共查询到20条相似文献,搜索用时 78 毫秒
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将苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)、废旧轮胎胶粉(GTR)和相容剂环氧天然橡胶(ENR)熔融共混,然后再分散到沥青中制备了SBS/GTR复合改性沥青,考察了ENR含量、SBS/GTR(质量比)对复合改性沥青热储存稳定性和基本性能的影响。结果表明,随着ENR含量的增加或SBS含量的减少,SBS/GTR复合改性沥青的热储存稳定性提高,当ENR质量分数为1.0%、SBS/GTR为50/50时,复合改性沥青的热储存稳定性最佳;随着ENR含量的增加,SBS/GTR复合改性沥青的软化点、针入度、延度和黏度变化不大,但当ENR质量分数为10.0%时,改性沥青的软化点明显升高,针入度下降,属于一种比较硬质的改性沥青,具有较好的施工和易性;随着SBS含量的减少,SBS/GTR复合改性沥青的软化点、黏度和延度均降低。 相似文献
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采用纳米CaCO3和苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)作为外加剂制备纳米CaCO3/SBS复合改性沥青。通过测试基本物理性能确定了外加剂的最佳掺量,通过流变性能测试、离析试验、荧光显微镜观察及热重分析等考察了沥青的性能及微观形貌。结果表明,两种外加剂复配的最佳比例为5%(质量分数,下同)的纳米CaCO3和4%的SBS;在纳米CaCO3改性沥青中掺加SBS后,复合改性沥青在不同温度下的黏度增大,高温抗车辙能力增强,低温性能得到明显改善,储存稳定性良好;纳米CaCO3分子、SBS分子和基质沥青分子三者具有良好的相容性,经复合改性后沥青的热稳定性增强。 相似文献
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贮存稳定的EVA/SBS复合改性沥青的性能研究 总被引:1,自引:0,他引:1
利用乙烯-醋酸乙烯酯无规共聚物(EVA)与苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)对沥青进行复合改性并对其进行动态硫化处理,测试了动态硫化前后试样的针入度、软化点、5℃延度、贮存稳定性等常规性能.并利用应变控制流变仪与光学显微镜对试样做了动态力学性能分析和相形态观察。通过对动态硫化前后试样性能变化的分析比较,结果表明:动态硫化后,试样的低温性能良好,而且由于试样内部弹性交联网络的形成,使试样的高温物理机械性能及高温贮存稳定性均获得了提高,降低了试样的温度敏感性。 相似文献
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采用苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改善BR/乙烯-乙酸乙烯酯共聚物(EVA)/高抗冲聚苯乙烯(HIPS)共混物的界面相容性,通过动态硫化法制备BR/EVA/HIPS TPV,并对其性能进行研究.结果表明:未加入SBS的BR/EVA/HIPS共混物未表现出橡胶类弹性体特征,而加入适量SBS的共混物表现出典型橡胶类弹性体特征;当SBS用量为8~12份时,BR/EVA/HIPS TPV的综合物理性能较好,拉伸断面平滑,界面相容性良好. 相似文献
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采用聚烯烃弹性体(POE)对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改性沥青进行复配改性,制备了POE/SBS改性沥青混合料。考察了POE用量对SBS改性沥青抗老化性能的影响。结果表明,POE/SBS复配改性能提升沥青混合料的高温抗老化性能,且对低温性能有一定的改善效果。POE改善了SBS改性沥青混合料的抗车辙和抗老化性能,但会在一定程度上降低其低温韧性。当在沥青中加入质量分数分别为4%和3%的SBS和POE,POE/SBS改性沥青混合料的综合性能较佳。 相似文献
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以正丁基锂为引发剂、环己烷为溶剂、环氧丙烷为降活剂、环氧氯丙烷为封端剂,采用负离子原位封端技术合成了不同数均分子量(_n)的端环氧基苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS),研究了端环氧基SBS及其改性沥青的性能,并与市售商品SBS进行了对比。结果表明,随着端环氧基SBS的_n增加,其拉伸强度提高而扯断伸长率下降;在_n相近的条件下,端环氧基SBS的拉伸强度和永久变形明显优于SBS;随着端环氧基SBS的_n增加,改性沥青的软化点升高,延度先增大后减小;当_n为10.1×10~4时,改性沥青的各项性能均达到最佳,其软化点、低温延度和离析软化点差值分别为74.1℃、39.1 cm、0.7℃;端环氧基SBS与沥青具有良好的相容性,改善了沥青的热储存稳定性。 相似文献
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用苯乙烯(St)、丙烯腈(AN)2种单体和乙烯一辛烯共聚物(POE)进行溶液接枝共聚合反应,制备了乙烯-辛烯共聚物接枝苯乙烯-丙烯腈共聚物(POE-g-SAN),探讨了接枝共聚反应条件,并对POE-g-SAN进行了表征.结果表明,接枝共聚反应的接枝率(GR)和接枝效率(GE)均随着St/AN(质量比)的减小而稍有增大,当POE/St-AN(质量比)为50/50时,GR与GE达到最大值;增加BPO用量有利于接枝反应;当反应物POE与St-AN在甲苯中的质量分数为27.5%时,GR与GE达到最大值;在反应前10 h,随着反应时间的延长,GR增大,GE在4 h时达到最大值77.8%,在反应10 h后,接枝反应几乎不再进行;在POE与St-AN接枝共聚反应中,POE已接枝了SAN支链,且GR越大,SAN支链越多;POE-g-SAN有2个玻璃化转变温度(Tg),约为-50℃和110℃;随着GR的增大,POE-g-SAN中POE相的Tg升高,熔融温度和熔融热均降低;随着共单体中AN配比量的增加,POE-g-SAN中SAN相的Tg升高. 相似文献
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Marco Pinna 《Polymer》2008,49(12):2797-2800
With the help of cell dynamics simulation we investigate morphology of thin block copolymer film around a nanoparticle. The obtained structures include: parallel, perpendicular, mixed and perforated lamellae, parallel and perpendicular cylinders and spheres. Analogy and difference with planar films are discussed. Our simulation suggests that novel porous nanocontainers can be formed by the coating of a sacrificial nano-bead by a block copolymer layer with a well controlled nanostructure. 相似文献
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The issue of self-healing materials is of paramount importance due to its intrinsic scientific value, as well as potential applications in a wide variety of fields, such as manufacturing, medicine, and electronics. We have investigated the behavior of poly(styrene-b-methylmethacrylate) diblock copolymer, following deformation performed by a silicon atomic force microscopy tip. We observed the changes in the polymer as it was subsequently heated in situ, and found how diblock “scars” can heal. These observations give important guidance to efforts that seek to create nanostructures using these methods, while also revealing fundamental insights into the mechanisms of polymer repair on the nanoscale. 相似文献
