具有梯度结构的微孔热塑性聚氨酯及其性能

doi:10.11949/0438-1157.20241095

摘要/Abstract

摘要：

具有梯度结构的发泡材料因创新结构设计和潜在多功能性受广泛研究。本工作以热塑性聚氨酯（TPU）为研究对象，通过一次升温发泡与二次卸压发泡制备了具有梯度泡孔结构的高倍率TPU发泡材料，并且探究了发泡条件影响机制。微观形貌表征显示，当发泡时间较短时，因基体中存在的温度梯度，可制得两侧孔径大、中间孔径小的梯度发泡材料，延长发泡时间则因温差降低制备出均匀发泡材料。力学性能测试结果表明，相较于均匀发泡材料，梯度发泡材料能量损失系数略高，但两者的相对差值随着发泡倍率的增高而降低，且具有更高的回弹率和更低的硬度，展现出高发泡倍率下优异的缓冲性能和回弹性。这为优化TPU发泡材料制备工艺提供了理论基础和实践指导，对TPU实现高性能、轻量化发展具有重要作用。

关键词: 升温发泡, 泡孔结构, 热塑性聚氨酯弹性体, 超临界流体, 力学性能, 聚合物加工, 泡沫

Abstract:

Foaming materials with gradient structure are widely studied due to their innovative structural design and potential multifunctionality. In this work, thermoplastic polyurethane (TPU) was used as the research object. High-ratio TPU foaming materials with gradient cell structure were prepared by primary temperature rising foaming and secondary depressurization foaming, and the influence mechanism of foaming conditions was explored. Microscopic morphology characterization showed that when the foaming time is relatively short, gradient foaming materials with larger cell sizes on both sides and smaller cell sizes in the middle can be prepared due to the temperature gradient existing in the polymer matrix. As the foaming time is prolonged, uniform foaming materials would be prepared due to the reduction of temperature difference. The mechanical properties of TPU foaming materials are tested. The results show that the energy loss coefficient of the gradient foaming materials is slightly higher compared with the uniform foaming materials. However, the relative difference between the two decreases with the increase in foaming expansion ratio. Moreover, the gradient foaming materials have lower hardness and higher resilience rate, demonstrating excellent cushioning performance and resilience at high foaming expansion ratios. This paper provides theoretical basis and practical guidance for optimizing the preparation process of TPU foaming materials and is of great significance for the realization of high-performance and lightweight development of TPU.

Key words: temperature rising foaming, cell structure, thermoplastic polyurethane elastomer, supercritical fluid, mechanical property, polymer processing, foam

中图分类号:

TQ 334.9

陈弋翀, 贾星雨, 钟文宇, 施俞晖, 彭瑶, 孙嘉阳, 胡冬冬, 赵玲. 具有梯度结构的微孔热塑性聚氨酯及其性能[J]. 化工学报, 2025, 76(2): 897-908.

Yichong CHEN, Xingyu JIA, Wenyu ZHONG, Yuhui SHI, Yao PENG, Jiayang SUN, Dongdong HU, Ling ZHAO. Microcellular thermoplastic polyurethane with gradient structure and its properties[J]. CIESC Journal, 2025, 76(2): 897-908.

图/表 9

图1 实验过程示意图

Fig.1 Experimental process schematic diagram

图2 不同饱和压力下CO2的溶解量（a）及CO2的扩散系数（b）

Fig.2 The solubility of CO₂ (a) and the diffusion coefficient of CO₂ (b) at different saturation pressures

图3 一次升温发泡的数据统计

Fig.3 Data statistics of primary temperature rising foaming

图4 二次卸压发泡前后的发泡倍率及其体积回复率

Fig.4 Expansion ratio and volume recovery rate before and after secondary depressurization foaming

图5 一次升温发泡后一定饱和压力（5 MPa）、不同发泡温度下制备的发泡样品收缩后的微观形貌

Fig.5 Microstructure of foaming materials prepared at different foaming temperatures under a certain saturation pressure (5 MPa) after shrinkage following the primary temperature rising foaming

图6 一次升温发泡后一定发泡温度（130℃）、不同饱和压力下制备的发泡样品收缩后的微观形貌

Fig.6 Microstructure of foaming materials prepared at different saturation pressures under a foaming temperature (130℃) after shrinkage following the primary temperature rising foaming

图7 二次卸压发泡后一定饱和压力（5MPa）、不同发泡温度下制备的发泡样品的微观形貌

Fig.7 Microstructure of foaming materials prepared at different foaming temperatures under a certain saturation pressure (5 MPa) after secondary depressurization foaming

