Preparetion And Shape Memory Properties Of Polyether Polyurethane And Its Composites

Introducing the research and development condition of liquid crystalline polyurethane and hyperbranched polyurethaneall over the world,then analyzing and discussing the synthesis and characterization of LCPU?LCPU/GO composites and HBPU.The main contents are as follows:(1)Three kinds of LCPU with different hard segment content which contains ionic groups were designed and synthesized.FT-IR?TG?XRD and POM were used to analyze the material,then swelling property?absorption and shape memory property were also analyzed.MDI?HDO?DMPA and PTMG-1000 were used to prepare the LCPU,and hard segments of PU1?PU2 and PU3 were 58%?48%and 38%respectively.The results showed that the LCPU had a good liquid crystalline and its cleaning point was around 200?,and when the hard segment was decreased,the swelling and absorption properties increased,and the shape memory property was also improved obviously.(2)Hummers method was used to prepare the graphene oxide(GO),then the LCPU was used as matrix and preparing the LCPU/GO composites,the contents of GO were 5%?10%?15%and 20%.The ratio of oxygen and carbon was 0.47 in GO we prepared,reaching a high degree of oxidation.In LCPI/GO composites,GO could disperse well in LCPU matrix.With the content of GO in composites increasing,the elongation at break,tensile strength and elastic modulus also increased,and when the content of GO reached 20%in composites,those three parameters had 77.5%,12.4%and 174.8%improvement compared with LCPU matrix respectively,and its shape memory property also increased obviously.Besides,inducing GO can improve the hydrophilism of material.(3)"First arm after core" synthesis method was used to synthesize a kind of hyperbranched polyurethane(HBPU)which contained a large number of ionic groups,and the contents of ionic groups were 1.19?1.42 and 1.65mmol/g respectively,through GPC analysis,the molecular weight of HBPU could reach over 140000,and when ionic groups increased,the HBPU could show a great mechanical property,and its elongation at break can reach 1700%,and this HBPU materials also have great shape memory property,the shape recovery rate can reach 99%.