POLYMERS FOR ADVANCED TECHNOLOGIES
·
2012
·Vol. 24
·期 2
·197-203
·
IF 2.007
Yan Liu,Yan Zhang,Zhenhu Cao,Mao Peng,Zhengping Fang
Novel oligomeric intumescent flame retardants, poly(amino phosphonate ester)s (PAPEs), containing both phosphorous and nitrogen, were synthesized by reacting diethyl phosphite with two different polyschiff bases obtained from the reaction of diamines with dialdehyde. The target PAPEs (designated as PAPE-d and PAPE-e, respectively) were characterized by 1 H NMR, 31 P NMR, Fourier Transform infrared spectroscopy, elemental analysis, gel permeation chromatography and thermogravimetric analysis (TGA) techniques. Thermal stability and flammability of ethylene-vinyl acetate copolymer (EVA)/PAPE blends with various PAPE content were investigated by TGA, limited oxygen index (LOI), vertical burning test (UL-94) and microscale combustion colorimeter (MCC). The results indicate that PAPEs effectively improve the flame retardancy of EVA. The EVA/30%PAPE-e blend has a LOI value of 28, and its peak heat release rate (PHRR) value in MCC measurement is reduced by 36%. At the same time, the EVA/PAPE blends also have high yield of residual char, indicating that PAPEs are effective charring agents. Scanning electron microscopy observations of the residues of the EVA/PAPE blends show the existence of compact char layer on the surface of the residues, which is responsible for the improvement of the flame retardancy of EVA. Copyright © 2012 John Wiley & Sons, Ltd.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Ting Wang,Yin Zhang,Yu Wang,Wei You
Anion exchange membranes (AEMs) bearing polyethylene (PE) backbones have general advantages of outstanding chemical stability, balanced rigidity and toughness, good compatibility with various ionic functional groups, and aromatic-free structures. However, previous preparation of aromatic-free PE-based AEMs relies on complicated monomer synthesis and noble transition-metal catalysts (for metathesis, hydrogenation, coordinative polymerization, etc.). We herein propose a novel approach using commercial poly(ethylene- co -vinyl acetate) (EVA) to conveniently produce a series of trimethylammonium- and piperidinium-functionalized PE-based AEMs. The synthetic process involves Mitsunobu derivatization to form amine-functionalized PE intermediates without the use of any transition-metal catalysts. The resultant AEMs have high hydroxide conductivities (up to 129 mS/cm at 80 °C), good alkaline stability in 5 M KOH at 60 °C for 30 days, and promising AEM water electrolysis performance.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2018
·
IF 3.193
Shijie Hou,Yong Jian Zhang,Pingkai Jiang
Synergistic effects of synthetic phosphonium sulfonates (PhSs) bearing different groups with expandable graphite (EG) on flame retardancy properties in poly(ethylene-co-vinyl acetate) (EVA) rubber blends have been studied by limiting oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), and thermogravimetric analysis (TGA). The EVA/EG/PhS composites revealed excellent flame retardancies. Upon adding 2.5 wt% of PhSs and 20 wt% of EG to EVA matrix, V-0 rating can be achieved. The heat release rate (HRR) and the total heat release (THR) of EVA/PhS-2(2.5 wt%)/EG(20 wt%) and EVA/PhS-4(2.5 wt%)/EG(20 wt%) blends decreased remarkably based on CCT. In addition, the thermal stabilities and mechanical properties of EVA/EG/PhS composites did not deteriorate comparing with those of EVA/EG composites.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
RADIATION PHYSICS AND CHEMISTRY
·
2017
·
IF 1.315
Guo-hui Wang,Man-li He,Dan-feng Jiang,Fan He,Shu-quan Chang,Yao-dong Dai
According to the requirements for neutron shielding and flame retardant properties of some nuclear devices, a new kind of polymer composite materials based on ethylene and vinyl acetate (EVA) polymer have been studied. EVA is the copolymer of ethylene and vinyl acetate, It can be used as materials for applications due to its flexibility, good processability, and low cost. Insulating EVA can be used for cable sheath, automotive sound damping and many other appication. Boron nitride (BN), zinc borate (ZB), magnesium hydroxide (MH) and EVA consisted the compounds with the properties of neutron shielding and flame retardant. With increasing of the contents of BN and ZB, the neutron shielding performance of materials increased up to 33.08%. With the increasing contents of MH and ZB as flame retardant, oxygen index of material have been improved. The elongation at break and tensile strength of material decreased with the increasing of filler powders. Sheet E was chosen and modified by electron beam accelerator in different doses. After modification by electron beam irradiation the sheets showed varying degrees of transformation in the OI, neutron shielding rate and mechanical properties.
