Research Preparation On Monomer Casting Polyamide6Copolymer Alloy Modified By Reactive Polymer

In this thesis, acrylonitrile-butadiene-styrene(ABS) and nanometer nitrile rubber(nano-NBR) which both have butadiene soft segment and acrylonitrile group were used for the preparation of MCPA6alloys by in situ polymerization of caprolactam anion. Changes of the polymer alloys in mechanical properties were observed through mechanical property tests, reactions between chemical groups were studied by fourier transform infrared spectroscopy(FTIR); scanning electron microscope(SEM)、differential scanning calorimeter(DSC) and thermo gravimetric analysis(TGA) were used to investigate the microscopic structure、crystallization and thermal performances thoroughly, performance improvements of MCPA6polymer alloys caused by the addition of different polymer were discessed, including modification principle.The analysis of FTIR showed that nitrile groups in nano-NBR participated in in-situ polymerization of caprolactam anion through copolymerization, occured alkaline hydrolysis reaction and formed nano-NBR/MCPA6polymer alloy, achieved in modifying MCPA6by nano-scale polymer, at first the spectra of polymer alloys decreased then they increased and reached the lowest point at2%content; the nitrile groups in ABS also participated in copolymerization, the characteristic absorption peaks in polymer alloys were significantly enhanced and spectra decreased with the increase of butadiene content.The SEM images showed that nano-NBR had much influence on the microstructure of MCPA6, the phase interface within copolymer alloy combined the best at2%content; the reactive nitrile groups in ABS generated ABS—co—MCPA6copolymer, which improved the compatibility of the copolymer, and the compatibility was enhanced with the decrease of butadiene, when the content of butadiene is around0.9%, it achieved the best at5%ABS749S,7.5%ABS750and10%ABS757.The analysis of DSC indicated that the addition of nano-NBR would not effect the original crystal form of MCPA6, meanwhile the content of stable a crystal form was increased, first it raised with the addition of nano-NBR, then it decreased and achieved the best stabilization at2%content; all three different types of ABS did not change the original crystal behavior of MCPA6either, but they inhibited the crystallization ability of MCPA6, reduced the degree of crystallinity and decreased with increasing butadiene soft segment.The study of TGA showed that at first the initial degradation temperature、the fastest degradation temperature and residual mass ratio at500℃all raised with the addition of nano-NBR, then they all decreased, and the copolymer achieved the best thermal stability at2%content; the thermal stabilities of MCPA6/ABS copolymer alloys were slighty reduced caused by the relatively easy decomposition soft part of butadiene, and they all kept reducing with the addition of ABS.The analysis of mechanical properties learned that the addition of a small amount of nano-NBR would enhance the toughness of the copolymer alloy tremendously, the notched impact strength was increased by57.5%compared to MCPA6at2%content, meanwhile the tensile strength was lowered by5.8%compared to MCPA6; the toughness of the copolymer alloys was also enhanced with the addition of all three types of ABS, when the content of butadiene is around0.9%, it achieved the best at5%ABS749S,7.5%ABS750and10%ABS757, the toughness was increased by57.5%、56.2%and17.8compared to MCPA6.By the alkaline hydrolysis reaction of nitrile groups, nano-NBR and three types of ABS all participated in in-situ polymerization of caprolactam anion through copolymerization and formed MCPA6copolymer alloys. With both reactive and nano-scal features of nano-NBR, we focused on learning the advantages of reactive polymer with nano-scale in copolymer modifying; with both reactive and flexible chain segments features, we emphasized the study on performance changes of reactive copolymer alloys caused by the addition of flexible chains.