Preparation method of compatibilization modified geotextile blanket based on waste polyester and rubber

Abstract

The invention relates to the technical field of composite modification of polymer waste, and discloses a preparation method of a compatibilization modified geotextile blanket based on waste polyester and rubber, which comprises the following steps: using a reactive interface shuttle plasticizer as a temporary plasticizer in a melt blending low-temperature stage to construct a processing window for waste polyester; in the high-temperature stage, the plasticizer reacts with the waste rubber to achieve interfacial compatibilization and self-locking to eliminate the plasticizing effect of the waste rubber, and the reaction event is further used as a chemical signal to trigger an interfacial co-reaction in-situ cross-linking agent to cross-link at an interface and construct a stress dissipation network. The processing temperature window and the final use performance of the material are separated, so that the problem of blending of the two materials, namely the waste polyester and the waste rubber which have conflicting thermal performance, is solved, and the final product has excellent interface bonding strength and recovers the due thermal stability and toughness of a polyester matrix at the same time.

Description

Technical Field

[0001] This invention relates to a method for preparing compatibilized modified geotextiles based on waste polyester and rubber, belonging to the field of polymer waste composite modification technology. Background Technology

[0002] Currently, melt blending is a common technique for preparing composite materials. It disperses polymer components in a molten state by applying high temperatures and mechanical shear. This technique is mature when dealing with polymer systems with similar thermal performance requirements. However, its inherent process limitations become apparent when handling materials with significantly conflicting thermal performance requirements, such as waste polyester and waste vulcanized rubber. For example, the melt processing of waste polyester typically requires temperatures around 260°C. The above temperature far exceeds the threshold for thermo-oxidative degradation of waste rubber, directly causing damage to its cross-linked network structure and loss of elasticity. The processing conditions necessary for one component are the conditions for irreversible damage to the properties of another component. This inherent technical contradiction is the fundamental reason limiting the high-value utilization of such waste materials. To solve this problem, attempts have been made in the field to improve the process by adding antioxidants or reactive compatibilizers within the framework of high-temperature blending. However, these methods still focus on providing limited remedies in a high-temperature environment that continuously damages rubber, without changing the process environment itself.

[0003] Against this backdrop, while there have been attempts in this field to apply waste rubber to other polymer matrices, these methods often circumvent the fundamental problem of thermal property conflicts by selecting specific low-temperature curing systems. They do not provide a universal solution for blending high-melting-point thermoplastic polymers (such as waste polyester) with waste rubber. For example, Chinese invention patent CN113980231A discloses a polyurethane tire based on mixed acid polyester polyol and waste rubber powder, and its preparation method. The technical solution of this patent is to use waste rubber powder as a functional filler, physically dispersing it in a liquid state. In the polyurethane prepolymer component, it is then cured and molded through low-temperature chemical crosslinking. This method essentially utilizes the low-temperature molding characteristics of the polyurethane system to avoid the degradation risk of waste rubber at high temperatures. However, its core is a filler-type physical blending, which does not address the interfacial compatibility problem of two solid polymers in the molten state. This approach does not provide any technical inspiration on how to solve the inherent contradiction between high-melting-point thermoplastic matrices such as waste polyester and heat-sensitive rubber in melt blending processing. Instead, it highlights the current situation in the field of dealing with such thermally conflicting materials, which lacks a general and effective interfacial modification strategy.

[0004] Specifically, existing technologies have the following shortcomings: 1. Antioxidants only slow down the rate of thermo-oxidative degradation at high temperatures; damage to rubber properties still occurs, and their effectiveness is unstable when the material sources are varied. 2. Conventional reactive compatibilizers also require high-temperature environments to facilitate their reactions, causing the compatibilization reaction to occur simultaneously with the thermal degradation of rubber. This results in a trade-off between establishing interfacial bonding and maintaining the integrity of the rubber structure. Therefore, seeking to improve the performance of a single additive does not solve the problem of material damage caused by processing. Thus, the technical problem this invention aims to solve is how to establish a new blending processing method that can create a temporary, safe low-temperature processing window for the rubber components during melt blending, and restore the final product's proper thermal stability after interfacial compatibilization. Summary of the Invention

[0005] This invention provides a method for preparing compatibilized modified geotextile based on waste polyester and rubber. Its main purpose is to solve the problem of how to construct a temporary low-temperature processing window to avoid high-temperature damage to the performance of rubber during the melt blending of waste polyester and rubber, while ensuring the thermal stability of the final product.

[0006] To achieve the above objectives, this invention provides a method for preparing compatibilized modified geotextiles based on waste polyester and rubber, the method comprising the following steps:

[0007] Step a, in the low-temperature stage of blending, at a processing temperature lower than the thermal degradation initiation temperature of waste rubber, the polyester-loving ends of the plasticizer molecules in the reactive interface of the system penetrate into the waste polyester matrix, breaking the inter-chain forces of polyester and making the waste polyester flowable.

