Research On The Synthesis Of Polyurethane Elastomers With Low Modulus And Wide Temoerature Damping Performance

The progress and development of science and technology led to the progress of society,also speed the high-speed,efficient and automated process,consequently of mechanical equipment,vibration&noise issues have become increasingly prominent.Vibration&noise reduces the performance of mechanical equipment,undermines its stability,pollutes the environment and endangers people's physical and mental health.The reduction of vibration&noise is an urgent problem to be solved.Damping technology is the most effective/important method to solve the problem of vibration&noise,and the damping materials is the key of the damping technology.Based on 4,4'-dicyclohexylmethane diisocyanate(HMDI),polyether polyol(PTMG 1000,EP 3600)and triisopropanolamine(TIPA)as the main raw materials,according to damping materials required for low modulus,wide temperature range,high damping,high temperature resistant performance,a series of PUE materials were synthesized by two-step method,which was designed by using the group contribution theory and polymer damping mechanism.The PUE materials were tested by the relevant test equipment and instruments.The effects of types of isocyanate and chain extender types,R and formulation parameters on the properties of PUE matrix were studied.The effects of modification and blending on the PUE matrix also were studied.The following conclusions could be made:1.The damping polyurethane elastomers are synthesized from PTMG 1000,EP 3600,HMDI,TIPA could meet the requirements.2.Compared with performance,the values of the reaction materials and the proportion(-NCO%,R value)of the reaction materials and the performance requirements of the base material for damping were determined.When using raw materials of HMDI,EP 3600,PTMG 1000,TIPA,with the content of NCO was 6.25%,the hard segment content was 15.30%and the R value was 1.20,the hardness of HMDI-type PUE matrix was 41 A,the tensile strength was 4.387 MPa,the elongation at break was 700%,damping temperature of tan8>0.30 was greater than 60?,the initial thermal decomposition temperature was 253?,mechanical retention rate was 68%under 100? hot air aging conditions for 15 d,the proportion can meet the requirement of low modulus,wide temperature range,high damping,high temperature resistant performance.3.After established the basic raw materials and parameters of PUE,it laid a foundation for the IPN modification of PUE,molecular chain of epoxy resin and polyurethane have certain compatibility and epoxy resin was involved with the synthesis of PUE to form a semi-interpenetrating network structure,the segments intersect and tangled to each other,formed the structure of microphase separation.A series of modified HMDI-type PUE were prepared by added epoxy resin with different content.When the content of-NCO was 6.25%,the hard content was 15.30%,the R value was 1.20,the amount of E-51 was 10%,the hardness of PUE was 29 A,the compression permanent deformation was 13%,the tensile strength was 4.997 MPa,the elongation at break was 967.7%,tan ? max was 1.220,Tg was-46?,the damping temperature of tan8>0.30 was greater than 75 ?,the initial thermal decomposition temperature was 283?,increased about 30?,the maximum weight loss rate was 377?,increased about 60?,tensile properties retention rate of 73.83%under thermal aging,increased about 5%.4.Different kinds of fillers were added into the PUE,and a series of PUE/filler composite materials were prepared and studied by related test methods.The results show that three kinds of composite had different degree of hydrogen bonds,the hardness trend change tendency was differ,HGM/PUE and MCC/PUE increased and the AO 80/PUE materials were the opposite with the increase of the addition amount;the tensile strength first increased and then decreased with the increase of the addition amount,the elongation of AO 80/PUE was increased,the HGM/PUE decreased and the MCC/PUE increased first and then decreased with the increase of the addition amount;Micro-phase separation was found,but there were agglomeration phenomenon among HGM/PUE,MCC/PUE and AO 80/PUE,AO 80/PUE was ideal for dispersion.The Tg of AO 80/PUE was moved to high temperature and the damping temperature range were widened,the peak of MCC/PUE damping factor increased to a certain extent and the peak of HGM/PUE damping factor decreased.Temperature resistance and the initial thermal decomposition temperature of the three PUE composites were improved.5.Damping PUE materials basically meet the requirement of low modulus,wide temperature range,high damping,high temperature resistance performance,the damping PUE material with phononic crystal theory provides a good foundation for solving the problem of vibration&noise issue.