Study On Structure And Properties Of Graphene Derivatives And Their Acrylate Copolymers And Styrene-butadiene Rubber Composites

As important nanomaterials,graphene oxide(GO)and reduced graphene oxide(r GO)have been applied in graphene/polymer composites,in which GO(rGO)caused significant improvements in properties of the composites and broaden their application in various fields.However,there are several factors that have a significant effect on the properties of the composites,such as the dispersion and spatial distribution of GO(rGO)in the composites,and the interfacial interaction between polymer matrix and GO(rGO).Therefore,to study the relationship between the above factors and the properties of the composites has important theoretical and practical significance.Herein,this dissertation explored living radical polymerization and other methods to synthesize a variety of acrylate copolymers used to modify GO(rGO),resulting in improving the dispersion of GO(rGO)in the polymer matrix and their interfacial interaction,thereby improving the properties of the composites.In addition,this dissertation also explored the use of different technologies to construct the three-dimensional network structure of r GO and the two-dimensional distribution of GO in the composites,which have important practical significance for the development of the composites with good mechanical properties and high thermal conductivity.The main contents are as follows:(1)In order to improve the interface between GO and polymers and to regulate the spatial distribution of GO,a block copolymer containing polyglycidyl methacrylate(PGMA)and polydimethylsiloxane(PDMS)segments was synthesized by atom transfer radical polymerization(ATRP).Then,the copolymers were added into GO dispersions to prepare GO/polymer composites by vacuum filtration coprecipitation method.The composites have high tensile strength and high toughness,which is related to the two-dimensional distribution of GO and the strong interfacial interaction force between GO and the copolymers.In addition,a random copolymer containing both PDMS and PGMA segments was prepared by free radical polymerization.Then the copolymers were incorporated with reduced graphene oxide(rGO)to prepare r GO/copolymer aerogels by freeze-drying.The composite aerogels have high compressive strength and high thermal conductivity,which are mainly attributed to the three-dimensional network structure of rGO and the strong interfacial interaction between rGO and copolymers.(2)In order to improve the dispersion of GO in PMMA and their interfacial reaction,a pyrene terminated block copolymer containing PDMS and PMMA segments was synthesized by ATRP.The block copolymers were used to modify GO to prepare GO hybrid fillers,which were then added into PMMA to prepare GO/PMMA composites.The composites exhibit high tensile strength and toughness,which are mainly attributed to the uniform dispersion of GO in the PMMA matrix,the strong interfacial interaction between GO and the matrix,and the flexible PDMS in the block copolymers.(3)In order to study the effect of the spatial distribution of rGO in styrene-butadiene rubber(SBR)and the dispersion of rGO on the properties of SBR composites,a block copolymer containing polystyrene and polyhydroxyethyl methacrylate segments was synthesized by reversible addition fragmentation chain transfer polymerization(RAFT).The block copolymers were grafted onto the surface of carbon nanotubes(CNT)to prepare copolymer grafted-CNT,which reacted with GO and ascorbic acid to prepare rGO hybrid fillers by esterification reaction reduction reaction.Then the rGO hybrid fillers were added into SBR by solution blending to prepare rGO/SBR composites.The composites have good mechanical properties and high thermal conductivity,which are mainly attributed to the structural similarity of polystyrene segments in hybrid fillers and SBR,the uniform dispersion of large aspect ratio carbon nanotubes “connecting” GO and the three-dimensional structure of the hybrid fillers.(4)In order to study the influence of the spatial distribution of rGO on the properties of SBR composites,a continuous porous silicone rubber was prepared by inorganic salt template method.Then the continuous porous silicone rubber was infiltrated into polydopamine-modified GO(PDA-rGO)dispersion to adsorb PDA-rGO on the pore wall of porous silicon rubber,thereby preparing PDA-rGO/silicone rubber composites with three-dimensional porous structure.Finally,the porous PDA-rGO/silicone rubber composites were filled with SBR to prepare rGO/SBR composites.The rGO/SBR composites exhibit excellent thermal conductivity due to the three-dimensional network structure of PDA-rGO nanosheets.