研究领域:
材料科学
·
核技术应用
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES COMMUNICATIONS
·
2024
·
IF 6.5
Bo Cheng,Yaru Sun,Wenchao Zhang,Yinjie Wang,Dinghua Li,Rongjie Yang
Ethylene-vinyl acetate copolymer (EVA) is widely used in various applications; however, its flammability limits the further application in wire and cable industries. Here, a core-shell aluminum hydroxide flame retardant (ATH@ADP@MCA) was prepared by a simple aqueous solution method. Results showed that the ATH@ADP@MCA not only decreased the aggregation in EVA but also had superior fire retardancy for the improved char formation ability and dilution of flammable gases. Only 55 wt% ATH@ADP@MCA can endow EVA with satisfying flame retardancy such as the UL-94 V-0 grade and low heat release. Higher values of the fire performance index (0.28 m 2 s/kW) were also achieved by EVA with 55 wt% ATH@ADP@MCA compared with those of EVA with the same loading of neat ATH. Moreover, ATH@ADP@MCA enhanced tensile strength without sacrificing the elongation at the break of EVA. This study illustrates that the core-shell ATH@ADP@MCA has a broad potential for developing EVA composites with excellent flame retardant and mechanical properties.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2018
·
IF 1.454
Zhengnan Sun,Guolin Jing,Ziyi Tu
The nano-hybrid pour-point depressant (PPD) was prepared with organically modified nano-silica covering in EVA. The effects of modified nano-silica/EVA on the flow behavior and wax crystallization of model oils with different wax contents were evaluated. Compared with pure EVA and nano-silica/EVA, modified nano-silica/EVA exhibited a better effect, when doped with 500 ppm, the pour point of the model oil containing 20 wt% wax was reduced from 33°C to 0°C. However, it is noteworthy that pour point cannot accurately reflect the effect of YSiO2/EVA as cold flow improver for a high wax content. The crystal morphology and crystallization behavior of the model oils at low temperature were also observed using polarizing optical microscopy (POM). The results indicated that modified nano-silica/EVA can reduce the size of the wax crystals and disperse the wax crystals by heterogeneous nucleation.
研究领域:
石油工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 23
·4101
·
IF 4.329
Zijin Wu,Yonggang Shangguan,Chunhui Zhang,Qiang Zheng
In order to improve the bonding performance, EVA composite hot melt adhesives were prepared by introducing crosslinking agent and silane coupling agent in this paper. A binary EVA resin blend as the base resin with appropriate viscosity and tensile shear strength was selected as hot melt adhesive. The effects of crosslinking agent and silane coupling agent on the properties of ethylene/vinyl acetate (EVA) composite hot melt adhesive were studied. By investigating the preparation and curing conditions of hot melt adhesive and the properties of hot melt adhesive after the introduction of dicumyl peroxide (DCP), the optimum temperature and dosage of DCP and its influence on the properties were determined. It was found that the tensile shear strength of hot melt adhesive increased from 0.247 MPa to 0.726 MPa when 2 phr DCP and 5 phr KH570 were added at the same time. The tensile strength and tensile shear strength of hot melt adhesive are only slightly improved when silicone coupling agents with different functional groups are added to EVA composite hot melt adhesive. However, it was found that excessive silane coupling agent would significantly reduce the tensile strength and shear peel strength of the material.
研究领域:
材料科学
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聚合物化学
·
粘合技术
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Wanting Wei,Pengfei Zhang,Feng Cao,Junhao Liu,Kun Qian,Diankun Pan,Yongtao Yao,Wenbing Li
When a 5G folding mobile phone is in a complex electromagnetic environment, it will unavoidably be subject to electromagnetic interference with a frequency of 450 MHz–6 GHz from electronic components on internal and external flexible printed circuits (FPCs). Here, we propose a method to prepare ultrathin, flexible and conductive polymer fiber composite (CPFC) with excellent shape memory effect and superb electromagnetic interference shielding effectiveness (EMI SE). The shape-memorized CPFC (SMCPFC) can be fabricated by three steps: (1) preparing highly cross-linked ethylene–vinyl acetate copolymer (EVA) fiber membrane by electrospinning and UV cross-linking; (2) synthesizing a polydopamine (PDA) layer on mat surface; (3) promoting the reduction of Ag nanoparticles on EVA@PDA fibrous composite surface. The electrical conductivity of SMCPFC can reach up to 2.5 × 10 5 S/m, and its average EMI SE is close to 90 dB at the frequency of 3.94–5.99 GHz. After cyclic stretching, folding, and ultrasonic washing, the conductivity and EMI SE maintains unchanged. In addition, SMCPFC has an outstanding electrothermally-driven shape memory effect. Shape can be programmed immediately at 0.55 V, and 50% strain sample exhibits EMI SE of 50.91 dB, which can blocks more than 99.99% electromagnetic waves. Shape can be recovered at 80 °C, EMI SE of recovery sample is roughly the same as that of the original sample (87.06 dB), and 99.9999997% electromagnetic waves can be consumed. The invention of this multifunctional SMCPFC gives a new way for FPC electromagnetic shielding film to develop towards the directions of intelligence and multi-functions.
