has an elongation at break increased by 250.5%, an energy storage modulus increased by 82.1%, a tensile strength increased by 23.9%, a bending strength increased by 42.6%, and an impact strength increased by 83.7%. In terms of thermal stability, VST is increased by 11.1℃, and T50 is increased by 54.9℃. The impact strength of the unmodified PVC is reduced by 48.5% at-20℃, while the modified sample maintains sufficient toughness under low-temperature conditions. The Weibull distribution curve confirms the mechanical stability of the ATP reinforced composite material, providing key guidance for optimizing the ATP / PVC composition design. These improvements are attributed to the enhanced interfacial adhesion between TCA modified ATP and NBR and their synergistic effect. This study not only produces high-performance composite materials, but also reveals the influence mechanism of the structure-property relationship on the thermal mechanical response of thermoplastic plastics. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0024] Figure 1 A preparation method flowchart of the enhanced PVC composite material according to the present application;

[0025] Figure 2 A schematic diagram of the second embodiment of the present application;

[0026] Figure 3 A schematic diagram of the third embodiment of the present application;

[0027] Figure 4 A schematic diagram of the fourth embodiment of the present application;

[0028] Figure 5 A schematic diagram of the fifth embodiment of the present application;

[0029] Figure 6 A schematic diagram of the sixth embodiment of the present application;

[0030] Figure 7 A schematic diagram of the seventh embodiment of the present application;

[0031] Figure 8 schematic diagram of embodiment eight of the present application;

[0032] Figure 9 schematic diagram of embodiment nine of the present application;

[0033] Figure 10 schematic diagram of embodiment nine of the present application;

[0034] Figure 11 schematic diagram of a preparation method of the enhanced polyvinyl chloride composite material according to the present application;

[0035] Figure 12 schematic diagram of the abstract of the present application. DETAILED DESCRIPTION

[0036] In order to make the above objectives, features and advantages of the present application more apparent and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0037] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0038] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment that excludes other embodiments.

[0039] Thirdly, the present application is described in detail in conjunction with the schematic diagram, and in the detailed description of the embodiments of the present application, the cross-sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the present application herein. In addition, the three-dimensional spatial dimensions including length, width and depth should be included in actual manufacture.

[0040] Embodiment one

[0041] Reference Figure 1 and Figure 11 According to one embodiment of the present application, a titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material is provided, and the composite material comprises:

[0042] PVC, ATP, NBR, TCA and other PVC processing aids are mixed thoroughly and dried at 80℃ for 4 hours;

[0043] In which, ATP is surface treated with different concentrations of TCA;

[0044] The above-mentioned PVC, ATP, NBR, TCA and other PVC processing aids are mixed thoroughly, and the mixed materials are melted, extruded and granulated to obtain the composite material.

[0045] As a kind of titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material described in the application, characterized in that: the ATP treated by TCA refers to the ATP treated by 1wt%, 1.5wt%, 2wt%, 3wt%, 4wt% (concentration is based on the mass fraction of attapulgite) TCA.

[0046] As a kind of titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material described in the application, characterized in that: the PVC, ATP, NBR, mATP and other PVC processing aids are melted, extruded and granulated at a temperature range of 170℃-180℃, and the particles produced are dried at 80℃ for 4 hours, and finally injection molded at a temperature of 180℃-190℃.

[0047] In order to facilitate the filling of experimental data, the English notes of each component are as follows: polyvinyl chloride is PVC, attapulgite is ATP, nitrile rubber is NBR, titanate coupling agent is TCA, and attapulgite modified by titanate coupling agent is mATP.

