In order to optimize the molding process of polyetheretherketone(PEEK) and improve the wear resistance of the material and expand the range of applications, carbon fiber (CF) is used as reinforcing phase and PEEK/CF composites under different heat treatment processes were prepared at different injection temperature conditions. Tribologic properties of composites are tested by tribo-wear testing machines, and surface analysis and performance tests are performed using a X-ray diffraction, a white light interferometer, and a scanning electron microscope. The results show that the injection temperature and heat treatment process have no effect on the phase of PEEK/CF composites. With the increase of injection temperature, the friction coefficient and wear of the sample surface show a trend of decreasing first and then increasing, while the friction coefficient and wear rate of the sample after tempering are smaller. When the injection temperature is 175 ℃, the friction coefficient of the tempered material is the lowest, which is 0.091 4, and the wear rate is the lowest, which is 0.106×10^-6 mm³/(N·m). The research indicates that appropriate injection temperature and heat treatment can improve the wear reduction and wear resistance of PEEK/CF composites.

A variety of silane coupling agents were used to modify hollow glass beads (HGB) to improve the interface compatibility between HGB and polypropylene (PP), and the maximum addition amount of modified HGB was explored. At the same time, low density polyolefin elastomer (POE) was introduced to toughen PP. The results show that the HGB modified by coupling agents has good compatibility with PP and improves the thermal stability of the composites, among which vinyl trimethoxysilane (A-171) has the best modification effect. Compared with the unmodified PP/HGB composites, the tensile strength and bending strength of PP/A-171-HGB are increased by 4.02 MPa and 9.28 MPa, respectively, and the density decreases to 0.902 g/cm³. When 10% modified HGB and 15% POE are added, the balance of rigidity and toughness of the composite can be ensured. Compared with the unmodified PP/HGB composites, the elongation at break of the composite is increased by 73.4%, and the density decreases to 0.864 g/cm³.

High quality industrial development focuses on grasping the progressiveness of technology, conforming to the trend of a new round of scientific and technological revolution and industrial change, and promoting Chinese path to modernization with the construction of a manufacturing power as the focus. At this stage, China has the advantages of tamping the foundation of modern industry and super large scale market, laying the foundation for high-quality industrial development and promoting Chinese path to modernization. Therefore, this paper analyzes the theoretical logic of high-quality industrial development promoting Chinese path to modernization from three aspects: Achieving common prosperity for all people, developing green low-carbon manufacturing, and cultivating new quality productivity. In order to further give the precise enabling role of high industrial quality for Chinese path to modernization, it is proposed to actively cultivate new industrial industries, build industrial talent gathering highlands, and promote industrial green development, so as to promote the cohesion of Chinese path to modernization.

In order to explore the potential application of poly(glycolic acid) (PGA) instead of poly(lactic acid) (PLA) in the modification of poly(terephthalic acid-butylene adipate) (PBAT), PGA (mass fractions 0~25%) and PBAT were blended by twin-screw melt blending, and the changes of thermal properties, mechanical properties, crystallization properties and barrier properties of the blends were analyzed. The results show that PGA acts as nucleating agent and reinforcing agent in the blend system, which can increase the crystallization temperature, tensile strength and elastic modulus, and decrease the crystallization enthalpy and thermal decomposition temperature. When the content of PGA increases to 25%, the Vicat softening point of the blend system reaches 89.4 ℃ and the hot deformation temperature reaches 41.6 ℃. With the increase of PGA content, the water vapor/oxygen barrier property of the blend system decreases at first and then increased. However, when the content of PGA increases to 25%, the elongation at break of the blend decreases to 221%. Based on the experimental results and related literature, the properties of 25% PGA and 25% PLA modified PBAT were compared. The results show that the mechanical properties and barrier properties of 25% PGA modified PBAT are significantly better than those of 25% PLA modified PBAT, and the degradation rate of M-25 is faster than that of N-25 in 0`90 days, both of which meets the degradation standard of industrial compost.

Electromagnetic shielding plastics with different mass fractions were prepared by melt blending three kinds of silver-coated copper powder (Ag@Cu) with ethylene-vinyl acetate copolymer (EVA). The effects of different mass fractions and particle sizes of Ag@Cu on the electrical conductivity, shielding properties and mechanical properties of EVA-based electromagnetic shielding plastics were investigated. EVA-based electromagnetic shielding plastics were toughened by maleic anhydride grafted ethylene-octene copolymer/ethylene-octene copolymer (POE-g-MAH/POE) toughening masterbatch and polyisobutylene (PIB)/terpene toughening masterbatch, respectively, to obtain highly filled electromagnetic shielding plastics. The results show that with the increase of Ag@Cu content, the electrical conductivity of EVA-based electromagnetic shielding plastics increases, while the mechanical properties decrease. The percolation threshold of the composites decreases with the increase of filler particle size. When the Ag@Cu filling content is 80%, the shielding effectiveness increases with the increase of filling particle size. Compared with POE-g-MAH/POE, the toughening effect of PIB/terpene is the best, the elongation at break is increased to 187.3%, the shielding effectiveness is kept above 70 dB in the range of 30~1 000 MHz, and it shows better extrusion processability.