[0008] In step b, during the high-temperature stage of blending, the reactive ends of the reactive interfacial shuttle plasticizer molecules covalently bond with the surface of the waste rubber that has migrated to the interface. This anchoring effect restricts the migration ability of the reactive interfacial shuttle plasticizer molecules in the waste polyester matrix, thereby eliminating its plasticizing effect. Furthermore, the covalent bonding event between the reactive interfacial shuttle plasticizer and the waste rubber activates a pre-set interfacial co-reactive in-situ crosslinking agent in the system. After the interfacial co-reactive in-situ crosslinking agent is activated, an in-situ crosslinking reaction occurs in the interfacial region between the waste polyester and the waste rubber, thereby constructing a stress dissipation network around the waste rubber particles.

[0009] Preferably, in the chemical structure of the reactive interfacial shuttle plasticizer, a steric hindrance group is included in the position of the reactive end functional group that can react with waste rubber; after the steric hindrance group is formed by covalent bonding, a three-dimensional physical barrier is formed next to the newly formed chemical bond, and the three-dimensional physical barrier increases the path barrier for water molecules to approach and attack the newly formed chemical bond.

[0010] Preferably, the method further includes a phase change-triggered catalyst support, which encapsulates the catalyst used to catalyze the reaction between the reactive interfacial shuttle plasticizer and waste rubber. The phase change-triggered catalyst support has a preset melting point. Satisfying the relation: ;in, This refers to the processing temperature during the low-temperature phase. The processing temperature is the high-temperature stage; the phase change triggered catalyst support is solid at the low-temperature stage to lock the catalyst, and melts at the high-temperature stage to release the catalyst.

[0011] Preferably, the mechanism by which the covalent bonding event activates the in-situ crosslinking agent of the interface co-reaction is as follows: the covalent bonding reaction generates a byproduct or causes a change in the local chemical environment of the interface, and the byproduct or the change in the chemical environment acts as a catalyst or activator to activate the in-situ crosslinking agent of the interface co-reaction to undergo a crosslinking reaction.

[0012] Preferably, the reactive interfacial shuttle plasticizer is an oligomer containing epoxy or isocyanate functional groups; the interfacial co-reaction in-situ crosslinking agent is a multifunctional epoxy compound or a blocked polyisocyanate, the activation conditions of which are matched with the reaction conditions of the reactive interfacial shuttle plasticizer and the waste rubber.

[0013] Preferably, the method also includes a polymer processing aid. At high temperatures, the polymer processing aid induces micro-phase separation due to the increase in melt viscosity caused by covalent bonding, thereby forming a dynamic lubricating layer in the melt.

[0014] Preferably, the processing temperature during the low-temperature stage is set to 220°C. Up to 230 The processing temperature during the high-temperature stage is set to 255°C. Up to 265 The range.

[0015] Preferably, the waste polyester is waste polyethylene terephthalate chips or fibers; the waste rubber is waste vulcanized rubber powder with a particle size in the range of 40 mesh to 100 mesh.

[0016] Preferably, the amount of reactive interfacial shuttle plasticizer added is set to 1% to 5% of the total weight of waste polyester and waste rubber; the amount of interfacial co-reactive in-situ crosslinking agent added is set to 0.5% to 3% of the total weight of waste polyester and waste rubber.

[0017] Preferably, the sterically hindered group is one or more groups selected from cyclohexyl, tert-butyl and adamantyl, and is attached to the α- or β-carbon atom of the reaction terminal functional group.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. By adding a reactive interfacial shuttle plasticizer to the melt blend, its polyester-friendly end interacts with the polyester during the low-temperature stage of the blending process, lowering the melting temperature of the polyester component. This allows the entire blending process to proceed at a temperature insufficient to cause significant thermal degradation of the rubber. Subsequently, during the high-temperature stage of the blending process, the reactive end of the plasticizer chemically bonds with the rubber. While forming interfacial compatibilization, its plasticizing effect in the polyester matrix is ​​terminated with the formation of chemical bonds. This process separates the material's processing temperature window from its final performance, enabling the compatible combination of waste polyester and waste rubber—two materials with conflicting thermal performance requirements—on standard melt blending equipment. At the same time, the polyester matrix in the final product regains its proper thermal stability.

[0020] 2. When the chemical structure of a reactive interfacial shuttle plasticizer contains a sterically hindered group near the reactive functional group that can react with rubber, this group forms a physical barrier next to the newly formed interfacial chemical bond, delaying the approach and erosion of water molecules. This method changes the guarantee of long-term interfacial stability from relying on the external environment or subsequent treatment to being determined by the structure of the interfacial molecules themselves, so that the prepared geotextile has more predictable durability in terms of interfacial bonding strength under long-term humid and hot service environment.

[0021] 3. When the melt-blended material also contains an interfacial co-reactive in-situ crosslinking agent, and the crosslinking reaction of the crosslinking agent is triggered by the chemical bonding process between the reactive interfacial shuttle plasticizer and the rubber, a gradient crosslinked network structure transition layer is generated in-situ in the interfacial region. This transition layer changes the stress transmission path inside the rubber particles and disperses the concentrated stress to a wider area, so that the failure mode of the material under stress changes from the cohesive tearing of the rubber particles to the tough yielding of the interfacial transition layer, thereby improving the fatigue resistance of the final product. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the compatibilization and modification process based on time-series chemical regulation according to the present invention.

[0023] Figure 2 This is a graph showing the correlation between the temperature and torque curves inside the extruder and key reaction events in this invention.

