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Application Of Chlorided Derivationes Of Fullerenes In Synthesis C60 Bonded Star-shaped Polymer

Posted on:2004-01-21Degree:DoctorType:Dissertation
Country:ChinaCandidate:J HuaFull Text:PDF
GTID:1101360092981174Subject:Polymer Chemistry and Physics
Abstract/Summary:PDF Full Text Request
Spherical PE and PE/PP in-reactor alloy granules of high porosity were synthesized by two-stage sequential polymerization of ethylene and propylene using a spherical high yield TiCl4/MgCl2 based supported catalyst. The prepolymerization technique was systematically studied by various methods. And it was found that prepolymerization of propylene by slurry at about 0.1 MPa and 40 C, and the prepolymerization time is no more than 5 minutes are necessary to get excellent morphology and high yield PE and PE/PP granules. The second stage is ethylene polymerization at higher pressure and higher temperature by slurry in 1L autoclave and the product is PE granules. As for PE/PP granules, replace ethylene in the autoclave with propylene after ethylene polymerization for a period of time, the final product is PE/PP alloy. The content of C2 and C3 in the PE/PP alloy can be adjusted according to the polymerization time of ethylene and propylene at the second stage.The morphology, particle size distribution, porosity and composition of the alloy granules were studied by optical microscope, scanning electron microscope (SEM), infrared (FTIR), polarized microscope (PLM), transmission electron microscope (TEM) and other means. The granules showed excellent spherical morphology, high porosity and narrow size distribution. Much of the tiny cavities present in the PE granules were filled up by PP in the alloy, resulting in lower porosity of the alloy than the PE granules. As disclosed by the DSC thermal behavior and revealed by PLM and TEM crystalline morphology of the alloy, the PE and PP phases are partially compatible with each other. The PE/PP alloy showed excellent impact strength and flexural modulus. A sample containing 64% PP showed a Notched Charpy impact strength of 56.5 kJ/m2 and a flexural modulus of 2450 MPa. The morphology of the impact fracture surface is characteristic of ductile materials, also implying the presence of strong interaction between the PE and PP components.The PE/PP alloy was fractionated into five fractions (20 C, 100 C, 113 C, 120 C and >120 C) through temperature-gradient extraction fractionation, and the fractionations were analyzed through infrared (RTIR), 13C-NMR and other means. The PE/PP alloy was found to contain mainly four portions: PP, PE, a series of segmented copolymer with PE and PP segment of different length, and an ethylene-propylene random copolymer. As disclosed by the RTIR, 13C-NMR and DSC, the insoluble fraction (>120 C) is mainly PP (about 80%) and small amount of PE (about 20%), the 120 C fraction is completely PE (more than 99%), the 100 C and 113 C fractions are segmented copolymer with PE and PP segment of different length, and the 20 C fraction is ethylene-propylene random copolymer. The total amount of insoluble fraction and 120 C fraction is more than 90%, and the weight percentage of the other three fractionations is no more than 10%.Spherical PP and PE/PP of high porosity graft polymerization of styrene in solid phase after styrene (St)/benzoyl peroxide (BPQ) mixture adsorbed into the granules under different conditions. Effects of various reaction parameters, such as St/PP weight ratio, BPO/St weight ratio, reaction temperature, reaction time on the amount of the grafted PS in the PP, graft efficiency, and themolecular weight of the product were investigated. The structure and phase morphology of the produced PP/PP-g-PS alloy were characterized by infrared (FTIR), different scanning calorimetry (DSC), GPC, viscometry and polarized microscope (PLM). The results showed that solid phase graft polymerization of St in PP granule produced PP/PP-g-PS alloy with high amount of grafted PS (maximum 24.3 wt% of PS based on PP/PP-g-PS) and high graft efficiency (maximum 56.7%). The size of PP crystals was greatly reduced after grafting PS on PP. The final product is still in the form of regular spherical granules, which is beneficial to the industrial process. Under the studied conditions, there was slight degradation of the PP chains in the graft reaction.The gr...
Keywords/Search Tags:Polymerization, Spherical Polyethylene, Spherical Polyethylene/Polypropylene alloy, Styrene, Maleic anhydride, Graft polymerization
PDF Full Text Request
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