In order to improve the toughening efficiency of polypropylene (PP) and study its toughening mechanism, PP/HDPE/EPDM blends were prepared by melt blending with PP/HDPE blends as matrix and ethylene propylene diene monomer (EPDM) as toughening modifier. The results show that the core-shell structure of EPDM and HDPE is dispersed in the matrix, and the interaction force between EPDM and matrix is enhanced. EPDM promotes the crystallization of PP, but inhibits the crystallization of HDPE, thereby refining the dispersed phase of the core-shell structure. With the increase of EPDM content (4%~12%), the impact strength of PP/HDPE/EPDM blends is enhanced, and EPDM can toughen PP while slowing down the rapid decline of PP tensile strength. When the EPDM content is up to 16%, the impact strength of the blend reaches 11.18 kJ/m², which is 158% higher than the PP/HDPE blends. The toughening mechanism of PP/HDPE/EPDM blend is the cavitation effect of EPDM shell and HDPE core structure, which enhances its energy absorption.

Na-GMMT/TPS pellets (TPS for short) were prepared with sodium montmorillonite as filler. TPS was blended with PBAT in different proportions, and TPS-PBAT composites were prepared by twin-screw extruder. The structure and properties of TPS-PBAT composites were characterized by universal material testing machine, X-ray diffraction (XRD), thermogravimetric analyzer (TG) and scanning electron microscope (SEM). The results show that when TPS is used as matrix, the tensile strength of the composites can be greatly improved while maintaining good elongation at break. The elongation at break of TPS-PBAT-4 composites is 233.3% and the tensile strength is 18.9 MPa. With the increase of TPS content, the diffraction peaks of the composites gradually flatten, indicating that the addition of TPS reduces the crystallinity of the composites. The addition of TPS improves the thermal stability of corn starch and PBAT. When PBAT is used as matrix, the compatibility between TPS and PBAT is poor. When TPS is used as matrix, there is no obvious boundary between TPS and PBAT, and it shows better compatibility.

Polyvinyl chloride (PVC) resin is hard and brittle. Adding fly ash (FA) will increase the hardness of PVC composites and deteriorate the processing plasticity, thus limiting the application range of PVC/FA composites. Dioctyl terephthalate (DOTP) and tris(2-hydroxyethyl) isocyanuric acid (THEIC) were used to improve the mechanical properties of PVC/FA composites. The effects of the ratio of DOTP and THEIC on the thermal stability, mechanical properties and electrical properties of PVC/FA cable composites were investigated. The results show that the combination of DOTP and THEIC can improve the thermal stability and mechanical properties of PVC/FA cable composites. When adding 29 phr DOTP and 1 phr THEIC at the same time, the elongation at break of PVC/FA2 composite is 107.98%. Compared with the composite without plasticizer, the elongation at break of PVC/FA2 is increased by 105.31%. The thermal decomposition temperature in the first stage and the second stage of PVC/FA2 is increased by 11.1 ℃ and 6.0 ℃ respectively, and the processability of the composite is significantly improved.

In order to improve the flame retardancy of polypropylene/magnesium hydroxide (PP/MH) composites and to grasp the intensity of different influencing factors on the flame retardancy of the materials, the MH particle size, contact angle, and the amount of additive were used as the three inputs, and the limiting oxygen index (LOI) of PP/MH composites was taken as the output. A three-layer BP neural network prediction model was established, and the orthogonal test results were used as samples to train it to predict the flame retardancy of the composites. The prediction results were verified by experiments. The results show that the effects of various factors on the flame retardancy of the PP/MH composites from large to small are MH content, MH contact angle and MH particle size. The optimal process parameters: the MH particle size is 0.2 µm, the MH contact angle is 135°, the MH content is 40%. Under these conditions, the LOI of PP/MH composite is as high as 31.5%. The BP neural network model can accurately predict the flame retardancy of composites, and the relative error between the predicted value and the experimental value is generally less than 5%. The prediction model of flame retardancy can be used to optimize the performance of materials, reduce the experimental workload, and improve the work efficiency.

The engine hood cover should not only consider the structural strength, stiffness and stability, but also meet the service temperature and weight reduction requirements, so the high temperature bismaleimide resin matrix composite is selected to manufacture the engine hood cover. CCF800H/QY260E, a high-temperature cured bismaleimide high-strength carbon fiber prepreg, was used to prepare a large curvature and complex stiffened mouth cover by co-curing and secondary bonding process, which can serve for a long time at 230 ℃. The molding technology of high temperature resin matrix composite parts, the method of laying closed ring reinforced edges and the positioning mode of stringer and reinforced edges with high efficiency and low cost were studied. The optimal selection of process auxiliary materials, tooling structure and materials, autoclave equipment and accessories for high temperature resin matrix composite parts was completed, and the high temperature resistant large curvature stiffened complex structure flap parts were successfully prepared.

