Study On Modification Of Nylon By Core-shell Structure Modifier

In this thesis,acrylonitrile-butadiene-bstyrene(ABS)core-shell structure modifier was synthesized by seeds emulsion polymerization,the core-shell ratio was 60/40.During graft polymerization,glycidyl methacrylate(GMA)was copolymerized onto polybutadiene to prepare fuctionalized modifiers.Free SAN chains were separated from the different modifiers by ultra-centrifugation.The modifiers were melt blended with polyamide 6(PA6).The influence of modifiers content and the free SAN chains on the rheological properties,mechanical properties,dynamic mechanical properties and morphology of PA6/ABS blends were investigated.The results showed that:The balanced torque of PA6/ABS blends increased with increment of modifier content.And the existence of free SAN chains had little effect on the torque of PA6/ABS blends.At the same conditions,the introduction of GMA resulted in higher balanced torque.To a certain extent,the presence of free SAN chains in the ABS-co-GMA modifier shorten the time of the melting equilibrium for the blends to melt,and reduced the processing viscosity of the blends.The Izod impact strength of PA6/ABS blends increased with the modifier content.And at the same rubber content,the separation of free SAN chains induced rapidly higher impact strength of blends.The break behavior of samples showed typical brittle behavior.With the introduction of GMA,brittle-ductile transition was observed,the impact strength of the blends increased with the increment of modifier content.And the separation of free SAN chains induced lower impact strength of blends at the same rubber content.The yielding strength and elastic modulus of PA6/ABS blends decreased with the increment of modifier content.The separation of free SAN chains had little effect on the yielding strength and elastic modulus of PA6/ABS blends.The elongation at break of blends decreased slightly with the increment of modifier content.And the separation of free SAN chains induced higher elongation at break of blends at the different rubber content.After introducing the epoxidized monomer GMA,the SAN free chains in the ABS-co-GMA modifier did not change the elastic modulus and the yielding strength of the blend at the same rubber content.The presence of free SAN chains induced significantly increasement of the elongation at break for the blends.For the PA6/ABS blends,removing the free SAN chains in the ABS modifier,the glass transition temperature of the PA6 and the SAN phase of the modifier were shifted to the high temperature and the low temperature respectively.The dispersion was changed better,and the compatibility between the two phases was improved.The performance of the blends was improved.For the PA6/ABS-co-GMA blends,free SAN chains play a certain role,the glass transition temperature of the PA6 and the SAN phase of the ABS-co-GMA modifier were closed relatively,the compatibility is improved,and the performance of the blends was changed better.