超临界CO_2对聚乳酸挤出发泡的影响  

Effect of Supercritical Carbon Dioxide on Extrusion Foaming for PLA

作　　者：马玉武[1] 信春玲[1] 何亚东[1] 李庆春[1,2] 

机构地区：[1]北京化工大学机电工程学院,北京100029 [2]教育部高分子材料加工装备工程研究中心,北京100029

出　　处：《中国塑料》2012年第12期72-75,共4页China Plastics

摘　　要：采用一种半结晶聚乳酸(PLA),利用双螺杆串联熔体泵系统,以超临界CO2为发泡剂,进行挤出发泡实验。研究了CO2含量对PLA泡沫密度、泡孔密度和泡孔直径的影响。结果表明,发泡剂CO2含量在7%～10%(质量分数,下同)之间时,得到表观密度最低为40kg/m3、泡孔直径为285μm、泡孔密度为1.5×106个/cm3的低密度PLA泡沫。随着CO2含量的增加,PLA泡沫的初始结晶峰减小,结晶度升高,说明超临界CO2对PLA的结晶具有促进作用。In this paper, a co-rotating twin screw extruder connected with a melt pump was employed to carry out the extrusion foaming of a semi-crystalline PLA. The effect of CO2 concentration on PLA foam density, cell density, and cell diameter was investigated. With 7 % to 10 % CO2, PLA foam with low density of 40 kg/m^3 , small cell diameter of 285 μm, and high cell density of 1.5×10^6/cm^3 was obtained. With increasing CO2 content, the initial crystallization peak of PLA foam decreased and the degree of crystallization increased, indicating that the supercritical CO2 promoted the crystallization of PLA in the extrusion foaming process.

关 键 词：聚乳酸 生物降解塑料 挤出 发泡 

分 类 号：TQ328.0[化学工程—合成树脂塑料工业]