| Under the background of "standing before breaking,steady double carbon road",the development trend of tires is: green,environmental protection and life health protection.Now commercial green tires are generally made of solution polymerized styrene-butadiene rubber,silica,silane coupling agent and other rubber processing additives,which are not able to keep up with the demand.Solution polymerized styrene-butadiene rubber,as a synthetic rubber processed from non-renewable petroleum resources,creates a large amount of carbon emissions in the production process and the reaction between silica and silane coupling agents generates a large amount of volatile organic compounds emissions,such as methanol or ethanol,which is detrimental to the environment and human health.In view of the above problems,the epoxidized natural rubber based on bio-based sources was studied in this paper.The epoxidized natural rubber with different epoxy degrees was successfully prepared and used as a macromolecular coupling agent to compound with natural rubber and silica,which improved the dispersibility of silica and the comprehensive performance of nanocomposite material.The bio-based rubber nanocomposite material with excellent comprehensive performance and low volatile organic compound emission was successfully prepared,which is expected to replace solution polymerized styrene-butadiene rubber and silane coupling agent to prepare high-performance green tires.The first part of the thesis is the preparation and characterization of epoxidized natural rubber with different epoxy degrees,which is the third chapter of the paper.The epoxy degree,glass transition temperature,molecular weight and gel content were characterized by nuclear magnetic resonance spectroscopy,differential scanning calorimetry and gel permeation chromatography and other methods.Through wide angle X-ray diffraction and mechanical properties test,the crystallization capacity and mechanical properties of epoxidized natural rubber were characterized so as to evaluate its feasibility as tire tread matrix material.In the second part of the paper,epoxidized natural rubber and silica are combined at different heat treatment temperatures to investigate the effect of heat treatment temperature on the combination strength between epoxidized natural rubber and silica,which is the fourth chapter of the paper.The degree of reaction between epoxy groups and silanol groups was evaluated by attenuated total reflection infrared spectroscopy,thermogravimetric analysis and X-ray diffraction.Compared with the natural rubber/silica composites,the introduction of epoxidized natural rubber can obviously improve the compatibility between rubber matrix and silica.With the increase of heat treatment temperature,the combination between epoxidized natural rubber and silica will be further enhanced.In the third part of the paper,the epoxidized natural rubber was introduced into the natural rubber/silica composite,and the mechanism of action of epoxidation natural rubber as macromolecule compatibilizer and coupling agent was investigated,which is the fifth chapter of the paper.In this part,ENR with different epoxy degree and incorporation ratio is used to improve the dispersion of silica in rubber matrix.The influence factors and mechanism of the interaction between epoxidized natural rubber and silica were further elucidated by dynamic and static mechanical properties and morphology analysis.The results show that the addition of epoxidized natural rubber significantly improves the dynamic properties of the composites,and the composites have better wet slip resistance with similar rolling resistance.But there are still great defects in static mechanical properties.After epoxidized natural rubber was combined with a small amount of silane coupling agent,a composite material with high tear resistance,high anti-wet skid performance and low rolling resistance was successfully prepared.The composite modified with epoxidized natural rubber and silane coupling agent has high mechanical properties and excellent anti-wet skid performance and the introduction of epoxidized natural rubber can reduce the cost and the carbon emissions and volatile organic compounds emissions in the tire processing,indicating epoxidized natural rubber has a broad application prospect in the development of new bio-based green tire. |
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