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首页> 外文期刊>Journal of Applied Polymer Science >IONOMER SYNTHESIS BY EMULSION POLYMERIZATION OF STYRENE AND SODIUM ACRYLATE
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IONOMER SYNTHESIS BY EMULSION POLYMERIZATION OF STYRENE AND SODIUM ACRYLATE

机译：苯乙烯和丙烯酸钠的乳液聚合合成离子聚合物

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The emulsion copolymerization of styrene and sodium acrylate is reported using either a water-soluble initiator (potassium persulfate, or KPS), or an oil-soluble one [2,2-azoisobutyronitrile (AIBN)]. Reaction rates are fast with both KPS and AIBN. With KPS, conversions >90% are achieved in 50 min, with AIBN, conversions reach 85% in 100 min. Particle size, measured by quasielectric light scattering (QLS), increases with conversion. Particle size in final latices is similar to 70-80 nm. Copolymer formation is confirmed by infrared (IR) spectroscopy, plasma emission spectroscopy (PES), and scanning electron microscopy (SEM). IR and PES indicate that mainly sodium acrylate reacts at the beginning of the reaction and then styrene is incorporated in the copolymer backbone. The copolymer produced with KPS contains more sodium acrylate than the one made with AIBN. These differences can be explained in terms of the reactivities and partitioning (local concentrations) of the monomers and of the type of initiator used. Thermomechanical analysis (TMA) of the copolymers reveals two transitions: one at similar to 100 degrees C, which is due to the glass transition temperature (T-g) of polystyrene blocky segments in the copolymer, and another one at higher temperatures, which is associated to the T-g of segments composed of alternated sodium acrylate and styrene units. The higher-temperature transition shifts to lower values as the reaction proceeds because these segments become richer in styrene. (C) 1997 John Wiley & Sons, Inc. [References: 23]
机译：据报道，使用水溶性引发剂（过硫酸钾或KPS）或油溶性的一种[2,2-偶氮异丁腈（AIBN）]可以使苯乙烯与丙烯酸钠进行乳液共聚。 KPS和AIBN的反应速度都很快。使用KPS，在50分钟内可实现> 90％的转化，而使用AIBN，则可在100分钟内达到85％的转化。通过准电光散射（QLS）测量的粒度随转化率而增加。最终胶乳中的粒径类似于70-80 nm。通过红外（IR）光谱，等离子体发射光谱（PES）和扫描电子显微镜（SEM）确认共聚物的形成。 IR和PES表明，主要丙烯酸钠在反应开始时反应，然后苯乙烯掺入共聚物主链中。用KPS生产的共聚物比使用AIBN生产的共聚物含有更多的丙烯酸钠。这些差异可以用单体的反应性和分配（局部浓度）以及所用引发剂的类型来解释。共聚物的热力学分析（TMA）显示了两个转变：一个在接近100摄氏度的温度，这是由于共聚物中聚苯乙烯嵌段链段的玻璃化转变温度（Tg），另一个在较高的温度下，这与由交替的丙烯酸钠和苯乙烯单元组成的链段的Tg。随着反应的进行，较高温度的转变转变为较低的值，因为这些链段变得富含苯乙烯。 （C）1997 John Wiley＆Sons，Inc. [参考：23]

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