Thermo-hygro mechanical flattening of bamboo with intact wall structure: synergistic enhancement of mechanical properties and dimensional stability

IF 12.7 1区材料科学 Q1 ENGINEERING, MULTIDISCIPLINARY

Composites Part B: Engineering Pub Date : 2025-04-29 DOI:10.1016/j.compositesb.2025.112582

Xianke Wang , Xiaohan Chen , Yuquan Li , Huanrong Liu , Bin Huang , Changhua Fang

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引用次数: 0

Abstract

This study developed a novel hot-pressing and humidity synergistic flattening technology that preserves the intact bamboo wall structure, addressing the issues of mechanical performance loss and poor dimensional stability caused by removing inner and outer layers in previous flattening processes while enabling synchronous drying. Through scanning electron microscopy, digital image correlation and dynamic vapor adsorption, the microstructural changes, chemical degradation mechanisms during hot-pressing, mechanical properties strengthening mechanism, and the deformation and full-field strain distribution of flattened bamboo during moisture absorption were revealed. The results demonstrated that an initial moisture content of 70 % yielded the highest flattening success rate (96 %) while enabling simultaneous drying, thereby simplifying the flattening process. The flattened bamboo exhibited significant improvements in flexural strength (207–215 MPa), flexural modulus (14.1–14.7 GPa), and compressive strength (109–112 MPa) compared to natural bamboo. Preservation of the intact bamboo wall structure reduced the external arc warpage about 70.8 % (soaking in water for one day) and lowered equilibrium moisture content through the formation of hydrophobic surfaces and reduced activity of hydrophilic groups. The thermo-hygro flattening process induced hemicellulose degradation, lignin crosslinking, and increased cellulose crystallinity, enhanced interfacial bonding, which collectively improved mechanical performance and dimensional stability. Through technological innovation and mechanism exploration, this research not only enhances the comprehensive performance of bamboo but also provides sustainable solutions for structural applications such as flooring, prefabricated housing components, and high-strength laminated composites, advancing bamboo's role in eco-friendly engineering.

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具有完整壁结构的竹材的热湿机械压扁：机械性能和尺寸稳定性的协同增强

本研究开发了一种新的热压和湿度协同压平技术，该技术保留了完整的竹壁结构，解决了先前压平工艺中由于去除内层和外层而导致的机械性能损失和尺寸稳定性差的问题，同时实现了同步干燥。通过扫描电镜、数字图像相关和动态水蒸气吸附等手段，揭示了竹材在热压过程中的微观结构变化、化学降解机制、力学性能增强机制以及竹材在吸湿过程中的变形和全场应变分布。结果表明，初始含水量为70%时，在同时干燥的情况下，压平成功率最高（96%），从而简化了压平过程。与天然竹子相比，扁平竹的抗弯强度（207 ~ 215 MPa）、抗弯模量（14.1 ~ 14.7 GPa）和抗压强度（109 ~ 112 MPa）均有显著提高。保留完整的竹壁结构可使外圆弧弯曲减少约70.8%（浸泡1天），并通过疏水表面的形成和亲水基团活性的降低降低平衡含水量。热湿压平过程诱导半纤维素降解，木质素交联，提高纤维素结晶度，增强界面键合，共同提高机械性能和尺寸稳定性。本研究通过技术创新和机理探索，不仅提高了竹子的综合性能，而且为地板、预制房屋构件、高强度层压复合材料等结构应用提供了可持续的解决方案，推进了竹子在环保工程中的作用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Composites Part B: Engineering 工程技术-材料科学：复合

CiteScore

24.40

自引率

11.50%

发文量

784

审稿时长

21 days

期刊介绍： Composites Part B: Engineering is a journal that publishes impactful research of high quality on composite materials. This research is supported by fundamental mechanics and materials science and engineering approaches. The targeted research can cover a wide range of length scales, ranging from nano to micro and meso, and even to the full product and structure level. The journal specifically focuses on engineering applications that involve high performance composites. These applications can range from low volume and high cost to high volume and low cost composite development. The main goal of the journal is to provide a platform for the prompt publication of original and high quality research. The emphasis is on design, development, modeling, validation, and manufacturing of engineering details and concepts. The journal welcomes both basic research papers and proposals for review articles. Authors are encouraged to address challenges across various application areas. These areas include, but are not limited to, aerospace, automotive, and other surface transportation. The journal also covers energy-related applications, with a focus on renewable energy. Other application areas include infrastructure, off-shore and maritime projects, health care technology, and recreational products.