With Fine Rigid Toughening Pa66

Poly(hexamethylene adipamide)(polyamide 66,PA66) exhibits excellent properties, such as high rigidity(tensile yield stress,flexural modulus),abrasion resistance,heat resistance,excellent chemical resistance etc.It has been widely used in machinery,electronic equipment,automobiles,and other fields.In order to enlarge the using ranges and satisfy the more requirements for performance,it is necessary to improve the toughness and rigidity of PA66 at the same time,a large number of fruitful researches have focused on the popular topics.Based on the analysis of mechanism of high toughness and rigidity,the works introduce the designing idea to improve toughness and rigidity of PA66 at the same time.The modified PA66 should be prepared through blending the pure PA66 with filler and multi-functional components.The filler can improve the rigidity of PA66.Multi-functional components not only react with PA66 and rigid filler surface,but also improve the toughness and maintained the rigidity simultaneously.Multi-functional components dispersing in PA66 improve the toughness of the matrix PA66,and concentrate in the interlayer between PA66 and rigid filler and form the moderate flexible interlayer with high interfacial adhesion by the effects of energy and entropy.The emergence of such structure can avoid that rigid interface induce the formation of micro-cracks of resin matrix in the interface area,transfer stress between the matrix resin and rigid filler,play completely the role of the rigid filler to enhance rigidity and strength.The resin matrix mainly exhibits shear yield deformation under the external forces,the good interface adhesion can effectively terminate shear deformation,crazing and absorb impact energy.Based on the above designs,the reactive toughening master batch(RTMB) was synthesized through the technique "grafting copolymerization,reactive blending" using PP, ethylene-propylene elastomer,styrene-butadiene rubber,containing epoxy functional groups of bridge agents(G) and auxiliary bridge agents(S).The PA66/RTMB/GF composites were prepared by thermal mechanical reactive blending.The structure and properties of RTMB, PA66/RTMB,PA66/RTMB/GF composites were investigated by means of fraction extraction, IR,SEM,PLM,DTA and mechanical properties measuring.The main results and conclusions are as follows:(1) The compositions of RTMB are composed of unreacted PP and elastomers,graft polymers of PP and elastomers with bridge agents,crosslinked copolymer of PP and elastomers,elastomers and elastomers by polymer bridge conjuction using bridge agents, homopolymer and copolymers of bridge agents.(2) The contents of RTMB have effect on the mechanical properties of PA66/RTMB.As the PA66/RTMB composition is 84/16,PA66/RTMB composite shows the excellent mechanical properties.The tensile yield stress(TYS),flexural modulus(FM) and notchod Izod impact strength(NIIS) of the PA66/RTMB composite are increased to 0.90time, 0.84times and 3.08 times as high as those of the pure PA66 respectively.(3) RTMB,GF and PA66 have chemical bonds through the chemical reaction between the epoxy functional group in RTMB,the bottom amide groups and carboxyl groups of PA66 chains and the amide groups in the GF surface.The moderate flexible interplay with high interfacial adhesion has been formed between the PA66 and GF.(4) The crystallization beginning and peak temperature of PA66 in PA66/RTMB/GF composite was increased 1.1℃and 1.1～5.5℃than those of pure PA66.With the content of RTMB increasing,PA66 nucleation and crystallization rate first increased and then decreased.GF can induce PA66 matrix to generate transcrystallization along the surface of GF.(5) The mechanical properties of PA66/RTMB/EPDM/GF composite are associated intimately with processing technology.Comparing with two-step methods of first blending GF and PA66 then RTMB and EPDM or first blending PA66,RTMB and EPDM then GF, the comprehensive mechanical properties of PA66/RTMB/EPDM/GF composite are best through one-step method;Comparing with screw speed of 40r/min,120r/min,the comprehensive mechanical properties of PA66/RTMB/EPDM/GF composite are best using screw speed of 90r/min.(6) As the GF content is 20%,with the content of RTMB increasing,the TYS,FM and NIIS of PA66/RTMB/GF composite were first increased and then decreased;As the RTMB content is 10%,with the content of GF increasing,the comprehensive mechanical properties of PA66/RTMB/GF composites increased gradually;As the PA66/RTMB/GF composition is 60/10/30,the TYS,FM and NIIS of the PA66/RTMB/GF composite are increased to 1.73 times,2.72 times and 3.86 times as high as those of the pure PA66 respectively.(7)As the PA66/RTMB/GF composition is 60/20/20,thermal deformation temperature of PA66/RTMB/GF composition is 201℃,which is obvious higher than that of the pure PA66(69.8℃).