Computer simulation technology is used to simulate the injection molding of a network security controller, and the flatness is optimized and analyzed. By comparing and analyzing the injection molding results of three injection schemes: center injection, long-side injection and short-side injection, the optimal injection scheme is short-side injection. Taking process parameters as independent variables and flatness as objective variables, orthogonal test was designed and data was analyzed. The results show that the influence of holding time on flatness is extremely significant, the influence of melt temperature and cavity temperature on flatness is significant, and the influence of injection time on flatness is not significant. The optimum combination of process parameters is A₃B₁C₃D₁. Through process optimization, the flatness is reduced to 1.070 7 mm, which is 28.2% lower than that of the initial process. The actual mold test results are qualified, which verifies the feasibility of this optimized process.

Silane coupling agents of KH550, KH560, and KH570 were employed for surface modification of silicon carbide whiskers (SiCw), and their effects on the hardness, flexural strength, and friction and wear performance of SiCw/polyimide (PI) composites were investigated. The results show that surface modification with KH550 and KH560 can effectively enhance the hardness and flexural strength of the composites, with KH560 showing more pronounced improvements. However, KH570 modification led to a notable reduction in hardness and flexural strength of the composites. When subjected to abrasion against GCr15 balls at loads ranging of 6~12 N, the surface modification with KH550 and KH560 significantly improves the wear resistance of the composites. Specifically, at lower loads (6 N) during abrasion, the KH560-modified composites exhibits the lowest wear rate, but as the friction load increases, the wear rate rises rapidly. Under higher loads of 9~12 N, the KH550-modified composites possesses the best wear resistance among all comparative samples. However, the wear resistance performance of KH570-modified samples is consistently poor under various loads, indicating that KH570 is not suitable for surface modification of SiCw in SiCw/PI composites.

Thermosetting materials are widely used due to their excellent performance, but their difficulty in reshaping leads to resource waste and environmental pollution. By introducing the dynamic covalent bond into the cross-linking network of polymers, vitrimers with thermosetting properties and recyclable properties are prepared. In the article, the synthesis characteristics of different covalent bond exchange types of vitrimers are summarized, and the reaction mechanism, advantages and disadvantages of transesterification, disulfide exchange and imine exchange are emphasized. According to the research status of vitrimers, the application prospects in the fields of self-healing and weldability are analyzed. Finally, according to the current market demand and material properties, the future development prospects of vitrimers are prospected.

Polylactic acid (PLA) is a biodegradable material with good degradability, mechanical properties and processing properties. However, PLA still has some problems such as poor heat resistance, which limits its application and development in the fields with high heat resistance requirements. Heat resistant modification of PLA has become a hot topic in academia and industry. In this paper, the thermal deformation process and modification mechanism of PLA were introduced, and the research progress of thermal modification of PLA was systematically described, including physical blending modification, processing field control, nucleation crystallization optimization, chemical long chain branching and other methods. The current research status of improving thermal resistance of PLA through nucleation crystallization optimization was emphatically discussed, and the advantages and disadvantages of different thermal modification methods were summarized. According to the properties of PLA material and its needs in actual use, it is predicted that its future development direction will focus on high efficiency and environmental protection, long-term stability, composite function and so on.

The article establishes a headspace gas chromatography method for the determination of vinyl chloride and vinylidene chloride monomer residues in medicinal composite sheet. The separation was performed by HP-INNOWAX capillary column (60 m×0.32 mm×0.5 μm), and hydrogen flame ionization detector was used for testing. Headspace equilibrium temperature was 80 ℃, equilibrium time was 30 min. The column temperature was 50 ℃. The split ratio was 10∶1. The inlet temperature was 200 ℃, and the FID detector temperature was 220 ℃. The results showed that the linear relationship between vinyl chloride and vinylidean chloride was good (r >0.999) in the range of 0.05~5.0 μg. The average recoveries were 102.1%, 101.3%, and the relative standard deviations (RSD) were 1.7% and 1.9%, respectively. The detection limit of vinyl chloride was 0.020 μg/g, and the detection limit of vinylidene chloride was 0.025 μg/g. This method is characterized by its simplicity in operation, accuracy of results, and high sensitivity, and is applicable for the determination of residual vinyl chloride and vinylidene chloride monomer in medicinal composite sheet.

The safety of degradable plastics is the focus of research.The study was based on the determination of main components in degradable plastic bags, and the migration of acetyl-tributyl citrate (ATBC) was analyzed. The migration of ATBC from degradable plastic bags to different food simulants was detected by gas chromatography-mass spectrometry (GC-MS). The migration rule of ATBC in different temperature, thickness and food simulants was studied at 10 days. Under the same temperature and thickness of degradable plastic bags, the migration amount of ATBC in 95% ethanol simulated solution was the largest. Other conditions being equal, the smaller the thickness, the greater the amount of ATBC migration. In the same food simulation solution with the same migration time, the higher the temperature, the greater the amount of ATBC. The type of food simulation liquid, migration temperature, migration time and thickness of plastic bags have important effects on the migration of ATBC in degradable plastic bags.

