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Study of Biodegradable Liquid Crystalline Polyester

Author: LiDongMei
Tutor: ZhengYuBin
School: Dalian University of Technology
Course: Materials Science
Keywords: Liquid crystal Polybutylene succinate Melt polymerization Chain extension reaction Biodegradable
CLC: TQ323.4
Type: Master's thesis
Year: 2005
Downloads: 198
Quote: 4
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Abstract


Due to the increasing deterioration of the environment , the biodegradable material is subjected to more and more attention . This thesis is synthesized by molecular design crystal monomer terephthalic acid (4,4 '- methoxy carbonyl) diphenyl ( POB ) , and as polybutylene succinate ( PBS ) copolymer components of the synthesis of a series of copolyesters containing a liquid crystal component , PBS was modified to improve its mechanical properties and processability performance . The effects of temperature and catalyst synthesis reaction of the liquid crystal monomer . The experimental results show that this reaction is an exothermic reaction , the catalyst is triethylamine great influence on the reaction . Melt transesterification reaction of the liquid crystal monomer and 1,4 - butanediol (BDO) and dimethyl succinate (BDS) copolymerized . Different processes on the molecular weight , and also investigated the impact of various factors on the transesterification reaction . Secondary feeding method can obtain a high molecular weight polymer ; identified by the melt transesterification process conditions : a transesterification temperature of 140 ~ 160 ° C , and raw material molar ratio ( alcohol / ester ) was 2.5:1 , after the experiments show that : The polycondensation stage temperature of 220 ° C ~ 230 ° C . The degree of vacuum in the polycondensation reaction should be as high as possible . Synthesis of terminal hydroxyl polyester with toluene-2 ??,4 - di-iso- cyanate (TDI) and hexamethylene diisocyanate (HDI) chain extender , in order to achieve the purpose of increasing the molecular weight . Isocyanate reaction kinetics of experimental investigation , experiments show that the chain extension reaction is second order reaction . In order to obtain more excellent performance of polyester material , changing the synthesis method. First, the synthesis of the liquid crystal oligomer ( TOBB ) and PBS, and then the chain extension reaction and diisocyanate TDI or HDI . Modified polyester having good mechanical and thermal performance compared to PBS . Improve toughness , elongation at break than the PBS enlarged five times . The decomposition temperature is also increased. Degradation of soil degradation and a variety of buffer solution . The experiments show that : the modified polyester remains biodegradable , degradation rate decreased as the liquid crystal content increases .

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CLC: > Industrial Technology > Chemical Industry > Synthetic resins and plastics industry > Polycondensation resin and plastic > Polyester resins and plastic materials
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