共查询到20条相似文献,搜索用时 453 毫秒
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主要研究了在以聚乙烯醇为保护胶体的醋酸乙烯乳液聚合中,乳液与环氧丙烯酸酯、聚氨酯、硅烷等官能团的接枝反应.在以过硫酸铵为引发剂、以聚乙烯醇为保护胶体的醋酸乙烯乳液聚合中,乳液与上述各类官能团间发生的接枝反应直接影响乳液的黏度、固体含量、剪切强度等宏观性质.研究发现官能单体脂肪醇聚氧乙烯醚、丙烯酸异辛酯(2-EHA)等单体和丙烯酸(AA)与乙烯基三乙氧基硅烷共同作用时对乳液的宏观性质影响显著. 相似文献
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以木薯淀粉为原料、高碘酸钠为氧化剂,在一定条件下制得双醛淀粉(DAS);然后以过硫酸铵(APS)为引发剂、聚乙烯醇(PVA)为保护胶体和醋酸乙烯酯(VAc)为DAS的接枝单体,再配合其他助剂制得双醛接枝淀粉基木材用胶粘剂。结果表明:当w(DAS中醛基)=20%、m(DAS)∶m(VAc)=1∶2.5、w(PVA)=75%、VAc为25 mL、接枝反应温度为65℃和反应时间为3 h时,胶粘剂的干、湿强度分别为3.0、2.4 MPa。 相似文献
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影响聚醋酸乙烯酯(PVAc)乳液粘度几种因素的探讨 总被引:4,自引:0,他引:4
对聚乙烯醇作保护胶体、2—甲基—2丙烯酰胺丙磺酸钠作乳化剂的聚醋酸乙烯乳液的反应机理及粘度的影内因素,聚乙烯醇、乳化剂、引发剂、加料方式及反应温度等对乳液粘度影响的规律进行了探讨。 相似文献
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影响聚醋酸乙烯树脂乳液粘度的因素及反应机理探讨 总被引:7,自引:2,他引:7
本文对以聚乙烯醇作保护胶体的聚醋酸乙烯乳液的粘度的影响因素(如聚乙烯酵、醋酸乙烯活性度、反应温度、引发剂等)及反应机理作了探讨。对醋酸乙烯聚合反应原理作了简介。 相似文献
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本文研究了聚乙烯醇与苯甲醇的接枝合成,探讨了在不同温度,不同摩尔比等不同条件对该反应产物性能的影响。获得较好的反应条件:反应温度120℃,浓硫酸作催化剂,聚乙烯醇与苯甲醇的摩尔比为1∶2时,接枝聚合物的耐水性得到了大幅度的提高。 相似文献
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以生物乙烯法生产的乙酸乙烯为单体、过氧化月桂酰-十二烷基二甲基叔胺为非腈复合引发剂、甲醇为溶剂进行溶液聚合反应的研究。实验考察了反应温度、反应时间、甲醇用量、引发剂用量对反应产物聚合率和聚合度的影响,采用正交试验优化了乙酸乙烯溶液聚合的反应条件,确定反应因素对聚合率和聚合度影响的相对大小。结果表明,最优的乙酸乙烯溶液聚合条件为:反应温度65℃,反应时间3h,甲醇用量10%,引发剂用量0.010%,获得聚乙烯醇产品的聚合度为3776,聚合率为45.29%。直观分析确定影响聚合率的因素主次顺序为引发剂用量> 反应时间> 甲醇用量> 反应温度;影响聚合度的因素主次顺序为甲醇用量 >引发剂用量 >反应温度 >反应时间。 相似文献
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Gilles Meunier Patrick Hemery Jean -Pierre Senet Sylvie Boileau 《Polymer Bulletin》1981,4(12):705-710
Poly(vinyl carbamates) and poly(vinyl carbonates) of high molecular weight have been obtained by polymerization of the corresponding monomers prepared from vinyl chloroformate. Poly(vinyl carbonates) can also be prepared by chemical modification of poly(vinyl chloroformate) with alcohols and phenols. Copolymerization parameters of phenyl vinyl carbonate with vinyl acetate have been determined in methylene chloride, at 35°C, with dicyclohexyl peroxydicarbonate as initiator. 相似文献
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Kinetic models for the rate constants of vinyl chloride polymerization in the presence of initiator mixtures were proposed. They may be used to design the initiator recipes for the vinyl chloride polymerization with uniform rate at different temperatures at which various grades of poly(vinyl chloride) will be prepared. 相似文献
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甲基乙烯基醚/马来酸酐共聚物合成研究 总被引:1,自引:0,他引:1
以过氧化十二酰为引发剂(IN),采用溶液自由基共聚合方法,实现了甲基乙烯基醚(MVE)与马来酸酐(MAN)的交替共聚合。通过详细研究反应温度、引发剂用量、溶剂配比、溶剂用量及反应时间等因素对共聚物产率及产品特性粘度的影响,优化了制备甲基乙烯基醚/马来酸酐共聚物的工艺条件。最后通过FTIR和13CNMR表征了共聚物的结构。 相似文献
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Summary The polymerization of vinyl monomers with the initiator systems of ferrocene and acid anhydrides were investigated. The initiator activity for radical polymerization of methyl methacrylate (MMA) was higher than that for styrene (St). However, isobutyl vinyl ether was not polymerized. The rate of polymerization of MMA with ferrocene/benzoic anhydride system was in proportional to the square root concentrations of both compounds of the initiator system, indicating the mechanism of radical polymerization. When an alternating copolymer of ethylene with maleic anhydride was used as an acid anhydride, a graft copolymer, which was soluble in dimethylformamide and tetrahydrofuran, was produced from radical polymerization of MMA. 相似文献
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Mohammad Javad Bijhanmanesh Mohsen Nasr Esfahany 《Chemical Engineering Communications》2016,203(11):1473-1483
An adopted mathematical model was developed to reduce the batch time required for the suspension polymerization of vinyl chloride in order to improve the productivity by continuous dosage of a fast initiator during polymerization reaction. The model was accompanied by a particle swarm optimization (PSO) algorithm, so as to optimize the initiator dosage rate during the process for a certain conversion. A pilot scale reactor was employed to verify the mathematical model predictions. This showed that the model predictions are in very good agreement with the experimental data. A proper initiator dosage trajectory during the course of the reaction was obtained in such a way that the reaction rate over the course of polymerization was constant and corresponded to the maximum rate in the conventional case (non-continuous addition of a mild initiator). The maximum reduction in reaction time relative to conventional polymerization for the predefined conversion was 53%. Analyzing the molecular characteristics of the samples showed that the molecular characteristics of the final poly(vinyl chloride) (PVC) product remained relatively unchanged under an optimum initiator dosage trajectory compared with the conventional process. 相似文献
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Summary The polymerization of certain 1,2-epoxides, styrene and n-butyl vinyl ether has been accomplished by the use of nitrosyl hexafluorophosphate as the initiator. Heretofor, nitrosyl hexafluorophosphate has been known as an initiator only for tetrahydrofuran. The polymers prepared had broad molecular weight distributions.Nitrosyl hexafluorophosphate (NOPP6) has been used to initiate the polymerization of tetrahydrofuran (ECKSTEIN and DREYFUSS, 1979; SEUNG, et al., 1981). In this communication we report on the use of NOPF6 for the polymerization of three 1,2-epoxides, namely styrene oxide (SO), cyclohexene oxide (CHO), and 1,2-epoxybutane (EB). In addition, styrene (S) and n-butyl vinyl ether (nBVE) were also polymerized with this initiator. 相似文献