查找使用阿拉丁产品的科研文献

The effects of carbon nanotube and magnesium maleate on the performance of ethylene-propylene-diene monomer (EPDM)/ polypropylene (PP) thermoplastic vulcanizate (TPV) with good shape memory behavior and electrical conductivity

Mengmeng Xu,Chengzhong Zong

The type of EPDM/PP TPV was the most widely used TPV with excellent mechanical property. To achieve functional property of EPDM/PP TPV, the EPDM/PP TPV compatibilized by magnesium maleate (MgMA) and maleic anhydride (MAH) was compounded with carbon nanotube (CNT) during dynamic vulcanization. The hydroxyl on CNT could reacted with the anhydride group on the graft products of polymer chains that promoted the uniform dispersion of CNT in TPV. The EPDM/PP TPV with excellent shape memory performance and electrical conductivity was successfully prepared. The successful reaction of CNT with anhydride on polymer chains in the compatibilized TPV M5C2 was verified by the result of FTIR, Raman spectrum and SEM image, which improved the mechanical performance, shape memory property and electrical conductivity of TPV M5C2 compared to TPV M0C2 with the same CNT content. TPV M5C1 obtained excellent shape memory performance with the R f of 96.0 % and R r of 93.9 %. The electrical conductivity of TPV M5C8 was as high as 1.6 × 10 −4  S·cm −1 demonstrating the formation of CNT conductive network in TPV.

Low-energy micron dispersion of entangled polymers based on phase inversion composition of emulsion

WenKai Cao,BinXiao Wei,YinChuan Pu,LiPeng Wang,SiQi Su,YongPing Bai

This article aims to propose a low-energy method for micron dispersion of entangled polymers. We chose Ethylene-Propylene-Diene Monomer (EPDM) as the entangled polymer and acrylic esters as the dispersants to prepare the organic dispersion of the entangled polymer based on the theory that in-situ polymerization of acrylic esters had the higher solubility parameter than the original monomer. The dispersion process of entangled polymer was similar to the phase inversion of emulsion due to the maximum viscosity and minimum interfacial tension at the point of dispersion. Specifically, the average diameter of the dispersed entangled polymer was 5–6 μm. The system could still maintain excellent dispersion stability without additional dispersants. Rheology characterized that the introduction of aliphatic isocyanate derivatives reacting with hydroxyl groups in the polyacrylate to form the cross-linked skeleton could enhance the stability of the system. Excitingly, this organic dispersion allowed flexible printed circuit to fold at any angle and direction when used as the coating, and the coating still maintained excellent dispersibility, flexibility, insulation, and adhesion after aging tests. This low-energy method for micron dispersion of entangled polymers could expand their applications in coatings and other fields while maintaining their own characteristics.

EFFECTS OF GRAFTED VINYL TRIETHOXY SILANE ON MOISTURE CROSSLINKED EPDM

Lin Zhengwei,Zhao Haotian,Chen Yanlu,Mao Jie,Hoch Martin,Shi Xinyan

An EPDM terpolymer grafted with silane vinyl triethoxysilane (EPDM-g-VTES) was prepared by melt grafting, with dicumyl peroxide (DCP) as an initiator. Next, dibutyl tin dilaurate was added as a catalyst to promote moisture crosslinking of EPDM-g-VTES. By means of the rheological response of the rubber compound, Fourier transform infrared spectroscopy, and moving die rheometer, the VTES graft ratio and DCP partial crosslinking (pre-crosslinking) of EDPM-g-VTES were characterized to show the feasibility of moisture crosslinking. The mechanical properties of moisture crosslinked EPDM-g-VTES specimens were tested by universal material tester. The results showed that when the weight ratio of VTES to DCP was fixed at 15:1, the VTES graft ratio and DCP partial crosslinking of EDPM-g-VTES increased with the increase of VTES content. But the torque in the moisture crosslinking curve of EPDM-g-VTES increased significantly with the extension of crosslinking time, which proved that EPDM grafted with VTES was cured by moisture successfully. The tensile strength and elongation at break of EPDM-g-VTES were improved by moisture cure. Furthermore, the moisture cured specimen with 3 wt% VTES had the best mechanical performance.

