【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。更多还原

【Abstract】 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/m3,small cell diameter of 285 μm,and high cell density of 1.5×106/cm3 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.更多还原