共查询到19条相似文献,搜索用时 687 毫秒
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通过电子束辐照研究了乙烯-甲基丙烯酸甲酯共聚物(EMMA)与三元乙丙橡胶(EPDM)不同共混比例材料的力学性能、硬度、交联度、结晶及形状记忆等,考察了辐照剂量和共混组分比例对材料性能的影响。结果表明,辐照提高了共混体系的力学性能和硬度,同时降低了结晶性能,这主要是由于辐照诱发了交联反应,使材料内部产生了交联结构。辐照交联为EMMA/EPDM共混物热收缩材料提供了形状回复的驱动力,但降低了形状固定率,通过控制交联度和结晶相所占比例,能够得到综合性能好的热收缩材料。当EMMA/EPDM(质量比)达到或高于3/7、辐照剂量控制在40~80 k Gy时,能够制备出满足基本要求的热收缩材料。 相似文献
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由中国科学院上海原子核研究所申请的专利(专利号 0 0 1 1 5 3 5 3 ,公布日期 2 0 0 0 0 9 2 0 )“辐射交联低烟无卤阻燃低温收缩聚烯烃热收缩材料”是一种低烟、无卤、阻燃且在较低温度 (≤ 90℃ )下可收缩的辐射交联聚烯烃热收缩材料。该材料制品由乙烯 乙酸乙烯酯共聚物和EPDM及抗氧剂、无卤阻燃剂、消烟剂、润滑剂、交联助剂经混合挤出造粒、挤出成型、辐射交联工艺制成。用该材料制备热收缩器件不仅原材料易得 ,而且加工方法简单、生产成本低、产品性能好 ,适合工业化生产辐射交联低烟无卤阻燃低温收缩聚烯烃热收缩材料$杭州… 相似文献
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1 前言交联聚烯烃废料主要是指热收缩电缆附件生产过程中的工艺废料和废品。热收缩电缆附件是一种具有“弹性记忆效应”的高分子材料复合物。产品以聚乙烯(PE)、氯化聚乙烯(CPE)、乙烯—醋酸乙烯共聚物(EVA)、三元乙丙橡胶(EPDM)、硅橡胶为基料,常填充不同填料,为具有“记忆效应”,须进行交联和扩张预应力处理。分子结构由原来的支链型转化为体型结构, 相似文献
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辐射交联热收缩聚乙烯的研究进展 总被引:1,自引:0,他引:1
介绍了辐射交联热收缩聚乙烯的研究现状,分析了热收缩机理以及辐射交联规律,重点讨论了辐射交联热收缩聚乙烯的制备工艺以及聚乙烯和乙烯醋酸乙烯共聚物、聚氨酯、氯丁橡胶等共混体系的研究,并分析了辐射交联热收缩聚乙烯的未来研究发展方向。 相似文献
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形状记忆聚合物的发展及应用 总被引:10,自引:0,他引:10
介绍形状记忆聚合物的发展历史及最新研究进展,从结构角度分析和探讨了聚合物产生形状记忆效应的原因,并对交联聚烯烃,聚氨酯,聚酯等热致形状记忆聚合物的特性及应用进行了介绍和评价,最后结形状记忆聚合物的发展前景进行了展望。 相似文献
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化学改性乙烯-乙酸乙烯共聚物(EVA)的形状记忆性能研究(Ⅰ)--拉伸比和乙酸乙烯(VA)含量对其形状记忆性能的影响 总被引:1,自引:1,他引:0
以过氧化二异丙苯(DCP)为引发剂对乙烯一乙酸乙烯共聚物(EVA)进行化学交联改性,制备具有形状记忆性能的EVA,通过对形状记忆性能和凝胶含量的测定等重点探讨了拉伸比和乙酸乙烯(VA)含量对其形状记忆性能的影响。结果表明,不同VA含量的EVA都存在一最佳拉伸比,在这一拉伸比下其形状记忆性能使各项参数达最大值;VA含量对未交联或交联度小的EVA的形状回复率影响很大,随着VA含量增加,形状回复率增大;VA含量对交联度大的已形成完善网络结构EVA的形状回复率的影响并不明显,形状固定率略降低。 相似文献
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A spherical TiCl4/MgCl2‐based catalyst was used in the synthesis of polyethylene/polypropylene/poly (ethylene‐co‐propylene) in‐reactor alloys by sequential homopolymerization of ethylene, homopolymerization of propylene, and copolymerization of ethylene and propylene in gas‐phase. Different conditions in the third stage, such as the pressure of ethylene–propylene mixture and the feed ratio of ethylene, were investigated, and their influences on the compositions, structural distribution and properties of the in‐reactor alloys were studied. Increasing the feed ratio of ethylene is favorable for forming random ethylene–propylene copolymer and segmented ethylene–propylene copolymer, however, slightly influences the formation of ethylene‐b‐propylene block copolymer and homopolyethylene. Raising the pressure of ethylene–propylene mixture results in the increment of segmented ethylene–propylene copolymer, ethylene‐b‐propylene block copolymer, and PE fractions, but exerts a slight influence on both the random copolymer and