The coloration and material yellowing problem in the production of high-density polyethylene TR580M from different batches are explored and analyzed. TR580M produced in different batches in one year was selected and analyzed by molecular weight and distribution, melt flow rate (MFR), oxidation induction time (OIT), volatile organic compounds (VOC), xylene insoluble matter, ash content and torque detection during processing. The results show that compared to the other batches, the higher TR580M chroma batch has lower ash content, higher xylene insoluble matter and VOC content, and more significant MFR changes at different shear rates and higher torque increases during processing. The main reason for the yellow color is that the residual activity of the catalyst produced in this batch is high, and the insufficient protection of the antioxidant system during the processing leads to the increase of the gel content.

Aiming at the difficulty of recycling traditional fiber-reinforced composites and the low strength of homogeneous fiber-reinforced composites, thermoplastic polyurethane homogeneous reinforced composites were prepared by in-mold reaction molding method in this paper. The influence of fiber preload on the properties of the prepared composites was investigated by mechanical property tests and micro-morphology. The results showed that the elongation at break of the composites gradually decreased and the tensile strength and modulus gradually increased with the increase of fiber preload in the range of 0~1.1 N. The tensile strength reaches a maximum of 20.99 MPa and strength enhancement efficiency of 84.6% at a preload of 0.9 N. The modulus enhancement efficiency reaches a maximum of 85.3% at a preload of 1.1 N. The mechanical properties of polyurethane homogeneous reinforced composites can be effectively enhanced by appropriate fiber preload.

As one of the components of vanadium batteries, the low conductivity of bipolar plates has become an important factor in restricting the improvement of battery performance. Polyethylene (PE) and various dimensional conductive fillers, such as spherical carbon black (CB), flake graphite (FG), linear carbon fiber (CF), and carbon nanotubes (CNTW), were used as the main raw materials to prepare a point-line-surface three-dimensional highly conductive network carbon plastic composite bipolar plate, and the conductive mechanism was analyzed. The results show that 33% CB can form a conductive path inside PE. The addition of 15% FG increases the contact area with carbon black, thereby enhancing the electrical conductivity of the carbon plastic composite bipolar plate. The addition of 7% CNTW and 5% CF in the bipolar plate forms short-range and long-range conductive pathways, resulting in optimal electrical conductivity and bending strength of 20 S/cm and 46.5 MPa, respectively. The energy efficiency of the bipolar plate reaches 70% at a high current density of 300 mA/cm², which is 6.5% higher than that of the CB/FG bipolar plate. The energy efficiency of the bipolar plate does not decrease significantly after 500 charge and discharge cycles, indicating that the bipolar plate has good rate capability and service life.

The study was to improve the heat resistance of polylactic acid (PLA) through blending modification. Ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) and poly(butylene succinate) (PBS) and talc powder (talc) were added to PLA matric to prepare PLA/E-MA-GMA/PBS/talc blends. The effects of PLA/E-MA GMA/PBS/talc content on the mechanical properties, flowability, rheological properties, heat resistance of the blends were studied. The results show that with the change of PLA/EMAGMA/PBS/ talc blend system, the tensile strength of the blends gradually decreases, while the toughness and impact strength gradually increase, indicating the existence of partial toughening and compatibility between the blend materials. Theheat deflection temperature of the untreated blends remains relatively stable at around 55 ℃, while the heat deflection temperature of the crystallized blends is generally higher than 90 ℃.

Using linear low-density polyethylene (LLDPE) and polyolefin elastomer (POE) as polyolefin materials and boron nitride (BN) as thermal conductivity filler, the LLDPE/POE/BN thermal conductivity composites was prepared by melt blending hot pressing method. The influence of the process on the dispersion structure of BN was studied, and the relationship between the structure and thermal conductivity of the composites was discussed. The thermal conductivity and temperature field of the composites were predicted by finite element simulation. The results show that the composites with different BN dispersion structures are obtained by three processes. The cocontinuous structure composites formed by BN dispersed in LLDPE phase has excellent thermal conductivity. When the mass fraction of BN is 40% and 50%, the thermal conductivity of the composites is 0.72 W/(m·K) and 0.91 W/(m·K), respectively. Based on the dispersion structure of BN, the structure model of the composites was constructed, the thermal conductivity of the composites was predicted successfully, and the better heat transfer behavior of the composites was revealed.

After altering ground tire rubber(GTR) with formic acid and hydrogen peroxide, the epoxidation product (EGTR) was produced. The poly(lactic acid) (PLA)/EGTR blends were then made using the melt blending method, and their micro-morphology, crystalline behavior, and mechanical properties were all carefully examined. The results showed that the carbon-carbon double bond on the GTR molecular chain was successfully oxidized to an epoxy group by formic acid and hydrogen peroxide. The EGTR particles were evenly distributed throughout the PLA matrix, demonstrating good compatibility between the two phases. Furthermore, low levels of EGTR promote PLA crystallization, while high levels of EGTR inhibit PLA crystallization. The PLA/5% EGTR blends had the highest crystallinity of 11.1%, which was 4.8 times higher than that of pure PLA. The blends tensile strength declined as the EGTR content increased, while the impact strength and elongation at break showed a tendency of first increasing and then decreasing. When 10% EGTR was added, the blends had the maximum elongation at break and impact strength, with good toughening effect and tensile strength, showing the best overall mechanical properties. The study provides a basis and technical foundation for modifying PLA with GTR as a toughening material and promotes the recycling of waste rubber.

