共查询到20条相似文献,搜索用时 78 毫秒
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采用氯化原位接枝的方法合成了以高密度聚乙烯(HDPE)为骨架、马来酸酐(MAH)为支链的接枝聚合物,反应中不需要加入任何引发剂.傅立叶红外光谱(FTIR)分析证明了该方法对HDPE改性的可行性.探讨了影响接枝聚合物力学性能的因素及变化规律.结果表明.接枝反应温度、接枝率以及MAH单体的加入量对MAH氯化接枝HDPE(HDPE-cg-MAH)的力学性能有很大的影响. 相似文献
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以氯气为引发剂,采用气-固相方法在加热条件下合成聚氯乙烯(PVC)、丙烯酸-2-羟基乙酯(HEA)的氯化原位接枝共聚产物(PVC—cg-nEA)。用IR、GPC、DSC等对氯化原位接枝共聚产物进行表征;初步探索产物的流变性能;讨论了单体加入量、反应温度、膨润时间等不同合成条件对产物力学性能的影响。试验结果表明,单体加入量10份,反应温度120℃,膨润时间24h,接枝共聚产物具有最佳的力学性能。 相似文献
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以低相对分子质量的聚丙烯为原料,采用气-固相法制备了聚丙烯的氯化原位接枝共聚物。溶解性测试发现,当氯化聚丙烯(CPP)的氯含量为50.1%时,溶解度可达到90.0%,基本可在二甲苯中完全溶解,但是CPP的附着力相当差,不能满足涂料要求。通过氯化原位接枝共聚(ISCGC)的方法向CPP大分子链引入极性基团可以提高产物的附着力。本研究讨论了单体种类及配比对产物附着力的影响,最终确定了体系为单体甲基丙烯酸缩水甘油酯/马来酸酐共聚接枝时,产物的附着力最佳,可达到0级。 相似文献
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以高密度聚乙烯(HDPE)为原料,甲基丙烯酸缩水甘油酯(GMA)为接枝单体,采用氯化原位接枝法,得到官能化氯化聚乙烯接枝聚合物(CPE-cg-GMA)。实验通过红外光谱(IR)、差示扫描量热(DSC)分析、扫描电镜(SEM)分析等表征手段对接枝共聚物的结构进行了初步探讨。结果表明,HDPE与GMA单体氯化原位接枝过程,接枝到HDPE骨架上的环氧基团水解形成了羟基,与其它大分子之间形成了氢键。此外,由于接枝链的存在,使大分子的结晶度与CPE相比显著降低,同时CPE-cg-GMA的综合力学性能大幅度提高。 相似文献
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王曙光 《化学推进剂与高分子材料》2007,5(1):62-64
采用固相法对聚乙烯(PE)进行氯化接枝苯乙烯/丙烯腈(St/AN)单体,制得了改性氯化聚乙烯(CPE)材料。探讨了氯化反应温度、氯含量、引发剂过氧化苯甲酰(BPO)用量和单体配比对聚合物力学性能的影响,实验中还对PE接枝了不同单体,结果表明,采用二段温度(70℃,120℃)法,氯质量分数为35%,BPO加入质量为0.24g,m(St)/m(AN)为1:1时,可制得力学性能较好的CPE材料。极性单体MA、AN及St的加入提高了CPE材料的拉伸强度。 相似文献
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Yingying Sun Gengping Wan Baoxing Wang Jiruo Zhao Ying Feng 《Journal of Polymer Research》2009,16(2):165-172
A graft copolymer composed of poly (2-hydroxy ethyl acrylate) (PHEA) as branched chains and chlorinated polyethylene (CPE)
as backbone, CPE-cg-HEA, was synthesized by in situ chlorinating graft copolymerization (ISCGC). The polymer has special molecular structure with short graft chains and abundant
branched points. The mechanical properties of CPE-cg-HEA were studied by tensile testing, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA). The morphologies
of tensile fractured surfaces for CPE and CPE-cg-HEA were investigated by scanning electron microscope (SEM). The testing results indicated the mechanical properties of the
in situ chlorinating graft copolymers have greatly improved compared with CPE with about the same chlorine content. Particularly,
there was a broad plateau on the stress–strain curve of the graft copolymer, which meant a high elastic-like deformation. 相似文献
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The aim of this study was to improve the mechanical properties of thermoplastic starch foams prepared from cassava starch blended with natural rubber latex by reactive blending. Potassium persulfate was used as an initiator for graft copolymerization between the starch and natural rubber during baking. The starch–natural rubber graft copolymer (starch‐g‐NR copolymer) was successfully produced during both suspension and melt blending based on 1H‐NMR and FTIR characterization. Natural rubber increased