摘要
研究了无机盐添加剂LiCl对超临界CO2诱导相转化所制得的微孔PVDF膜的形貌和晶体结构的影响.对不含盐的体系,PVDF膜显示出液-液分相和结晶作用两种过程的形貌特性,即由互相连接的PVDF粒状微晶包围的蜂窝状孔结构.而对含盐体系,PVDF膜内部形成了大孔结构.随着LiCl加入量的增加,大孔尺寸先增大后减小.宽角X-射线衍射分析表明,由不含盐体系所制得的膜中PVDF晶体结构为α型(Ⅱ型),而由含盐体系所制得的膜中PVDF晶体结构则为β型(I型).感应耦合等离子体质谱分析表明,约16%～22%的LiCl仍然残留在PVDF膜中.
The effect of LiCl, a salt additive, on the morphology and crystal structure of porous poly（vinylidene fluoride） （PVDF） membrane prepared by supercritical CO2 - induced phase inversion process was investigated in detail. For a salt - free casting dope, the formed PVDF membrane exhibited morphological characteristics resulting from both liquidliquid phase separation and crystallization, i. e., cellular pores surrounded by inter-linked PVDF particulate crystallites. In contrast, when PVDF was precipitated from salt -containing dopes, macrovoids were formed in the membrane. As the LiCl was added, macrovoid size increased to a maximum but then decreased as additional amounts of LiCl were added. WAXD analysis indicated that the PVDF crystallites were in a （type Ⅱ） and t3 forms （type Ⅰ） for salt - free and LiCl - containing membranes, respectively. The analysis by inductively coupled plasma-mass spectrometry （ICP- MS） revealed that 16%-22% of the added LiCl in solution remained in PVDF membranes.
出处
《膜科学与技术》
CAS
CSCD
北大核心
2009年第2期28-33,共6页
Membrane Science and Technology
关键词
氯化锂
聚偏氟乙烯
超临界二氧化碳
微孔膜
大孔
lithium chloride
poly（vinylidene fluoride）
supercritical carbon dioxide
microporous membrane
macrovoid
