Preparation Of Polymer Particles Based On C₈/C₉ And Maleic Anhydride Via Self-Stablized Precipitation Polymerization

C8/C9 mixture is a by-product produced during the production of ethylene in chemical industry, and its output capacity is very considerable. In the present work, we dierectly synthesize copolymer particles based on the C8/C9 mixture and MAH via self-stablized precipitation polymerization.Xylene was selected as the reaction medium for the polymerization system. We have researched the influences of monomer feed ratio, monomer concentration, initiator concentration, polymerization temperature and reaction time on the morphology, size and size distribution of the as-prepared polymer particles. The main works are as follows:1. C8/C9-MAH copolymer particles were prepared via self-stable precipitation polymerization. The influences of reaction medium, initiator concentration, polymerization temperature on the morphology and size of the as-prepared polymer particles were investigated in detail. Based on the experimental results, xylene was used as the solvent and selected the proper reaction temperature and initiator concentration2. We have observed the size and morphology of the polymer particles by SEM. The experimental results indicated that the diameter of the copolymer particles increased with increasing initiator and monomer concentration, and the diameter range of C8-MAH and C9-MAH particles were 1100-3200nm and 2200-2800nm, respectively. Morover, the surface of C8-MAH particles was smoother and the size distribution was much narrower. Furthermore, with increasing ratio of MAH in the monomer feed, the diameter of the copolymer particles first increased and decreased in the end, and there were some secondary particles form in the reaction system when with high MAH concentration.3. The chemical structure of the C8/C9-MAH copolymer particles were studied by IR and NMR, and the content of anhydride groups was determined by elemental analysis and titration. The results showed that there were 45.97% anhydride groups in the Cg-MAH copolymer particles, and 30% of the C8 mixture can copolymerize with maleic anhydride via self-stablized precipitation polymerization. The reactive composition of C8 mixture includes styrene, allyl benzene, vinyltoluene, indene and methylindene. For C9-MAH copolymer particles, the content of anhydride groups was 45.52%, and 37% of the C9 mixture can copolymerize with maleic anhydride via self-stablized precipitation polymerization. The reactive composition of C9 mixture includes styrene, allyl benzene, vinyholuene, indene, cyclopentadiene and dicyclopentadiene.4. The molecular weight and polydispersity index (PDI) of the obtained copolymer were characterized using GPC. The GPC results indicated that the molecular weight of the obtained C8/C9-MAH copolymers decreased gradually with polymerization time prolonging. The molecular weigh decreased from 16000 to 8000 for Cs-MAH, while the molecular weight of C9-MAH decreased from 8000 to 6000.