There is an increasing demand for the use of “green”-based materials as reinforcement and matrix materials in composites. However, the ability of these natural-based materials to perform as consistently and reliably as conventional materials is still relatively unknown. A key importance in the viability of these materials is the evaluation of the content of voids and imperfections, which may affect the properties of the entire composite. In this study, the microstructure of tubular-braided composites manufactured from cellulose fibers and a partially bio-derived resin was studied with the use of micro-computed tomography. These methods were used to determine the effect of modifying braid angle, resin type, and curing method on fiber volume fraction, void volume, and void distribution. It was determined that the void content increased with the increase in braid angle, and vacuum-bagging reduced the total void content. The sample with the smallest braid angle produced with vacuum-bagged curing contained a void fraction of 1.5%. The results of this study proved that the materials used could be viable for further testing and development and that micro-computed tomography imaging is valuable for identifying how to improve consistency and minimize imperfections to create more accurate and reliable natural fiber-braided composites.

中文翻译：

---

天然纤维和生物基质管状编织复合材料的显微计算机断层扫描分析

越来越需要使用“绿色”基材料作为复合材料中的增强材料和基体材料。然而，这些基于天然材料的材料能否像传统材料一样始终如一、可靠地发挥作用，仍然相对未知。这些材料的可行性的一个关键重要性是评估空隙和缺陷的含量，这可能会影响整个复合材料的性能。在这项研究中，使用微型计算机断层扫描技术研究了由纤维素纤维和部分生物衍生树脂制成的管状编织复合材料的微观结构。这些方法用于确定修改编织角、树脂类型和固化方法对纤维体积分数、空隙体积和空隙分布的影响。确定空隙率随着编织角的增加而增加，并且真空装袋降低了总空隙率。用真空袋固化生产的具有最小编织角的样品含有 1.5% 的空隙率。这项研究的结果证明，所使用的材料可用于进一步的测试和开发，并且显微计算机断层扫描成像对于确定如何提高一致性和最大限度地减少缺陷以创建更准确和可靠的天然纤维编织复合材料很有价值。