| Natural rubber (NR) has been extensively used in many areas, for its outstanding properties. In the vulcanization process of rubber materials, sulfur/accelerator curing system could form monosulfide bonds, disulfide bonds or polysulfide bonds, which causing the rubber to have better tear strength and fatigue durability. And on the contrary, peroxide curing system could generate carbon-carbon bonds, which producing better thermal aging resistance and compression set. For the above explanation, the research of dual-curing system gets attention of combining the two systems. Traditionally, fillers are added into the elastomer materials by mechanical blending, but this approach produces poor dispersion of fillers and leads to poor properties of material. Now, fillers could be modified by the method of chemical reactions, which could make fillers achieve the better dispersion, and create better network structures between macromoleculars and particles. And fillers play not only the role in reinforcement, but also the cross-linking agent, which improving properties of composites. This method is worthy of research.There are two parts of this article. Firstly, the research of several dual-curing system of natural rubber were studied. Secondly, the preparation and properties of silica/PDMS composite materials were studied.At the first part, the sulfur/HVA-2 system, sulfur/HVA-2/DCP system, sulfur/different peroxide system and sulfur/3M curing system of NR were investigated. And the orthogonal experiments analysis of different effects of different curing agents on properties of NR was investigated. It was found that, for the sulfur/HVA-2 system, with increasing the dosage of HVA-2, the aging coefficient and FTFT coefficient of NR vulcanizates increased first and then decreased. And the comprehensive properties was best when the dosage of HVA-2 is 1.0 phr. For the sulfur/HVA-2/DCP system, it was found that the mechanical properties and thermal-oxidative aging properties were better than individual curing system. And when the content of HVA-2 is 1.5 phr, the tensile fatigue property and comprehensive properties were best. For the sulfur/different peroxide system and sulfur/3M curing system, it was found that properties of NR of sulfur/3M system was the best relatively. And then for the further research of sulfur/3M system, the result was that when the ratio of sulfur/3M was is 3:1, the comprehensive properties were best. Then, for further research, the optimal recipe system was choosen by comparison. By the orthogonal experiment and the analysis of variance, the result was that ZDMA, HVA-2 and TAIC had highly significant effects on elongation at break, and ZDMA, HVA-2 and TAIC had significant effect on the tear strength and tensile fatigue property of NR. And BDDA had effect on the elongation at break, tear strength and tensile fatigue property. And ZDMA had significant effect on thermal-oxidative aging properties of NR composites. Finally, the best combination formula was chosen.At the second part, first of all, the preparation method and properties of silica/PDMS composites were investigated. At first, active sulfonate groups were grafted on the surface of silica, and then the product grafted the amino groups by sulfonic acid reacting with PDMS, and continually the composite producing network structure between the silica and PDMS by the reactive HDI, and finally the elastomer materials was prepared. The prepared composites were characterized through the use of various test tools, such as IR, TEM, and studied the dynamic mechanical properties of the composite. The result showed that the composite had a certain degree of flexibility, and dispersion of particle was good, dynamic loss performance is relatively better. |
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