[0048] Table 1: PVC and its composite material formula table

[0049]

[0050]

[0051] Table 2: PVC processing aid formula table

[0052] PVC / phr Ca / Zn / phr SA / phr PE Wax / phr ESO / phr 100 5 0.5 0.8 5

[0053] A preparation method of a titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material, characterized in that, the preparation method is applicable to any one of the above composite materials, and the preparation method comprises the following steps:

[0054] S1: material drying: PVC, attapulgite, nitrile rubber, titanate coupling agent and other PVC processing aids are mixed thoroughly and dried at 80℃ for 4 hours;

[0055] S2: After dropping different concentrations of titanate coupling agent into the attapulgite, it was transferred to a small high-speed mixer for sufficient stirring, and then the surface-treated attapulgite was placed in an oven at 120°C for 3h;

[0056] S3: The components of the composite material were mixed thoroughly, and the uniformly mixed material was subjected to melting, extrusion and granulation at a temperature range of 170°C-180°C, and the granules were dried at 80°C for 4h, and finally injection molding was performed.

[0057] Example Two

[0058] Reference Figure 2 For one embodiment of the present application, Fourier transform infrared spectroscopy (FTIR) (Thermo Scientific Nicolet IS20) was used to chemically analyze ATP, mATP in the wave number range of 400-4000 cm -1 . X-ray diffraction (XRD) and 5°-80° scanning at 5° / min (2θ) were used to characterize the crystal structure. The surface elemental composition and chemical state were detected by X-ray photoelectron spectroscopy (XPS), and the wettability was evaluated by water contact angle measurement.

[0059] In Figure 2 , (A) FT-IR, (B) XRD, (C) XPS total spectrum (D) Si 2p part of ATP, (E) Si 2p part of mATP, (F) SEM of mATP, (G) mapping of mATP, (H) contact angle of ATP, (I) contact angle of mATP.

[0060] In order to explore the influence of TCA on the surface modification of ATP, the infrared spectral characteristics of unmodified and modified ATP were comprehensively analyzed. From Figure 2 A, it can be seen that the infrared spectrum of unmodified ATP shows characteristic mineral absorption peaks, including O-H stretching vibration at 3400 cm -1 , Si-O stretching vibration in the range of 1000-1100 cm -1 , and Si-O-Si bending vibration near 470 cm -1 , which together indicate that the main component is silicate mineral. After modification with titanate coupling agent, significant changes in infrared spectrum were observed, confirming that the coupling agent has effectively interacted with the surface of ATP. It is particularly noteworthy that the intensity of O-H stretching vibration at 3458 cm -1 and the intensity of O-H bending vibration at 1643 cm -1 are significantly reduced, indicating that the content of surface hydroxyl groups is significantly reduced. In addition, in the range of 2800-3000 cm -1The appearance of C-H stretching vibrations in the region further confirms the successful incorporation of the organic group in the coupling agent. These spectral changes not only indicate the successful modification of the ATP surface chemistry but also highlight the enhanced compatibility with other substances, thereby laying a strong foundation for its potential in various applications.

[0061] The XRD pattern of ATP typically shows distinct peaks reflecting its unique mineral structure. These peaks reflect the specific arrangement of the crystal, indicating the stability of its layered structure and characteristic interplanar spacing. For example, the primary diffraction peaks of ATP typically occur at 2Θ = 8°, 19°, 22°, and 26°, corresponding to its characteristic crystal planes and lattice spacing (d-spacing) of 1.1 nm, 0.47 nm, 0.41 nm, and 0.34 nm, respectively. Figure 2 B) After modification with titanate coupling agent, no new diffraction peaks appeared in the XRD pattern. This indicates that the coupling agent did not cause significant changes to the overall crystal structure of ATP. Therefore, although there is an interaction between the coupling agent and the ATP surface, the XRD pattern shows that the crystal structure has not changed significantly.

[0062] Comparing the XPS spectra before and after modification can effectively analyze the elemental composition of the sample. Initially, the ATP surface showed characteristic peaks of Si2p and O1s, indicating siloxyl groups. After modification, a new Ti 2p peak appeared along with the original peak, verifying the successful grafting of titanium from TCA to the ATP surface ( Figure 2 C). In the Si 2p spectrum of unmodified ATP, peaks of Si-OH (103.4 eV) and Si-O-Si (102.7 eV) were observed ( Figure 2 D). Importantly, after modification, a feature indicating Ti-O-Si (102.2 eV) bond was identified in both Si 2p and Ti 2p spectra ( Figure 2 E). This further confirms the reaction between the titanium part of the coupling agent and the silicon groups on the ATP surface, resulting in a new chemical bond. The formation of Ti-O-Si bonds not only changes the chemical environment of the ATP surface but also has the potential to significantly enhance its compatibility and dispersibility with other materials.