In order to improve the flame retardancy of EPS insulation materials, different volume ratios of magnesium oxychloride cement (MOC) were added to EPS and its properties were studied. The results show that the mechanical properties of EPS insulation materials gradually increase with the increase of MOC volume ratio. As the volume ratio of MOC increases, the dry density and thermal conductivity of EPS insulation materials continue to increase, indicating a continuous decrease in insulation performance. The limited oxygen index (LOI) of pure EPS is only 18.1%. As the MOC volume ratio increases, the LOI of EPS insulation material gradually increases and combustion becomes more difficult, significantly improving its flame retardancy. When the MOC volume ratio is 9%, EPS insulation material can self extinguish in a short period of time. As the volume ratio of MOC increases, the combustion performance level of EPS insulation materials gradually increases from flammable B₃ level to non flammable A₂ level. Based on the requirements for the performance of EPS insulation materials in JG/T 536—2017, when the volume ratio of MOC is 9%, the comprehensive performance of EPS insulation materials is optimal. At this time, the compressive strength and tensile strength of EPS insulation materials are 0.256 MPa and 0.198 MPa, respectively, with a dry density of 149 kg/m³, a thermal conductivity of 0.055 3 W/(m·K), and a flame retardant grade of A₂.

In this paper, a new foam concrete-extruded polystyrene composite wall panel (FCPW) is proposed. In order to investigate the response of these wall panels to the loading conditions that may occur during an earthquake event, a total of three specimens were designed in this study to study the seismic performance of the wall panels with different sizes of cyclic loads applied to them. By analyzing the seismic parameters such as hysteresis curve, skeleton curve, ductility and stiffness degradation factor of the wall panels, it is concluded that the wall panels have good seismic performance. Both the test phenomenon and damage mechanism indicate that shear damage is the damage form of the specimen. Comparing the specimens, it can be seen that the height-to-width ratio and the strength of the specimen itself have obvious effects on the seismic performance. The larger the height-to-width ratio is, the larger the ductility is and the better the seismic performance is. The smaller the thickness of the concrete is, the smaller the ductility is and the worse the seismic performance is. This study helps to update the iteration of composite wall panels composed of extruded plastic board and concrete and provide a reference for future research.

This study utilized glucose as the main raw material to prepare carbon nanospheres (CNs) using a hydrothermal method. Polyvinylpyrrolidone (PVP) was employed to modify the CNs, resulting in PVP grafted CNs (PVP-g-CNs). The structural morphology and functional group changes of the CNs before and after modification were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Additionally, the dispersibility and adsorption performance of the modified CNs for methylene blue (MB) were tested. The results showed that the modified CNs exhibited an increased size and altered surface structure, while the amorphous crystal structure remained unchanged. PVP-g-CNs demonstrated good dispersibility in water, and adsorption tests revealed that when the PVP addition amount was 0.50 g and the MB solution mass concentration was 30 mg/L, the maximum adsorption capacity of PVP-g-CNs for MB reached 155.03 mg/g, with the adsorption capacity increasing with the pH of the solution. The fitting results of the adsorption model showed conformity to the pseudo-second-order kinetic model and the Langmuir model, with a theoretical maximum adsorption capacity of 238.095 2 mg/g, thus demonstrating excellent adsorption performance.

The article reviews the latest research progress of modified cellulose filled polylactic acid composites, aiming to promote further research and application of this composites. By introducing the application of different modification methods to improve the performance of polylactic acid, such as surface modification of cellulose, functionalization research, grafting copolymerization modification, etc, the performance improvement effect of modified cellulose filled polylactic acid composites was summarized, including mechanical properties, thermal stability, degradation properties, antimicrobial properties, oxygen permeability, UV shielding, crystalline morphology, slow release behavior, etc. Finally, further research in this field was discussed, such as exploring the nucleation mechanism and composite properties of modified cellulose filled polylactic acid, as well as the synergistic mechanism of multiple modification methods and the microstructure of composites. Future research should focus on optimizing modification methods, studying filling mechanisms, and improving the microstructure of composites to achieve better modification effects and performance enhancement. At the same time, further explore more suitable modification methods and composites preparation processes, promote the development of this field and expand its application areas.

A method for determination of the migration of three new plasticizers, triisooctyl phosphate (TOP), diisooctyl sebacate (NINS) and diisooctyl 1,2-cyclohexane dicarboxylate (DEHT), in six food simulants was established. A liquid chromatography-tandem quadrupole time-of-flight high resolution mass spectrometer (HPLC-QTOF) was used to separate the target substances by gradient elution on a T3 column (100 mm×2.1 mm, 2.7 μm) with methanol and 5 mmol/L ammonium formate as the flow, and the detection was carried out under information dependent acquisition mode (IDA). Besides, the migration of positive biodegradable food contact material samples at different contact times, temperatures and food simulants was studied. The results showed that the three new plasticizers had good linearity (R ²>0.99) in the concentration range of 0.005~0.250 mg/L, the detection limit was between 0.1~0.9 μg/L, and the recovery rate was between 79.3%~108.0%, while the RSD was between 0.84%~9.80%. The migration regularity showed that under the same conditions, in 50% ethanol simulant results the highest migration rate of TOP, and in 95% ethanol simulant results the highest migration rate of NINS. The amount of migration increases with the increase of temperature and migration time, while the migration increases rapidly first and then tends to equilibrium after 4 days. This research could provide technical support for the quality control of biodegradable food contact materials for enterprises and regulatory agencies.

