New Filler-Suppoted Rubber Additives And Their Effects On The Structure And Performance Of Rubber And Rubber Blends

Nowadays,the preparation of rubber nanocomposites with high performance has become more and more important in rubber industry.Graphene is a new rubber nano-filler with excellent comprehensive performance.Solution-based chemical reduction of graphene oxide?GO?to graphene is one of the most important approaches to produce individual graphene sheet on a large scale for practical applications.Hydrazine hydrate is well accepted reducing agent because of its high reduction efficiency.Nevertheless,hydrazine hydrate is highly explosive and toxic,and the reaction conditions are stringent.Unmodified graphene sheets are difficult to disperse homogeneously in rubber matrix due to the strong van der Waals force among graphene sheets.And the graphene-rubber interfacial interaction is always weak because of the hydrophobic and oil-phobic graphene surface.Therefore,one of the most successful way to obtain high-performance graphene rubber composites is organic modification of graphene.On the other hand,low molecular weight rubber additives are easy to migrate from the rubber matrix,which not only reduces the efficiency of rubber additives,but also pollutes environment.Herein,in order to overcome the shortcoming of traditional rubber auxiliaries and develop green efficient graphene oxide?GO?reducing agent and modifier for obtaining high-performance graphene rubber composites,we present an efficient and rapid one-step approach for reducing and modifying GO simultaneously under a mild condition using routinely available commercial vulcanization accelerator and antioxidant with nucleophilic groups as reducer,organic modifier and stabilizer to prepare organically modified graphene.A new environment-friendly and multi-functional rubber/graphene nanocomposite was prepared by combining rubber additives reduced and modified GO with rubber.They were systematically studied that the dispersion of rubber additives reduced and modified GO and interfacial interaction between rubber additives reduced and modified GO and rubber and their effects on structure and properties of rubber.At the same time,combined with the previous work,it is also studied that effects of silica/graphene-supported vulcanization accelerator on the crosslinking kinetics and property of natural rubber?NR?/styrene butadiene rubber?SBR?blends.The main contents are as follows:?1?An efficient,green and facile one-step method to reduce and modify GO simultaneously was presented by using vulcanization accelerator M as reducer and organic modifier.Apart from the excellent reduction capability to GO,M molecules were also covalently grafted onto the reduced GO surface?M-G?,which significantly reduced the irreversible agglomeration of the prepared nanosheets and improved the compatibility between graphene nanosheets and rubber,leading to the uniform dispersion of graphene nanosheets in rubber matrix with strong graphene-rubber interfacial interaction.SBR composites with M-G showed superior tensile strength,extensibility and thermal conductivity to SBRcomposites with hydrazine hydrate reduced GO containing equal amount of M.?2?Using antioxidant RD to reduce and modify GO?G-RD?simultaneously was presented by an efficient,green and facile one-step method under mile condition.Apart from the excellent reduction capability to GO,RD were also covalently grafted onto the reduced GO surface,which significantly reduced the irreversible agglomeration of the prepared nanosheets and improved the compatibility between graphene nanosheets and rubber,As a result,rubber composites with G-RD nanosheets showed much better combination of enhanced mechanical strength,superior thermal conductivity and exceptionally high long-term thermo-oxidative aging resistance than rubber composites with hydrazine hydrate reduced GO containing equal filler and antioxidant contents.?3?Using vulcanization accelerator CZ to reduce and modify GO?CZ-G?simultaneously was presented by an efficient,green and facile one-step method under mile condition.HR PyGC-MS was successfully used to analyze effects of CZ-G on the crosslinking kinetics of components of rubber blends.As a result,SBR composites with CZ-G showed superior tensile strength,extensibility and thermal conductivity to NR/SBR composites with hydrazine hydrate reduced GO containing equal amount of CZ.CZ-G can accelerate NR vulcanization making vulcanization rate of NR and SBR more similar to achieve covulcanization.?4?HR PyGC-MS was successfully used to analyze effects of silica-supported vulcanization accelerator?SiO₂-s-CZ?on the crosslinking kinetics and properties of NR/SBR blends.Results showed that SiO₂-s-CZ narrowed the gap of the vulcanization rates of NR and SBR.Typically,the vulcanization rates of NR?0.228?and SBR?0.260?phase are more similar to each other,showing a covulcanization in the rubber blends.In addition,it is found that SiO₂-s-CZ is better dispersed in rubber,NR/SBR blends filled with SiO₂-s-CZ show enhanced mechanical strength,low rolling resistance and less fuel consumption when applied in rubber tire.