[0024] Figure 3 This is a schematic diagram of the configuration of the automated production system based on process control according to the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in further detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0026] This invention discloses a method for preparing compatibilized modified geotextiles based on waste polyester and rubber. In a melt blending apparatus, a group of synergistically functioning and sequentially controlled chemical additives are added to establish a dynamically changing processing environment. The method first utilizes the chemical additives to temporarily alter the melting characteristics of the waste polyester material, allowing for mixing and dispersion of the materials within a range below the degradation temperature of the waste rubber. Subsequently, as the temperature rises, a pre-defined interfacial reaction completes the compatibilizing bonding of the two phases, simultaneously eliminating the temporary effects introduced to establish the low-temperature range. This solves the problem of thermal property mismatch between high-melting-point polymers and heat-sensitive polymers in blending within a continuous process, resulting in a composite material possessing both interfacial bonding strength and matrix mechanical properties. To achieve this, the core step of this preparation method is the melt blending of waste polyester, waste rubber, and one or more functional additives. The additives mainly include a reactive interfacial shuttle plasticizer (RISP), which refers to an oligomer with a polyester-loving end and a highly reactive end. In the low-temperature processing stage, it acts as a physical plasticizer to lower the melting point of polyester, and in the high-temperature stage, it is anchored to the interface through chemical bonding. An interfacial co-reaction in-situ crosslinking agent (ICIC) can be selectively added according to specific performance requirements. ICIC refers to a multifunctional compound whose activation conditions match the RISP bonding reaction. It is used to construct a network structure in the interfacial region through in-situ crosslinking reaction. A phase change triggered catalyst support (PCTC) is a support composed of a catalyst coated with a crystalline wax shell. The release timing of the catalyst is controlled by the physical phase change (melting) of the shell. A polymer processing aid (HPA) is a polymer additive used in this invention to induce micro-phase separation and form a dynamic lubricating layer in the high-temperature stage, such as ultra-high molecular weight silicone-polycaprolactone block copolymer.

[0027] In the specific implementation process, the initial material of this method is a physical mixture, the components of which include: waste polyethylene terephthalate (PET) chips or fibers, whose conventional melt processing temperature is not lower than 260°C. The process involves: waste vulcanized rubber powder (CR) with a particle size range of 40 to 100 mesh, whose thermal degradation initiation temperature is lower than that of PET; and a reactive interfacial shuttle plasticizer (RISP) added at a weight of 1% to 5% of the total weight. RISP is an oligomer containing both polyester-friendly and reactive ends, such as an oligomer containing epoxy or isocyanate functional groups. Specifically, the epoxy equivalent of the RISP is precisely calibrated to be in the range of 180 g / eq to 220 g / eq, and the hydrophilic-lipophilic balance of its polyester-friendly ends is set between 8.5 and 12.0 to ensure that, in a molten environment at 225°C, the molecular chains can physically penetrate the PET matrix at a diffusion rate of 1.2 mm per second. The method is carried out in a twin-screw extruder with multi-temperature zone control, where the initial heating zone of the extruder is set to a low-temperature stage, and the processing temperature is maintained at 220°C. Up to 230 At this temperature, RISP molecules utilize their polyester-loving ends to form non-covalent bonds with the PET matrix, penetrating and breaking the intermolecular forces between polyester macromolecular chains, acting as a temporary plasticizer. This allows PET to reach a fluid state at a temperature below its conventional melting point, thus enabling blending within a safe temperature range for the rubber components. When the material is conveyed to the high-temperature zone at the end of the extruder, the temperature is raised to 255°C. Up to 265 At this time, the RISP molecules that have migrated to the PET and CR interface are activated by heat at their reactive ends and undergo covalent bonding with the active groups on the rubber surface. This chemical anchoring effect forms a molecular bridge between the two phases, achieving interfacial compatibilization. At the same time, this anchoring effect restricts the migration ability of RISP molecules in the PET matrix, thereby terminating its plasticizing function. This causes the glass transition temperature of the waste polyester matrix to recover from 62 degrees Celsius in the low-temperature plasticized state to 74 degrees Celsius, reaching more than 95% of the glass transition temperature of pure polyester. The PET matrix then recovers its inherent rigidity and heat resistance.

[0028] To improve the long-term interfacial stability of geotextiles in humid environments, one approach is to attach a chemically inert steric hindrance group to the chemical structure of the RISP molecule, near the reactive functional group that can react with rubber, such as at the α- or β-position carbon atom. This group can be selected from cyclohexyl, tert-butyl, or adamantyl. After the RISP-rubber interfacial covalent bonding reaction is completed, this steric hindrance group, due to its three-dimensional volume, forms a physical barrier next to the newly formed chemical bond, increasing the steric hindrance for water molecules to approach and attack the bond, thereby reducing the hydrolysis rate of the interfacial chemical bond and improving the long-term durability of the material. To address the problem of stress concentration within the waste rubber particles after the increased interfacial bonding force may lead to particle cohesive tearing, another approach is to add 0.5% to 3% (by weight) of an interfacial co-reaction in-situ crosslinking agent (ICIC) to the blend. ICIC is a multifunctional... The reaction activation conditions of the epoxy compound or the blocked polyisocyanate are matched with the bonding reaction conditions of RISP and rubber. In the high-temperature interfacial reaction stage, the covalent bonding event between RISP and rubber triggers or catalyzes the in-situ crosslinking reaction of ICIC molecules in the interfacial region by generating specific byproducts or changing the local chemical environment of the interface. This process generates a stress dissipation layer with a gradient network structure around the rubber particles. The physical construction logic of this gradient structure is based on the concentration diffusion difference of ICIC from the interface to the matrix at 260°C, which is 0.2 mm to 0.5 mm per minute. This results in a stepwise discrete distribution of crosslinking density from the CR surface to the PET matrix, decreasing by 15% per 10 μm interval. This network structure can disperse stress and change the failure mode of the material from cohesive tearing of particles to tough yielding in the interfacial transition zone, thereby improving the toughness and fatigue resistance of the product.

