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Study On The Interface Matrix Emulsion Polymerization Of Syndiotactic Ultra-high Molecular Weight Polystyrene With Narrow Molecular Weight Distribution

Posted on:2013-03-06Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiFull Text:PDF
GTID:2231330371997474Subject:Applied Chemistry
Abstract/Summary:PDF Full Text Request
In this paper, long chain ethoxylated fatty amines were used as surfactant of styrene emulsion polymerization. Unlike other types of styrene polymerization, Polystyrene (PS) obtained from this polymerization system showed double or trimodal distribution characterized by GPC. Through studying, the low part molecular weight was obtained from BPO/ethoxylated fatty amines initiator system, meanwhile, the lower part was from BPO/Na2S2O4initiator system. The number averaged molecular weight of the high part molecular weight had reached1.25X10, which was in Ultra-high molecular weight polystyrene’s (UHMWPS) range. The UHMWPS was obtained from the ethoxylated fatty amine oxides prepared from BPO’s oxidation.Based on the study, this paper had developed novel reactive surfactants long chain ethoxylated fatty amine oxides (AO) of industrial grade for styrene emulsion polystyrene, without adding any other initiator, chain transfer agent and electrolyte and purification process, and had got UHMWPS with narrow molecular weight distribution and rich syndiotacticity. The main contents are listed as follows:Long chain ethoxylated fatty amine oxides were synthesized from H2O2oxidation reaction with high conversion. The chemical structure and surface properties were tested by API-ES and surface tension-meter. Those amine oxides showed good surfactivity and low CMC concentration.The AO initiator systems were studied systematically. The effects of reaction time, H2O/styrene ratio, amount of amine oxides and corresponding amine addition on the rate of emulsion polymerization, polystyrene’s microstructure, molecular weight and its distribution, glass transition temperature and crystalline properties were investigated. Synthetic UHMWPS was characterized with GC、1H-NMR、13C-NMR, DS、FT-IR.The results showed that the number averaged molecular weights of the obtained UHMWPS increased with monomer conversion, presented certain "living" characteristics. The number averaged molecular weights gave a highest value of2.53X106and molecular weight distributions (MWD) were unimodal throughout the reaction and the minimum MWD was l.10. As polymerization matrix, long chain ethoxylated fatty amine oxides could control polymer’s microstructure. The microstructure confirmed by NMR, DSC and solvent extraction method showed that UHMWPS was rich in syndiotactic structure (rr%>84%) and had wide crystal melting temperature from220oC to290oC.This novel interface matrix polymerization initiator with stable free radicals characteris-tics and emulsifying property could be prepared easily and cheap in price, meanwhile, provide a new method for UHMWPS and rich syndiotactic polystyene’s research.
Keywords/Search Tags:Reactive surfactants, Interface controlled matrix emulsion polymerization, Ultra-high molecular weight polystyrene, Narrow molecular weight distribution, Richsyndiotactic polystyrene
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