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首页> 外文期刊>Journal of Applied Polymer Science >Tailoring new bisphenol a ethoxylated shape memory polyurethanes
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Tailoring new bisphenol a ethoxylated shape memory polyurethanes

机译：剪裁新的双酚A乙氧基化形状记忆聚氨酯

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摘要

Shape memory polyurethanes (SMPUs) have generated great attention because of their unique properties. These properties are result of a particular molecular structure consisting of flexible molecular chains with low glass transition temperatures alternating with hard urethane segments. In this field, bisphenol A (BA) has been used for a long time as chain extender due to the good properties of the obtained SPMU materials. Nevertheless, the high toxicity of this compound has caused a high decrease on its use. For this reason, it has been selected a lower toxicity compound, bisphenol A ethoxylate (BAE). In this work, it is described a new SMPUs based on BAE and the influence of the hard segment on the thermo-mechanical properties and shape memory capacity. For that, both the proportion of the components and the diisocyanate employed (2,4-toluene diisocyanate (TDI), 4,4 '-methylene bis(phenylisocyanate) (MDI) or a TDI/MDI mixture) have been modified. Then, depending on the molecular architecture achieved, the polyurethanes present different properties, which were studied by different techniques, such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic-mechanical thermal analysis (DMTA). It has been observed that glass transition temperature (T-g) increases as the hard phase content in the PU samples increases. In addition,T-g-MDI > T-g-MDI-TDI > T-g-TDI, so it is possible to control theT(g)of the material, that is, shape memory transition temperature varying the diisocyanate. Finally, the shape memory capacity of the PUs was evaluated by thermo-mechanical analysis (TMA). All the synthesized PUs have shown good shape memory effect with fixation ratios up to 80% and recovery ratios close to 100%.
机译：形状记忆聚氨酯（SMPU）因其独特的性能而受到广泛关注。这些特性是由具有低玻璃化转变温度的柔性分子链与硬质聚氨酯段交替组成的特定分子结构的结果。在该领域，双酚A（BA）由于所获得的SPMU材料具有良好的性能，长期以来一直被用作扩链剂。然而，这种化合物的高毒性导致其使用量大幅下降。因此，选择了一种毒性较低的化合物，双酚a乙氧基化物（BAE）。本文描述了一种基于BAE的新型SMPU，以及硬段对其热机械性能和形状记忆能力的影响。为此，对所用组分的比例和二异氰酸酯（2,4-甲苯二异氰酸酯（TDI）、4,4'-亚甲基双（苯异氰酸酯）（MDI）或TDI/MDI混合物）进行了改性。然后，根据所获得的分子结构，聚氨酯呈现出不同的性能，这些性能通过不同的技术进行了研究，例如热重分析（TGA）、差示扫描量热分析（DSC）和动态机械热分析（DMTA）。已经观察到，玻璃化转变温度（T-g）随着PU样品中硬相含量的增加而增加。此外，T-g-MDI>T-g-MDI-TDI>T-g-TDI，因此可以控制材料的温度（g），即改变二异氰酸酯的形状记忆转变温度。最后，通过热机械分析（TMA）评估PUs的形状记忆能力。所有合成的PUs均表现出良好的形状记忆效果，固定率高达80%，回收率接近100%。

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