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PEG(聚乙二醇)基热塑性形状记忆聚氨酯先由本体聚合法合成,而后经熔纺制得温度调节纤维。纤维线密度为100dtex,强度为0.7cN/dtex,断裂伸长率为488%。分别用偏光显微镜、差氏扫描量热法、动态机械分析、热重分析研究了纤维的相变行为、结晶形态、动态力学性能和耐热性能。纤维中PEG软段在晶态和无定形之间的相转变过程中,伴随有热量的储存和释放;而起物理交联作用的氢键硬段,限制了软段的自由运动,所以在PEG相转变温度以上,纤维仍然具有一定的机械强力。差示扫描量热法测定该聚合物熔点和结晶温度分别为44.7℃和20.9℃,并且纤维具有大约100J/g的大潜伏热储存能力。动态力学性能分析表明,在PEG相转变温度以上、160℃以下,纤维有稳定的弹性模量。热重分析表明,与纯PEG相比,纤维的温度应用范围更宽。热机械循环拉伸测试结果证实纤维有很好的形状记忆功能,形状固定率超过85.8%,回复率大于95.4%。
Poly (ethylene glycol) -based thermoplastic shape memory polyurethane is first synthesized by bulk polymerization and then melt-spun to produce temperature-regulated fibers. The fiber linear density was 100 dtex, the strength was 0.7 cN / dtex and the elongation at break was 488%. The phase transition behavior, crystal morphology, dynamic mechanical properties and heat resistance of the fibers were investigated by polarized light microscopy, differential scanning calorimetry, dynamic mechanical analysis and thermal gravimetric analysis. During the phase transition between crystalline phase and amorphous phase, the PEG soft segment in fiber is accompanied by the storage and release of heat, while the hydrogen-bonded hard segment, which plays the role of physical crosslinking, limits the free movement of the soft segment. Therefore, Phase transition temperature above, the fiber still has some mechanical strength. The melting point and crystallization temperature of this polymer were measured by differential scanning calorimetry at 44.7 ° C and 20.9 ° C, respectively, and the fiber had a large latent heat storage ability of about 100 J / g. Dynamic mechanical properties analysis showed that above the PEG phase transition temperature, below 160 ℃, the fiber has a stable elastic modulus. Thermogravimetric analysis shows that the temperature of the fiber is wider than pure PEG. Thermomechanical cyclic tensile test results confirmed that the fiber has a good shape memory function, the shape of the fixed rate of more than 85.8%, the recovery rate is greater than 95.4%.