Migration of antioxidants from food-contact rubber materials to food simulants

Lijing Lu,Chang Cheng,Li Xu,Liao Pan,Hai Feng Xia,Lixin Lu

The migration behavior of 4,4′-thiobis (6- tert -butyl-m-methyl phenol) (antioxidant 300) and hexamethylene bis [3-(3,5-di- tert -butyl-4-hydroxyphenyl) propionate] (antioxidant 259) from ethylene-propylene-diene monomer (EPDM) to food simulants was studied under different processing conditions [various temperatures (40, 70, 100 °C), autoclaving, and microwave]. The influencing factors for migration behavior were discussed. Neither antioxidant 300 nor 259 was detected in either 10% ethanol or 4% acetic acid. The migration of antioxidants increased with rising temperature, particularly, the maximum migration of antioxidant 259 at 100 °C was 2.78 and 1.51 times higher than that at 40 °C and 70 °C respectively. Pretreatment under autoclaving and microwave promoted the migration rate and thus should be paid more attention during the food processing. The diffusion coefficients were obtained by fitting the migration data based on the Crank model and the values were between 4.86 × 10 −12 and 8.96 × 10 −7 cm 2 /s. Moreover, the relationship between the diffusion coefficients and temperature was found to conform to the Arrhenius formula. These results for the migration of antioxidants from EPDM to food simulants provide reference for the risk assessment of antioxidant migration from food contact rubber materials to food while using rubber products in food processing.

Improving Dispersion and Mechanical Properties of Natural Rubber and Ethylene Propylene Diene Monomer Composites With Ionic Liquid-Modified Helical Carbon Nanofiber

Fusen Wu,Peixiu Tian,Yongzhong Jin,Wenping Xu,Hangjia Yan,Jian Chen,Lin Pi,Meng Wang,Kaiyi Lin,Rui Xu,Ziyu Wang

This study presents an innovative “ionic liquid (IL) modification-spray compounding” technique to enhance the dispersibility of helical carbon nanofiber (HCNF) and fabricate IL-modified HCNF/silica composite fillers. These fillers were used to reinforce natural rubber/ethylene-propylene-diene monomer (NR/EPDM) composites. Results show that the composite filler modified with 1-butyl-3-methylimidazolium tetrafluoroborate ([C 4 MIM]BF 4 ) achieved the most uniform dispersion in the rubber matrix. Compared with the pure silica sample, the composite material exhibited improvements in shore hardness, stress at 300% strain, tensile strength at break, tear strength, rebound resilience, and abrasion resistance by 6.46%, 24.43%, 12.02%, 6.94%, 12.01%, and 22.75%, respectively. IL played a crucial role in the surface modification of HCNF, enabling their excellent dispersion and full reinforcement efficiency within the matrix. This research provides a novel and industrially promising strategy to address the dispersion issues of HCNF and improve the comprehensive properties of composite materials, opening up new avenues for the development of related materials.

Effects of poly-(p-phenylene terephthamide) powder coated with polydopamine on ethylene-propylene-diene-terpolymer grafted maleic anhydride

Yuan Ye,Deng Sufen,Song Shaokun,Hu Weibo,Dong Lijie

In this paper, we reported a technique for the surface modification of poly-( p -phenylene terephthamide) (PPTA) powder coated with polydopamine (PDOPA). We used air oxidation to self-polymerize dopamine (DOPA) to ensure that the PPTA powder was coated. Our results indicate that the modified surface of PPTA powder enhances compatibility with the polymer matrix without damaging its structure. Additionally, it is possible to control the coating thickness of PDOPA by regulating the reaction time. The modified PPTA powder improved the comprehensive property of ethylene-propylene-diene-terpolymer grafted maleic anhydride (EPDM- g -MAH), and it proved that this method can enhance the strength and electric insulativity of EPDM- g -MAH.