The material used for the pipeline distributor is polyamide66 (PA66), which is made by injection molding process and analyzed by molding flow by Moldflow software, and the injection molding process is affected by many factors. In this paper, the melt temperature, injection pressure, holding pressure and cooling time are taken as the research variables, and the warpage deformation of the parts is taken as the research objective to establish the response surface model, so as to reduce the warpage deformation of the parts by obtaining a set of better combinations of molding process parameters. The results show that when the melt temperature is 238 ℃, the injection pressure is 50 MPa, the holding pressure is 30 MPa and the cooling time is 110 s, the warpage deformation of the parts is 2.264 0 mm, which is reduced by 2.118 7 mm compared with before optimization, and the overall quality is significantly improved.

Microplastic pollution has become a concern around the world, when microplastics interact with other pollutants such as heavy metals in the soil system, microplastics will adversely affect the growth and development of plants, but the interaction between microplastics and heavy metals on plants is less studied. In this study maize seeds were used as the research object to explore the effects of polypropylene microplastics(PP-MPs) and heavy metal cadmium (Cd) on seed germination, seedling growth and oxidative stress of maize with different particle sizes (50 μm and 100 μm). The results showed that the germination rate, germination potential and viability index of PP-MPs+Cd treated seeds were improved, Cd treatment and PP-MPs treatment had inhibitory effects on the mean germination time (MGT), and Cd, 50 μm PP-MPs+Cd and 100 μm PP-MPs+Cd treatments all had certain inhibitory effects on MGT to varying degrees. Cd and 100 μm PP-MPs+Cd treatment inhibited the growth of maize seeding roots and shoots on both the third and the seventh days. On the third day, the fresh weight and dry weight of Cd treatment and 100 μm PP-MPs+Cd treatment decreased by 8.32%, 17.31%, 9.91% and 17.86%, respectively. Overall, PP-MPs+Cd treatment promoted catalase (CAT) and peroxidase (POD) activities in maize roots and shoots, but POD activity decreased by 2.82% at 100 μm PP-MPs+Cd treatment. This study provides a basis for the toxic effects of microplastics and heavy metals on the growth of maize and other crops.

This article aims to prepare a nitrogen, silicon, and phosphorus multiple synergistic high-efficiency flame retardant and study its application performance. Firstly, allyl substituted melamine was synthesized by melamine powder and allyl bromide. After copolymerizing it with vinyltrimethoxysilane, a nitrogen-silicon containing melamine copolymer was obtained. Using the equal volume impregnation method, a certain mass of Type I ammonium polyphosphate (I-APP) powder is mixed with an equal volume of nitrogen-silicon containing melamine copolymer solution to prepare nitrogen silicon flame retardant copolymer coated I-APP flame retardant (MAPP). Pre mix polypropylene(PP) with a certain mass fraction of I-APP or MAPP flame retardant, and then perform melt blending, extrusion, and granulation in a twin-screw extruder to prepare PP flame retardant composites. Mechanical and vertical combustion tests were conducted on PP flame-retardant composites. The results showed that when MAPP was added up to 20%, it could reach the V-0 flame retardant level, while pure I-APP, even with 30% addition, remained below the V-0 level and had lower mechanical properties. It can be seen that the compatibility of I-APP coated with nitrogen silicon copolymer is better, and the synergistic flame retardant efficiency among nitrogen, silicon, and phosphorus is higher.

A 5VA environmentally friendly flame retardant polypropylene (PP) composites was prepared using a twin-screw extrusion mechanism. The effects of flame retardant addition, flame retardant surface treatment, and twin-screw thread combination on the flame retardancy, physical and mechanical properties, and production status of PP composites were studied. The results show that when the flame retardant content is 33%, the flame retardancy of PP composites reaches 5VA level, but it significantly reduces the tensile strength, elongation at break, impact strength, and melt flow rate. Silane coupling agents, titanate coupling agents, and silane wax treated flame retardants have improved the toughness and flowability of 5VA environmentally friendly flame retardant PP composites, with the best effect of silicone wax. In scaled up production, SK deep thread components are added to the cutting end of the thread combination to compact the material, and internal mixing and SME components are added to reduce shear and promote dispersion, effectively solving the problems of foaming and difficult pulling of 5VA grade flame-retardant PP composites that prevent normal production.

