Preparation And Property Of Silicone Rubber Material As Balloon Catheter

Silicone rubber is widely used in health care, electronic appliances, automotive, aerospaceand other industries, due to low and high temperature resistance and solvent resistance, goodsoftness, good air permeability, physiological inertia and biological compatibility, withoutadhesion with human tissue blood, easy disinfection and so on. It has been attracted more andmore attention on the application and research in the field of medical, because of its excellentbiological compatibility. Silicone rubber balloon catheter is general as surgical clinical auxiliarymedical apparatus for use, which plays an important role in surgical urethral catheterization,hemostasis, drainage, irrigation, bladder washing and diagnosis imaging. However poor tensileand tearing property of silicone rubber were result from the large flexible between molecularchains, low cohesive energy density, the difficulty in crystallizing, which would restrict theapplication clinical catheter dilated ballon due to easily bursting during catherterizationencumbrances and difficult removing after use. This would also increase the patients’ pain andeconomic pressure. Therefore, to develop the silicone rubber material with high tear strength,high elasticres ilience and its preparation process is the key problem in the silastic implantmaterials. It is of great significance to enhance the level of medical equipment technology andpromote the development of medical field in our country.The effect of the content of crosslinking agent benzoyl peroxide (BPO) and reinforcingfiller cellulose nanocrystals on mechanical properties of silicone rubber were investigated andthe vulcanization process was optimized, in which medical methyl vinyl silicone rubber (VMQ)was used as materials. Then the resistance to corroding and chemical stability of VMQ sampleswere tested by soaking of artificial urine, to provide the necessary method for the preparation ofthe medical silicone implant materials with high comprehensive performance. This workincludes several aspects as follows:(1) The impact of curing time, temperature, pressure on mechanical property of VMQ wasinvestigated by orthogonal experiment. Results showed that,160℃,5min,12MPa and thepost cure of200℃,6h were the best vulcanizing process, under which the tear strength,tensile strength, stretching deformation rate and elongation at break of VMQ were20.15KN/m,9.31MPa,8.68%, and1465%. DMA test showed that uneven in internal interface andcrosslinked network structure in silicone rubber was improved due to decomposition of remaining vulcanizing agents through post cure, which leads the increase of the glasstemperature Tg. The mechanical properties of VMQ was reduced little after soaking ofsimulated urine for14d, which was from20.15KN/m and9.01MPa of original to18.47KN/mand8.61MPa. Scanning electron microscopy (FE-SEM) results showed that urine soaking hasa certain influence on surface of VMQ, but little on the internal structure.(2) The effect of benzoyl peroxide (BPO) as a crosslinking agent on the performance ofVMQ was investgated in this dissertation. Results showed VMQ with0.1phr BPO has the thetear strength of20.58KN/m, tensile strength of9.03MPa, deformation rate of8.58%andelongation at break of1460%. DMA results showed that appropriate amount of BPO adding toVMQ increased the internal crosslinking network structure of VMQ, and limited the freedommovement of silicone molecule chain segment and hindered the matrix transformation from theglass state into viscoelastic state, leading to incease of Tg. The mechanical strength of VMQwas reduced little after soaking of simulated urine for14d. Compared to non-soaking VMQ,tear strength and tensile strength was reduced by7.24%to19.23KN/m and5.87%to8.56MParespectively.(3) The reinforcing effect of cellulose nanocrystals (NCC) was researched by the test ofmechanical properties and morphology. The results showed that adding of NCC had no use inimproving the mechanical strength of VMQ, but a significant effect on the decrease of thedeformation rate. However, the stress-strain curve of VMQ displayed that the materials tensilemodulus of VMQ at1000%was obviously improved by adding NCC, which showed that NCCis effective in reinforcing VMQ. Due to the increase of brittleness and decrease of elongation atbreak, the strength at break was reduced. The tear and tensile strength of VMQ were reducedlittle after soaking of simulated urine for14d, Which were the93.44%and94.8%ofnon-soaking VMQ. The VMQ kept its mechanical properties stably in urine environment.