Silk as a Natural Reinforcement: Processing and Properties of Silk/Epoxy Composite Laminates

Abstract

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.

Promising Mechanical, Thermal, and Ballistic Properties of Novel Epoxy Composites Reinforced with Cyperus malaccensis Sedge Fiber

“…However, at the end of the last century, concerns on the widespread pollution caused by non-degradable materials, such as common plastics, as well as climate changes resulting from carbon dioxide emissions, motivated a tendency to replace synthetic by natural fibers in composite materials. These fibers, naturally produced by living organisms, such as animals [ 4 ] and plants [ 5 ], consume less energy to be processed and rapidly degrade in natural environments, reducing disposal problems and contributing to the sustainability of the projects.…”

A Transparent, Skin‐Inspired Composite Film with Outstanding Tear Resistance Based on Flat Silk Cocoon

“…[19,20] Among them, the silk fiber is widely used as the reinforcing phase because of its low density, outstanding mechanical advantage, and sustainability. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Besides its high strength and toughness, another intriguing but less studied mechanical property of skin is its remarkable tear resistance, resulting from the rearrangement of skin collagen fibers in the tensile-loading direction. [39] In this work, we show that this stress redistribution mechanism can be utilized to construct fiber-reinforced supporting substrates with excellent tear resistance.…”

Mechanical Properties of Composites Reinforced with Textile

“…Hamidi et al used silk as a natural reinforcement in the case of silk/epoxy composite laminates [13]. They considered that the application of an external pressure after the resin infusion led to an improvement of the silk/epoxy interface and thus to better behavior of the composite material to the mechanical efforts.…”