[0029] Considering the potential differences in reactivity between batches of waste raw materials in industrial applications, another implementation method to ensure process stability involves adding a phase change triggered catalyst support (PCTC) to the material. The PCTC has a catalyst core and an outer crystalline wax shell layer, with the wax shell layer having a melting point... Set to satisfy the relation ,in This refers to the processing temperature during the low-temperature phase. This refers to the processing temperature during the high-temperature stage; in the low-temperature and medium-temperature zones of the extruder, PCTC exists in a solid state, physically isolating the catalyst from the reactant system and preventing premature occurrence of the main reaction; when the material enters at a temperature exceeding... In the high-temperature region, the wax shell melts, releasing a catalyst to drive the interfacial bonding reaction rapidly and completely. This design controls the initiation timing of the chemical reaction through a physical phase transition process, allowing the preparation method to adapt to fluctuations in the activity of the raw materials. In addition, to address the problem of a sharp increase in melt viscosity in the later stages of processing that may be caused by the catalytic reaction, a high molecular weight processing aid (HPA), such as an ultra-high molecular weight silicone-polycaprolactone block copolymer, can be added to the material. In the high-temperature stage, when the apparent viscosity of the blended melt rises to 1500 Pa·s and the screw shear rate exceeds 200 s⁻¹, micro-phase separation is induced due to changes in the chemical environment of the blended system and the increase in viscosity. The separated HPA molecules form a dynamic lubricating layer in the high-shear region of the melt. This process establishes a negative feedback regulation mechanism: the increase in viscosity promotes the formation of the lubricating layer, and the formation of the lubricating layer inhibits further increases in viscosity, thereby ensuring the fluidity of the melt in the later stages of processing, which is beneficial to the uniform dispersion of the material and the stability of the final product performance.

[0030] Example 1: In a large-scale water conservancy project for seepage prevention, the geotextile raw materials were specified as waste polyethylene terephthalate (PET) fiber bundles and 80-mesh waste vulcanized rubber powder (CR) from different sources and batches. The geotextile was then processed at 260... During conventional high-temperature melt blending processes at the above temperatures, CR particles undergo thermo-oxidative degradation, resulting in the final product's mechanical properties failing to meet design specifications and causing continuous scrapping of production batches. In this scenario, the method described in the aforementioned specific implementation method is applied, blending waste PET, CR with 3% by mass of reactive interfacial shuttle plasticizer (RISP) and 1.5% by mass of interfacial co-reactive in-situ crosslinking agent (ICIC); the process temperature is set at 225°C in the initial section of the twin-screw extruder. The RISP molecule, through its polyester-friendly end effect, causes the PET fiber bundle to melt at a temperature below its conventional melting point, thereby achieving uniform physical dispersion with the CR particles under conditions that prevent the latter from degrading. Mechanical analysis of the intermediate sample containing only RISP showed that although the PET matrix and CR particles had formed a good interfacial bond, the fracture started inside the CR particles, that is, the failure mode of the material was cohesive tearing of the particles. This indicates that the improvement of the interfacial strength makes the strength of the waste rubber particles themselves the limiting factor for the system's performance.

[0031] As the material rotates with the screw and enters the high-temperature zone at the end of the extruder, the process temperature is raised to 260°C. At this time, two closely related chemical processes are triggered sequentially. First, RISP molecules migrating to the interface region covalently bond with the CR surface. This chemical anchoring, while forming interface compatibilization, terminates the plasticizing effect of RISP molecules in the PET matrix. Second, the bonding reaction between RISP and CR acts as an in-situ chemical signal, immediately triggering the cross-linking reaction of ICIC molecules distributed around the interface, generating a gradient cross-linked stress dissipation network in situ on the surface and shallow region of the CR particles. The formation of this network alters the stress transmission path from the PET matrix to the interior of the CR particles, dispersing the concentrated stress to a wider area. Finally, this complete... The geotextile samples prepared by the whole formula and process showed that the stress failure mode changed from cohesive tearing of CR particles to ductile yielding in the interfacial transition zone. The tensile strength and fatigue cycle count were increased by more than 60% and 200% respectively compared with the samples using only RISP. This method decouples the material processing temperature window and the final performance requirements through the temporary plasticizing effect of RISP. Then, through the reaction self-locking of RISP and the in-situ triggered crosslinking of ICIC, the mechanical properties of the final product are restored and enhanced. Thus, high-performance composite materials that meet specific engineering requirements can be prepared using waste raw materials with large performance fluctuations on standard blending equipment.

