Sun Jiaxing, Zhang Xiao, Bai Long, Li Zhiguo, Jia Zhao, Gu Jiyou
College of Materials Science and Engineering, Northeast Forestry University, Key Laboratory of Bio-based Material Science and Technology, Ministry of Education, Harbin 150040, China.
Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 163000, FIN-00076 Aalto, 02150 Espoo, Finland.
Materials (Basel). 2018 Dec 6;11(12):2482. doi: 10.3390/ma11122482.
A novel strategy for fabricating inverted core-shell structured latex particles was implemented to investigate the morphology and properties of polyvinyl acetate (PVAc)-based latex. In this study, active grafting points were synthesized onto the surface of PVAc latex cores via grafting acrylonitrile (AN) to obtain a controllable coating growth of the shell monomer, styrene (St). The effect of shell growth on the morphological evolvement was explored by tuning the time of shell monomer polymerization. Unique particle morphologies, transferring from "hawthorn" type, over "peeled pomegranate" type, to final "strawberry-like" type, were observed and verified by electron microscopy. The morphological structure of latex particles exerted a significant effect on the particle size, phase structure, and mechanical properties of the obtained emulsions. The water-resistance of PVAc-based latex was also evaluated by the water absorption of latex films. More importantly, the experimental results provided a reasonable support for the controlled growth of St monomer, that is, the self-nucleation of dispersive St monomer can be transformed to in-situ coating growth on the PVAc core surface depending on the AN-active grafting points. This fabricating approach provides a reference for dynamical design and control of the latex particle morphology.
为了研究聚醋酸乙烯酯（PVAc）基胶乳的形态和性能，实施了一种制备倒置核壳结构胶乳颗粒的新策略。在本研究中，通过接枝丙烯腈（AN）在PVAc胶乳核表面合成活性接枝点，以实现壳单体苯乙烯（St）的可控包覆生长。通过调整壳单体聚合时间，探索了壳生长对形态演变的影响。通过电子显微镜观察并验证了独特的颗粒形态，从“山楂”型，经过“去皮石榴”型，最终转变为“草莓状”型。胶乳颗粒的形态结构对所得乳液的粒径、相结构和机械性能产生了显著影响。还通过胶乳膜的吸水率评估了PVAc基胶乳的耐水性。更重要的是，实验结果为St单体的受控生长提供了合理支持，即分散的St单体的自成核可以根据AN活性接枝点转化为在PVAc核表面的原位包覆生长。这种制备方法为胶乳颗粒形态的动态设计和控制提供了参考。
