Preparation Of Polyurethane From Polyester Polyol Glutarate And Its Properties

Polyurethane is a kind of polymer with repeated carbamate groups in the molecular chain.Because of its high strength,good elasticity and easy forming,it is widely used in various fields.At present,most of the dicarboxylic acids used in the preparation of polyester polyurethane are adipic acid,but glutaric with similar structure to adipic acid is an odd dibasic acid,while polyester polyurethane prepared by using it as an acid source should has a lot of unique advantages.Therefore,in this paper,polyester polyols were synthesized by glutaric acid in different processes,and then polyurethane elastomer and waterborne polyurethane ware prepared by means of them,espectively,at the same time that their properties were studied.The main research contents are as follows:When glutaric acid reacts with propylene glycol,by changing the experimental conditions such as the ratio of alcohol to acid,polycondensation temperature,polycondensation time and the amount of catalyst,the influence of different experimental processes on the color of synthetic polyols was explored,and different molecular weights of polyester polyols of glutaric acid series were synthesized.The ratio of 1,2-propanediol to 1,3-propanediol was changed to prepare polyester polyols with different crystallinity.The results show that the polyester polyols with low color can be prepared under the optimized processing conditions.The minimum color of the polyester polyols with molecular weight 900 is 17,and the minimum color of the polyester polyols with molecular weight 2000 is 41.The polyester polyol of glutaric acid series was prepared in a reactor to study the amplification reaction in the process.Different molecular weight of polyester polyol of glutaric acid series was synthesized by changing polycondensation temperature,polycondensation time and catalyst dosage.The results show that compared with the small-scale test,the amount of raw material and the reaction time need to be increased for the preparation of polyester polyols with the same molecular weight.The reaction of polyester polyol of glutaric acid series with MDI was studied.A series of polyurethane elastomers were prepared by changing the experimentalparameters such as isocyanate content,chain extension coefficient and molecular weight of polyols.Fourier infrared spectroscopy,DSC,TG,universal tensile machine and other technical means were used to characterize its microstructure and main properties,while low temperature chamber was used to measure its various properties in low temperature environment.The results show that the polyurethane elastomers of glutaric acid series has the glass transition temperature of less than-40 ℃,the decomposition temperature of more than 300℃,excellent high temperature resistance,and good low temperature resistance under the condition of test temperature lower than-40 ℃.The hardness and tensile strength of the elastomers increase with the decrease of temperature,and their elongation at break decreases with the decrease of temperature.A series of transparent waterborne polyurethane emulsions were prepared by reaction of self-made polyester polyol of glutaric acid series and IPDI.The optimum technological conditions for synthesizing these polyurethane emulsions were explored by changing the R value,polyol type,DMPA content and three ethylamine content,while thair microstructure and stability were investigated by Fourier transform infrared spectroscopy,TG and rotational viscometer.The results show that the transparent polyurethane emulsions with good stability can be synthesized by using polyester polyol of glutaric acid series.