[0032] Example 2: To verify the synergistic effect of key chemical additives in the method of the present invention and their effect on improving the performance of the blend system, the following experiment was conducted; the raw materials used in the experiment included: waste polyethylene terephthalate (PET), intrinsic viscosity 0.78 dL / g; 80-mesh waste vulcanized rubber powder (CR); reactive interfacial shuttle plasticizer (RISP); and interfacial co-reactive in-situ crosslinking agent (ICIC); the experimental equipment was a twin-screw extruder with a screw length-to-diameter ratio of 40:1, and the temperature control accuracy of its heating zone was ±1. The experiment consisted of four groups: control group A, control group B, control group C, and the experimental group using the method of this invention. The formulations of each group differed in the presence or absence of functional additives. Control group A was a physical blend of PET and CR; control group B added 3% (by weight) maleic anhydride-grafted polypropylene to group A; control group C added only 3% RISP to group A; and the experimental group added both 3% RISP and 1.5% ICIC to group A. The weight ratio of PET to CR was set to 70:30 in all groups. The preparation process was standardized: the temperature from the extruder feed zone to the compression zone was 225°C, the low-temperature stage. The homogenization zone and die head temperature are 260°C, which is the high-temperature stage. The screw speed was 300 r / min. After the extruded material was cooled and pelletized, standard specimens for mechanical property testing were prepared by injection molding. The prepared specimens were used to test tensile strength and elongation at break according to GB / T1040.1-2018 standard, and tear strength according to GB / T529-2008 standard. The performance test data of each specimen group are listed in Table 1.

[0033] Table 1: Test data of mechanical properties for different groups.

[0034] Sample group name RISP content (wt%) ICIC content (wt%) Tensile strength (MPa) Elongation at break (%) Tear strength (kN / m) Control group A 0 0 18.5 4.2 15.3 Control group B 0 0 23.1 6.5 20.8 Control group C 3 0 35.4 8.1 33.7 experimental group 3 1.5 38.2 25.6 45.1

[0035] Referring to Table 1, data from control group A show that the unmodified PET / CR blend exhibits low mechanical properties due to poor compatibility. Data from control group B shows that the improvement in system performance using conventional compatibilizers is limited. Data from control group C confirms the role of RISP in enhancing interfacial bonding, with significant increases in tensile strength and tear strength compared to controls A and B, but limited increases in elongation at break, a phenomenon corresponding to the cohesive tearing failure mode of rubber particles. Compared to control group C, the experimental group shows a further slight increase in tensile strength, while elongation at break and tear strength increase by 216% and 33.8%, respectively. This data confirms a synergistic effect between RISP and ICIC, whereby the interfacial reaction of RISP triggers in-situ crosslinking of ICIC, and the resulting interfacial transition network structure compensates for the insufficient strength of the rubber phase.

[0036] Example 3: This example combines Figures 1 to 3 This document describes a method for preparing compatibilized modified geotextiles based on waste polyester and rubber, as follows: Figure 1 As shown, the starting materials are waste polyester PET chips or fibers, waste vulcanized rubber powder (CR) with a particle size range of 40-100 mesh, and functional additives added selectively as needed. The materials first enter the low-temperature blending stage. In this stage, the reactive interfacial shuttle plasticizer RISP plays a temporary plasticizing role, creating a safe processing window for the waste rubber and completing the uniform physical dispersion of the materials. Then, the materials enter the high-temperature reaction stage by heating. In this stage, RISP is anchored at the interface and self-locks to eliminate its plasticizing effect, thereby restoring the properties of the polyester matrix and triggering a key interfacial reaction. This interfacial reaction can be precisely controlled by the phase change triggered catalyst carrier PCTC through melt release of the catalyst to shield the raw material activity fluctuations and improve process stability. On the other hand, this covalent bonding event can also trigger the in-situ crosslinking agent ICIC to generate a gradient crosslinking network in the interfacial region. This network disperses stress to a wider area by constructing a stress dissipation mechanism, thereby improving the toughness and fatigue resistance of the material.

[0037] like Figure 2 As shown in the figure, the solid line represents the temperature curve. The dashed line represents the motor torque percentage. In the low-temperature zone comprised of the feeding section, conveying section, and compression section, the process temperature is maintained at 225°C. Around this point, the RISP (Reactive Rubber Processor) plays a plasticizing role, and the motor torque gradually increases to about 40% as the material is compacted and initially plasticized. After the material passes through the melting section and enters the high-temperature zone consisting of the reaction section, homogenization section, and metering section, the temperature is raised to 260°C. Around 10:00, the interfacial bonding reaction and the ICIC in-situ crosslinking reaction occur successively, leading to an increase in melt viscosity and a corresponding increase in motor torque to 70%, reaching a maximum of 72% in the subsequent region. Throughout the high-temperature stage, the torque value remains stable within the 65%-85% stable process window specified by the process.

[0038] like Figure 3 As shown, the system is centered around a multi-temperature zone twin-screw extruder. Upstream of the extruder are waste polyester silos, waste rubber powder silos, and functional additive silos. The materials are precisely proportioned by an automatic batching and mixing system and then fed into the extruder. The extruder's drive motor is controlled in a closed loop by a process control system. This process control system monitors the main motor torque and screw speed in real time and independently monitors and controls the temperature of each zone within the extruder, including the feeding zone, low-temperature blending zone, high-temperature reaction zone, and homogenization and metering zone. This ensures that the process parameters are accurately achieved. After being processed by the extruder and extruded through the die, the material passes through a cooling and shaping device and a pelletizer before finally being sent to the finished product silo. The entire system establishes an automated and continuous production process by linking the chemical reaction process with the equipment parameters.

