The Influence Of Nano-fillers On The Structure And Properties Of Alternating Multilayered Silicone Rubber

Compared to the general polymeric materials,silicone rubber has more peculiar properties such as non-toxic and odorless,wide temperature range,electrical insulation,aging resistance and chemical stability,etc.Therefore,it is widely used in aerospace,medical,chemical industry,electronic cable,agriculture and many other fields.However,the poor strength of pure silicone rubber greatly limits its application in many fields.It is great essential to develop the high strength and functionalized silicone rubber.In this research,the preparation of functionalized silicone rubber with new processing method,alternating multilayered co-extrusion,is put forward.A series of alternating multilayered silicone rubber materials were prepared by adopting advanced multilayered co-extrusion technology,in addition,three kinds of fillers,which are carbon nanotubes（CNTs）,graphene（GNs）,silica（nano-SiO₂）respectively,were filled in silicone rubber to improve the strength and function.The micro-structure,mechanical properties,dielectric properties and electromagnetic shielding were studied.The major results are as follows:1.Multilayered co-extrusion technology was used to control the content and distribution of nano-SiO_2,3,9,17,33,65-and 129 L soft/hard alternating silicone rubber materials were successfully prepared.The results shown that the multilayered silicone rubber has a regular two-dimensional and continuous layer structure.With the layer number increases,the tensile strength and elongation at break both increase,and the compression resistance is improved.Compared to that of 3-layer silicone rubber,the elongation at break and tensile strength of the 129-layer silicone rubber increase42.5%and 70.2%,respectively.2.The alternating conductive layer/insulating layer alternating multilayer silicone rubber material was successfully obtained by selectively filling carbon nanotubes.Carbon nanotubes disperse uniformly in silicone rubber matrix without agglomeration.At the same time,high content filled multilayer silicone rubber still maintain good mechanical strength and elasticity,and the mechanical strength of multilayer silicone rubber material could be further improved by regulating the ratio of layer thickness.In addition,the dielectric properties of multilayer silicone rubber show typical anisotropy in thickness direction,extrusion direction and perpendicular to extrusion direction because of the orientation arrangement of carbon nanotubes.3.The effect of CNTs and GNs mixed fillers on tear resistance of multilayer silicone rubber materials was investigated.The results show that with the increase of the number of layers,the dispersion and orientation arrangement of the fillers in the matrix enhances.The addition of two-dimensional lamellar graphene can effectively improve the mechanical properties of silicone rubber materials.when the number of layers is 129,the mechanical strength is as high as 6.96 Mpa.Alternating multilayer silicone rubber material can effectively hinder the crack propagation because of its unique multilayered structure,the crack direction is deflected,and the tear resistance of silicone rubber material is improved.In addition,the dielectric properties of multilayer silicone rubber show typical anisotropy.Finally,compared with the pure component,the electromagnetic shielding performance of 129 layers of silicone rubber can reach 6.2 dB,which is 3.7 times higher than that of pure component.