Preparation And Properties Of Functional Graphene/Thermoplastic Polyurethane Composites

Thermoplastic Polyurethane(TP U)is a comprised of hard and soft segment type linear block polymers.The TPU has been widely used for adhesives,coatings,biomedical and composites applications.Due to the similarity of the polymer,the insulation of TPU would caused fire and explosion because of the charge accumulated in TPU surface.While some water vapour and gas molecules can easily infiltrate TPU films,affect its application in the field of barrier.Therefore,it is very important to study the anti-static and barrier properties performance of TPU.Graphene,as a novel carbonic material,is regarded an ultrathin,high transparency,high conductivity and favourable barrier against gas diffusion.In this paper,we study the different functional graphene/TPU composites,and make a detailed study on their microstructure,barrier properties,mechanical properties and antistatic properties.TPU composite films with different content ratio of graphene oxide were fabricated by the solution casting method.And searching for the best in situ thermal reduction temperature point by thermogravimetric analysis,the results show that 200℃is the best temperature of reduction,and the percolation threshold of the composite material(HRGO/TPU)was 2.3%.The mechanical properties of the composites were restored After second coating(SHRGO/TPU).Reduction of GO by using green and non-pollution reducing agent of L-ascorbic acid.The results show that the oxygen groups of GO surface could well be the removal by L-ascorbic acid.The functional grapheme(LRGO-o)after the inorganic salt deposition can be stable in the organic solvent in a short time,and the LRGO-o/TPU has a lower percolation threshold with 1.7%Functionalized graphene oxide(DD-GO)were prepared by treatment of graphene oxide(GO)with didodecyldimethylammonium bromide(DDAB),and the DD-RGO was reduced by ascorbic acid.The results of XPS show that the DDAB insert into graphene layer by chemical bond.FESEM show that DD-RGO with fold layer structure is evenly dispersed in TPU matrix,and coated on the surface fracture of composite films.when the mass fraction of DD-RGO is 2wt%,compared with the pure TPU film,the oxygen transmission rate have been reduced by 50%and the Volume resistivity have been increased by 7 orders of magnitude.The barrier properties and antistatic properties of composite films have been improved significantly.The functional graphene/carbon nanotubes(FRGO-CNTs)were first prepared by non covalent modification of functional modification graphene(FRGO)and carbon nanotubes(CNTs),and the resulting FRGO-CNTs can well disperse in DMF,inhibite agglomeration and show a good compatibility with TPU composite.when the mass fraction of FRGO-CNTs is 2wt%,compared with the pure TPU film,the onset temperature of thermal degradation of composite is improved by 49 ℃ and the oxygen transmission rate have been reduced by 53.2wt%.The percolation threshold of FRGO-CNTs/TPU composite films is lower:the volume resistivity is 5×105Ω·cm whitch has been decreased by 7 orders of magnitude when the FRGO-CNTs is 0.8wt%.The mechanical properties of composites increase and then decrease with the increasing of fillers content.