Nonlinear electrical conductivity and thermal properties of AgNPs/BN/EPDM composites for cable accessory

Q. G. Chi,M. Yang,C. H. Zhang,T. D. Zhang,Y. Feng,Q. G. Chen

Synergistic Aramid Nanofiber/Graphene Oxide Interlocking Interface in PI/EPDM Composites: Regulation on Ablation Behavior

Junjie Liu,Luxiang Zhao,Bolin Xiao,Youquan Ling,Yanjiang Bai,Mei Liang,Yang Chen,Huawei Zou

The primary material used for insulation layers in solid rocket motors is fiber-reinforced ethylene-propylene-diene monomer (EPDM) rubber-based composites. However, current research has primarily focused on the relationship between fiber/rigid resin matrix interfaces and macroscopic properties, while studies investigating the influence of fiber-flexible rubber matrix interfaces on composite macroscopic performance remain remarkably scarce. To deeply investigate the influence of the fiber-flexible rubber matrix interface on the macroscopic performance of composites, this study proposes a combined approach of coating and surface nanostructuring to construct a hybrid interfacial phase composed of graphene oxide (GO) and aramid nanofibers (ANF) between polyimide (PI) fibers and EPDM. Specifically, ANF stably binds with GO through π–π* interactions, forming a three-dimensional nanoscale surface structure that introduces nanolevel roughness. Low-field nuclear magnetic resonance (NMR) and ablation resistance analyses demonstrate that this structure facilitates the formation of a denser cross-linked network and a high-temperature-resistant architecture with uniformly dispersed GO on the fiber surface. As a result, the composite exhibits a 50% increase in tensile strength and an approximately 15% reduction in carbonization rate. This work demonstrates that optimizing the microinterfacial layer between fibers and the matrix not only enhances macroscopic mechanical properties but also achieves superior ablation resistance. The findings provide critical guidance for the development of high-performance EPDM-based insulation materials.

Synergistic enhancement of CsPbBr3 perovskite nanocrystals via ZnO and EPDM for stable wide-color-gamut display

Ziyang Niu,Zijun Huang,Peng Wang,Xiuquan Gu,Yulong Zhao

All-inorganic perovskite CsPbBr 3 nanocrystals (NCs) are promising for wide-color-gamut displays due to their high photoluminescence quantum yield (PLQY) and narrow emission bandwidth, yet their ionic nature renders them susceptible to degradation by moisture, heat, and mechanical stress, while surface defects induce non-radiative recombination. Herein, we propose a synergistic protection strategy combining ZnO inorganic modification with EPDM flexible polymer encapsulation. A ZnO heterojunction is constructed in situ on CsPbBr 3 NCs via a solution method, after which the modified NCs are dispersed in an EPDM matrix to fabricate flexible composite films. Structural and optical characterizations confirm that ZnO modification effectively suppresses non-radiative recombination, prolonging the average photoluminescence (PL) lifetime to 14.54 ns. XPS and DFT calculations reveal strong interfacial chemical interactions between CsPbBr 3 and ZnO, with an adsorption energy of −1.923 eV, suggesting effective surface-defect passivation. Stability tests demonstrate that after 6 days of water immersion, heating at 90 °C for 60 min, 200% mechanical stretching, and 100 h of UV irradiation, the composite retains 65%, 60%, and 80% of its initial PL intensity, respectively, showing substantially improved multidimensional stability. A white light-emitting diode fabricated using the film exhibits CIE chromaticity coordinates of (0.34, 0.32) and color gamut coverages of 121.2% NTSC and 98.2% Rec. 2020. This strategy simultaneously addresses defect passivation and environmental instability in perovskites, offering a feasible route towards commercial perovskite-based optoelectronic devices.

