用 FTIR研究纤维素/聚乙烯醇共混物结晶性

将纤维素(Cell)和聚乙烯醇(PVA)分别溶于二甲基亚砜-四乙基氯化铵(DMS(?)-TEAC)混合溶剂中,混和后(Cell/PVA=100/0—0/100)在玻璃板上铸膜,乙醇为固化剂.薄膜在硅油中热处理。用傅里叶变换红外光谱仪(FTIR)研究了共混物薄膜的结构特性.结果表明,共混物各组分分子间无化学键缔合。将结晶吸收带1369cm~(-1)(Cell)和1143cm~(-1)(PVA)与参考吸收带2887cm~(-1)(Cell)和2908cm~(-1)(PVA)之比定义为结晶度指数。发现各组分的结晶度指数均随其含量增加而增大,并随另一组分含量增加而减小,说明共混物薄膜中两组分大分子间有较强的相互作用。因此可以推断,在非晶区 Cell 与 PVA 是混溶的,而晶区是不混溶的.热处理使共混物薄膜中两组分的结晶度都增大。

STUDIES ON THE CRYSTALLINITY OF CELLULOSE/POLYVINYL ALCOHOL BLEND BY MEANS OF FTIR

Dissolving cellulose(CELL,(?)=750)and polyvinyl alcohol(PVA,(?)=1800)inDMSO-TEAC solvent with concentration 5%(wt)respectively,then mixing thesetwo solutions to obtain mixed solutions(100/0—0/100),the films with thickness10—20μm were prepared.After annealing the films in silicone oil,and analyzingby means of FTIR,the results show that there are no chemical bonds betweenthe elements of each component.Using the areas of CELL 2887cm~(-1)peak andPVA 2908cm_(-1)peak as the reference bands for quantitatively analyzing thecrystallization of each component in the blend,and defining the ratio of the crystall-ization sensitive bands 1369cm_(-1)(CELL)and 1143cm_(-1)(PVA)to the areas of referencebands as the crystallinity index,it is found that the crystallinity index of each comp-onent increase as the increase of its content,and decrease as the increase of the con-tent of another component.That shows that the interaction between the macromolec-ules of CELL and PVA in the blend is very strong,and that CELL and PVA aremiscible in the amorphous region,but non-miscible in the crystalline region.In add-ition,the miscibilities under any ratioes are very strong,and the amorphous regionincreases,the crystalline region decreases,the crystallinities of each component de-crease also.Through annealing,the crystallinities of two components increase.