The Preparation And Characterization Of FKM/HNBR Elastomeric Alloys And Its Aramid Pulp Composites

Fluororubber have excellent properties such as high temperature resistance,oil resistance,corrosion resistance and aging resistance.At present,more than 60%of fluororubber materials are used for sealing in high temperature environment such as automobile engines.However,the application of fluororubber is restricted by its poor processing performance,low temperature resistance and compression set and high cost.Hydrogenated nitrile butadiene rubber(HNBR)has excellent low temperature properties,good processing properties and mechanical properties.In this paper,hydrogenated nitrile butadiene rubber(HNBR)and fluorine rubber(FKM)were used to prepare high performance FKM/HNBR elastomeric alloys.The effects of vulcanization system,blending ratio,compatibilizer,cross-linking agents and aramid pulp on the comprehensive properties of elastomer alloys were investigated.The main research contents include:The vulcanization properties and physical and mechanical properties of FKM(F246,GFLT-600s)and HNBR(A3406,B3627)rubber with different fluorine content and cyano content were studied.Two independent vulcanization systems,bisphenol AF and peroxide BIBP,were used based on fluorine rubber F246 and hydrogenated nitrile butadiene rubber A3406.The curing speed are close,and the blends can be well co-vulcanization at 170 ?.The FKM/HNBR elastomeric alloys with different blending ratios were prepared.The phase structure was observed by TEM and SEM,and the physical and mechanical properties,dynamic mechanical properties and heat resistance of FKM/HNBR were characterized.The results show that the FKM/HNBR blending ratio of 60/40 has the best comprehensive properties.The compatibilizer of KBM-403(?-glycidoxypropyltrimethoxysilane)and Tris(Trimethylol aminomethane)can significantly improve the compatibility of FKM/HNBR two phases.The tensile strength of FKM/HNBR(60/40)increased from 15.4 MPa to 17.8 MPa,the elongation at break increased from 348%to 364%,and the compression set decreased from 14.6%to 12.3%.The DMA spectrum showed a single peak,which confirmed that the two kinds of rubber had good compatibility.The glass transition temperature(Tg)of elastomeric alloys decreases from-2.5? to-7.2?.The low temperature resistance can be improved by the blending of FKM and HNBR.The results show that a compact IPN structure is formed by the combination of three-functional cross-linking agent TAIC and two-functional group HVA-2,it can effectively improve the mechanical properties and heat resistance.The tensile strength is increased to 1 8.2 MPa,and the high compression set decreases to 11.72%,especially for 22 hours at 150??The poly dopamine modified aramid pulp fiber was formed by dopamine self-polymerization.The DOPA@PPTA/HNBR master batch was prepared by adding modified aramid pulp to HNBR and mixing with FKM to prepare DOPA@PPTA/HNBR/FKM.The elemental and group changes of aramid pulp were characterized by FTIR,XPS and XRD.And the microstructure of fibers observed by SEM.The results showed that the aramid pulp was successfully modified by dopamine,the roughness of the pulp and the types of active functional groups increased,and the bonding degree between the pulp and the matrix was good.The addition of modified aramid pulp increased the vulcanization rate,shortened the vulcanization time and greatly increased the elongation at break.The elongation at break increases from 352%to 687.4%and the compression set increases from 11.72%to 9.86%when the filling content is 1 phr.