Study On The Preparation And Functionalization Of Thermoplastic Silicone Vulcanizated

With the progress of society and the development of electronic technology,public have higher and higher requirements for wearable devices.At present,most of the raw materials of wearable devices rely on imports and are expensive.The popular dynamic vulcanized silicone rubber(TPSiV)is a composite material which is mainly prepared from thermoplastic polyurethane elastomer(TPU)and silicone rubber as the matrix.TPSiV has both a smooth feel and good mechanical properties,but due to the difference in polarity between TPU and silicone rubber,compatibility has always been a problem to be solved.At the same time,the product function is relatively single and can't meet the needs of the market.In response to the above problems,TPU and silicone rubber were used as the matrix to prepare TPSiV through dynamic vulcanization,the effects of processing parameters and compatibilizers on the performance of TPSiV were investigated.On this basis,conductive or flame-retardant functional fillers were added to TPSiV,thus functionalized TPSiV was developed.The specific research content and conclusions are as follows:(1)Silicone rubber was dynamically vulcanized with different plastics to prepare plastic/organic silicone rubber blends.The results show that:compared with the pure plastic matrix,the mechanical properties of the blends decreased,and the decrease was more obvious with the increase of the rubber-to-plastic ratio;however,the hydrophobicity of the modified material was enhanced to varying degrees.Among them,the static water contact angle of the HDPE-based blend was increased maximumly by21.2°,and the heat resistance of the blend was improved.(2)TPU-based TPSiV was prepared,and the influence of processing parameters on the performance of TPSiV was explored.The best composition and processing parameters were:1180A type TPU and YT3150 silicone rubber were dynamically vulcanized at a ratio of 7:3 at 180 ~oC with 0.5 wt%crosslinking agent and 0.1 wt%catalyst.The tensile strength and elongation at break of TPSiV reached 13.6 MPa and864%,respectively.(3)A series of silicon-containing polyurethanes compatibilizer was synthesized,and the influence of different compatibilizers on the mechanical properties of the resulting TPSiV was explored.The results showed that the compatibilizer with fixed NCO/OH ratio of 1.75 and PTMG/HSO ratio of 4:1 exhibited the best effect.The tensile strength and elongation at break of TPSiV reached 12.7 MPa and 728%,respectively.(4)Five conductive fillers were added to the TPSiV matrix,respectively.Among them,carboxylated multi-arm carbon nanotubes(MWCNT-COOH)displayed the best effect as conductive fillers,and the percolation threshold was 3 phr;compared with the pure matrix,the hardness of conductive TPSiV was increased,whereas the tensile strength and elongation at break have decreased decreased;the stress relaxation resistance and creep resistance of the composite material was improved.The MWCNT-COOH as a conductive filler formed the best network in the matrix,and there was no obvious aggregation.(5)The flame retardant TPSiV was prepared,and the effects of single and compound flame retardants on the performance of TPSiV were investigated,respectively.The experimental results showed,when the weight ratio of red phosphorus to aluminum hydroxide was 2:3 with 25 phr,the flame retardant effect of TPSiV reached FV-0 level,and the limiting oxygen index(LOI)was the highest;when the ratio of MLP200 to aluminum hydroxide was 3:1 with 40 phr,the flame retardant effect of TPSiV reached FV-0 level.