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采用欠量加料核壳型乳液合成法,以十二烷基磺酸钠和烷基酚聚氧乙烯基醚乳化剂为复合乳化剂,以丙烯酸甲酯和丙烯酸丁酯为核单体,以乙烯基三乙氧基硅烷和丙烯酸丁酯为壳单体,KPS为引发剂,制备出核预聚体和壳预聚体,又以乳化剂、水、p H缓冲剂、核预聚体制备出核种子乳液,然后通过半间歇法加入壳预聚体和壳引发剂制得核/壳型硅丙乳液。对乳液进行了红外光谱测定,并初步探讨了乳化剂的用量、乳液p H值、乳化温度、引发剂的用量等因素对合成过程中乳液稳定性的影响。结果表明,当乳化剂的用量为单体总量的5%,引发剂用量为单体的0.7%,乳化温度为75~80℃,p H在接近中性的6.5~8.0时,制得硅丙乳液稳定性最好。 相似文献
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核—壳型丙烯酸乳液压敏胶聚合工艺的研究 总被引:11,自引:2,他引:9
以VAE乳液为核,以BA-VAc-HEMA等混合单体为壳,采用核-壳乳液聚合工艺研制出一种新型丙烯酸乳液压敏胶,讨论了核,壳,乳化剂,引发剂,聚合温度等因素对压敏胶性能的影响,VAE用量12.5%,BA:VAc:HEMA:AA=8.7:1.2:0.3:0.1,使用过硫酸铵加NH4S2O8-NaHSO3氧化还原体系为引发剂,制得的压敏胶性能优良。 相似文献
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以带羧基的乳胶粒为种子进行了甲基丙烯酸甲酯、甲基丙烯酸和二乙烯基苯的种子乳液共聚合,制备了轻度交联的核乳液,将该核乳液在包壳反应并进行碱处理后,制得了中空聚合物微球。研究了核乳胶粒制备过程中羧基单体的种类、单体的加料速率、乳化剂的用量等因素对核乳胶粒直径及其分布以及中空聚合物微球结构形态的影响,结果表明,采用甲基丙烯酸作为羧基共聚单体时,比采用丙烯酸的聚合体系稳定性更好,同时也更有利于提高羧基单体的用量。实验证明,必须采用“饥饿”式单体进料方式,否则会有新乳胶粒生成且聚合稳定性变差。应采用半连续补加乳化剂工艺,当乳化剂总量为核单体总量的0.15%(wt)时能保持聚合稳定性且能保证无新乳胶粒生成。 相似文献
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采用种子乳液聚合法合成新型低温反应型聚丙烯酸酯乳液粘合剂,即以丙烯酸丁酯(BA)、丙烯酸异辛酯(EHA)、苯乙烯(St)为软、硬单体,丙烯酸(AA)为功能单体,以过硫酸钾为引发剂,并选用一种适当的交联单体合成了性能优良的聚丙烯酸酯涂料印花粘合剂。讨论了引发剂用量、乳化剂用量、阴/非离子乳化剂的配比、乳液滴加时间、保温时间等对聚合物的影响。确定了乳液聚合最佳工艺条件:乳化剂用量为o8%,阴/非乳化剂质量比为4:3,引发剂用量为0.8%,乳液滴加时间60min,保温时间60min。 相似文献
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采用种子乳液聚合法,以十六烷基三甲基溴化铵(CTAB)为乳化剂,偶氮二异丁眯盐酸盐(AIBA)为引发剂,引入亲水性阳离子单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)及功能性单体丙烯酰胺(AM)〔m(DMC)∶m(AM)=1∶1〕来制备用于可再分散乳胶粉的阳离子苯丙乳液。探讨了聚合反应温度、乳化剂用量、引发剂用量、种子单体用量、阳离子单体用量等对乳液及可再分散乳胶粉性能的影响。确定最佳配方和工艺条件为:聚合反应温度为(80±2)℃、DMC添加量为2%(以主要聚合单体质量计,下同)、CTAB用量为2%(以单体总质量计,下同)、AIBA用量为0.53%(以单体总质量计,下同)、种子单体用量为10.0%(以单体总质量计,下同)。在该工艺条件下,合成的阳离子苯丙乳液粒径大小和分布适中、性能稳定,由其所制得的可再分散乳胶粉含水率低、平均粒径小、再分散性优良。 相似文献
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乳液聚合法丙烯酸酯类聚合物的合成及抗静电性能考察 总被引:1,自引:0,他引:1
通过种子预乳化半连续乳液聚合技术,以苯乙烯(St)、丙烯酸丁酯(BA)和丙烯酸羟乙酯(HEA)为共聚单体,合成一类新型的两亲聚合物。考察了引发剂用量、乳化剂用量、反应温度等因素对乳液聚合工艺及聚合物的影响,优化了反应条件,同时对合成聚合物的结构、表面电阻率及亲水性进行了考察。结果表明:当乳化剂质量分数为0.75%、引发剂质量分数为0.5%、HEA质量分数为40%时,合成的乳液稳定性能最佳,转化率高达98.42%;聚合物的表面电阻率低达4.93×105Ω,且其亲水性好。 相似文献
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以苯乙烯(St)为单体,十二烷基硫酸钠为乳化剂、过硫酸钾为引发剂,碳酸氢钠和氢氧化钠为复合缓冲剂,通过乳液聚合反应,合成了粒径分布均匀的聚苯乙烯纳米微球(PSt)。在确定缓冲剂用量及引发剂滴加方式的条件下,经正交实验优选出最佳合成工艺条件如下:蒸馏水与苯乙烯的体积比为1.5:1、乳化剂用量为苯乙烯质量的1.0%、引发剂用量为苯乙烯质量的1.2%、反应时间为8h,反应温度为80℃。在此条件下转化率为94.58%,并用扫描电镜(SEM)和红外光谱(FTIR)对其进行了表征。 相似文献
