无皂核壳蓖麻油基聚氨酯苯丙杂化乳液

Surfactant-free core-shell castor oil-based polyurethane styrene/acrylic hybrid emulsion

以蓖麻油、异佛尔酮二异氰酸酯(IPDI)和二羟甲基丙酸(DMPA)为主要原料制得具有表面活性的蓖麻油基聚氨酯水分散体(CPU),采用红外光谱(FT-IR)、核磁共振(NMR)表征了其结构,测定其临界胶束浓度(CMC)为70g/L。在CPU中进行苯乙烯(St)与丙烯酸丁酯(BA)的共聚合,制备了无皂核壳杂化乳液。通过胶膜吸水率、铅笔硬度和冲击强度测试,研究了CPU中蓖麻油及DMPA的用量对杂化乳液性能的影响,确定了较佳用量为:IPDI19.25g,蓖麻油30g,DMPA3.71g。采用透射电镜(TEM)和FT-IR表征了杂化乳液的结构,并采用热重(TG)、示差扫描量热仪(DSC)表征了乳胶膜的热性能。结果表明,杂化乳液具有清晰的核壳结构;当m(壳)∶m(核)=6∶4,核中单体m(St)∶m(BA)=7∶3时,可制得硬度为3H、吸水率为5.9%、耐冲击强度为54kg·cm的杂化膜。

An aqueous surface-active castor oil-based polyurethane dispersion （CPU） was synthesized with castor oil, isophorone diisocyanate （IPDI） and dimethylol propionic acid （DMPA） as main materials. The structure of CPU was characterized by FT-IR and nuclear resonance spectroscopy （NMR）, and the critical micelle concentration （CMC） in water was tested as 70 g/L. A surfactant-free core–shell hybrid emulsion was prepared by copolymerization of styrene （St） with butyl acrylate （BA） in CPU. The effects of the dosages of DMPA and castor oil in CPU on the properties of hybrid emulsion were studied by testing the film’s water absorbing rate, pencil hardness and impact strength, and the good dosages were determined as follows： IPDI 19.25 g,castor oil 30 g, and DMPA 3.71 g. The structure of the hybrid emulsion was characterized by transmission electron microscopy （TEM） and FT-IR, and the thermal performance of the film was examined by thermogravimetry （TG） and differential scanning calorimetry （DSC）. The results indicated that the hybrid emulsion has distinct core–shell structure, and a hybrid film with a hardness 3H, water absorption rate 5.9%, and impact strength 54 kg·cm can be prepared when the mass ratio of shell to core is 6：4, and the mass ratio of St to BA is 7：3 in core monomers.