[0039] Example 4: When processing a batch of waste PET fibers and 60-mesh CR granules from a specific source, a standardized engineering calibration procedure was adopted to determine the specific addition amounts of reactive interfacial shuttle plasticizer (RISP) and interfacial co-reactive in-situ crosslinking agent (ICIC) in this raw material system to achieve an optimized combination of tensile strength and elongation at break in the final product. This procedure aims to specify, through systematic experiments, the addition range of 1% to 5% RISP and 0.5% to 3% ICIC into a suitable combination of addition amounts for the current material. This calibration procedure was performed on a twin-screw extruder with the same functional specifications as the production equipment, and its process parameters were fixed, with the low-temperature processing stage temperature set at 225°C. The high-temperature processing stage has a temperature of 260°C. The screw speed was 300 r / min. An orthogonal design was used in the experiment, with the amount of RISP and ICIC added as variables. The amount of RISP added was taken at three levels: 1.0%, 3.0%, and 5.0%, and the amount of ICIC added was taken at three levels: 0.5%, 1.5%, and 2.5%. A total of nine formulation samples were prepared. After all samples were treated under standard conditions for 24 hours, their tensile strength and elongation at break were tested using a material testing machine according to GB / T1040.1-2018 standard. The arithmetic mean of five test results for each group was taken.

[0040] Experimental data analysis shows that when the RISP addition was 1.0%, the melt pressure monitoring values ​​during the extrusion process fluctuated significantly, indicating that the low-temperature processing window was not fully established and the material was unevenly dispersed, resulting in large dispersion and low average values ​​of the final sample's performance indicators. When the RISP addition increased from 1.0% to 3.0%, the tensile strength of each corresponding group improved, indicating improved interfacial bonding. However, when the RISP addition continued to increase to 5.0%, the tensile strength showed a decreasing trend, and the heat distortion temperature of the material decreased. This phenomenon indicates that excessive RISP molecules remained in the matrix, producing an unintended plasticizing effect. The addition of ICIC mainly affected the elongation at break of the material. At any RISP concentration level, ICIC... When the IC addition amount increased from 0.5% to 1.5%, the elongation at break increased. However, when the IC addition amount reached 2.5%, the elongation at break of the sample decreased, showing a trend of increased brittleness. This corresponds to the excessive rigidity of the interface layer caused by excessive cross-linking. Based on the data from all groups, the combined performance of tensile strength and elongation at break of the product was optimal when the RISP addition amount was set at 3.0% and the ICIC addition amount was set at 1.5%. This calibration procedure transforms the process of selecting the amount of additives from a broad range to an engineering process based on specific raw materials, oriented towards multi-objective performance, and reproducible through standardized experiments. This provides an operational method for determining process parameters for waste materials from different sources.

[0041] Example 5: When a new batch of waste vulcanized rubber powder (CR) with unknown surface reactivity is received in industrial production, a process parameter adaptation procedure for this batch of material is implemented to ensure the stability of the melt blending process. This procedure quantifies the reactivity of CR to select a material with a specific melting point. Phase change triggered catalyst carrier (PCTC) is used to control the interfacial reaction rate and ensure the performance consistency between product batches.

[0042] This procedure first characterizes the incoming material in a torque rheometer, setting the rotor speed of the torque rheometer to 60 rpm and the chamber filling rate to a constant ratio of 75%. 5g of this batch of CR powder is mixed with 0.15g of reactive interfacial shuttle plasticizer (RISP) at 240°C. Mixing was carried out at a constant temperature, and the torque of the system was continuously monitored. The time from the start of mixing to the point where the torque showed an inflection point was recorded, and this time was recorded as the reaction induction period. The numerical value characterizes the relative reactivity of the CR powder; The 30s threshold determination logic is as follows: Within a 300s monitoring window after the material enters the high-temperature reaction zone, the control system extracts the motor torque increment in 200ms increments. When the absolute value of the cumulative increase in torque exceeds 10.5% within five consecutive sampling cycles, the high-precision timer is automatically triggered to stop and lock the time value; subsequently, based on the measured... The value is selected from a stockpile of PCTCs containing various PCTCs with different melting points. The crystalline wax shell is composed of narrowly distributed microcrystalline wax with a molecular weight between 500 and 800. The physical phase transition point is precisely controlled by adjusting the isoalkane content in the microcrystalline wax. The selection rule is set as follows: if the measured... If the time is below a preset threshold, such as 30 seconds, it indicates that the raw material has high activity, and a material with higher activity should be selected. The PCTC, its At 250 Up to 255 The range is used to delay catalyst release, if If the activity level is higher than this threshold, it indicates that the raw material has low activity; therefore, a material with lower activity should be selected. The PCTC, its At 240 Up to 245 The process allows for the release of catalysts in advance within a certain timeframe. By implementing this procedure, the preparation method can adapt to fluctuations in the chemical state of the raw materials, transforming a chemical process affected by the uncertainty of the raw materials into a deterministic process controlled by physical phase transitions.

