Department of Polymer Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 Gabriela Narutowicza Street, 80-233 Gdansk, Poland.
Int J Mol Sci. 2021 Jul 12;22(14):7438. doi: 10.3390/ijms22147438.
This study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols-poly(trimethylene glycol)s-with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4'-diphenylmethane diisocyanates and the bio-based 1,4-butanodiol (used as a chain extender and used to control the [NCO]/[OH] molar ratio). The impacts of the structure of flexible segments, the amount of each type of prepolymer, and the [NCO]/[OH] molar ratio on the chemical structure and selected properties of the TPUs were verified. By regulating the number of flexible segments of a given type, different selected properties of TPU materials were obtained. Thermal analysis confirmed the high thermal stability of the prepared materials and revealed that TPUs based on a higher amount of prepolymer synthesized from PO3G2700 have a tendency for cold crystallization. An increase in the amount of PO3G1000 at the flexible segments caused an increase in the tensile strength and decrease in the elongation at break. Melt flow index results demonstrated that the increase in the amount of prepolymer based on PO3G1000 resulted in TPUs favorable in terms of machining.
本研究涉及通过控制柔性段的化学结构来获得绿色热塑性聚氨酯（TPU）。使用了两种类型的基于生物的聚醚多元醇-聚（三亚甲基二醇），平均分子量约为 1000 和 2700 Da（分别为 PO3G1000 和 PO3G2700）。TPU 是通过两步法制备的。硬段由 4,4'-二苯甲烷二异氰酸酯和基于生物的 1,4-丁二醇（用作扩链剂，用于控制[NCO]/[OH]摩尔比）组成。验证了柔性段结构、每种预聚物的用量以及[NCO]/[OH]摩尔比对 TPU 化学结构和所选性能的影响。通过调节给定类型的柔性段数量，获得了 TPU 材料的不同特性。热分析证实了所制备材料的高热稳定性，并表明基于 PO3G2700 合成的预聚物量较高的 TPU 具有冷结晶的趋势。在柔性段中增加 PO3G1000 的量会导致拉伸强度增加，断裂伸长率降低。熔体流动指数结果表明，增加基于 PO3G1000 的预聚物的量会导致 TPU 在加工方面更有利。