[0063] Based on the SEM and mapping of ATP ( Figure 2 F-G). The dense distribution of Ti elements on the ATP surface indicates a successful interaction between TCA and the ATP surface. This surface grafting technique enhances the interaction between ATP and other substances, thereby improving its performance.

[0064] Example Three

[0065] With reference to Figure 3 For one embodiment of the present invention, a scanning electron microscope is used to observe the micro-morphology of the material, and after surface gold spraying treatment, all the fractured cross sections are examined under vacuum conditions.

[0066] To observe the dispersion of ATP in the PVC matrix, the samples were subjected to low-temperature fracture by liquid nitrogen immersion, and then the brittle fracture surface was examined by SEM. As shown in Figure 3 The sample without ATP showed a smooth fracture surface, with typical characteristics of brittle fracture, as indicated by A-A2. Figure 3 B1-B2 clearly shows that more than half of the ATP particles have a clear gap with the PVC matrix. During the tensile process of ATP / PVC composite, these gaps become stress concentration zones, reducing the effective stress distribution, leading to PVC macromolecules reaching the fracture threshold faster. In Figure 3 In C2, the modification of TCA coupling agent significantly reduces the number and size of these gaps, which explains the mechanical property enhancement of PVC composites after modification, because the coupling agent strengthens the interaction between ATP and PVC. As shown in Figure 3 As shown in D-D2, due to the partial compatibility between nitrile rubber and PVC and its low loading concentration, no obvious phase separation was observed on the fracture surface after incorporating NBR. However, local areas of the fracture surface exhibit a fibrous network structure. This phenomenon is mainly attributed to the hydrogen bonding and dipole-dipole interactions between nitrile rubber and PVC molecular chains. Especially under external force, these interactions promote chain entanglement, leading to the formation of a network structure at the fracture site. As a toughening agent, nitrile rubber forms an adhesive network on the fracture surface to disperse stress and slow down crack propagation.

[0067] Example Four

[0068] Referring to Figure 4 For one embodiment of the present application, the DMA span is -30-130°C, the frequency is 5°C / min, 1Hz, and the rheological torque-time curve is obtained by torque rheometer (185°C, 40rpm).

[0069] In Figure 4 , (A) storage modulus, (B) loss modulus, (C) rheological properties.

[0070] The synergistic effect of TCA modified ATP and NBR was further deciphered by rheology and dynamic mechanical analysis. The plasticizing time of TCA treated ATP was shortened from 400s to 100s Figure 4 C), confirming the weakening of intermolecular friction between ATP and PVC chains, which originated from the hydrophobic alkyl chains grafted on the surface of ATP. This improved dispersion directly contributed to the enhancement Figure 4 of the storage modulus of mATP / PVC in A, because well-dispersed mATP particles limited the segmental mobility of PVC through covalent Ti-O-Si bridges. Although the incorporation of NBR increased the melt viscosity Figure 4 C) due to premature plasticization and particle adhesion, it significantly improved the loss modulus Figure 4B). This viscoelastic energy dissipation mechanism is responsible for maintaining the impact strength at -20°C Figure 8 A), where the flexible butadiene segment in the nitrile rubber absorbs the crack propagation energy.

[0071] Example Five

[0072] Referring to Figure 5 , the mechanical properties such as tensile (GB / T 1040.1-2018, 10 mm / min), flexural (GB / T 9341-2008, 2 mm / min) and notched impact strength (GB / T 1843-2008) were evaluated using a universal testing machine and an impact machine, and the data were averaged for five tests.

