| PEB-g-SAN, synthesized by suspension grafting copolymerization of Styrene and acrylonitrile from Poly(ethene-co-1-butene) (PEB), was blended with styrene-acrylonitrile copolymer (SAN) to prepare a high impact plastic AEBS. AEBS is characterized by excellent weatherability and yellow discoloration resistivity because of no double bond in molecule chain of PEB. AEBS can be used as engineering plastics as a replacer of ABS.The effect of fAN(fAN was equal to AN/St-AN), fPEB(fPEB was equal to PEB/(PEB+St-AN)),content of initiator BPO,content of solvent toluene, main dispersant PVA,assistant dispersant, water/oil ratio, reactive temperature and reactive time on the monomer conversion ratio (CR), average grafting ratio (GR), grafting efficiency (GE) and the notched impact strength of AEBS were investigated systematically. The results showed that when fAN was 35wt%, fPEB was 55wt% and content of BPO was 1wt%, CR, GR and GE were 94.8 %,38.2 % and 49.3 % respectively. Under these conditions, the synthesized PEB-g-SAN had a highest toughening effect on SAN resin and the notched Izod impact strength of AEBS reached 42.8KJ/m2, which was 35 times higher than SAN resin.The components of the grafted copolymer were separated by different solvent and were qualitatively/quantitatively analyzed by using Fourier transform infrared spectroscopy (FTIR).The results showed that St-AN was successfully grafted onto the molecule chain of PEB.The main reaction products were PEB-g-SAN(36.5wt%~49.4wt%), ungrafted PEB(29.2wt%~40.6wt%),SAN by copolymerization and homopolymerization of St and AN(5.4wt%~18.9wt%). Through the study of effects of reaction time on reaction behavior of PEB/St-AN, it was found that the mainly graft reaction which generated graft copolymer was finished before the first 170 minutes of reaction. And then the polymerization was mainly copolymerization and/or homopolymerization.PEB-g-SAN was separated by Acetone, n-Hexane, THF and Cyclohexane and the FAN(content of AN in g-SAN) were determined by quantitative analysis by FTIR. The quantitative relationship between fAN and fAN was set up. It was found that fAN was less than fAN and FAN was increased with the increasing of fAN. The relative molecular mass and molecular mass distribution was determined by GPC analysis.The effect of the polarity of graft chain g-SAN and relative molecular mass of PEB-g-SAN on miscibility between PEB-g-SAN and SAN resin was studied. The reasults showed that when the polarity of graft chain g-SAN had a huge difference with polarity of SAN resin, the relative molecular mass of PEB-g-SAN had a small effect on miscibility between PEB-g-SAN and SAN resin.When the polarity of graft chain g-SAN and SAN resin were close, the relative molecular mass of PEB-g-SAN had significant influence on the miscibility. PEB-g-SAN whose relative molecular mass was higher had batter miscibility with SAN resin.TEM and SEM analysis showed that the phase structure of AEBS was co-continue structure and he toughening machenism was severe shear yielding when AEBS reach its highest notched Izod impact strength. When the PEB content was low, the toughening mechanism of the blends was branch and termination of crack with slight cavitations, then changed into extensive cavitations, and finally changed into severe shear yielding as PEB increasing.DMA analysis showed that the miscibility between PEB-g-SAN and SAN resin was good. TG and DTG analysis showed that thermal stability of SAN resin was improved after being blending with PEB-g-SAN. The effect of fAN,fPEB and content of PEB on the stability of SAN resin was small. The melt flow rate(MFR) of AEBS decreased as PEB increasing. The less PEB content in the blends was, the better rheological and processing properties were.
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