the flexural modulus of starch/natural rubber foams without potassium persulfate, thus indicating the compatibility of the blends. The starch‐g‐NR copolymer, acting as a compatibilizing agent, enhanced the impact strength of foams, but it did not improve the flexural modulus. This may be due to the potassium persulfate decreasing the molecular weight of the natural rubber. Relative humidity also played an important role on the mechanical properties. Foams became more ductile at higher relative humidities. Since foam density increased with an increasing natural rubber content, the specific impact strength was also considered. A soil burial test showed that the cassava starch foams and foams containing 15 pph of natural rubber were fully biodegraded within 8 and 18 weeks, respectively. The starch‐g‐NR copolymer delayed biodegradation of foams and foams containing high natural rubber content, i.e., 35 pph, showed a low ability to be biodegraded. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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氯丁橡胶和MMA的接枝共聚研究 总被引:7,自引:0,他引:7
以氯丁橡胶A - 90、MMA、2 40 2酚醛树脂为主料 ,以甲苯、丁酮为溶剂 ,以BPO为引发剂 ,在 30 0L聚合釜中进行了接枝氯丁胶的试验和生产。讨论了原料配比、聚合工艺对接枝胶性能的影响 ,通过正交设计确定了最佳配方。本研究的接枝氯丁胶固含量 (2 0± 1) % ,粘度 2 5 0 0~ 30 0 0mPa·S ,对多种制鞋材料均有较高的粘接强度 ,其各项性能均可满足制鞋厂生产要求 相似文献
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Graftings of acrylonitrile and methyl methacrylate onto lignosulfonate were studied, respectively, with and without the lignosulfonate ozonized. Copolymerization was redox-initiated by peroxideferrous ions. Monomer conversion and grafting efficiency depended essentially on reaction medium and the maount of peroxide charged. Among the media employed, the magnitude of the medium effect on conversion was found to be in the following order: water, dioxane, and methanol. The conversions in water of acrylonitrile and methyl methacrylate were 55 and 90%, respectively, when using 3% hydrogen peroxide. Beyond this 3 % charge, both the grafting efficiency and the degree of lignosulfonate grafted approached certain limits. Ozonization appeared to be capable of stimulating the active centers in lignin macromolecules, whereon acrylic monomers could be grafted. Better grafting efficiency was obtained with the ozonized lignosulfonate. 相似文献
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黄原胶与丙烯酰胺接枝共聚反应的研究 总被引:1,自引:0,他引:1
以过硫酸铵为引发剂,在氮气保护下,研究了黄原胶与丙烯酰胺的接枝共聚反应。考察了单体浓度、引发剂浓度、反应温度和反应时间等因素对接枝率及接枝效率的影响,探讨了过硫酸铵引发黄原胶接枝丙烯酰胺共聚反应的基本规律。采用红外光谱、X射线粉末衍射对接枝共聚物的结构进行研究,用热重分析法表征了产物的热性能,并初步探讨了接枝机理。结果表明,过硫酸铵能有效地引发黄原胶与丙烯酰胺的接枝共聚反应,并且接枝率和接枝效率随单体浓度、引发剂浓度、反应温度的变化出现极大值,随反应时间的延长不断上升,直至基本不变。 相似文献
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高温溶液法制备SBR的结构和性能研究 总被引:1,自引:0,他引:1
以正丁基锂(n-BuLi)为引发剂、醚类化合物为调节剂、环己烷/正己烷为溶剂,采用阴离子高温聚合工艺合成了溶聚丁二烯/苯乙烯橡胶(SSBR)。通过GPC、NMR分别测试了SSBR的相对分子质量及其分布和微观结构;并对硫化胶性能和门尼粘度进行了测定。考察了调节剂、温度等因素对SSBR的相对分子质量及其分布、共聚物微观结构、序列分布以及动态力学性能和物理机械性能的影响。研究结果表明:所用调节剂是有效的SSBR高温聚合调节剂,可很好地调节SSBR中的乙烯基含量,获得微观结构适中的中高乙烯基丁苯共聚物;n(调节剂)/n(Li)对聚合速率及共聚物的1,2-结构含量有明显的影响,但对共聚物的相对分子质量分布无明显影响;温度对共聚物的转化率及微观结构均有一定的影响。 相似文献