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分析了聚醋酸乙烯酯乳液冻融稳定性差的原因,指出可能影响聚醋酸乙烯酯乳液冻融稳定性的各种因素。从乳化剂、保护胶体、共聚单体、添加材料等几个方面,对国内外提高聚醋酸乙烯酯乳液冻融稳定性的研究进行了介绍。 相似文献
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采用半连续乳液聚合的方法,以醋酸乙烯酯、丙烯酸丁酯为单体,十二烷基磺酸钠和吐温-80为乳化剂,过硫酸铵为引发剂,制备了醋酸乙烯酯-丙烯酸丁酯共聚乳液,探讨了乳化剂配比、电机转速、预乳液滴加速率、预乳化时间等因素对聚合、乳胶粒粒径、乳液性能的影响。结果表明:提高乳化剂乳化能力、降低预乳液滴加速率,可以提高单体转化率、降低乳液乳胶粒粒径,幷使凝胶率降低;乳胶粒粒径较大的共聚乳液具有较好储存稳定性和离心稳定性,且在储存过程中,粒径未大幅增大。但这些乳液的冻融稳定性和高温稳定性较差;醋酸乙烯酯-丙烯酸丁酯共聚物的热稳定性能远高于聚醋酸乙烯酯。醋酸乙烯酯-丙烯酸丁酯共聚物是无规共聚物,即使存在聚醋酸乙烯酯和聚丙烯酸丁酯均聚物,二者形成的也是均相共混物;醋酸乙烯酯-丙烯酸丁酯共聚乳液黏度低于20mPa·s。 相似文献
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介绍2007年国内对聚醋酸乙烯酯乳液的最新研究进展,如:聚醋酸乙烯酯乳液合成方法的研究;新型乳化剂和保护胶体的研究;醋酸乙烯酯生产废液中丁烯酸乙烯酯的提取及应用研究;针对特殊使用目的的乳液改性研究等。 相似文献
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聚醋酸乙烯酯乳液的耐水性改性研究进展 总被引:8,自引:0,他引:8
聚醋酸乙烯酯乳液价格低、生产方便、黏合强度大、环保,但是其耐水性不好。文章综述了近年来国内外对提高聚醋酸乙烯酯乳液耐水性研究的进展。分别从醋酸乙烯单体、乳化剂、保护胶体入手,分析了聚醋酸乙烯酯乳液耐水性差的原因。然后分别从与醋酸乙烯外交联共混、共聚、保护胶体改性、采用反应性乳化剂和新型乳液聚合技术来论述提高聚醋酸乙烯乳液耐水性的方法。通过这些方法改性后的醋酸乙烯酯乳液的耐水性提高,很好的满足了经济发展的需求,拓宽了其应用范围,具有好的发展前景。 相似文献
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通过半种子连续乳液聚合工艺,以过硫酸铵为引发剂,以非离子和阴离子乳化剂为复合乳化剂,加入一定量的保护胶体,利用叔碳酸乙烯酯(Veova10)和丙烯酸异辛酯(2-EHA)为改性单体,合成了高固含量的改性聚醋酸乙烯酯乳液。研究了乳化剂用量,阴/非离子乳化剂质量比,叔碳酸乙烯酯、丙烯酸异辛酯和保护胶体用量对合成乳液的稳定性、黏度及吸水性的影响。研究结果表明,乳化剂质量分数为3.0%,阴/非离子乳化剂质量比为1:2,叔碳酸乙烯酯质量分数为20%,丙烯酸异辛酯质量分数为10%,保护胶体质量分数为0.25%时,乳液具有较好的稳定性、耐水性和成膜性。 相似文献
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环保型聚醋酸乙烯酯乳液的改性研究 总被引:3,自引:1,他引:2
聚醋酸乙烯乳液又称为白乳胶,在日常生活中应用广泛,但由于自身的固有缺点,使其应用受到限制。研究了乳化剂、引发剂及反应温度等工艺条件对聚合物性能的影响,通过选择改性单体与醋酸乙烯乳液进行共聚改性研究,研制出一种粘接强度高、耐水性良好的环保型水性胶粘剂。 相似文献
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乳化剂在聚醋酸乙烯乳液聚合中的应用研究 总被引:1,自引:0,他引:1
以烯丙氧基羟丙磺酸钠(HAPS)、甲基丙烯酸羟丙磺酸钠(HPMAS)、乙烯基磺酸钠(SVS)、烯丙氧基壬基酚聚氧乙烯(10)醚硫酸铵(DNS-86)和磺基琥珀酸癸基聚氧乙烯醚酯二钠(DNS-628)为乳化剂,采用一次投料法合成乳液,选择适宜醋酸乙烯乳液聚合的乳化剂。结果表明,在该聚合条件下,DNS-86和DNS-628适合醋酸乙烯酯乳液聚合。采用半连续种子乳液聚合,以DNS-628为乳化剂,设计理论乳液固含量为45%,当加入量为1.0%时,可合成稳定的乳液;以DNS-86为乳化剂,加入量为2.0%~6.0%时,合成的乳液不稳定,采用预乳化工艺,加入量为6.0%时可合成稳定的乳液。以DNS-86和DNS-628为乳化剂合成的乳液,其固含量、稀释稳定性、粘度、粒径和热老化性能等基本性能与传统乳化剂的明显不同。 相似文献
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Poly (vinyl acetate) (PVAc) latexes are economically important products with many desirable features. They are used as adhesives for porous materials in various processing stages of industries. Synthesis parameters have an important role on the physico-chemical properties of PVAc latexes such as: viscosity, average molecular weight, degree of polymerization, and surface morphology. In this work, PVAc was prepared via semicontinous emulsion polymerization (delayed monomer and initiator addition process) in the presence of ammonium persulfate (APS) as conventional anionic initiator, poly (vinyl alcohol) (PVA) as stabilizer, and sodium lauryl sulfate (SLS) as anionic emulsifier. The surface morphology of PVAc microspheres was, examined using a scanning electron microscope (SEM) and atomic force