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通过正离子聚合法制备了异丁烯-对甲基苯乙烯无规共聚物,考察了单体浓度、聚合温度以及聚合时间对正离子聚合的影响,并通过光照溴化反应对共聚物进行溴化改性,制备出主链结构完全饱和的溴化异丁烯-对甲基苯乙烯无规共聚物(BIMS),对其结构与性能进行了表征。结果表明,在-80℃、单体质量分数为25%~28%时,异丁烯与对甲基苯乙烯正离子共聚合,聚合物的数均分子量可达2.1×10~5。随着温度的降低,聚合物的数均分子量增大,分子量分布变窄。随着溴含量的增加,BMIS中苄基溴含量也增加,当溴质量分数为1.9%时,聚合物中苄基溴摩尔分数达到1.38%。BIMS热稳定性较好,在较低的温度下仍能保持橡胶的高弹性,且耐热氧老化性能优异。 相似文献
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特高含水期水驱剩余油挖潜的实践与认识 总被引:1,自引:0,他引:1
针对北三东区块存在的问题,应用精细地质研究成果,通过多学科有机结合,综合运用多种油藏动静态数据,精确预测剩余油分布,搞清特高含水部位、剩余油富集部位、注采完善程度。针对剩余油分布零散的实际情况,优选补孔措施井、措施层位,通过补孔完善局部单砂体注采关系,进行剩余油的挖潜。实践表明,通过补孔完善单砂体注采关系,挖潜不完善井区的剩余油,可以取得较好开发效果。 相似文献
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结合厦门市快速公交系统(BRT)一期工程车站站台雨蓬制造实践,针对站台雨棚弧形刚架的结构特点、工艺难点和现场施工条件,介绍了用钢板组拼方法自制弧形方钢管的重点工艺技术,以及防止焊接变形等的质量保证措施。 相似文献
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The oxide dispersion strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivities,high-temperature strength and microstructure stability.To date,the state-of-art to fabrication of them was the internal oxidation (IO) process.In this paper,alumina dispersion strengthened copper (ADSC) powders of nominal composition of Cu-2.5 vol%Al2O3 were produced by reaction milling (RM) process which was an in-situ gas-solid reaction process.The bulk ADSC alloys for electrical and mechanical properties investigation were obtained by sintering and thereafter hot extrusion.After the hot consolidation processes,the fully densified powder compacts can be obtained.The single γ-Al2O3 phase and profile broaden effects are evident in accordance with the results of X-ray diffraction (XRD);the HRB hardness of the ADSC can be as high as 95;the outcomes should be attributed to the pinning effect of nano γ-Al2O3 on dislocations and grain boundaries in the copper matrix.The electrical conductivity of the ADSC alloy is 55%IACS (International Annealing Copper Standard).The room temperature hardness of the hot consolidated material was approximately maintained after annealing for 1 h at 900 ℃ in hydrogen atmosphere.In terms of the above merits,the RM process to fabricating ADSC alloys is a promising method to improve heat resistance,hardness,electrical conductivity and wear resistance properties etc. 相似文献
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