聚乙二醇功能化氧化石墨烯/聚氨酯复合材料的制备与性能

Preparation and Properties of Polyethylene Glycol Functionalized Graphene Oxide/Polyurethane Composites

用聚乙二醇对氧化石墨烯进行表面接枝改性,通过机械共混法制备了聚氨酯/改性氧化石墨烯复合材料。动态力学热分析表明,2%氧化石墨烯的加入会导致胶料的玻璃化转变温度向高温偏移6.2℃,而2%改性氧化石墨烯的加入则会使硫化胶的玻璃化转变温度向低温偏移6.2℃,这表明改性氧化石墨烯可以改善胶料的耐低温性能。此外,2%改性石墨烯的加入同时使硫化胶的拉伸强度和断裂伸长率分别提升76.6%和9.8%。强韧性能同时提升的机理是聚氨酯分子链通过氢键与改性氧化石墨烯产生了很强的相互作用。应变过程中,改性氧化石墨烯-橡胶分子链间生成的氢键被破坏,应变能在这一过程中被耗散,从而实现了聚氨酯橡胶强度与韧性的同时提升。破坏的氢键在停留过程中会可逆回复。提高停留温度和延长停留时间有利于氢键的回复。

The graphene oxide was graft modified with polyethylene glycol,and then the polyurethane/modified graphene oxide composite was prepared by mechanical blending.The results of dynamic mechanical thermal analysis show that the glass transition temperature of the vulcanizate shifts to low temperature by 6.2℃with the addition of 2%graphene oxide,indicating that the low temperature resistance of the vulcanizate is improved.In addition,the tensile strength and elongation at break of the vulcanizate are increased by 76.6%and 9.8%with the addition of 2%modified graphene oxide.The mechanism is that the polyurethane molecular chains have strong interactions with modified graphene oxide through hydrogen bonds.During the strain process,the hydrogen bonds generated between modified graphene oxide-polymer chain are destroyed,which consumes a lot of energy,thereby enhancing the strength and toughness of polyurethane.The destroyed hydrogen bonds will reversibly recover during the storage.Increasing the storage temperature and extending the storage time facilitate the recovery of hydrogen bonds.