图8 不同发泡条件下的发泡材料的泡孔尺寸

Fig.8 Cell size of foaming materials under different foaming conditions

图9 不同发泡材料的力学性能数据统计

Fig.9 Data statistics of mechanical properties of different foaming materials

参考文献 38

1	Zhai W T, Jiang J J, Park C B. A review on physical foaming of thermoplastic and vulcanized elastomers[J]. Polymer Reviews, 2022, 62(1): 95-141.
2	Iba H, Nishikawa Y, Urayama K. Nonlinear stress-strain behavior of elastomer foams investigated by various types of deformation[J]. Polymer, 2016, 83: 190-198.
3	Lan B, Li P Z, Yang Q, et al. Dynamic self generation of hydrogen bonding and relaxation of polymer chain segment in stabilizing thermoplastic polyurethane microcellular foams[J]. Materials Today Communications, 2020, 24: 101056.
4	Belmonte P, Ramos M J, Rodríguez J F, et al. Transformation of TPU elastomers into TPU foams using supercritical CO₂. A new reprocessing approach[J]. The Journal of Supercritical Fluids, 2023, 192: 105806.
5	Yu C T, Lai C C, Wang F M, et al. Fabrication of thermoplastic polyurethane (TPU)/thermoplastic amide elastomer (TPAE) composite foams with supercritical carbon dioxide and their mechanical properties[J]. Journal of Manufacturing Processes, 2019, 48: 127-136.
6	Ge C B, Wang S P, Zheng W G, et al. Preparation of microcellular thermoplastic polyurethane (TPU) foam and its tensile property[J]. Polymer Engineering & Science, 2018, 58(S1): E158-E166.
7	Zhai Y, Yu Y F, Zhou K K, et al. Flexible and wearable carbon black/thermoplastic polyurethane foam with a pinnate-veined aligned porous structure for multifunctional piezoresistive sensors[J]. Chemical Engineering Journal, 2020, 382: 122985.
8	Belmonte P, Céspedes M, Ramos M J, et al. Foaming of thermoplastic polyurethane using supercritical CO₂ and N₂: antishrinking strategy[J]. The Journal of Supercritical Fluids, 2024, 211: 106311.
9	Lu Q W, Macosko C W. Comparing the compatibility of various functionalized polypropylenes with thermoplastic polyurethane (TPU)[J]. Polymer, 2004, 45(6): 1981-1991.
10	Xing S W, Lv C F, Lin M J, et al. A flexible superhydrophobic thermoplastic polyurethane porous surface with good self-cleaning function prepared by supercritical CO₂ foaming[J]. The Journal of Supercritical Fluids, 2024, 210: 106294.
11	Fei Y P, Jiang R T, Fang W, et al. Highly sensitive large strain cellulose/multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanocomposite foams: from design to performance evaluation[J]. The Journal of Supercritical Fluids, 2022, 188: 105653.
12	Koizumi M, Niino M. Overview of FGM research in Japan[J]. MRS Bulletin, 1995, 20(1): 19-21.
13	Shi H Y, Zhou P, Li J, et al. Functional gradient metallic biomaterials: techniques, current scenery, and future prospects in the biomedical field[J]. Frontiers in Bioengineering and Biotechnology, 2021, 8: 616845.
14	Liu Z Q, Meyers M A, Zhang Z F, et al. Functional gradients and heterogeneities in biological materials: design principles, functions, and bioinspired applications[J]. Progress in Materials Science, 2017, 88: 467-498.
15	Miao X G, Sun D. Graded/gradient porous biomaterials[J]. Materials, 2010, 3(1): 26-47.
16	Long L C, Wang Z K, Chen K. Analysis of the hollow structure with functionally gradient materials of moso bamboo[J]. Journal of Wood Science, 2015, 61(6): 569-577.
17	Frey M, Biffi G, Adobes-Vidal M, et al. Tunable wood by reversible interlocking and bioinspired mechanical gradients[J]. Advanced Science, 2019, 6(10): 1802190.
18	Li X Y, Lu L, Li J G, et al. Mechanical properties and deformation mechanisms of gradient nanostructured metals and alloys[J]. Nature Reviews Materials, 2020, 5: 706-723.
19	Mao A R, Chen J W, Bu X C, et al. Bamboo-inspired structurally efficient materials with a large continuous gradient[J]. Small, 2023, 19(35): 2301144.
20	Gao X L, Chen Y C, Chen P, et al. Supercritical CO₂ foaming and shrinkage resistance of thermoplastic polyurethane/modified magnesium borate whisker composite[J]. Journal of CO₂ Utilization, 2022, 57: 101887.
