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以偶氮二甲酰胺(AC)为发泡剂,采用自由发泡法制备了聚氯乙烯(PVC)/氯化聚乙烯橡胶(CM)/丁腈橡胶(NBR)发泡材料,考察了CM/NBR(质量比)、填料品种及用量、氯化石蜡用量对发泡材料性能的影响。结果表明,随着NBR并用量的增加,发泡材料的发泡倍率逐渐增大,泡孔逐渐变大且更加均匀,收缩率变化不大,但阻燃性能降低,综合考虑,选取CM/NBR为20/30;Al(OH)3和滑石粉均可改善发泡材料的阻燃性能,随着Al(OH)3和滑石粉用量的增加,发泡材料的发泡倍率和收缩率均变小,泡孔均匀程度变差,阻燃性能提高;随着氯化石蜡用量的增加,发泡材料的发泡倍率先增大后减小,均匀的泡孔结构逐渐出现较多的大孔,收缩率变化不大,阻燃性能提高。 相似文献
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填料对乙烯-醋酸乙烯酯橡胶发泡材料性能的影响 总被引:1,自引:0,他引:1
使用无转子发泡硫化仪、RPA橡胶分析仪、体视显微镜以及力学性能测试仪器等研究了白炭黑和炭黑对乙烯-醋酸乙烯酯橡胶(EVM)硫化发泡特性、发泡材料微观结构和性能的影响。结果表明,白炭黑用量较少时,体系焦烧时间和正硫化时间均延长,发泡剂分解速度提高。与相同用量的白炭黑体系相比,炭黑体系不易焦烧,正硫化时间较长,发泡剂分解速度较快。白炭黑体系泡孔质量好于炭黑体系,其中添加30份白炭黑的泡沫材料具有最低密度。RPA分析结果表明,减少白炭黑用量或采用炭黑作填料均能降低体系储能模量(G′)和损耗模量(G″),炭黑体系泡沫材料动态模量具有较强温度敏感性。 相似文献
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以CM/EPDM并用胶为基材制得发泡材料,研究了不同填料和增塑剂对发泡材料性能的影响。结果表明,添加碳酸钙和纳米碳酸钙均可制得泡孔均匀、力学性能优良的发泡材料;碳酸钙用量为20~30份且DOP用量为20份时,发泡材料硫化速率和发泡剂分解速率匹配较好,密度小,发泡倍率高,力学性能好;DOP/石蜡油并用且随石蜡油用量的增加,发泡材料发泡倍率提高,密度减小。 相似文献
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采用模压法进行发泡,研究了氯化聚乙烯(CM)与聚氯乙烯(PVC)的共混比和发泡剂用量对发泡体的泡体性能、泡孔结构的影响。结果表明,不同CM/PVC共混比的复合材料,随体系中CM的增加,发泡密度逐渐减小、泡孔体积和发泡倍率逐渐增大,当CM/PVC=50/50时,发泡材料具有较好的综合性能;改变共混体系中发泡剂AC的用量,测试泡体性能及观察泡孔结构得出,随AC发泡剂用量的增加,发泡材料的发泡密度减小,其相应的物理机械性能如拉伸强度、撕裂强度逐渐降低。 相似文献
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以废轮胎热解炭黑(CB_P)为增强填料,制备了发泡三元乙丙橡胶(EPDM),分析了CB_P的基本性能,研究了CB_P填充EPDM混炼胶的门尼黏度、硫化特性及发泡EPDM的物理机械性能、泡孔形态、压缩特性和能量吸收特性,并分别与牌号为N 660的炭黑、高岭土及碳酸钙填充EPDM进行了对比。结果表明,CB_P的主要成分是碳元素,灰分质量分数高达14.4%,粒径分布宽;在4种填料中,CB_P填充EPDM混炼胶的门尼黏度仅低于N 660填充EPDM混炼胶,焦烧时间和正硫化时间最短;CB_P填充发泡EPDM的拉伸强度和定伸应力优于高岭土和碳酸钙填充发泡EPDM,但发泡倍率小于后两者;CB_P填充发泡EPDM的泡孔大小均匀,泡孔直径为28μm,闭孔结构规则,孔壁光滑完整;在相同应变下,CB_P填充发泡EPDM的吸能能力与高岭土填充发泡EPDM相近。 相似文献
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苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况,合成乙苯,苯乙烯所用的催化剂种类,并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。 相似文献
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Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile
Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, 13C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc. 相似文献
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The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu3Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu3Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters. 相似文献
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《国际聚合物材料杂志》2012,61(1-4):113-122
Abstract Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed. 相似文献
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G. R. Hamed 《The Journal of Adhesion》1983,16(1):31-39
A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength. 相似文献
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Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method1 was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity. 相似文献
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责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体. 相似文献