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Study of High-Efficient Supported Catalysts for Synthesizing Poly-(Propylene-carbonate) and Their Founctional Applications

Author: HouQiaoLi
Tutor: LiuBaiPing；XuJianBo
School: East China University of Science and Technology
Course: Chemical Engineering
Keywords: Propylene carbonate Rare earth ternary catalyst H -modified silica-supported A phase transfer agent Porous membrane
CLC: TQ314
Type: Master's thesis
Year: 2012
Downloads: 13
Quote: 0
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Abstract

Carbon dioxide is a major factor in causing the greenhouse effect, has a very important significance fixed so comprehensive utilization of resources from carbon or carbon dioxide from the environmental point of view. Poly (propylene carbonate) copolymerized with ethylene oxide generated by CO2, the higher the utilization of CO2, and the aliphatic polycarbonate having a certain degree of biological degradation resistance and mechanical properties, will be very broad application prospects. Now, however, the catalytic efficiency is not high, the reaction polymerization for a long time, and higher production costs of the product makes the CO2 with ethylene oxide copolymer polycarbonate industrialized production slowed. By using silica gel and modified silica gel as a carrier load ternary catalyst of rare earth (i.e., trichloroacetic acid, yttrium, diethyl zinc and glycerol) research, under the premise that the selectivity of the catalyst does not decrease, increase the activity of the copolymerization reaction of carbon dioxide with the PO and reduce the cost of industrial production, the industrial production in order to accelerate the process. Ternary Rare Earth catalysts supported on silica gel system and H-modified silica gel supported catalysts preparation method to find the carrier with the best ratio of the catalyst, in order to get the best load programs to improve CO2 with propylene oxide polymerization reactivity; then analyze the material properties of the resultant polymer product. Results Showing: modification amount Q2 when the H-modified silica supported the catalyst system the best performance, the polymerization activity was increased by more than 100% in a 1L Polyreactor. The resulting product structure analysis showed that the catalyst load of the structure of the polymer product, such as the basic composition of a carbonate, the carbonate unit content as well as the materials glass transition temperature substantially no change, and is not supported catalyst for comparison, were prepared by the reaction of polymer molecular weight of more than 200,000, a molecular weight distribution significantly narrowed, wherein the the H modified rate Q2 of the silica-supported catalyst obtained polymer GPC curve of the bimodal trend. After repeated purification process, the resulting polymer can effectively improve the thermal properties of the material, that is effective to remove some impurities in the product of the thermal stability of the polymer has an important role. In addition, the article also investigated Z and supported rare earth ternary catalytic system add Z to the reaction performance of the rare earth ternary catalytic system, the polymerization product of the resultant material performance analysis. The polymer structure analysis showed that: add Z to the structure of the polymer, such as the basic composition of a carbonate, the carbonate unit content as well as the materials glass transition temperature substantially no change in the rare earth ternary catalyst: The results show that: the rare earth ternary catalyst Add Z1 can significantly improve the catalyst activity, in a 1L polymerizer polymerization activity can be increased by 44%, and a molecular weight increase up to 20 million or more, and the molecular weight distribution becomes narrower more obvious. Add Z4 is not conducive to the activity increased, the molecular weight decreased more significantly. Z1 catalytic activity when added to the H-modified silica-supported rare earth ternary catalyst system has improved significantly, the amount of silicone added to 5g 1L polymerizer polymerization activity is relatively pure rare earth ternary catalyst system activity increased by 144%; and polymerization consisting essentially of the structure of the matter, such as carbonate, the carbonate unit content as well as the materials glass transition temperature, substantially no influence. The paper also prepared for the first time a polycarbonate porous film, the film-forming method is very simple, the effects of the film-forming conditions. Aliphatic polycarbonate non-toxic, non-polluting, non-flammable, biodegradable plastic.

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