Effect Of Reactive Compatibilization On The Morphology And Physical Properties Of Nylon 6/Acrylonitrile-Butadiene-Styrene Blends

Polymer blends offer an important route to manufacturing new materials with combinations of properties unavailable for a single polymer.In this thesis,the relationships among structure,microdeformation process and mechanical behavior in Nylon 6 and acrylonitrile-butadiene-styrene(ABS)blends were studied.A styrene-maleic anhydride(SMA)copolymer was proposed as a reactive compatibilizer for Nylon 6/ABS blends in a twin screw extruder.This polymer is endowed with miscible with the SAN copolymer matrix of ABS materials,and the anhydride groups react with Nylon 6 at the carbonate linkage to form a SMA-g-Nylon 6 copolymer.The reaction between SMA and Nylon 6 was described and confirmed by Molau test,FTIR analysis and rheological measurement using Hakke rheometer.Transmission electron microscopy(TEM)techniques were used to examine the morphology of this system and correlate the properities of the Nylon 6/ABS/SMA blends with the morphology of the dispersed phase and interfacial adhesion in these blends.Large dispersed phase particles are formed in case no compatibilizers are utilized in the Nylon 6/ABS blends.The SMA-g-Nylon 6 graft copolymer molecules reside at the Nylon 6/ABS interface and provide improved morphological stability by suppressing phase coalescence and decreasing interfacial tension.An addition of a small amount of SMA compatibilizer causes a significant reduction in ABS particle size.A noticeable improvement in particle-matrix interfacial adhesion is also observed.The influence of blend composition and reactive compatibilizer on the crystallinity and melt of Nylon 6 was examined with the use of differential scaning calorimetry(DSC).The ABS particles could act as nucleation agents in Nylon 6 phase,which brought out changes on the crystallization temperature,crystallization extent and crystallization rate.It is founded that the fracture toughness of Nylon 6/ABS blends can be significantly improved by adding SMA.Also,the fracture energies required for both crack initiation and crack propagation of iPP are greatly increased.The fracture of thin(3.2 mm)and thick(6.4 mm)specimens of Nylon 6/ABS/SMA blends was examined by notched Izod impact test.Load-deflection data of single edge notch tensile test also were analyzed as a function of tensile speed.Moreover,the toughness of Nylon 6/ABS/SMA blends were measured over a wide temperature region.Results reveal that the combining effects of particle size and volume fraction of ABS on the toughness of Nylon 6/ABS/SMA blends can be described through plotting brittle-ductile transition of the impact strength versus the interparticle distance(ID)on the assumption that ABS domain relieves the triaxial tension via internal cavitation or interfacial debonding.The toughening mechanisms in blends of Nylon 6/ABS/SMA were studied using scanning electron microscopy.The effect of interfacial adhesion on fracture behavior of Nylon 6/ABS/SMA blends strongly depends upon temperatures were tested.The difference of relation amomg temperature,fracture behavior and interfacial adhesion can be understood in terms of the deformation mechanisms,i.e. in the case of poor interfacial adhesion,the toughness lies on whether debonding existing at the interface relieves triaxial tension or not.It is believed that for good interfacial adhesion,internal cavitation followed by matrix shear yielding is a predominant factor for toughening.Furthermore,the fracture surfaces of these blends were probed to elucidate how interfacial adhesion affects the impact strength of the blends.It was found that increasing temperature and decreasing interparticle distance have equivalent effects on the brittle-tough transition of toughening Nylon 6 with ABS.