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Synthesis, characterization, crystallinity, mechanical properties, and shape memory behavior of polyurethane/hydroxyapatite nanocomposites
Journal of Intelligent Material Systems and Structures ( IF 2.4 ) Pub Date : 2020-06-17 , DOI: 10.1177/1045389x20932212
Maryam Jalili Marand 1, 2 , Mostafa Rezaei 1, 2 , Amin Babaie 1, 2 , Reza Lotfi 1, 2
Affiliation  

Herein, polycaprolactone diols with diverse molecular weights were synthesized by ring-opening method. Then, polyurethanes were synthesized through two-step pre-polymerization method by polyaddition of hydroxyl and –NCO groups. Afterward, a set of polyurethanes/hydroxyapatite nanocomposites were synthesized through solution casting as well as in situ polycondensation methods. The exact nominal molecular weights of the synthesized polycaprolactones were determined by proton nuclear magnetic resonance (hydrogen-1 nuclear magnetic resonance). Hydrogen bonding index of ester and urethane carbonyl groups (HBI(C = O)) of samples was determined through Fourier-transform infrared spectroscopy. Results showed that the incorporating of the hydroxyapatite nanoparticles has reduced HBI(C = O). X-ray diffraction patterns and differential scanning calorimetry thermographs confirmed the barrierity and nucleation performance of hydroxyapatite nanoparticles, and the variation of phase mixing degree of polyurethane’s hard and soft segments has altered the crystals size and degree of crystalline in polyurethane/hydroxyapatite nanocomposites. Field emission scanning electron microscope images showed that hydroxyapatite nanoparticles have been uniformly dispersed through in situ polymerization method. Mechanical properties were studied in the terms of HBI(C = O), hydroxyapatite nanoparticles content, and degree of crystallinity. Two different programming procedures were used to evaluate shape fixity and recovery ratios of samples at room temperature and 60°C.

中文翻译:

聚氨酯/羟基磷灰石纳米复合材料的合成、表征、结晶度、机械性能和形状记忆行为

在此,通过开环法合成了不同分子量的聚己内酯二醇。然后,通过羟基和-NCO 基团的加聚,通过两步预聚合法合成聚氨酯。随后,通过溶液浇铸和原位缩聚方法合成了一组聚氨酯/羟基磷灰石纳米复合材料。合成聚己内酯的准确标称分子量通过质子核磁共振(氢 1 核磁共振)确定。通过傅里叶变换红外光谱测定样品的酯和氨基甲酸酯羰基(HBI(C = O))的氢键指数。结果表明,羟基磷灰石纳米颗粒的掺入降低了 HBI(C = O)。X 射线衍射图和差示扫描量热热图证实了羟基磷灰石纳米粒子的阻隔性和成核性能,聚氨酯硬段和软段的相混合程度的变化改变了聚氨酯/羟基磷灰石纳米复合材料的晶体尺寸和结晶度。场发射扫描电子显微镜图像显示,羟基磷灰石纳米颗粒通过原位聚合方法均匀分散。在 HBI(C = O)、羟基磷灰石纳米颗粒含量和结晶度方面研究了机械性能。使用两种不同的编程程序来评估样品在室温和 60°C 下的形状固定性和恢复率。
更新日期:2020-06-17
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