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首页> 外文期刊>Journal of Applied Polymer Science >VISCOELASTIC PROPERTIES AND FILM MORPHOLOGY OF HETEROGENEOUS STYRENE-BUTADIENE LATEXES
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VISCOELASTIC PROPERTIES AND FILM MORPHOLOGY OF HETEROGENEOUS STYRENE-BUTADIENE LATEXES

机译：异质苯乙烯-丁二烯胶乳的粘弹性和薄膜形态

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Heterogeneous carboxylated styrene-butadiene (S/Bu) latexes were prepared by a two-stage emulsion polymerization process, using three PS seeds with different molecular weights. The second-stage polymer was a copolymer with a fixed S/Bu ratio of 1 : 1 and a methacrylic acid (MAA) content of either 1 or 10 wt %. Morphological studies by transmission electron microscopy (TEM) as well as studies of the viscoelastic properties by mechanical spectroscopy have been performed on films prepared from the latexes. The studies showed that the glass transition temperature, T-g, of the second-stage polymer was considerably affected by copolymerization with MAA. An increase in the MAA content in the second-stage polymer increased the T-g of this phase significantly. Addition of DVB as a crosslinking agent in the preparation of the PS seed phase substantially increased the rubbery moduli of the films, whereas the glass transition temperature of the second-stage polymer was unaffected. On the other hand, the presence of a chain transfer agent reduced the glass transition of the second-stage copolymer containing 1 wt % MAA dramatically, whereas the rubbery modulus was unaffected. When the MAA content was increased to 10 wt % the influence of the MAA monomer had a dominating effect on T-g. Latexes containing 10 wt % MAA had T-g values close to each other, regardless of chain transfer agent present in the second-stage polymerization. It was found that the morphology of the latex particles influenced the rubbery modulus of the films. The presence of irregularly shaped seed particles in samples prepared from a crosslinked PS seed bad a considerable reinforcing effect on the films, whereas spherical seed particles originating from core-shell particles had a less reinforcing effect. (C) 1996 John Wiley & Sons, Inc. [References: 23]
机译：通过两阶段乳液聚合工艺，使用三种分子量不同的PS种子，制备了非均相的羧化苯乙烯-丁二烯（S / Bu）胶乳。第二阶段聚合物是具有固定的S / Bu比为1：1且甲基丙烯酸（MAA）含量为1或10重量％的共聚物。已经对由胶乳制备的膜进行了通过透射电子显微镜（TEM）的形态学研究以及通过机械光谱学的粘弹性质的研究。研究表明，第二阶段聚合物的玻璃化转变温度T-g受与MAA共聚的影响很大。第二阶段聚合物中MAA含量的增加显着增加了该相的T-g。在制备PS晶种相中添加DVB作为交联剂，大大提高了薄膜的橡胶模量，而第二阶段聚合物的玻璃化转变温度却未受影响。另一方面，链转移剂的存在显着降低了包含1重量％MAA的第二阶段共聚物的玻璃化转变，而橡胶模量不受影响。当MAA含量增加到10wt％时，MAA单体的影响对T-g具有主要作用。不管第二阶段聚合中存在链转移剂如何，含有10wt％MAA的胶乳的T-g值彼此接近。发现胶乳颗粒的形态影响膜的橡胶模量。由交联的PS种子制得的样品中不规则形状的种子颗粒的存在对薄膜的增强效果不好，而源自核-壳颗粒的球形种子颗粒的增强效果较小。 （C）1996 John Wiley＆Sons，Inc. [参考：23]

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