Comparison Between Hydroxyl-terminated Polybutadiene Polyurethane Urea And Two Other Elastic Sealants

Polyurethane has been widely used in modern industry.There are many factors that influence the performance of polyurethane,one of which is chain extender.This paper analyzes and verifies chain extenders affecting HTPB-PUA performance.E-300.P1000 and their mixture were used to cure the HTPB pre-polymer.Mechanical properties were tested in the means of strain-stress,DMA and compression.The results showed that:chain extenders did not influence the Tgl of the Samples.The Sample which used E300 had a better high-temperature platform and a wider usable temperature range.PUA-1's tensile stress and hardness were higher,compression rate was lower.PUA-3 was soft and tensile elongation was higher.On the basis of these studies,I compared the performances of PUA with PS and EP.Properties of them were tested in the means of swelling test,stress-strain and cyclic load and compression test.The results showed that:PUA had the best water resistance,EP's water absorption was remarkable and had a remarkable decrease in mechanical properties after that.In the three samples,PS has the best cold resistance properties and was relatively insensitive to the decrease of temperature,the lowest usable temperature ofthe three was about-20?.PS and PUA had good elastic restoring properties,PS was especially suitable for some occasion requiring high softening and low temperature,EP did not perform well in both cyclic loading and cyclic compression.In all,PUA has good mechanical properties,excellent water resistance and remarkable elastic restoring properties.It is a promising elastic sealant.