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摘要: 為拓寬材料的阻尼溫域,增大聚氨酯應用范圍,基于聚氨酯的結構可設計性,引入含有甲苯-2,4-二異氰酸酯(TDI)和聚乙二醇單甲醚(MPEG)的預聚體制備帶長支鏈的聚氨酯。長支鏈一端固定一端活動的特點賦予其特有的運動與松弛。甲苯-2,4-二異氰酸酯的存在不僅延長了支鏈長度,增大了支鏈與分子間的纏結程度,還使支鏈含有強極性的吸電子的異氰酸酯基和氨基甲酸酯基,使得支鏈與主鏈間具有較強的氫鍵作用。因此,從氫鍵及微相分離角度來分別探究聚氨酯阻尼的影響因素。結果表明,長支鏈占比增加,儲能模量比值達到268.28,聚氨酯的微相分離程度降低,氫鍵作用增強,在氫鍵作用和微相分離程度降低的雙重作用下聚氨酯的有效阻尼(阻尼因子大于0.3)溫域超過150 ℃(?50~100 ℃),極大改善了聚氨酯彈性體的阻尼性能。此外,加入支鏈后聚氨酯具有一定的自修復性,對延長聚氨酯的使用壽命有較大意義。Abstract: The continuous improvement of people’s living standards and quality puts higher and higher demands on polymer materials, and damping materials such as polyurethane elastomer used for vibration and noise reduction have also received increasing attention. However, the application of polyurethanes is limited to some extent owing to the narrow effective damping temperature range of polyurethane. Therefore, polyurethane containing a branched chain has been prepared from the perspective of its structural designability, in which the prepolymer synthesized by the reaction of polyethylene glycol monomethyl ether (MPEG) with toluene 2,4-diisocyanate (TDI) is performed as a branched chain. Herein, the long branched chain with one end fixed at the end gives its unique movement and relaxation, contributing to the superior damping performance of polyurethane to some extent, and the presence of TDI not only prolongs the length of the branch and increases the entanglement degree between the branches and the molecules but also makes the branches contain a strong polar electron-withdrawing isocyanate group and a urethane group, impacting the branch and the main chain with strong hydrogen bonding effect. Herein, the influencing factors of polyurethane on damping property are explored separately from the perspective of hydrogen bonding and microphase separation. By means of Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), atomic force microscopy (AFM), and broadband dielectric relaxation spectroscopy, the results show that E'30 °C/E'70 °C is able to reach 268.28 with the increased proportion of branches, indicating the dropped degree of microphase separation of polyurethanes. Furthermore, the hydrogen bonding effect is enhanced by characterization with FTIR. The two aforementioned effects make the damping properties of polyurethanes more excellent; the effective damping (tan δ ≥ 0.3) can even exceed 150 °C (?50?100 °C). Simultaneously, the polyurethane has a certain self-healing property after the introduction of branches, which is of great significance to extend the service life of polyurethanes
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Key words:
- damping /
- long branched chain /
- polyurethane /
- self-healing /
- hydrogen bonding /
- microphase separation
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表 1 亞氨基氫鍵化與非氫鍵化分峰數值
Table 1. Peak values of free N-H bond and ordered N-H bond
Wb/% H-bond peak integral Non H-bond
peak integralPeak ratio of H-bond and
non-H-bond33 1.5584 1.7620 0.8844 50 2.4290 2.7284 0.8903 60 3.5887 3.4588 1.0376 表 2 甲苯-2,4-二異氰酸酯型聚氨酯的儲能模量
Table 2. Store modulus of polyurethanes based on TDI
Wb/% E'?30 °C/MPa E'70 °C/MPa E'?30 °C/E'70 °C 0 265.68 3.08 86.26 33 97.77 1.09 89.70 50 52.98 0.55 96.33 60 67.07 0.25 268.28 259luxu-164 -
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