Research On Layered Clay-Modified Nano-Silica Composites To Reinforcer Silicone Rubber

With the rapid development of aerospace technology,rubber has played an increasingly important role in the field of aerospace materials.As the matrix of advanced composite materials for aviation,rubber is an important way to achieve lightweighting of aviation devices and gradually becomes the focus of research on aviation materials.The use of nano-fillers for rubber reinforcement is currently the most effective way to enhance the comprehensive performance of rubber materials,among which silica is a widely used rubber reinforcing filler.However,the compatibility of silica with rubber is poor,and it is easy to agglomerate in rubber,which affects the reinforcing effect of fillers on rubber to a certain extent.Nanocomposite filler is to integrate the functionalities of different components of fillers to complement each other,so that the composite filler can play the best reinforcing effect in rubber.In this study,methyl vinyl silicone rubber（MVQ）was used as the matrix,nano silicon dioxide（SiO₂）was selected as the main reinforcing filler,and different kinds of layered clay and nano SiO₂were introduced to prepare the composite filler,to study the reinforcing effect of the composite filler on MVQ,to investigate the reinforcing mechanism of the composite filler,and to prepare high-performance MVQ composites.The main contents of this study are as follows:1.Hydrotalcite（LDH）was organically modified using the anionic modifier sodium dodecyl benzene sulfonate（SDBS）,nano-SiO₂was grown in situ on the LDH sheet,and a highly dispersed LDH-SiO₂composite packing was prepared and MVQ was reinforced.The unique two-dimensional layered structure of LDH can effectively inhibit the agglomeration of nano-SiO₂,improve the dispersion of composite filler in rubber,and improve the fracture elongation of LDH sheet.The tensile strength of LDH-SiO₂/MVQ composites was 4.03 MPa and the elongation at break was 233.8%,which were 1.32 times and 1.91 times those of SiO₂/MVQ,respectively.2.The ZAC-LDH-SiO₂composite fillers with different Ce³⁺contents were prepared by introducing rare earth metal cerium（Ce）to partially replace Al³⁺between LDH layers using the unique layer structure and anion substitutability of LDH.Compared with Al³⁺,Ce³⁺has a higher coordination number and can accept more unpaired electrons provided by ligands thus forming more stable coordination compounds,while rare earth elements have a strong affinity to react with oxygen to form more stable rare earth oxides of cerium oxide,thus significantly improving the thermal stability of the composites.The tensile strength of ZAC-LDH-SiO₂/MVQ rubber composites was 5.59 MPa and elongation at break was 255.9%,which are 1.39 and 1.09times higher than those of LDH-SiO₂/MVQ,respectively.3.Montmorillonite（MMT）was organically modified using the cationic modifier cetyltrimethylammonium bromide（CTAB）,and nano-SiO₂was grown in situ on the surface of montmorillonite（MMT）after organic modification,and MMT/SiO₂composite packing was prepared.MMT is organically modified,and the surface is grafted with organic molecular chains,which increases the compatibility between the filler and the rubber matrix,and the layer spacing becomes larger after MMT is organically modified,which is conducive to the intercalation of the rubber molecular chain and increases the contact area between the filler and the rubber.The tensile strength of MMT-SiO₂/MVQ composites is 4.99 MPa and the elongation at break is 234.14%,which are 1.62 times and 1.90 times those of SiO₂/MVQ,respectively.