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151.
Flame retardant composites must perform their protective roles permanently, also under conditions of intermittent or long‐term exposure to sunlight, moisture or increased temperature. The aim of our work was characterization of the thermo‐oxidative ageing (90 °C) and the changes in flammability of ethylene‐vinyl acetate copolymer composites with 40 and 60 wt.% of magnesium hydroxide. The neat polymer and its composites were investigated for their thermal (DSC) and structural (FTIR) characteristics as well as their density, melt flow index, tensile properties and combustibility during ageing test. As FTIR results identified the different carbonyl groups in copolymer were created, the highest oxidation intensity was observed for neat copolymer. That process was accompanied by the scission of the polymer macromolecules, especially for first 700 h of thermal ageing. Thermo‐oxidative ageing resulted also in the reduction of flammability of the test materials. The highest reduction was observed for neat polymer. The changes in some properties as analysed both for the copolymer and for its composites after over 700 h of ageing were indicative for initiation of cross‐linking of copolymer molecules after that time. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
152.
我国乙烯-乙酸乙烯共聚物现状及发展建议 总被引:3,自引:0,他引:3
阐述了乙烯-乙酸乙烯共聚物的特性、用途及国内外生产、消费和价格变化情况,介绍了乙烯-乙酸乙烯共聚物的生产技术,提出了发展建议。 相似文献
153.
154.
Shyh-shin Hwang Sung-po Liu Peming P. Hsu Jui-ming Yeh Jui-pin Yang Chiu-lin Chen 《International Communications in Heat and Mass Transfer》2012
Ethylene vinyl acetate (EVA)/montmorillonite (MMT) nanocomposites diluted from master batch (50 wt.%) with EVA and EVAgMA was used in this study. The organoclay EVA nanocomposites were then injection molded by conventional and microcellular methods. Nitrogen was used as the blowing agent. The effect of organoclay content and MA grafted EVA on the morphology and the mechanical and rheological properties of the EVA–clay nanocomposites were then investigated. The results showed that the mechanical properties (tensile and impact) increased as the clay content increased. Cell size decreased as the clay loading increased. The EVAgMA nanocomposites had better mechanical properties than the EVA nanocomposites. XRD results showed that the EVAgMA nanocomposites have an exfoliated layered structure while the EVA nanocomposites are intercalated. Rheological results showed the viscosity is clay loading dependent and that the shear thinning effect occurs at high shear rates. 相似文献
155.
何代华 《武汉理工大学学报(材料科学英文版)》2010,(2)
Ethylene-Vinyl Acetate (EVA) redispersible powder and latex were used to modify mortar. Three kinds of curing regimes: standard curing, high temperature curing and freeze-thaw circle curing were adopted to cure the bonded samples. Bonding strength of EVA modified mortar was tested at 28 days. The development of bonding strengths under all three curing regimes were discussed and compared. The experimental results show that bonding strength increases with the increase of EVA content in mortar. The curing regi... 相似文献
156.
研究了电子束辐照剂量和氢氧化铝(ATH)的含量对线性低密度聚乙烯(LLDPE)/乙烯-醋酸乙烯酯(EVA)共混物凝胶含量和力学性能的影响。辐照剂量是影响LLDPE/EVA/ATH阻燃体系凝胶含量的主要因素,而ATH对其凝胶含量的影响较小。随着ATH含量的增加,LLDPE/EVA共混物的拉伸强度逐步增加,断裂伸长率迅速下降。所有阻燃体系的拉伸强度均是随着辐照剂量的增加而逐步增大,但辐照剂量对这些阻燃体系的断裂伸长率的影响却比较复杂。 相似文献
157.
158.
The vinyl acetate (VA) content in ethylene vinyl acetate (EVA) can significantly affect its performance as an encapsulant in photovoltaic modules under field conditions. EVA films of varying VA content (18, 24, 33, and 40%) have been prepared using twin screw extruder with the necessary additives and subsequently cured at 150 °C. All the EVA films have been subjected to UV radiation at a wavelength of 340 nm for 1000 and 2000 h to simulate accelerated field aging. The effects of accelerated aging on the gel content, mechanical properties, transmittance, Fourier transform infra-red (FTIR) spectra, thermal stability, degree of crystallinity, and yellowness have been studied. The observations made in this study of UV aging up to 2000 h suggests that the optimum range of VA content in EVA should be between 18 and 33% by weight. VA content beyond 40% degrades almost all properties needed for an encapsulate material after aging of only 2000 h. VA content of around 18% is the most stable under UV aging conditions but has a slightly lower value of transmittance for the unaged sample although the difference in transmittance between different specimens decreases with UV aging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48268. 相似文献
159.
本文研究了不同防老剂在硅橡胶/EVA共混物中的抗氧的作用,利用热分析技术分析了共混物的抗氧化能力。研究结果表明,防老剂可以有效抑制硅橡胶/EVA共混物的热氧化过程,可使共混物的耐热氧老化性能从100℃提高到170℃以上,短期可达180℃~200℃。 相似文献
160.
在综述文献及试验的基础上,介绍了以热电厂中空干灰为原料制作PVC绝热材料及EVA泡沫材料的配方和所得产品的性能。并以理论计算及试验为依据,提出了用流化床筛析法由热电厂飞灰中筛选中空干灰(绝大部分颗粒粒径为27μm)的操作过程。此过程的设备简单、容易操作,因此是热电厂飞灰综合利用的切实可行的工艺路线。 相似文献