[0073] In Figure 5 , (A) stress-strain curves, (B) tensile strength and elongation at break, (C) notched impact strength, (D) flexural strength.

[0074] To investigate the effect of different TCA concentrations on the mechanical properties of ATP / PVC composites, tensile, flexural and impact tests were performed. With the increase of TCA content from 0wt% to 4.0wt%, the tensile strength and elongation at break of mATP / PVC composites first increased and then decreased slightly. At low filler loading (3wt%), mATP slightly reduced the effective plastic deformation zone of the composite and hindered the chain mobility of PVC molecules. The effect was best when the TCA content was 2.0wt%, the tensile strength was 64.5MPa Figure 5 B), the elongation at break was 105% Figure 5 B). In addition, the impact strength reached 5.75kJ / m2 Figure 5 C). The flexural strength of mATP / PVC composites was similar to the tensile properties, reaching 99.37MPa Figure 5 D). These phenomena can be attributed to the insertion of long alkyl chains of TCA into the PVC molecular chain, where van der Waals force-induced entanglement occurs; this is further confirmed by the significant reduction in voids observed in the SEM micrographs. These findings indicate that this modification reduces the surface energy of ATP, improves filler dispersion, and enhances the adhesion between mATP and the PVC matrix, thereby significantly improving the toughness of the material.

[0075] Example Six

[0076] Referring to Figure 6 , the mechanical properties of ATP before and after modification of the tensile fracture surface and SEM were compared. (A) Tensile strength, (B) elongation at break, (C) notched impact strength, (D) flexural strength, (E) ATP / PVC, (F) mATP / PVC.

[0077] ATP is composed of very fine particles and lamellar structures. When its content is low, such as 3-5wt%, it can be uniformly dispersed in the polymer matrix. This helps to increase the intermolecular forces between polymer chains. When the content is 3%, the tensile strength and elongation at break of the material are 57.8 MPa and 80% respectively Figure 6 A). This is because fine particles can fill the microvoids in the polymer matrix, enhancing the density and uniformity of the material, preventing stress concentration, and thus improving the tensile strength. The surface of ATP usually contains certain polar groups, such as hydrogen bonds, which enable it to act as a "stress dissipater". It exhibits excellent adhesion between the two phases, enabling it to act as a bridge between the fracture surfaces. The interface absorbs part of the stress released during the fracture process, thus delaying the pull and improving the toughness of the material. Therefore, materials containing ATP usually exhibit better elongation at break. However, unmodified ATP tends to agglomerate, forming larger gaps and defects, such as aggregates in ATP / PVC composites. In the tensile test, these defects act as stress concentration points, reducing the effective stress area and causing the PVC polymer chains to reach the breaking limit faster. As the ATP content increases, the impact strength continues to decrease Figure 6 C), because ATP is a hard particle. When introduced into PVC, these filler particles can act as stress concentration sites. Under external load, stress tends to concentrate around these filler particles. Especially under impact, poor adhesion between the filler and the matrix can lead to crack initiation and propagation. However, at low TCA concentrations, the treatment may not completely cover the ATP particles, resulting in partial aggregation. On the other hand, too high a concentration can lead to the appearance of additional interphases, disrupting the harmony between the matrix and the reinforcing components. Therefore, this can lead to a decrease in dimensional stability and an increase in brittleness. At 2.0wt% TCA, mATP is uniformly distributed within the PVC matrix. Compared to unmodified ATP / PVC composites, mATP / PVC composites with 2.0wt% TCA have increased tensile strength, elongation at break, bending strength, and notched impact strength by 11.53%, 31.54%, 8.30%, and 45.20% respectively Figure 6 ) Therefore, 2.0wt% TCA is the optimal concentration for modified ATP / PVC composites, which can significantly enhance the mechanical properties of ATP / PVC.

