| In this paper,we take the damping performance of suspended chain modified polyurethane materials as the starting point,and introduce a suspended chain structure with one end bonded to the main chain structure and the other end free to rotate in the long flexible interlocking chain structure of the original polyurethane system,so as to improve the damping performance of polyurethane materials by using various synergistic compound effects of suspended chains.The effect of different types of suspension chain extenders on the damping performance of polyurethane materials was first investigated.The study showed that the flexible long suspension chain structure with polar groups,monoglyceride stearate(GML),had the best damping performance and the highest tanδpeak compared with other suspension chains.When the dosage is 60%,the system has the lowest degree of micro-phase separation and the best overall damping performance.Based on the difference in the activity of characteristic functional groups,we innovatively synthesized chain extenders with hydroxyl groups at both ends and polar groups in the middle suspension chain with controlled molecular weight by using poly(ethylene glycol)monomethyl ether(MPEG),isophorone diisocyanate(IPDI)and2-amino-1,3-propanediol as raw materials,and characterized their structures by FTIR,~1H-NMR,GPC and other testing methods.The synthesized chain extenders were applied to polyurethane microporous elastomer materials to investigate the effects of molecular weight and amount of suspended chains on the damping properties of the materials.Within a certain range,the higher the molecular weight of the suspension chain,the better the damping performance of the material,and the peak tanδand effective damping temperature range of the material increase.The material performance was best at molecular weight 1000,with 34.0%and 62.3%increase in tanδpeak and effective damping temperature range,respectively,compared with the unmodified sample,and the bubble pore size was more dense and tiny.And as the amount of suspension chain increases,the stronger the hydrogen bonding within the system,the better the damping performance of the material.The effects of suspended chains and dynamic disulfide bonds on the damping properties and self-healing ability of polyurethane elastomers were examined,and both were found to reduce the degree of microphase separation in the material system and increase the tanδpeak and effective damping temperature domain of the material.When the two are combined,the increase in the amount of dynamic disulfide bonds can effectively broaden the effective damping temperature range of the material up to 131.57°C;the self-healing rate of the material is greatly improved up to 95%. |