PP fractions. The impact strength of PE/PP/EPR in‐reactor alloys can be markedly improved by increasing the feed ratio of ethylene in the ethylene–propylene mixture or increasing the pressure of ethylene–propylene mixture. However, the flexural modulus decreases as the feed ratio of ethylene in the ethylene–propylene mixture or the pressure of ethylene–propylene mixture increases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2481–2487, 2006 相似文献
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通过形状记忆性能测试、DSC和DMTA等热分析技术重点,探讨了结晶对EVA形状记忆性能的影响以及形状记忆性能的工艺性和使用性能的影响。结果表明,随着结晶度的增加,形状回复率变化不大。而形状固定率增加;热固性SMP的形状回复性由交联网络的完善程度决定,结晶度对其影响不大;结晶对形状记忆材料的响应温度和模量有较大影响,结晶度高响应温度高,常温模量高。形状固定率由聚合物的力学松弛特别是蠕变决定,结晶度只是其影响因素之一,不是决定性因素。从形状记忆机理出发初步揭示了影响热固性形状记忆高分子材料形状记忆性能的本质因素。 相似文献
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对丙烯/1-丁烯无规共聚物(PPB)与丙烯/乙烯抗冲共聚物(PPE)的结晶行为进行对比,在等温结晶时,通过相对结晶度随时间的变化关系、等温结晶曲线等研究,表明丙烯/1-丁烯无规共聚物结晶速率明显低于丙烯/乙烯抗冲共聚物,同时丙烯/乙烯抗冲共聚物的等温结晶速率随乙烯单元含量增加没有明显降低。根据Avrami方程计算了共聚物的结晶活化能,证明丙烯/1-丁烯无规共聚物的结晶能力较丙烯/乙烯抗冲共聚物低。扫描电镜分析丙烯/1-丁烯无规共聚物在丁烯单元摩尔分数2.39%时没有韧性拉伸,而丙烯/乙烯抗冲共聚物在乙烯单元摩尔分数3%时出现韧性拉伸。 相似文献
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Toshikazu Kobayashi Barbara A. Wood Akio Takemura Hirokuni Ono 《Polymer Engineering and Science》2008,48(11):2247-2257
Blends of poly(ethylene terephthalate) (PET) and poly (ether esteramide) (PEEA), which is known as an ion conductive polymer, were prepared by melt mixing using a twin screw extruder. Antistatic performance of the molded plaques and the effects of adding ionomers such as lithium neutralized poly(ethylene‐co‐methacrylic acid) copolymer(E/MAA‐Li), magnesium neutralized poly(ethylene‐co‐methacrylic acid) copolymer(E/MAA‐Mg), and zinc neutralized poly(ethylene‐co‐methacrylic acid) copolymer (E/MAA‐Zn) were investigated. Antistatic effect of adding poly(ethylene‐co‐methacrylic acid) copolymer(E/MAA) and polystyrene, and poly(ethylene naphthalate) (PEN) into PET/PEEA blends were also investigated. Here we confirmed that lithium ionomer worked the most effectively in those blend systems. We also confirmed that E/MAA worked to enhance the antistatic performance of PET/PEEA blends. Morphological study of these ternary blends system was conducted by TEM. Specific interaction between PEEA and E/MAA‐Li, and E/MAA were observed. Those ionomers and copolymer domains were encapsulated by PEEA, which could increase the surface area of PEEA in PET matrix. This encapsulation effect explains the unexpected synergy for the static dissipation performance on addition of ionomers and E/MAA to PET/PEEA blends. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers 相似文献
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形状记忆树脂是一种新型的功能高分子材料,目前已开发成功的品种有聚降冰片烯、高反式聚异戊二烯、丁苯共聚物和聚氨酯等。在形状记忆原理的基础上,论述了它们的制造方法、性能、重要应用等,并对我国开展记忆树脂的研究与开发提出了建议。 相似文献