[0078] Example Seven

[0079] Reference Figure 7 For one embodiment of the present invention, the mechanical properties and mechanisms of mATP / PVC composites with different contents of nitrile rubber were studied. (A) Tensile strength and elongation at break, (B) Notched impact strength, (C) Bending strength, (D) Tensile specimen, (E) SEM image of PVC tensile fracture surface, (F) SEM image of mATP / NBR / PVC tensile fracture surface.

[0080] Nitrile butadiene rubber (NBR) was incorporated as an impact modifier in mATP / PVC composites at concentrations ranging from 1 to 9 phr. At 3 phr NBR, the tensile strength of the composite decreased by only 5.3% compared to mATP / PVC composites without NBR. Figure 7 A), but the impact strength increased by 28.7% ( Figure 7 B). Meanwhile, although the flexural strength of the composite material decreases with increasing nitrile rubber content ( Figure 7 C), but when the nitrile rubber content is between 1-3 phr, the flexural strength increases slightly. This can be attributed to the fact that nitrile rubber not only enhances the fracture toughness of the material, but also effectively mitigates crack propagation under external stress through the sliding and stretching of its molecular chains, thereby improving the performance of the composite material under flexural stress. Comparative analysis of the tensile fracture surfaces between the original PVC sample and the nitrile rubber modified sample shows that the surface roughness of the modified composite material is significantly improved (C). Figure 7 E and 7F) are associated with excellent mechanical properties. This phenomenon stems from the integration of toughening structures in the PVC matrix, which activate multi-scale energy dissipation mechanisms, including crack initiation, shear band propagation, and crack deflection during stress loading.

[0081] Example 8

[0082] Reference Figure 8 In one embodiment of the invention, for the low-temperature impact test, the sample and the thermos flask were frozen at -20°C for 48 hours, and the test was performed within 30 seconds of removal. The impact strength of unmodified PVC decreased by 48.5% at -20°C, attributed to its rigid molecular chains and high polarity, which exacerbated brittleness under low-temperature conditions. Figure 8 A). The modified composite material (mATP / NBR / PVC) maintained 6.4 kJ / m² at -20°C. 2 The impact strength is significantly reduced, and the performance loss is significantly mitigated. TCA enhances chain flexibility by reducing intermolecular forces through its long-chain organic groups, while NBR improves low-temperature toughness through polar compatibility and its elastic butadiene segments, thereby promoting molecular migration.

[0083] Example 9

[0084] Reference Figure 9 As an embodiment of the present invention, Weibull reliability analysis is employed. (A) Weibull plot for 0% ATP, (B) Weibull plot for 1% ATP, (C) Weibull plot for 3% ATP, (D) Weibull plot for 5% ATP, (E) Comparison of simulation results and experimental results, (F) R-squared value of the bent curve fitting. 2 value..

[0085] Bending strength data directly indicate the material's resistance to deformation under stress, which has important practical significance in applications such as PVC pipes subjected to earth pressure and automotive structural parts resisting mechanical loads. To quantitatively evaluate the influence of ATP content on the reliability of the bending strength of PVC composites, the experimental data were statistically analyzed using the two-parameter Weibull distribution model. The Weibull stress (σ) - strain (ε) relationship is expressed as:

[0086]

[0087] where E represents the bending strength, σ is the measured strength, σ0 represents the characteristic strength (scale parameter), and β represents the shape parameter (indicating the strength variability). We investigated how the ATP content (0, 1, 3, 5 wt%) controlled β and σ0 to elucidate its influence on mechanical properties. By linearizing equation (1) through double logarithmic transformation, equation (2) is obtained:

[0088]

[0089] Plotting the relationship between ln[ln(Eε / σ)] and ln(Eε) yields a linear relationship, and its slope and intercept directly yield β and σ0 when fitting the experimental (E, σ, ε) data. Figure 9 Weibull plots for PVC / ATP composites. Linear correlation (R 2 > 0.99) confirms the Weibull distribution compliance of all four materials. Both σ0 and β increase with increasing ATP content. At 1-5 wt%, ATP is uniformly dispersed in the polymer matrix, enhancing intermolecular interactions. Therefore, the higher β value indicates a decrease in strength variability, confirming that ATP simultaneously improves strength and reliability. The stress-strain curves simulated using equation (1) and the derived parameters (E, σ0, β) have strong consistency with experimental data (E), verifying the analysis results. Figure 9

[0090] Example Ten

[0091] With reference Figure 10 For one embodiment of the present invention, thermal stability was studied by thermogravimetric analysis (TGA) at 30-800 °C and 10 °C / min. Vicat softening temperature (VST) was determined according to ISO 306:2004 (10 x 10 x 4 mm 3 samples, 50 °C / h).

