纤维素/琼脂糖复合膜的制备、表征及其形状记忆性能研究

Preparation,characterization and shape memory properties of cellulose/agarose composite film

近年来,形状记忆材料因其刺激响应性在纺织、航空航天、生物医疗等领域备受关注。在此,采用碱/尿素水溶液作为共溶剂,环氧氯丙烷作为交联剂,制备出具有水、热刺激形状记忆性能的纤维素/琼脂糖复合膜。该膜显示出良好的透明度和力学性能,透光率超过90%,干强和湿强可达132和5.4 MPa。同时,该膜在水刺激下的固定率(R_(f))和回复率(R_(r))分别达95%和84%以上,热刺激下的R_(f)和R_(r)分别达58%和85%以上,表现出较好的形状记忆效果。机理分析表明:氢键的断裂和形成导致复合膜具有水刺激形状记忆行为,琼脂糖结晶的破坏与形成是复合膜具有热刺激形状记忆行为的关键。

In order to solve the problems of non-renewable and non-degradable of the traditional shape memory polymer(SMP)based on synthetic polymer,more attention is payed to the development and application of natural polymer based SMP.In this study,natural polymers of cellulose and agarose are used as raw materials,alkali/urea aqueous solution serves as co solvent and epichlorohydrin is used as crosslinking agent.After blending,crosslinking,washing and drying,cellulose/agarose composite films with different ratios are successfully prepared.The shape memory performance of the composite films is characterized.The wet composite films and the hot water soaked composite films are fixed at a set angle through different angles of mold,respectively.The wet film is dried at room temperature,and the composite film soaked in hot water is solidified at low temperature,and then the composite films fixed at a certain angle are obtained.After,the composite films with the certain angle are put into water and hot water,and the composite films returns to the initial shape.The shape fixation rate and recovery rate of the composite film are calculated by the certain angle and recovery angle.The results show that the films have good shape memory properties for water stimulation through the formation and breaking of hydrogen bonds,and the destruction and formation of agarose crystals also show good shape memory behavior to thermal stimulation.The shape fixation rate and shape recovery rate are above 95%and 84%in water induction,and 58%and 85%in hot water induction.Besides,it is found that with the increase of the agarose,the mechanical properties change.The tensile strength of the dry film and wet film decrease from 132 MPa and 5.4 MPa to 101 MPa and 1.9 MPa,and the elongation at break increase from 14.2%and 133.8%to 20.3%and 195.2%,respectively.At the same time,the structure of the composite film is uniform,and the transmittance is more than 90%.This work can provide a new idea for the development of natural polymer based SMP.