Hamidi Youssef K, Yalcinkaya M Akif, Guloglu Gorkem E, Pishvar Maya, Amirkhosravi Mehrad, Altan M Cengiz
Mechanical Engineering Program, University of Houston-Clear Lake, Houston, TX 77058, USA.
School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019, USA.
Materials (Basel). 2018 Oct 30;11(11):2135. doi: 10.3390/ma11112135.
With growing environmental awareness, natural fibers have recently received significant interest as reinforcement in polymer composites. Among natural fibers, silk can potentially be a natural alternative to glass fibers, as it possesses comparable specific mechanical properties. In order to investigate the processability and properties of silk reinforced composites, vacuum assisted resin transfer molding (VARTM) was used to manufacture composite laminates reinforced with woven silk preforms. Specific mechanical properties of silk/epoxy laminates were found to be anisotropic and comparable to those of glass/epoxy. Silk composites even exhibited a 23% improvement of specific flexural strength along the principal weave direction over the glass/epoxy laminate. Applying 300 kPa external pressure after resin infusion was found to improve the silk/epoxy interface, leading to a discernible increase in breaking energy and interlaminar shear strength. Moreover, the effect of fabric moisture on the laminate properties was investigated. Unlike glass mats, silk fabric was found to be prone to moisture absorption from the environment. Moisture presence in silk fabric prior to laminate fabrication yielded slower fill times and reduced mechanical properties. On average, 10% fabric moisture induced a 25% and 20% reduction in specific flexural strength and modulus, respectively.
随着环保意识的增强，天然纤维最近作为聚合物复合材料的增强材料受到了广泛关注。在天然纤维中，丝绸因其具有可比的特定机械性能，有可能成为玻璃纤维的天然替代品。为了研究丝绸增强复合材料的加工性能和性能，采用真空辅助树脂传递模塑（VARTM）工艺制造了由机织丝绸预成型件增强的复合层压板。发现丝绸/环氧树脂层压板的特定机械性能具有各向异性，且与玻璃/环氧树脂层压板相当。丝绸复合材料在主编织方向上的比弯曲强度甚至比玻璃/环氧树脂层压板提高了23%。发现在树脂注入后施加300 kPa的外部压力可改善丝绸/环氧树脂界面，导致断裂能和层间剪切强度明显增加。此外，还研究了织物湿度对层压板性能的影响。与玻璃毡不同，发现丝绸织物容易从环境中吸湿。在层压板制造之前，丝绸织物中的水分会导致填充时间延长，并降低机械性能。平均而言，10%的织物湿度会使比弯曲强度和模量分别降低25%和20%。
