Study On Co-vulcanization System And Compatibility Of FKM/MVQ Blend

With the requirements for materials in various fields become more and more harsh,it is difficult for general rubbers and single rubber to adapt to current industrial requirements.More attention has been paid to the blending and modification of specific rubbers.However,the problem of co-vulcanization and compatibility of blended rubber still remain big challenges.As we know,fluororubber has good oil resistance and heat resistance,but its processability and low temperature resistance are poor.While silicone rubber has high temperature resistance and excellent processing property,but its oil resistance is poor.Based on that,the fluororubber and silicone rubber are blended in order to study co-vulcanization and compatibility of blended rubber preparing FKM/MVQ alloy elastomer with excellent comprehensive performance.The main contents of the paper include:(1)Firstly,this article uses different vulcanization systems to vulcanize a single rubber testing its vulcanization properties.Secondly,the most suitable vulcanization system BIBP+TAIC for blending rubber was optimized.Finally,a series of different ratios of FKM/MVQ alloy elastomer were prepared for vulcanization performance test?mechanical property test?oil resistance performance test and aging resistance test.The results show that:when the blending ratio is 50:50,the vulcanization time of the blending rubber is 93.25s,which is the closest to the midpoint of the vulcanization time of the two single rubbers(97.96 s),and the torque difference is 11.74dN.m,the tensile strength up to 4.61 MPa,and breaking elongation up to 205.39%.The three-factor and three-level orthogonal experiments with vulcanizing agent,vulcanization aid and vulcanization temperature were used to optimize the vulcanization formula.It was found that the addition of BIBP of 1 part,TAlC of 2.5 part and vulcanization temperature of 165 ? was the best comprehensive performance of blended rubber.The maximum torque of the blended rubber is 19.34dN.m,and the tensile strength and elongation at break can reach 5.29MPa and 230.68%,respectively.It has been found by SEM test that the optimization of the vulcanization conditions are not optimized,the vulcanized rubber has a smooth cross section,the brittleness of the blended rubber is large,and the mechanical properties are poor.After the vulcanization conditions are optimized,the cross section of the blended rubber is rough,the brittleness of the blended rubber is reduced,and the toughness is increased.In a word,the mechanical properties of the blend are optimized.Through the extreme value analysis method,we found that the most important factor affecting the blended rubber is the addition amount of the vulcanization aid TAIC,followed by the addition amount of BIBP,and finally the vulcanization temperature.(2)A new compatibilizer FKM-g-SiR was designed and synthesized,selecting vinyl-terminated silicone oil of different vinyl content by thermodynamic grafting onto fluororubber molecular chains.The microstructures of the blends before and after adding compatibilizers were analyzed by TEM.It was found that the synthesized compatibilizers could effectively improve the two-phase structure,reduce phase domain between the two phases and improve the compatibility of the blends.The effect of vinyl silicone oil with different vinyl content(0.09%,0.21%,0.63%)as grafting agent on compatibilizer compatibilizing effect was studied.It was found that the vinyl silicone oil with 0.63%reaches the best performance.Additionally,the low temperature resistance of the blend was the best,the glass transition temperature is-2 ?.Different amounts of compatibilizer were added to FKM/MVQ blends(0 parts,5 parts,10 parts,20 parts).It was found that with the increase of the amount of compatibilizer,the performance of the blended rubber was obtained.Significantly improved,in which the tensile strength of the blended rubber increased from 3.78 MPa to 5.76 MPa(up 52.38%),the elongation at break increased from 151.6%to 280.8%(up 85.22%),and the mass change rate of the blended rubber was from 12.5.%decreased to 7.9%,and the breaking strength retention of the blended rubber increased from 102%to 113.4%.