二醋酸纤维素与增塑剂熔融体系的制备与表征

Preparation and characterization of plasticizing melting system consisting of cellulose diacetate and plasticizers

为大幅降低二醋酸纤维素(CDA)的熔融温度,利用哈克转矩流变仪分别制备了CDA/1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)、CDA/二甲基亚砜(DMSO)和CDA/[EMIM]Ac/DMSO 3种体系,分析了这3种体系制备过程中温度及转矩与时间的关系,并利用X射线衍射仪、热重分析和流变仪等研究了这3种体系的结构与性能。研究结果表明:离子液体[EMIM]Ac对CDA具有良好的增塑作用,CDA/[EMIM]Ac体系可形成均一相态;DMSO对CDA增塑作用较弱,CDA在DMSO中既不能溶解也不能熔融,其以溶胀态分散在CDA/DMSO体系中;以DMSO代替部分[EMIM]Ac,不仅可降低成本,更能促进[EMIM]Ac的增塑作用;CDA/[EMIM]Ac及CDA/[EMIM]Ac/DMSO 2种体系的热分解温度虽远低于原料CDA,但又远高于它们各自的熔融流动温度,熔融加工稳定性好。

Cellulose diacetate（CDA） has high mehing temperature, and is an important derivative of cellulose. In order to significantly reduce the melt processing temperature of CDA, the systems of CDA/ 1-ethyl-3-methylimidazolium acetate （ [ EMIM]Ac）, CDA/dimethyl sulfoxide （ DMSO ） and CDA/ [ EMIM ] Ac/ DMSO were prepared in HAAKE rheocord. The curves of temperature-time and torque-time in the process of three systems were analyzed, respectively. The structures and performances of the systems were investigated by XRD, TGA and rheometer, respectively. The results show that, ionic liquid [EMIM]Ac is so effective as a plasticizer for CDA that the plasticizing melting system of CDA/[EMIM]Ac is a homogeneous one. The plasticizing effect of DMSO to CDA is weak. CDA can neither dissolve nor melt in DMSO, and it can scatter in the plasticizing system of CDA/DMSO in the swollen state. Replacing of part of [ EMIM ~ Ac with DMSO can not only reduce costs, but also promote plasticizing effect of [ EMIM] Ac. The melt processing stability of the plasticizing melting systems of CDA/[ EMIM ] Ac and CDA/[ EMIM ] Ac/DMSO is good because their thermal decomposition temperature is well above their melt flow temperature, although their thermal decomposition temperature are lower than that of raw CDA.