The Research Of Damping Performance Of The Modified Polyurethane Elastomers

Usually, the temperature region where Tanδ≥0.3can be regarded as the effective damping region. In order to improve the damping performance of polyurethane elastomers, we can choose a few special structure of diisocyanate, chain extenders and macrodiols to change the macromolecular chain structure of PU. The structure of the chain extender can directly influence the properties of polyurethane elastomer. The effect of hanging chain on the properties of polyurethane is obvious. This thesis wants to synthesize unconventional chain extender with different structure to improve the damping properties of the polyurethane.Two kinds of diols with side chain, Trimethylolpropane-derived diol (TMP-derived diol) and benzyl2,2-bis(methylol)propionate(BHP), were designed and synthesized. These two diols and commercialized GMS were mixed respectively with4,4’-diphenyl ether diamine (ODA) with different molar ratios as chain extenders of novel polyurethane elastomers (PUs). The PUs were characterized by Infrared (FT-IR), thermal analysis (DSC), dynamic mechanical analysis (DMA) and the influences of the diols chain extenders on the microphase separation and damping properties of PUs were analyzed. It was found that a moderate number of16C alkyl chain or a small number of side chain with bulky groups, like benzene ring, can hinder the formation of Hydrogen-Bonds in hard segments, and the greater the volume of the groups on the hanging chain, the stronger the effect on the formation of Hydrogen-Bond. The diols with side chain can compensate for the reduction of Hydrogen-Bonds between N-H and C=O, when the hanging chain can introduce a sufficient number of Hydrogen-Bonds. DSC analyses showed that the Tg of the novel PUs extended by TMP-derived diol is increased, which is believed to reveal the enhanced phase mixing; in contrast, the Tg of the novel PUs extended by GMS and BHP is decreased, which indicates the enhanced phase separation. DMA analyses showed that16C alkyl chain and hindered phenol groups attached on hard segments can improve the Tan δ above Tg in evidence. The temperature range of Tanδ≥0.3of the PU samples extended by GMS and ODA (the molar ratio is4:6) is expanded to61.8℃; as the molar ratio of the hindered phenols attached on hard segment increased(4â†'6), Tan δmax is decreased firstly and then increased. The temperature range of Tanδ≥0.3of the PU samples extended by6molar ratio TMP-derived diol is greater than93℃.