[0092] In Figure 10 , (A) TG of PVC composites, (B) T50wt% of PVC composites, (C) DTG of PVC composites, (D) VST of PVC composites. ​

[0093] Figure 10 TGA, DTG and VST curves of various composites are shown. The results show that the thermal decomposition of PVC and its composites mainly occurs in two temperature ranges of 250-370 °C and 370-520 °C. The first stage is mainly related to the dehydrochlorination of PVC, leading to the formation of polyene structure and significant HCl release. Here, C-C, C-H and C-Cl bonds are broken, with C-Cl bond being the easiest to break, releasing a large amount of Cl radicals. The second stage is mainly related to the chain scission of PVC macromolecules. Increasing the ATP content from 3wt% to 7wt% improves the T50 value by 39.8 °C, and a further increase of 10.2 °C is observed after TCA modification Figure 10 B). This enhancement is due to ATP acting as a physical barrier in the PVC matrix, inhibiting the release of volatiles during degradation, thus delaying thermal decomposition and increasing the degradation temperature. TCA improves the ATP-PVC compatibility and interfacial bonding, prolonging the retention time of C=C bonds in the composite and helping to improve the T50 value. The incorporation of nitrile rubber slightly reduces T50 due to its inherent lower thermal stability at high temperatures, which is a trade-off between flexibility and heat resistance of the composite. Although nitrile rubber enhances flexibility and ductility, its thermal decomposition byproducts at high temperatures slightly reduce the degradation temperature of the composite. The addition of mATP improves the maximum weight loss temperature of the composite by 3.5 °C Figure 10 C)

[0094] ATP clay as a filler enhances the stiffness of the composite and limits the mobility of the polymer chain. With the increase of ATP content, VST rises accordingly, 8 °C higher than pure PVC Figure 10 D). TCA modified ATP shows enhanced dispersion and compatibility in the PVC matrix, thus enhancing the interfacial adhesion between the filler and the matrix. This results in a more uniform structure and improves the overall stiffness of the composite. The movement of PVC chain segments is more effectively hindered, resulting in a VST 2-3 °C higher than that of ATP / PVC composite. However, the addition of an appropriate amount of nitrile rubber will cause a slight decrease in VST, and this decrease becomes more pronounced as the nitrile rubber content increases. This is due to the inherent flexibility of nitrile rubber, which effectively improves the flowability of PVC chain.

[0095] The present application adopts the "rigid filler-flexible network" synergistic reinforcement strategy. Specifically, the interfacial stress transfer efficiency is optimized by modifying ATP with TCA. Combined with NBR phase, an energy dissipation network is formed, breaking the traditional "strength- toughness" inverse relationship in composites. In this work, a simple dry modification process is used to functionalize the surface of ATP with rich organic long chains, effectively enhancing the organic-inorganic compatibility.

[0096] Through the above-mentioned multiple sets of experiments, the results show that compared with the modified PVC composite material, the PVC-based composite material containing 2wt% TCA modified ATP and NBR has an elongation at break increased by 250.5%, a storage modulus increased by 82.1%, a tensile strength increased by 23.9%, a bending strength increased by 42.6%, an impact strength increased by 83.7%. In terms of thermal stability, VST is increased by 11.1℃, and T50 is increased by 54.9℃. The impact strength of unmodified PVC at-20℃ is reduced by 48.5%, while the modified sample maintains sufficient toughness under low temperature conditions. The Weibull distribution curve confirms the mechanical stability of the ATP reinforced composite material, providing key guidance for optimizing the ATP / PVC composition design. These improvements are attributed to the enhancement of the interfacial adhesion between TCA modified ATP and NBR and their synergistic effect. This study not only produces high-performance composites, but also reveals the influence mechanism of the structure-property relationship on the thermal-mechanical response of thermoplastic plastics.