研究领域:
材料科学
·
电子工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·
IF 3.5
Zhang Tongwei,Qin Huijie,Bao Lihong,Dang Bo,Li Jianxi
This paper introduces a novel hybrid material, MoS 2 @Ag@PA, with a core–shell structure aimed at improving the fire safety and critical properties of ethylene vinyl acetate (EVA). The incorporation of 2% of this hybrid material results in a remarkable enhancement in both thermal conductivity and tensile strength of EVA composites, increasing by 52.4% and 22.6%, respectively. Furthermore, the inclusion of 2% of this material leads to a significant reduction in the peak of heat release rate, total heat release, and total smoke production of the EVA composites by 36.2%, 28.1%, and 29.7%, respectively, compared to pure EVA. This indicates a substantial improvement in fire safety, mechanical properties, and thermal conductivity of the EVA composites. The enhanced flame retardancy of the EVA composites is primarily attributed to the synergistic effect of various substances within the hybrid material. Therefore, the design of these hybrids presents a promising approach to enhance the overall performance of EVA.
研究领域:
材料科学
·
火灾安全工程
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产品关联
DOI
高影响因子
PHYSICA SCRIPTA
·
2024
·
IF 2.6
Siyi Xu,Danyi Li,Wenrui Wang,Lin Lin,Ying Sun,Jihao吉豪 Li李,Linfan Li
In recent years, there has been significant interest in using two-dimensional MoS2 to enhance flame retardancy, which has proven challenging. MoS2@Fe3O4 nanosheets were successfully synthesized via a one-step method called radiation reduction to boost MoS2's flame retardant properties. Incorporating these MoS2@Fe3O4 nanocomposites notably improved the flame retardancy of ethylene vinyl acetate copolymer (EVA). Compared to pure EVA, EVA nanocomposites with 1 part of MoS2@Fe3O4 showed a 17.4% reduction in peak heat release rate, 40.4% decrease in total heat release, and 52.9% reduction in total smoke release, with scaly residue content improving from 0.4% to 12.6%. Additionally, MoS2@Fe3O4 incorporation enhanced the mechanical and friction properties of EVA composites, increasing tensile strength by 25.7% and elongation at break by 10.4% compared to pure EVA. This study presents an effective and simple method for producing modified MoS2 nanosheets that enhance flame retardancy, as well as mechanical and friction properties of EVA composites.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 111
·110409-110415
·
IF 3.289
Jin Dong,Baoping Lin
As an effective luminescent down-shifting (LDS) species, Eu3+ complexes have been doped in ethylene-vinyl acetate (EVA) films to improve the spectral response of silicon photovoltaic modules in the ultraviolet region. One key point about the improvement of photoelectric conversion efficiency by the LDS technique is increasing the fluorescence intensity of the EVA composite film as far as possible while staying within the visible light transmittance of the film. Around this point, we attempt to offer an idea for further studies. In this study, nano-SiO2 modified by a silane coupling agent was doped into EVA film with a fixed content of Eu3+ complex by the casting method. The experimental results show that when the modified SiO2 content is within 4%, the fluorescence of the EVA composite film gradually increases with increase in the modified SiO2 content and before formation of EVA composite film, the fluorescence intensities have no difference between the mixture with modified SiO2 and that without modified SiO2. SEM and AFM images of the EVA composite films show that the complex particles are probably enwrapped by aggregations of the modified SiO2 during the film-forming process, which strengthens the rigidity of the Eu3+ complex in the structure and results in the enhancement of fluorescence intensity. When the modified SiO2 content is within 2%, the visible light transmittance of the EVA film only slightly decreases. The photoelectric conversion efficiency of polycrystalline silicon solar cell coated with the composite film increases from 12.13% to 12.29%. Hence, the study provides a feasible approach to improve the LDS technique and has a potential application value.
研究领域:
材料科学
·
光伏技术
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2025
·
IF 7.7
Yadi Jia,Pinjing He,Fan Lü,Wei Peng,Hua Zhang,Khamphe Phoungthong
In response to the growing challenge of photovoltaic waste management, developing sustainable and value-added treatment strategies is imperative. In this study, ethylene-vinyl acetate (EVA) resins sourced from waste photovoltaic modules and virgin materials were utilized for the production of hierarchical porous carbon (HPC) and methane-rich combustible gas via autogenic pressure pyrolysis coupled with KOH activation. Temperature-dependent pyrolysis revealed that 700 °C was the optimal condition, yielding pyrolysis gas with a high methane content (43.39 vol%) and producing graphitized carbon spheres. Subsequent KOH activation generated HPC with a large specific surface area of 765.4 m 2 /g. When applied as a supercapacitor electrode in 6 mol/L KOH electrolyte, the HPC exhibited a high specific capacitance of 152 F/g at 0.2 A/g. Additionally, EVA resins with higher vinyl acetate content and melt index (MI) produced greater amounts of methane and pyrolytic carbon, while the resins with lower MI values showed enhanced reactivity toward chemical activation. This work offers a green and efficient route for the high-value recycling of EVA in PV waste and contributes to the sustainable synthesis of advanced HPC materials for energy storage applications.
研究领域:
环境科学
·
材料科学
·
能源化学
·
废弃物资源化
·
电化学储能
·
高分子材料工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）