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We performed the emulsion polymerization of styrene successfully with potassium persulfate (KPS) as an initiator and sodium dodecylsulfonate as an emulsifier under high‐power pulsed microwave irradiation (PMI). We investigated the effects of the temperature, the concentration of initiator, and various parameters of PMI (i.e., irradiation power, duty cycle, irradiation energy, and pulse width) on the polymerization. The results indicated that PMI, compared to conventional heating (CH), caused a significant increase in the decomposition rate of KPS (2.4 times higher than that under CH at about 70°C) and in the amount of particles (5 times higher than that under CH); consequently, the polymerization rate was effectively enhanced. For initiator concentrations of 0.10 and 0.20 wt %, the enhancement of the polymerization rate under PMI was 129 and 38% greater, respectively, than that under CH. The glass‐transition temperature and the regularity composition of the polymers under PMI and CH showed no difference, which indicated that PMI had little effect on the physical properties and microstructure of the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 28–35, 2003 相似文献
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Magnetic poly(styrene butyl acrylate methacrylic acid) [P(St–BA–MAA)] microspheres were prepared by emulsifier‐free emulsion polymerization in the presence of a polar solvent and a ferrofluid prepared by a coprecipitation method. The effects of some polymerization parameters, such as the medium polarity, reaction temperature, initiator content, and surfactant content in the ferrofluid, on the particle diameter and particle size distribution of magnetic P(St–BA–MAA) microspheres were examined in detail. The results showed that the electrostatic repulsion in the polymerization system significantly affected the monodispersity of the resulting magnetic polymer microspheres. The proper electrostatic repulsion, achieved through changes in the medium polarity and amount of surfactant in the polymerization system, improved the monodispersity, but a higher or lower repulsion led to a decrease in the monodispersity. Although the existence of surfactant and magnetite particles reduced the monodispersity more or less, the polymerization behavior of an emulsifier‐free emulsion polymerization in the presence of the ferrofluid was analogous to that of a conventional emulsifier‐free emulsion polymerization. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1733–1738, 2003 相似文献