Research On The Characterization Of Crosslinking Of The Rubber Vulcanized By Sulfur And Its Application

Crosslinked rubber is widely used as an important strategic industrial material by its entropy elasticity, and its structure of crosslinking network is the important basis of entropy elasticity. Because the control and characterization of the crosslinking network is poor, the development of rubber science and engineering was delayed. In order to control the crosslinking network accurately, the precise characterization of the crosslinking network is essential. Thus, the aim of this paper is only try to find a method of precise characterization. The main contributions are as follows,A one to one crosslinking system was developed by TMTD, in which one TMTD molecular forms one crosslink. Subsequently, Crosslink density of SBR and NR vulcanized by TMTD was measured with equilibrium swelling method with different solvents. The results showed that the crosslinking network was damaged by the solvation, especially for the high crosslinking system. An idea was brought forward that some unknown polymer-solvent interaction parameter e.g. polymer-solvent interaction parameters of the polymer blending, new type of rubber and modified rubber can be estimated by Flory formula with calculated crosslinking density from TMTD concentration in rubber matrix, and the concentration of TMTD was suggested to be low, for example 2 phr. Then a new method was acquired for the precise characterization of crosslinking network of complex systems (industrial conventional rubber recipe).In addition, Crosslink density of SBR vulcanized by TMTD was measured with equilibrium swelling method under different testing temperature, and the results showed that the crosslink density of rubber without filler was not affected by temperature under the test condition. A method was built up that physical crosslink and chemical crosslink of the filler was measured by the different temperatures and different solvents. The method was applied into the measurement of crosslink density of the SBR filled by the carbon black and graphite/NBR nanocomposites prepared by the latex blending, and the contribution of carbon black and graphite to the chemical crosslink was evaluated.In other ways, based on the determination of the crosslink density of SBR filled with different fillers, by virtues of chemical probe, the crosslink type was also determined and the results showed that the surface activity and particle size of filler will affect the crosslink density and crosslink type of rubber. Finally, the characterization of the crosslinking network by NMR and FTIR were evaluated and some advices were put forward.