In the present study, polyurethane (PU) was prepared using a pre-polymer (two-shot) process with a novel phloroglucinol chain extender. PU nanocomposite was prepared by incorporating acid-FMWCNTs in pristine-PU. Polystyrene (PS) was functionalized with the nitro group through our previously reported method. The ternary blend composites (PU/PS-NO₂/FMWNTs) were prepared using acid functionalized multiwall carbon nanotubes (FMWCNTs) for enhanced properties and selectivity. Nitro-functionalized-PS/PU composite properties were compared with pristine-PU and its blend composite. The structure of the pre-designed PU polymer and its composites were confirmed by the FTIR and the degree of crystallinity and amorphous state was determined with XRD analysis. Excellent thermal stabilities were confirmed through a TGA thermogram with an increase in the loading amount of FMWCNTs. Excellent tensile strength 59.2 ± 2.6 MPa with 0.1 g loading amount of FMWCNTs with enhanced flexibilities was achieved. The significant change in surface morphologies and porosity suggested enhanced interaction (physical and chain entanglement) of FMWCNTs and nitrated-PS with PU chain as the loading amount of filler increased. The resulted porous spongy cluster (as seen in SEM images) provides efficient shape recovery strain with excellent flexibility to the composite material without compromising repeatability. Almost 100% shape recovery was observed for all samples with repeated recoveries. The recovery time of PU nanocomposite observed is shorter than neat polyurethane and PU/PS-NO₂ blends because of their better conductive nature but causes brittleness, which can easily initiate a crack in the sample compared to a blended sample.

中文翻译：

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用于智能和可持续机器人应用的机械坚固且高弹性热诱导形状记忆聚氨酯基复合材料

在本研究中，使用预聚物（二次）工艺和新型间苯三酚扩链剂制备聚氨酯 (PU)。PU 纳米复合材料是通过将酸-FMWCNT 掺入原始-PU 中制备的。通过我们之前报道的方法，聚苯乙烯 (PS) 被硝基功能化。三元共混复合材料（PU/PS-NO ₂/FMWNTs) 是使用酸功能化的多壁碳纳米管 (FMWCNTs) 制备的，以提高性能和选择性。将硝基功能化 PS/PU 复合材料的性能与原始 PU 及其混合复合材料进行了比较。预先设计的 PU 聚合物及其复合材料的结构通过 FTIR 确定，结晶度和无定形状态通过 XRD 分析确定。随着 FMWCNT 负载量的增加，通过 TGA 热分析图证实了优异的热稳定性。实现了 59.2 ± 2.6 MPa 的优异拉伸强度，0.1 g 的 FMWCNT 加载量具有增强的柔韧性。表面形貌和孔隙率的显着变化表明，随着填料负载量的增加，FMWCNT 和硝化 PS 与 PU 链的相互作用（物理和链缠结）增强。由此产生的多孔海绵簇（如 SEM 图像所示）为复合材料提供了高效的形状恢复应变和出色的柔韧性，同时不会影响可重复性。对于具有重复恢复的所有样品，观察到几乎 100% 的形状恢复。观察到的 PU 纳米复合材料的恢复时间比纯聚氨酯和 PU/PS-NO 短₂混合，因为它们具有更好的导电性，但会导致脆性，与混合样品相比，这很容易在样品中引发裂纹。