Study On Synthesis And Temperature Resistance Of Polyurethane Elastomer

Polyurethane elastomer(PUE)is a polymer material containing a large number of carbamate groups.It has a very wide range of applications in mining,construction,medical materials,clothing,mechanical parts,automotive parts and other fields.Compared with other materials,it has good mechanical properties,wear resistance,oil resistance,chemical resistance,and various processing methods.However,its longterm use temperature cannot exceed 80 °C,and its short-term use temperature cannot exceed 120 °C.It is easy to soften and deform above 100 °C,which limits its application to a certain extent.Therefore,it is imperative to explore the factors affecting the temperature resistance of polyurethane elastomers,which is of great significance to the improvement and development of PUE performance.The properties of polyurethane elastomers are closely related to the factors such as soft segment,hard segment and synthesis process.Therefore,polyurethane elastomers were prepared by prepolymer method and one-step method in this experiment.The factors such as f value,sample preparation method,plasticizer,polyol type,polyol molecular weight,polyol combination,isocyanate type,hard segment content,isocyanate combination and chain extender type were studied.The mechanical properties test,infrared,thermal analysis,thermal weight loss,dynamic mechanical properties test and low temperature brittle fracture test at room temperature and high temperature were carried out.The influence of various factors on the properties of materials was explored.The study found :Many aspects of the synthesis process are affecting the performance of the material.As the f value gradually increases from 0.95 to 1.07,the material has the best performance when the f value is 0.98,and the material performance when the f value is1.07 is significantly lower than other groups of samples.Different synthesis methods were selected.The material prepared by prepolymer method had the best comprehensive performance,and the material prepared by one-step method had the worst performance.Changing the amount of plasticizer 809,the material with 5 %plasticizer has the best comprehensive performance.With the addition of polar plasticizer,it not only reduces the viscosity of the material,but also promotes the microphase separation of the material.Therefore,if you need to reduce the viscosity of the material,you can add an appropriate amount of polar plasticizer.The soft segment occupies a large proportion in the material and has a great influence on the material properties.By changing the type of polyols,PCL polyurethane elastomer has the best comprehensive performance,PCDL elastomer material has the best mechanical properties,PTMG elastomer has the worst performance,and PCL polyurethane elastomer has the best high and low temperature resistance.Using polyols with different molecular weights,PCDL2000 polyurethane elastomer has the best comprehensive performance.The mechanical properties and temperature resistance of2000 molecular weight are obviously better than those of 1000 molecular weight,and the temperature resistance of polyester type is better than that of polyether type.PCL2000 and PCDL2000 were used and the ratio was changed.When the ratio of PCL2000 / PCDL2000 was 30 / 70,the comprehensive performance of the material was the best.With the increase of the proportion of PCL,the glass transition temperature and brittleness temperature of the material decrease.As the main component of polyurethane materials,hard segment plays an important role in improving the strength and high temperature resistance of materials.Using different kinds of isocyanates,PPDI polyurethane elastomer has the best comprehensive performance,MDI-50 has the worst comprehensive performance,MDI elastomer has the best mechanical properties,and PPDI elastomer has the best high and low temperature resistance.With the increase of hard segment content from 28 % to38 %,the hardness and strength of the material increased,the elongation at break decreased,and the glass transition temperature increased gradually.Two kinds of isocyanates NDI and MDI were used and the ratio was changed.When the ratio of NDI/ MDI was 50 / 50,the comprehensive performance of the material was the best,and the comprehensive performance was the worst when the ratio was 90 / 10.With the increase of the ratio,the tensile tear high temperature tensile strength and hardness of the material increased first and then decreased,and the glass transition temperature gradually decreased.Changing the type of chain extender,the sample with chain extender MCDEA / 6200 = 80 / 20 has the best comprehensive performance,and the sample with BDO as chain extender has the worst performance.The temperature resistance of MCDEA and 6200 is also the best.