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The deformation behavior of block copolymers is examined. Interdomain bridges, loops, cilia and floating chains in spherical, cylindrical and lamellar domain morphologies are considered. In the theoretical model, which is analogous to the “three-chain” model in classical rubber elasticity theory, interdomain chains are confined between pairs of infinite, parallel impenetrable walls constructed at the surfaces of nearest neighbor domains. The domains are taken as undeformable. The quantities which are calculated are: the Young's modulus; the partial molar elastic free energy of swelling; and the stress-strain relation for simple extension. 相似文献
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Dynamic mechanical properties, low-temperature impact behavior, flexural modulus and heat distortion temperature (HDT) of isotactic polypropylene (i-PP) and propylene-ethylene block copolymer (Co-PP) toughened with styrene-ethylene butylene-styrene triblock copolymer (SEBS), at blending ratios of 0–30 phr, were studied and compared. A scanning electron microscopic morphology study of the impact-fractured surfaces demonstrated the changes in fracture mechanisms at various temperatures and SEBS contents. SEBS remarkably improves the impact endurance in the lower-temperature range when blended with Co-PP in comparison with i-PP, due to the increased compatibility in the interface between SEBS particles and the Co-PP matrix. 相似文献
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Water-based epoxy-acrylic graft copolymer 总被引:13,自引:0,他引:13
High molecular weight epoxy resins have been grafted with styrene−methacrylic acid monomers; the epoxy-g-(styrene-methacrylic acid) copolymer was water-reducible when neutralized with a base. Characterization of graft sites in the epoxy-g-acrylic copolymer by 13C NMR spectroscopy is described. Grafting takes place at the aliphatic carbons of the epoxy resin. The rationale for this behavior is presented. 相似文献
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D.J. Cook D.R. Morgan V. Sirivivatnanon R.P. Chaplin 《Cement and Concrete Research》1976,6(2):235-243
Studies to determine the influence of mixtures of monomers (and subsequently copolymers) on the behaviour of premix copolymer cement materials are described in this paper. Five system viz styreneacrylonitrile, styrene-vinyl acetate, methyl methacrylate - vinyl acetate, butyl methacrylate - methyl methacrylate and butyl acrylate - methyl methcrylate, were investigated. Setting time and hydration studies were carried out on premix cement pastes while compressive strength tests were carried out on premix mortars, to determine the influence of monomer volume, surfactants and polymerisation method. The results indicated, as has most of the work on premix systems, that the influence of the copolymers was to increase setting time, decrease the degree of hydration as measured by percentage of chemically combined water and decrease strength relative to that of specimens continuously moist cured. 相似文献
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Polyacrylamide (PAM)-grafted dextrine (DEX) copolymers were prepared by heating a film-forming precursor solution consisting
of PAM, corn starch-derived DEX, cerium (IV) nitrate hexahydrate, and water, at 150° or 200°C; these solutions were applied
as water-based primer coating systems to aluminum (Al) substrates. Grafting PAM on the DEX not only inhibited the fragmentation
of DEX structures caused by oxidation at 200°C in air, but also aided in fabricating coating films that were less susceptible
to moisture and minimized the rate of permeation of electrolyte species through the film layers. In addition, the grafted
DEX coating films favorably reacted with the Al substrate to form Al-O bonds at interfaces. Consequently, Al panels coated
with a highly grafted DEX copolymer had a salt-spray resistance of 600 hr.
Energy Efficiency and Conservation Division., Dept. of Applied Science, Upton, NY 11973.
This work was performed under the auspices of the U.S. Department of Energy, Washington, D.C. under Contract No. DE-AC02-76CH0016,
and supported by the U.S. Army Research Office Program MIPR-7HDOEAR040. 相似文献
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