Synthesis of Poly(L-Lactic Acid) Catalyzed by Solid Super-Acid Under Microwave Irradiation through Direct Melt Polycondensation
A novel green process that combined solid super-acid catalyzing and microwave irradiating was invented in the synthesis of high molecular weight poly (L-lactic acid)(PLLA). The factors that affected the viscosity average molecular weight (M |? ) such as the quantity of solid super-acid, irradiating time, reacting temperature, and degree of vacuum were investigated. The light yellow-colored PLLA with M |? up to 2.7×10 4 was obtained when the quantity of solid super-acid was 0.4% weight of dehydrated lactic acid, the irradiating time for polymerization was 60 min, the polymerization temperature was 260 and the degree of vacuum was 0.0 ℃95Mpa. DSC and TG results showed that the Tg of the PLLA catalyzed by solid super-acid had been improved 5.3 ℃compared to that synthesised through autocatalytic process. In this process, the reacting time for direct melt polycondensation of L-lactic acid was significantly reduced from 30~48h in conventional heating to less than 1.2h under microwave irradiation in a constant temperature. And specific microwave effects were believed to take place. Moreover, as this was a solution-free process, no toxic substances were discharged.
poly (L-lactic acid) solid super-acid microwave irradiation environment- friendly material
Cao Hailei Wang Peng Yuan Weibo
State Key Laboratory of Urban Water Resoure and Environment, Harbin Institute of Technology , 150090 Research Center for Green Chemistry and Technology, School of Municipal and Environmental Engineerin
国际会议
The 12th Asian Pacific Confederation of Chemical Engineering Congress(第十二届亚太化工联盟大会暨化工展览会)
大连
英文
2008-08-04（万方平台首次上网日期，不代表论文的发表时间）