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Development of Production of Functional Polymer Particles in Supercritical Carbon Dioxide

超临界二氧化碳生产功能聚合物颗粒的进展

基本信息

批准号：
12450373
负责人：
OKUBO Masayoshi
金额：
$ 6.98万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Recently, in addition to water, there have been increasing interests in supercritical carbon dioxide (scCO_2) as environmentally favorable media. The use of scCO_2 as medium for polymerizations has several potential advantages : low cost, low toxicily, eases of medium removal and recycling, and marked variations of solubility power, viscosity and polarity by relatively small changes in temperature and pressure without altering medium composition. The papers describing the dispersion polymerization of vinyl monomers such as methyl methacrylate (MMA) and styrene in scCO_2 have been published in the past eight years. Some fluorinated polymers and poly(dimethylsiloxane) (PDMS)-based polymers have been identified as being soluble in CO_2 or CO_2-philic and have been used as colloidal stabilizers, and there has been increasing interest on the colloidal stabilizers which are effective in scCO_2. In general, PDMS-based polymers may have advantages over fluorinated polymers from the viewpoints that PDMS-based polymers are much less expensive and their solubility in conventional organic solvents makes the characterization of the products obtained easy. In this research, PMMA particles could be produced by dispersion polymerization of MMA in scCO_2 using PDMS-based azoinitiator as inistab (initiator + stabilizer). Production of PMMA particles by the dispersion polymerization of MMA in scCO_2 in the presence of amino propyl terminated PDMS as colloidal stabilizer was also succeeded.Moreover, polydivinylbiphenyl particles were produced by precipitation polymerization of divinylbiphenyl without any stabilizer in scCO_2 at ca. 30 MPa for 24 h at 65℃. The effects of initiation rate of polymerization on the conversion, the fluidity of powder, the degree of coagulation/ the amount of low molecular weight by-products, and the amount of vinyl groups in the particles were examined.

近年来，除了水之外，超临界二氧化碳（scCO_2）作为一种环境友好的介质越来越受到人们的关注。用超临界CO_2作为聚合介质具有成本低、毒性小、易于去除和回收利用、在不改变介质组成的情况下，通过较小的温度和压力变化可使溶解力、粘度和极性发生显著变化等优点。乙烯基单体如甲基丙烯酸甲酯（MMA）和苯乙烯在超临界CO_2中的分散聚合反应是近八年来的研究热点。一些含氟聚合物和聚二甲基硅氧烷（PDMS）基聚合物被认为是可溶于CO_2或亲CO_2的聚合物，并被用作胶体稳定剂，而对scCO_2有效的胶体稳定剂的研究也越来越受到人们的关注。一般而言，从基于PDMS的聚合物便宜得多并且它们在常规有机溶剂中的溶解性使得所获得的产物的表征容易的观点来看，基于PDMS的聚合物可具有优于氟化聚合物的优点。本研究以PDMS为偶氮引发剂，在超临界CO_2中进行MMA的分散聚合，制备了PMMA微球。以甲基丙烯酸甲酯（MMA）为分散剂，以端氨基聚二甲基硅氧烷（PDMS）为胶体稳定剂，在超临界CO_2中进行分散聚合，成功地制备了PMMA粒子;在65℃、30 MPa、24 h条件下进行。考察了聚合引发速率对转化率、粉末流动性、凝聚度/低分子量副产物量以及颗粒中乙烯基含量的影响。