[0043] Example 6: To determine the stable process window of the method of the present invention in continuous production, it is necessary to establish a correlation model between the key operating parameters of the extruder and the melt reaction state before processing a specific batch of waste PET and CR raw materials. The purpose of this model is to indirectly characterize the degree of reaction and viscosity change of the molten blend in the barrel by monitoring a physical quantity that can be obtained online and in real time, namely the torque of the main motor of the extruder, thereby setting a quantitative and executable process control range for actual production. The establishment process of this procedure is as follows: using an extruder with a set standard temperature curve (low temperature zone 225) High temperature zone 260 The twin-screw extruder continuously runs the formulated material at a fixed screw speed (e.g., 300 r / min), and uses an online torque sensor to record the main motor torque when it reaches a steady state; subsequently, the set temperature of the high-temperature zone is adjusted within a small range (e.g., at 2...). The step size is 255. Up to 265 The screw speed (adjusted in 20r / min increments, between 280r / min and 320r / min) and the steady-state motor torque values ​​corresponding to different parameter combinations are recorded. Simultaneously, samples extruded under each parameter combination are taken and their key mechanical properties, such as elongation at break, are tested. Through data correlation analysis, an optimal operating range for the motor torque is determined. This torque value is mapped to a physical viscosity index through a preset conversion step relationship in the process control system. The lower limit torque value (e.g., 65%) corresponds to a melt apparent viscosity of 1100 Pa·s, representing the minimum threshold for the interface reaction to reach quality compliance. The upper limit torque value (e.g., 85%) corresponds to a melt apparent viscosity of 1650 Pa·s, which is set as a critical safety point close to a sharp increase in melt viscosity that may lead to overload. Thus, a motor torque range between 65% and 85% is established as the stable process window for this batch of material on this equipment.

[0044] In subsequent mass production, the operator's core task is to keep the real-time monitored value of the main motor torque within the calibrated stable process window by fine-tuning the screw speed or temperature. Any deviation from this window is used as an early warning signal that process adjustments are needed. This method simplifies the control of complex melting reaction processes into the monitoring of a single, directly measurable equipment parameter.

[0045] Example 7: When transferring the method of the present invention from a laboratory-scale extruder to an industrial-grade production line with a larger screw diameter and a length-to-diameter ratio of 48:1, the screw speed needs to be increased to 450 r / min to achieve the target capacity. Under these high-shear and high-throughput conditions, a trial production was conducted using the experimental group's formulation (without HPA). The online monitoring system showed that when the material flowed through the high-temperature reaction zone, the torque of the extruder's main motor rapidly increased to more than 90% of the rated value and triggered an overload protection alarm, causing the production to be unable to operate stably and continuously. This phenomenon verified the melt viscosity trap problem.

[0046] To address this technological challenge, while maintaining the same proportions of the components in the aforementioned formulation, an additional 0.5% (by weight) of high molecular weight processing aid (HPA) was added to the material, and the production process was repeated. During this process, the system used 50Hz high-frequency sampling of the main motor current to calculate the apparent viscosity of the melt in real time. The viscosity threshold of 1500 Pa·s and the shear rate of 200 / s were determined based on 10 sets of torque-viscosity discrete point lookup data measured by a torque rheometer at 260°C, combined with the geometric parameters of the extruder screw length-to-diameter ratio of 48:1. The torque was obtained by mapping it to the control system register using a linear scaling factor of 0.85. During the second run at the same screw speed of 450 r / min, the online monitoring system showed that the main motor torque remained consistently within the 70% to 75% range throughout the process, without any sharp increases or overload alarms, ensuring stable and continuous production. This result demonstrates that HPA, through its reaction-induced phase separation and dynamic lubrication mechanism, buffered the dramatic increase in melt viscosity caused by rapid and extensive interfacial reactions, ensuring the process feasibility and robustness of the method under industrial scale-up conditions.

[0047] To further verify in principle the key role of the method described in this invention in avoiding thermal damage to materials, the following comparative examples are set up to reproduce the technical problem of performance degradation caused by the mismatch between processing temperature and material thermal stability.

[0048] Comparative Example 1: This comparative example aims to simulate the conventional high-temperature melt blending process in the background art, used to process the same waste polyester (PET) and waste vulcanized rubber powder (CR) materials as in Example 2. The only difference from the test group is that this comparative example does not use the reactive interfacial shuttle plasticizer (RISP) and interfacial co-reactive in-situ crosslinking agent (ICIC) of the present invention, but instead uses a conventional reactive compatibilizer (maleic anhydride grafted polypropylene) in the art, and is processed under a single high-temperature condition. The raw materials used in the test include: the same waste polyethylene terephthalate (PET) and 80-mesh waste vulcanized rubber powder (CR) as in Example 2, with the weight ratio of PET to CR fixed at 70:30. The functional additive is 3% (by weight) maleic anhydride-grafted polypropylene; the preparation process is carried out on the same twin-screw extruder as in Example 2, with the screw speed also set to 300 r / min. Since the formulation does not contain components that can plasticize PET at low temperatures, in order to achieve a flowable melt state for blending with CR, the temperature of all heating zones of the extruder (from the feed zone to the die) must be set to 260°C. During the extrusion process, a trace amount of irritating odor was observed emanating from the vent of the die head. This is a typical phenomenon of thermal degradation of waste rubber at this temperature. The surface gloss of the extruded strip was poor, and it exhibited high brittleness after cooling. The extruded material was subjected to the same cooling pelletizing and injection molding process to prepare standard strips for mechanical property testing. The prepared strips were tested according to the same test standards as in Example 2 (tensile properties according to GB / T1040.1-2018, tear properties according to GB / T529-2008). The data obtained are shown in the table below.

