Understanding the influence of hydrogen bonding and diisocyanate symmetry on the morphology and properties of segmented polyurethanes and polyureas: Computational and experimental study
Understanding the influence of hydrogen bonding and diisocyanate symmetry on the morphology and properties of segmented polyurethanes and polyureas: Computational and experimental study
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DOI：
10.1016/j.polymer.2014.07.028
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发表时间：
2014-09-02
期刊：
影响因子：
4.6
通讯作者：
Wilkes, Garth L.
中科院分区：
文献类型：
--
作者：
Sami, Selim;Yildirim, Erol;Wilkes, Garth L.
采用量子力学计算(QMC)和耗散粒子动力学(DPD)方法，通过端羟基或端胺聚四亚甲基醚(PTMO-1000)与1，4-苯二异氰酸酯(PPDI)和1，3-苯二异氰酸酯(MPDI)的化学计量反应，研究了链段聚氨酯和不含扩链剂的链段聚氨酯中短程和长程氢键的性质及其对微相形态的影响。还研究了对称的PPDI与基于MPDI的模型氨酯和尿素化合物之间由于有序的氢键网络而实现远程连接的可能性。重点了解了二异氰酸酯的对称性和硬段之间氢键的性质对形态发展的影响。QMC结果清楚地表明，基于PPDI的氨酯基和尿素基团之间的氢键存在长程有序的可能性，而基于MPDI的体系则没有这种行为。DPD结果有力地支持了QMC的研究，并清楚地证明了PPDI基嵌段共聚物中氨酯和尿素基团之间的氢键长程连接的可能性，导致了这些体系中微相分离形态的形成，这在扭结的MPDI基嵌段氨酯和尿素共聚物中没有观察到。计算结果有力地支持了基于PPDI和MPDI的嵌段聚氨酯和聚脲的形态、热性能和力学性能的实验观察。(C)2014爱思唯尔有限公司。保留所有权利。
Quantum mechanical calculations (QMC) and dissipative particle dynamics (DPD) siniulations were utilized to understand the nature of the short and long-range hydrogen bonding and its influence on the microphase morphology in segmented polyurethanes and segmented polyureas prepared without chain extenders through the stoichiometric reactions of hydroxy or amine terminated poly(tetramethylene oxide) (PTMO-1000) with 1,4-phenylene diisocyanate (PPDI) and 1,3-phenylene diisocyanate (MPDI). The possibility of long-range connectivity due to a network of well-ordered hydrogen bonds between symmetrical PPDI and kinked MPDI based model urethane and urea compounds were also investigated. Special emphasis was given on the understanding of the influence of diisocyanate symmetry and nature of the hydrogen bonding between hard segments on the morphology development. QMC results obtained clearly indicated the possibility of long-range ordering of hydrogen bonds between PPDI based urethane and urea groups, while MPDI based systems did not display such a behavior. DPD results strongly supported the QMC studies and clearly demonstrated the possibility of long-range connectivity of hydrogen bonds between urethane and urea groups in PPDI based segmented copolymers, leading to the formation of microphase separated morphologies in these systems, which was not observed in the kinked MPDI based segmented urethane and urea copolymers. Computational results obtained strongly supported the experimental observations reported on the morphology and thermal and mechanical properties of these segmented polyurethanes and polyureas based on PPDI and MPDI. (C) 2014 Elsevier Ltd. All rights reserved.