Multifunctional Graphene Films Based on Designer Hyperbranched Comb-like Multi-arm Copolymers
It is highly desirable to produce high-performance,multifunctional graphene films through relatively simple process.Herein,a hyperbranched comb-like multi-arm copolymer,HBPE@PHDA,was designed and synthesized by combining the chain walking ethylene polymerization and atomic transfer radical polymerization of hexadecyl acrylate(HDA).The HBPE@PHDA noncovalently functionalized graphene was further obtained by exfoliating graphite in chloroform under sonication with the copolymer as stabilizer,and subsequently HBPE@PHDA/Graphene composite films were fabricated from the resultant graphene dispersion via vacuum filtration.The structure and composition of the HBPE@PHDA were characterized by gel permeation chromatography(GPC),proton nuclear megnetic resonance(1H-NMR)and melt rheological measurements,and the performance of the resultant graphene composite films was evaluated.It is confirmed that the HBPE@PHDA consists of a hyperbranched polyethylene(HBPE)core and multiple comb-like poly(hexadecyl acrylate)(PHDA)side chains,and as a stabilizer,the copolymer can effectively promote the exfoliation of graphite in chloroform,rendering the HBPE@PHDA-functionazlied graphene free of structural defects.And meanwhile,the copolymer can crystallize through the PHDA side chains in the resultant graphene composite film system,which simultaneously imparts the latter with excellent mechanical,anisotropically thermal transfer,and shape memory performance.As an example,the composite film with 60 wt％graphene exhibits a tensile strength,3.0 MPa,a thermal conductivity in plane,29.4 W·m·K-1 with an anisotropical ratio,36.8.This work provides a new simple way for producing flexible,high-strength,multifunctional graphene films.
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维普
