共查询到18条相似文献,搜索用时 156 毫秒
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焦磷酸锰(Mn~(3 ))络阴离子引发淀粉与丙烯酸酯接枝共聚的研究 总被引:4,自引:0,他引:4
以廉价无毒的Mn3+作为引发剂引发丙烯酸酯与淀粉接枝共聚,重点研究了引发剂浓度、单体浓度、反应温度及反应时间对淀粉接枝丙烯酸乙酯的影响规律。结果表明,单体转化率均可达95%,接枝效率和接枝率最高分别可达60%和170%,接枝物分子量在1.0×105~2.5×105,接枝频率在1100左右 相似文献
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采用廉价无毒的焦磷酸锰(Mn^3+)络离子作为引发剂,以十二烷基硫酸钠为乳化剂,对淀粉与苯乙烯及二元单体接枝共聚进行了初步探索,研究了单体浓度,引发剂浓度,反应温度及反应时间对接枝反应的影响趋势,发现Mn^3+具有良好的引发效果,接枝效率在65%~90%,接枝率可达200%,对淀粉与St/AN,St/EA二元单体接枝共聚的研究表明接枝效率不高。 相似文献
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研究了玉米淀粉与苯乙烯的接枝共聚反应,以焦磷酸锰络刚离子为引发剂,以十二烷基硫酸钠为乳化剂,考察了引发剂浓度、反应时间及反应温度对接枝反应的影响,实验结果表明最高接枝率可达130%,接枝效率可达68%。接枝淀粉在α-淀粉酶溶液中酶解28d,表明其具有生物降解性能,失重率可达36.1%。 相似文献
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研究了淀粉与苯乙烯 (St)、甲基丙烯酸甲酯 (MMA)的接枝聚合反应。以焦磷酸锰 [Mn(H2 P2 O7) 3 ]3 -为引发剂 ,以十二烷基苯磺酸钠为乳化剂 ,考察引发剂浓度、反应温度、单体浓度对原位聚合反应中单体的转化率(X % )、接枝率 (G % )、接枝效率 (GE % )的影响。实验结果表明最高接枝率可达到 5 2 .4 % ,接枝效率可达 77.2 %。 相似文献
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以球形纤维素珠体为原料,丙烯腈(AN)和丙烯酰胺(AM)为单体,硝酸铈铵和过硫酸钾(KPS)为引发剂,制备纤维素珠体-AN-AM接枝共聚物,并通过正交单因素实验,研究了反应温度、引发剂用量、单体用量、反应时间等因素对接枝效果的影响。实验结果表明:当反应温度为60℃,引发剂硝酸铈铵用量为20%,KPS用量为15%(引发剂与单体AN的质量百分比),单体AN浓度为0.75 mol/L,AM浓度为0.28 mol/L,硝酸浓度为0.14 mol/L,反应时间为3 h时,接枝效果最好。此条件下,AN、AM与纤维素的接枝率可达259.4%,接枝效率可达49.40%。 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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以马来酸酐(MAH)为单体、苯乙烯(St)为共单体、过氧化二异丙苯(DCP)为引发剂,采用溶剂热法分别制备了苯乙烯-丙烯腈共聚物(AS)接枝物AS-g-MAH以及AS-g-(MAH-St).利用红外光谱对接枝物进行了结构表征,证明MAH已经成功接枝在AS链上.并用反式滴定法测定了接枝率,讨论了引发剂用量、马来酸酐用量、反应温度、反应时间、反应物浓度和共单体用量对接枝率的影响.结果表明:随着引发剂用量的增加和反应时间的延长,接枝率先增大,然后趋于平稳;随着马来酸酐用量、反应温度和反应物浓度的增加,接枝率先增大后下降;共单体苯乙烯的加入对接枝率的提高有很大的促进作用. 相似文献
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Graft copolymerization of acrylonitrile onto bagasse and wood pulps has been studied using ceric ammonium nitrate as initiator. The effect of order of reactants addition on grafting was examined: three methods were studied. Addition of the pulp to a mixture of initiator and monomer (method A) resulted in more efficient grafting than the other two methods. The reaction produced more grafting at 50°C than at 30°C or at 40°C. The results showed that the monomer and initiator concentrations are the major factors influencing the grafting rate of acrylonitrile. Increasing the acrylonitrile or initiator concentration was accompanied by a substantial increase in graft yields. Increasing the initiator concentration is more effective on polymerization rate than the increase in monomer concentration. The extent of grafting of this monomer can best be controlled by reaction time. Water swelling of pulps significantly affected the grafting rate of acrylonitrile as well as the ceric consumption during grafting. The reactivity of bagasse pulp towards grafting of acrylonitrile is higher than that of wood pulp due to a more open structure of cellulose in bagasse pulp as well as the presence of some lignin which accelerates grafting. Ceric consumption during grafting depends on the nature of the pulp as well as the monomer and initiator concentrations, time, temperature, and the method of grafting. More Ce(IV) is consumed during grafting than during oxidation of the pulps under identical reaction conditions, due to homopolymer formation which accompanied grafting. The ceric consumption by bagasse during grafting or oxidation is somewhat greater than that consumed by wood pulp under similar reaction conditions. 相似文献
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《Reactive and Functional Polymers》2002,50(1):49-55
The melt grafting of a long-chain unsaturated carboxylic acid such as oleic acid (OA) and undecylenic acid (UA) onto polypropylene (PP) in a Haake Rheocord RC90 mixer was studied. The influence of initiator concentration, monomer concentration and reaction temperature on grafting was investigated. The experimental results show that a higher degree of grafting was obtained using mixed initiators (DCP/BPO=1:1). Increasing the monomer concentration leads to an initial rapid increase in the degree of grafting. The addition of styrene reduced the degradation of PP as well as the degree of grafting. The monomer chain length influenced grafting significantly, the degree of grafting decreasing with increasing chain length of the grafting monomer. The results of differential scanning calorimetry (DSC) indicated that the crystalline properties of PP grafted with OA and UA were different from those of PP grafted with acrylic acid (AA), which may be attributed to the nucleation effect of the grafted long chain of OA and UA. 相似文献
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接枝型环氧-苯丙树脂水分散液的合成与性能研究 总被引:3,自引:0,他引:3
通过化学接枝法合成了稳定的水性环氧树脂。研究了接枝温度、引发剂浓度对单体接枝率的影响;亲水单体含量、中和度对接枝共聚物水分散稳定性的影响;考察了功能硅单体(A-1757)的引入对接枝共聚物膜的耐水、耐介质性的影响。结果表明,接枝温度为112~115℃,亲水单体含量为22%(占总单体质量分数),中和度为110%时,单体接枝率可达84.09%,所得改性接枝共聚物水分散稳定性最好,且具有较小的粒径。功能硅单体的引入能大大提高耐水、耐介质性。 相似文献