[0049] Table 2: Mechanical property test data of Comparative Example 1.

[0050] Sample group name Tensile strength (MPa) Elongation at break (%) Tear strength (kN / m) Comparative Example 1 22.8 5.9 20.1

[0051] Furthermore, scanning electron microscopy (SEM) analysis of the tensile fracture surface of the sample in Comparative Example 1 revealed that the edges of the detached pits of the rubber particles were smooth, indicating weak interfacial bonding between the rubber particles and the polyester matrix. Simultaneously, the cross-section of the rubber particles remaining in the matrix exhibited a sponge-like, loose, porous structure, providing direct evidence that the internal cross-linking network was severely damaged during high-temperature processing. The experimental results demonstrate that when using conventional high-temperature blending processes, to meet the necessary processing temperature for melting the PET component, significant thermal degradation of the CR component is inevitable, causing it to lose its original elasticity and reinforcing properties. Even with the addition of conventional reactive compatibilizers, it is impossible to compensate for the loss of overall material toughness (manifested as elongation at break and tear strength) due to the destruction of the rubber phase's own structure. This result, conversely, confirms that the technical solution of this invention, which constructs a temporary low-temperature processing window to protect the structural integrity of the heat-sensitive component, is a prerequisite for realizing the high-value utilization of such thermally conflicting materials.

[0052] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0053] Finally, 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.

Claims

1. A method for preparing compatibilized modified geotextile blankets based on waste polyester and rubber, characterized in that, The method includes the following steps: Step a, in the low-temperature stage of blending, at a processing temperature lower than the thermal degradation initiation temperature of waste rubber, the polyester-loving ends of the plasticizer molecules in the reactive interface of the system penetrate into the waste polyester matrix, breaking the inter-chain forces of polyester and making the waste polyester flowable. In step b, during the high-temperature stage of blending, the reactive ends of the reactive interfacial shuttle plasticizer molecules covalently bond with the waste rubber surface that has migrated to the interface; and the occurrence of the covalent bonding event between the reactive interfacial shuttle plasticizer and the waste rubber activates a pre-set interfacial co-reactive in-situ crosslinking agent in the system. After the interfacial co-reactive in-situ crosslinking agent is activated, an in-situ crosslinking reaction occurs in the interfacial region between the waste polyester and the waste rubber.

2. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 1, characterized in that, In the chemical structure of reactive interfacial shuttle plasticizers, a steric hindrance group is contained in the position of the reactive end functional group that can react with waste rubber; after the steric hindrance group is formed by covalent bonding, it forms a three-dimensional physical barrier next to the newly formed chemical bond.

3. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 1, characterized in that, The method also incorporates a phase change-triggered catalyst support, which encapsulates the catalyst used to catalyze the reaction between the reactive interfacial shuttle plasticizer and waste rubber. The phase change-triggered catalyst support has a preset melting point. Satisfying the relation: ;in, This refers to the processing temperature during the low-temperature phase. The processing temperature is the high-temperature stage; the phase change triggered catalyst support is solid at the low-temperature stage to lock the catalyst, and melts at the high-temperature stage to release the catalyst.

4. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 1, characterized in that, The mechanism by which covalent bonding events activate in-situ crosslinking agents for interfacial co-reaction is as follows: the covalent bonding reaction produces a byproduct or causes a change in the local chemical environment of the interface, and the byproduct or the change in the chemical environment acts as a catalyst or activator.

5. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 1, characterized in that, Reactive interfacial shuttle plasticizers are oligomers containing epoxy or isocyanate functional groups; The in-situ crosslinking agent for interfacial co-reaction is a multifunctional epoxy compound or a blocked polyisocyanate, whose activation conditions are matched with the reaction conditions of the reactive interfacial shuttle plasticizer and waste rubber.

6. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 3, characterized in that, The method also incorporates a polymer processing aid, which induces microphase separation at high temperatures due to the increase in melt viscosity caused by covalent bonding.

7. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 1, characterized in that, The processing temperature for the low-temperature stage was set to 220°C. Up to 230 The processing temperature during the high-temperature stage is set to 255°C. Up to 265 The range.

8. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 1, characterized in that, Waste polyester refers to waste polyethylene terephthalate chips or fibers; waste rubber refers to waste vulcanized rubber powder with a particle size ranging from 40 mesh to 100 mesh.

9. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 1, characterized in that, The amount of reactive interfacial shuttle plasticizer added was set to 1% to 5% of the total weight of waste polyester and waste rubber; the amount of interfacial co-reactive in-situ crosslinking agent added was set to 0.5% to 3% of the total weight of waste polyester and waste rubber.

10. The method for preparing a compatibilized modified geotextile based on waste polyester and rubber according to claim 2, characterized in that, The sterically hindered group is one or more groups selected from cyclohexyl, tert-butyl, and adamantyl, and is attached to the α- or β-carbon atom of the reaction terminal functional group.

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