microscope (AFM). It is evident from the SEM photographs that all the particles became microspheres and are uniform in shape. The use of AFM for imaging of polyvinyl acetate confirms a typical sphere polymer. The effect of changes in the different parameters such as concentration of emulsifier, initiator concentration, and presence or absence of buffer on the vinyl acetate (VAc) conversion, the steady state polymerization rate, the viscosity-average molecular weight, and the final latex viscosity of synthesized PVAc were investigated. The effects of anionic emulsifier on the synthesized PVAc are also compared with those obtained by the nonionic emulsifier. The comparison indicated that the VAc monomer conversion and the final latex viscosity of the anionic system were higher than for the nonionic system but the viscosity-average polymer molecular weight of the anionic system was lower than that of the nonionic system. The adhesive strength of the synthesized PVAc latex was examined and the load and deflection data were reported. 相似文献
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Exfoliated polyvinyl acetate/montmorillonite nanocomposite (PVAc/MMT) was prepared via in situ emulsion polymerization. The
resulting PVAc with various organophilic MMT contents was investigated. In the nanocomposite latex preparation, sodium lauryl
sulfate (SLS), ammonium persulfate (APS), and poly (vinyl alcohol) (PVA) are used as anionic emulsifier, conventional anionic
initiator, and stabilizer, respectively. The samples were characterized using elemental analysis, X-ray diffraction (XRD),
scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM). The XRD and AFM
results demonstrate that the MMT well dispersed at molecular level in the PVAc matrix. Thermal properties of the nanocomposite
were studied by using differential scanning calorimetric analysis (DSC). The exfoliated PVAc/MMT nanocomposite showed a higher
glass transition temperature and a better thermal stability compared to the pure PVAc. 相似文献
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以VAE[醋酸乙烯酯(VAc)-乙烯共聚物]为种子乳液、聚乙烯醇(PVA)为保护胶体、叔碳酸乙烯酯(VoeVa10)为VAc的共聚单体、OP-10为乳化剂、己二酰肼(ADH)/双丙酮丙烯酰胺(DAAM)为交联体系和叔丁基过氧化氢/甲醛次硫酸钠为氧化还原型引发剂,采用种子乳液聚合法制备了VAc/VoeVa10/DAAM共聚乳液;然后在反应后期加入后交联剂(ADH),得到改性聚醋酸乙烯酯(PVAc)乳液。结果表明:当w(PVA1788+PVA1799)=3%、m(PVA1788)∶m(PVA1799)=1∶1、m(VoeVa10)∶m(VAc)=(10~15)∶100、w(氧化剂)=0.3%、w(VAE)=10%、w(OP-10)=2%、m(ADH)∶m(DAAM)=(0.5~1.5)∶1.0且w(DAAM)=2%时,相应乳液具有优异的耐水性和稳定性,并且其涂膜柔韧性和粘接性能俱佳。 相似文献
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丙烯酸(酯)改性聚醋酸乙烯酯乳液的研制 总被引:2,自引:1,他引:1
采用半连续种子乳液聚合法,使用丙烯酸(AA)功能性单体和丙烯酸丁酯(BA)软单体对醋酸乙烯酯(VAc)进行了共聚改性,制备出高固含量(50.2%)的聚醋酸乙烯酯(PVAc)改性乳液。该乳液适合用于喷雾干燥法制备可再分散聚合物粉末,并且其耐水性和耐碱性等都得到了明显地改善。对影响共聚物的诸多因素进行了较为全面地考察,得出最佳的工艺条件为:AA用量为主单体质量的3%~4%,BA用量为主单体质量的5%~10%,保护胶体用量为混合单体质量的7.5%~15%,引发剂用量为混合单体质量的0.4%~0.5%,阴/非离子型复合乳化剂的质量比为1∶2~1∶3、用量为混合单体质量的2%~3%,分散剂、消泡剂和酸碱缓冲剂等助剂均为适量,加料时间为3~4h,反应温度为70~75℃。 相似文献