A biomass-based charring agent was synthesized and applied to the modification of ammonium polyphosphate (APP) flame retardant to enhance the fire safety performance of epoxy resin (EP). After the reaction of melamine (MA) and vanillin in different ratios to form a carbonized coating (MV), APP was coated to obtain the bio-based charcoal-forming agent modified APP flame retardant (MV@APP), which was added to EP. It was found that the flame retardant obtained from the 1∶2 mass ratio of MA to vanillin in the same flame retardant additive ratio (5%) was the most effective in EP (MV@APP/EP-2), with the peak heat release rate, total heat release and total smoke production reduced by 57.2%, 66.4% and 62.7%, respectively. Thermal stability analysis shows that the addition of MV@APP improves the thermal stability as well as the amount of residual carbon. In addition, the compatibility between the flame retardant and EP was improved by the modification of APP by the organic charcoal-forming agent, and the flexural properties of EP were enhanced by the addition of the flame retardant.

Polylactic acid (PLA) is a high-modulus, high-strength biodegradable thermoplastic polyester used in the packaging, textile and medical industries. Conventional plasticizers are usually non-biodegradable, the study used low molecular polyhexanediol succinate (PHS) blended with poly (L-lactic acid) (PLLA) to obtain a fully degradable system. The compatibility, crystallization and mechanical properties of the blended system were investigated by differential scanning calorimetry, polarizing microscope and universal testing machine. The results show that the crystallinity of PLLA/PHS ratios of 100/0, 95/5, 90/10, 85/15, and 80/20 were 7.5%, 8.7%, 11.5%, 14.1%, and 14.2%, respectively. The crystallinity of the blends increased with increasing PHS content, indicating that PHS successfully promoted PLLA crystallization. In addition, the crystallization rate of 80/20 was increased 10-fold and the semi-crystallization time was halved compared to pure PLLA. The elongation at break of the blends increased from less than 10% for pure PLLA to about 60% (PHS content 20%), with a slight decrease in strength and modulus. The elastic modulus of the blends decreased continuously with the increase of the PHS content, from 2.25 GPa for pure PLLA to 1.86 GPa at 20% PHS content.

The research focused on detecting solvent residues in two typical composite film bags made of biaxially oriented polypropylene/low-density polyethylene (BOPP/LDPE) and nylon/cast polypropylene (PA/CPP), and investigated their migration patterns. The non-compliance rate of solvent residue in the selected two typical material samples is 90%. After 18 months of storage at room temperature, the total solvent residue in BOPP/LDPE samples decreased by 95%, and the total solvent residue in PA/CPP samples decreased by more than 88.2%. Four different temperatures were tested, and after 1 hour at 80 ℃, the residual solvents in the BOPP/LDPE samples evaporated completely; the total amount of solvent residue in PA/CPP samples decreased by more than 95.8%. Both an increase in experimental temperature and an extension of time will cause a decreasing trend in the total solvent residue and benzene residue in the composite film bag. The material, test temperature, and test time of plastic composite film bags for food have important effects on the migration pattern of solvent residues in two typical material samples. It is suggest revising the corresponding testing method standards, actively promoting the evaluation of green packaging for products, and better ensuring the quality of plastic composite film bags for food.

Various dynamic force fields or coupling force fields are introduced into the molding process of ultra-high molecular weight polyethylene (UHMWPE), which effectively solves the problems of long molding cycle, high energy consumption, difficult to manufacture high-performance products and difficult to be applied to the molding of composites in static molding methods such as molding and sintering. In this paper, the research and application of dynamic force fields such as high velocity compaction force field, ultrasonic vibration force field, shear/tension force field, pulse vibration force field, and synergistic effect of pulse vibration force field and melt flow field in the molding of UHMWPE and its composites are described respectively. The principles and characteristics of UHMWPE dynamic molding under the action of each dynamic force field are analyzed. Finally, by comparing and analyzing the advantages and disadvantages of various dynamic molding methods of UHMWPE, it is concluded that the tension force field, pulse vibration force field, and synergistic effect of pulse vibration force field and melt flow field can significantly improve the properties of UHMWPE, providing new ideas and directions for UHMWPE efficient molding.

In this paper, three kinds of high density polyethylene(HDPE) of small hollow polyethylene 5831D, BL3 and BM593 produced using titanium-based catalysts were taken as raw material, are studied in depth in combination with the characteristics of three different reactor configurations: Three-reactor cascading, double-reactor cascading, and double-loop reactor systems. Firstly, through a physical property analysis of 5831D, BL3, and BM593, the paper explores their polymerization performance and product characteristics under various reactor configurations. Subsequently, a comparative analysis is performed using techniques such as differential scanning calorimetry and capillary rheometry to characterize and contrast the three raw materials. The research reveals differences in molecular structure, molecular weight distribution, and melt properties among the HDPE products produced in different reactors. For instance, 5831D from the three-reactor cascading system exhibits lower melt flow rate (MFR) compared to BL3 from the double-reactor cascading system, but it possesses a more complex molecular structure, contributing to an enhanced M_w of the product. The molecular weight distribution of products from different reactors varies, with the three-reactor system yielding a broader distribution, which is more conducive to processing. Additionally, the study encompasses tests and analyses related to product melt properties, crystalline performance, thermodynamic characteristics, shear-thinning viscosity, and more. Through systematic experiments and analyses, the paper elucidates the advantages and disadvantages of these three processes in the production of small hollow polyethylene. The research results not only provide guidance for optimizing the production process of small hollow polyethylene but also offer valuable insights into the synthesis mechanism of HDPE.