21	Wang G L, Liu J X, Zhao J C, et al. Structure-gradient thermoplastic polyurethane foams with enhanced resilience derived by microcellular foaming[J]. The Journal of Supercritical Fluids, 2022, 188: 105667.
22	Mannella G A, Conoscenti G, Carfì Pavia F, et al. Preparation of polymeric foams with a pore size gradient via thermally induced phase separation (TIPS)[J]. Materials Letters, 2015, 160: 31-33.
23	Zhu L J, Wang G L, Xu Z R, et al. A new microcellular foaming strategy to develop structure-gradient thermoplastic polyurethane foams with enhanced elasticity[J]. Materials & Design, 2023, 234: 112325.
24	Zhou C C, Wang P, Li W. Fabrication of functionally graded porous polymer via supercritical CO₂ foaming[J]. Composites Part B: Engineering, 2011, 42(2): 318-325.
25	Jiang J J, Zhou M N, Li Y Z, et al. Cell structure and hardness evolutions of TPU foamed sheets with high hardness via a temperature rising foaming process[J]. The Journal of Supercritical Fluids, 2022, 188: 105654.
26	Ngo M T, Dickmann J S, Hassler J C, et al. A new experimental system for combinatorial exploration of foaming of polymers in carbon dioxide: the gradient foaming of PMMA[J]. The Journal of Supercritical Fluids, 2016, 109: 1-19.
27	Wang W, Liao X, He Y S, et al. Thermoplastic polyurethane/polytetrafluoroethylene composite foams with enhanced mechanical properties and anti-shrinkage capability fabricated with supercritical carbon dioxide[J]. The Journal of Supercritical Fluids, 2020, 163: 104861.
28	Zhang R, Huang K, Hu S F, et al. Improved cell morphology and reduced shrinkage ratio of ETPU beads by reactive blending[J]. Polymer Testing, 2017, 63: 38-46.
29	Nofar M, Batı B, Küçük E B, et al. Effect of soft segment molecular weight on the microcellular foaming behavior of TPU using supercritical CO₂ [J]. The Journal of Supercritical Fluids, 2020, 160: 104816.
30	Chen Y C, Li D Y, Zhang H, et al. Antishrinking strategy of microcellular thermoplastic polyurethane by comprehensive modeling analysis[J]. Industrial & Engineering Chemistry Research, 2021, 60(19): 7155-7166.
31	Chen Y C, Zhong W Y, Jia X Y, et al. Microcellular thermoplastic polyurethane (TPU) with multimodal cell structure fabricated based on pressure swing strategy and its compressive mechanical properties[J]. Industrial & Engineering Chemistry Research, 2024, 63(19): 8833-8845.
32	Zhong W Y, Hu D D, Jia X Y, et al. A novel semi-continuous preparation mode of ultra-low density thermoplastic polyurethane foam[J]. Chemical Engineering Journal, 2024, 481: 148402.
33	Chu C C, Yeh S K, Peng S P, et al. Preparation of microporous thermoplastic polyurethane by low-temperature supercritical CO₂ foaming[J]. Journal of Cellular Plastics, 2017, 53(2): 135-150.
34	Li R S, Lee J H, Wang C D, et al. Solubility and diffusivity of CO₂ and N₂ in TPU and their effects on cell nucleation in batch foaming[J]. The Journal of Supercritical Fluids, 2019, 154: 104623.
35	Sun F K, Zhou M H, Yi F F, et al. Facile fabrication of lightweight and high expanded TPU/PBS bead blend foam with segregated microcellular network for reduced shrinkage and enhanced interface bonding[J]. The Journal of Supercritical Fluids, 2024, 212: 106334.
36	Lee Y H, Lee C W, Chou C H, et al. Sustainable polyamide elastomers from a bio-based dimer diamine for fabricating highly expanded and facilely recyclable microcellular foams via supercritical CO₂ foaming[J]. European Polymer Journal, 2021, 160: 110765.
37	Lu J W, Zhang H, Chen Y M, et al. Effect of chain relaxation on the shrinkage behavior of TPEE foams fabricated with supercritical CO₂ [J]. Polymer, 2022, 256: 125262.
38	Chen Y C, Yu J B, Ling Y J, et al. Comprehensive analysis of mechanical properties of microcellular polypropylene: experiment and simulation[J]. Polymer Testing, 2022, 116: 107812.

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