[0097] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, which should be covered by the scope of the claims of the present application.

Claims

1. A titanate coupling agent modified attapulgite-reinforced polyvinyl chloride composite material, characterized in that, The composite material includes: After thoroughly mixing polyvinyl chloride, attapulgite, nitrile rubber, titanate coupling agent and other polyvinyl chloride processing aids, the mixture is dried at a constant temperature of 80°C for 4 hours. Among them, attapulgite was surface-treated with titanate coupling agents of different concentrations; The above-mentioned polyvinyl chloride, attapulgite, nitrile rubber, titanate coupling agent and other polyvinyl chloride processing aids are thoroughly mixed, and the mixed material is melted, extruded and granulated to obtain the composite material.

2. The titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to claim 1, characterized in that: The attapulgite treated with titanate coupling agent refers to attapulgite treated with titanate coupling agent at mass concentrations of 1 wt%, 1.5 wt%, 2 wt%, 3 wt%, and 4 wt% (concentration based on the mass fraction of attapulgite).

3. The titanate coupling agent modified attapulgite-reinforced polyvinyl chloride composite material according to claim 1, characterized in that: The constant temperature is 80℃, and the drying time is 4 hours.

4. The titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to claim 1, characterized in that: The polyvinyl chloride, attapulgite, nitrile rubber, titanate coupling agent-treated attapulgite, and other polyvinyl chloride processing aids are melted, extruded, and granulated in a temperature range of 170℃ to 180℃. The granules are dried at 80℃ for 4 hours and finally injection molded at a temperature of 180℃ to 190℃.

5. The titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to claim 1, characterized in that: The attapulgite treated with the titanate coupling agent increases the compatibility between the attapulgite and the matrix polyvinyl chloride, making the internal structure of the material more compact and thus improving the mechanical properties of the composite material.

6. The titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to claim 1, characterized in that: The loss modulus and storage modulus of the composite material reinforced by incorporation of attapulgite treated with titanate coupling agent.

7. The titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to claim 1, characterized in that: The rheological properties of the composite material reinforced by the incorporation of attapulgite treated with titanate coupling agent significantly shorten the material processing time.

8. The titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to claim 2, characterized in that: The interfacial adhesion between attapulgite treated with titanate coupling agent and the matrix is ​​enhanced, which increases the roughness and viscosity of the composite material inside and on the surface, complicates the heat transfer path of the material during the melting process, and improves the heat resistance of the composite material.

9. The titanate coupling agent modified attapulgite reinforced polyvinyl chloride composite material according to claim 1, characterized in that: Impact resistance at low temperatures of the composite material reinforced with attapulgite treated with titanate coupling agent and nitrile rubber.

10. A method for preparing a titanate coupling agent modified attapulgite-reinforced polyvinyl chloride composite material, characterized in that, The preparation method is applicable to any one of the composite materials in claims 1-10 above, and the preparation method includes the following steps: S1: Material drying: After thoroughly mixing polyvinyl chloride, attapulgite clay, nitrile rubber, titanate coupling agent and other PVC processing aids, dry at a constant temperature of 80℃ for 4 hours. S2: Different concentrations of titanate coupling agent were dripped into attapulgite clay, then transferred to a small high-speed mixer for thorough mixing. The surface-treated attapulgite clay was then placed in an oven at 120℃ for 3 hours. S3: The components of the composite material are thoroughly mixed. The uniformly mixed material is melted, extruded and granulated in a temperature range of 170℃~180℃. The granules are dried at 80℃ for 4 hours and finally injection molded at a temperature of 180℃~190℃.

Images