In order to improve the wettability of high density polyethylene (HDPE) surface, the surface of HDPE was modified by oxygen (O₂) and nitrogen (N₂) plasma respectively, the surface contact angles before and after modification were tested with water (H₂O) and diiodomethane (CH₂I₂), the wettability changes of the modified surface were analyzed, and the optimal process for improving the surface wettability by plasma of O₂ and N₂ was determined. Furthermore, the surface morphology, chemical structure and functional groups of HDPE were analyzed by scanning electron microscopy (SEM), fourier infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the wettability and surface energy of HDPE were increased significantly after being treated by O₂ and N₂ plasma.The optimum process for improving the surface wettability of HDPE by two kinds of plasma was as follows: Power 800 W, time 10 s, flow rate 1.5 L/min for O₂, power 1 000 W, time 15 s, flow rate 2.5 L/min for N₂. After plasma treatment, the surface of HDPE was etched and pitted, and oxygen-containing functional groups C=O, O—C=O, and nitrogen-containing functional groups —C—NH₂,—C—NH— were introduced into the surface of HDPE. N₂ optimal plasma treatment has a better effect on the surface wettability of HDPE than that of O₂.

With the continuous improvement of resin performance requirements in the field of friction materials, the toughness requirements of phenolic resin are getting higher and higher. In this study, three thermoplastic resins containing polyamide (PA), liquid nitrile rubber (LNBR), and liquid carboxyl nitrile rubber (CLNBR) were used to toughen and modify phenolic resin (PF), and cured samples with different thermoplastic resin / PF ratios were prepared. The thermal and mechanical properties of the composite resin were evaluated. The toughening effects of three thermoplastic resins on PF were compared and analyzed. The results show that when thermoplastic resin is added to PF, the compression rate and deformation rate increase, and the compressive elastic modulus, storage modulus, hardness and thermal decomposition temperature decrease. PA and PF have better compatibility. When the mass ratio of PA / PF is 1∶10, the composite resin has the best thermal stability and toughening effect. The crosslinking density is 18 251 mol/m³, the glass transition temperature is 199.4 ℃, the hardness is 123.12 HRR, the compressive elastic modulus is 1 953 MPa, the compression resilience is good, and the permanent deformation rate is low.

To investigate the mechanical and operational properties of acrylate polymer blended with polyvinyl chloride resin (ABR) pipes in low-temperature environments, the study conducted compression and tensile performance tests on ABR, high performance unplasticized polyvinyl chloride pipe (PVC-UH), and unplasticized polyvinyl chloride (PVC-U) pipes of PN1.0 MPa specification under various temperature conditions. An experimental study on the tightness under internal pressure and angular deflection performance of the three types of pipes in a 5 ℃ environment was also carried out. Based on test and experimental results, a numerical simulation study of the deflection angle sealing performance of ABR pipes at low temperatures was conducted. The results indicate that at low-temperature conditions, the mechanical performance of ABR pipes surpasses that of PVC-UH and PVC-U pipes, the incorporation of acrylate polymer (ACR) modifier significantly enhances the compression, tensile, and leak resistance properties of ABR pipes at low-temperature conditions. At 5 ℃, the yield strength of ABR pipe material is 57.1 MPa, the elastic modulus is 3 679.3 MPa, the elongation at break is 71.5%, the ring stiffness is 22.67 kN/m², and the ring flexibility is excellent. Simultaneously, in a 5 ℃ environment, the sealing integrity of ABR pipe joints remains intact under the influence of 0.4 MPa static hydraulic pressure and an 8° deflection angle displacement.

Magnesium carbonate trihydrate fibers were synthesized by co-precipitation method using magnesium sulfate heptahydrate (MgSO₄·7H₂O) and potassium carbonate (K₂CO₃) as raw materials and sodium dodecylbenzene sulfonate (SDBS) as structural guiding agent. EVA composites were prepared by melt blending using silane-modified magnesium carbonate trihydrate fiber as a flame retardant. The effects of modified magnesium carbonate trihydrate fibers on the mechanical properties, thermal stability and flame retardancy of EVA composites were investigated by means of a universal testing machine, a limiting oxygen index meter (LOI), a thermogravimetric analyzer (TG), and a cone calorimeter (CCT). The results show that at 40 ℃, the stirring rate is 350 r/min, the molar ratio of MgSO₄·7H₂O to K₂CO₃ is 3∶1, and the addition amount of SDBS is 3% of the theoretical production fiber mass, MgCO₃·3H₂O fibers with good dispersibility can be prepared. The mechanical properties of EVA can be significantly improved by MgCO₃·3H₂O fibers modified by silane coupling agent, and the tensile strength of the composites is increased to 13.7 MPa and the elongation at break is increased to 176% when the addition amount is 40%. The heat release rate and smoke release rate are greatly reduced to 231 kW/m² and 0.029 m²/s, respectively.