Study on the influence of hollow glass microspheres structure on the ablation performance of EPDM rubber

Wang Mingchao,Chen Xin,Wang Yuan,Wu Lei,Zhou Jun,Liu Li,Lin Zibin,Ren Wenjun,Liu Chen

The increasing demand for lightweight and ablation-resistant materials in solid rocket engines has spurred the application of hollow glass microspheres (HGM) due to their low density and high thermal stability. In this study, the effects of different glass microspheres, including solid and hollow HS46 and HS38 microspheres, on the ablation and carbonization behavior of EPDM, PI/EPDM and PPTA/EPDM composites were evaluated using oxyacetylene tests and SEM. The results revealed that the addition of HGM decreased the ablation rates, with reductions of 13.2% for solid microspheres, 2.9% for HS46 compared with HGM-free composites. The presence of organic fibers further reduced ablation rates. Solid microspheres exhibited the most pronounced effect due to their superior thermal stability, whereas hollow microspheres with larger diameters tended to increase ablation rates as a result of fragmentation. Notably, the combined addition of HGM and fibers such as PI and PPTA reduced ablation rates by 50%. These findings provide valuable insights for designing advanced aerospace thermal insulation materials that are lightweight, thermally stable and exhibit enhanced ablation resistance.

Impacts of Silicone Grease Swelling on Surface and Interface Insulation Performance and Trap Characteristics of Grafted EPDM

Duo Ji,Chunyang Li,Zhen Li,Xu Yang,Xiansheng Chen,Hong Zhao

The swelling of rubber caused by silicone grease significantly accelerates the deterioration of the electrical properties of cable accessories, particularly at the surface and interface regions. This study investigates the impact of swelling aging on the insulation performance and trap characteristics of ethylene propylene diene monomer (EPDM) modified by the voltage stabilizer 4-allyloxy-2-hydroxybenzophenone (AOHBP). Physicochemical characterization, electrical measurements, and molecular dynamics simulations were employed to analyze the evolution of EPDM insulation performance under silicone grease swelling. Results indicate that the swelling process alters the trap distribution and reduces the density of deep traps, thereby weakening the material's insulation performance. However, compared to unmodified samples, the grafted EPDM exhibits a higher EPDM/XLPE interfacial breakdown strength and improved anti-swelling capability. Mechanism analysis reveals that the grafted AOHBP introduces steric hindrance, which inhibits the diffusion of silicone grease molecules into the EPDM matrix, effectively alleviating the degradation of surface and interface insulation performance induced by swelling.

One-Pot Ketone Functionalization of EPDM toward Recyclable and Creep-Resistant Elastomers Cross-Linked with Biobased Amines

Chenru Tian,Ganggang Zhang,Xi Zhang,Kuan Liang,Xin Ye,Liqun Zhang

Abstract Introducing dynamic covalent networks into conventional ethylene-propylene-diene monomer (EPDM) rubber offers a promising strategy for developing thermally reprocessable elastomers; however, it requires the introduction of reactive functionalities onto the chemically inert hydrocarbon backbone. Herein, ketone-functionalized EPDM (K-EPDM) was prepared through a one-pot strategy combining epoxidation and oxidative cleavage of the double bonds in EPDM. Then, K-EPDM was cross-linked with biobased amines to construct imine-cross-linked elastomers. Exchangeable imine linkages served as the primary reversible cross-linking motifs, whereas a small fraction of irreversible epoxy-amine cross-links derived from residual epoxy groups provided additional constraints for improving dimensional stability. The resulting elastomers exhibited tunable mechanical properties, good elastic recovery, thermally activated stress relaxation, reduced creep deformation, thermally induced shape adaptability, and high retention of mechanical performance after repeated thermal reprocessing. Hence, this work provides a simple and promising strategy to synthesize ketone-functionalized rubber, which can be further cross-linked with biobased amines to obtain dynamically cross-linked EPDM elastomers with thermal reprocessability and improved creep resistance.