The Formation of All-Silk Composites and Time-Temperature Superposition

Abstract

Extensive studies have been conducted on utilising natural fibres as reinforcement in composite production. All-polymer composites have attracted much attention because of their high strength, enhanced interfacial bonding and recyclability. Silks, as a group of natural animal fibres, possess superior properties, including biocompatibility, tunability and biodegradability. However, few review articles are found on all-silk composites, and they often lack comments on the tailoring of properties through controlling the volume fraction of the matrix. To better understand the fundamental basis of the formation of silk-based composites, this review will discuss the structure and properties of silk-based composites with a focus on employing the time-temperature superposition principle to reveal the corresponding kinetic requirements of the formation process. Additionally, a variety of applications derived from silk-based composites will be explored. The benefits and constraints of each application will be presented and discussed. This review paper will provide a useful overview of research on silk-based biomaterials.

Keywords: biomaterials; silk-based composites; time–temperature superposition.

Figure 1

Illustration of the common chemical structure and amino acid sequence of a silk fibroin protein with a hexapeptide sequence.

Figure 2

Illustration showing hierarchical structure of raw silk fibre with SF core and sericin coating.

Figure 3

Tensile properties of all-silk composites in silk-thread format: (a) Young’s modulus of ASCs for various dissolution times and temperatures; (b) shifting each temperature dataset to a reference temperature dataset, 40 ${}^{\circ }$C, in log space; (c) master curve of Young’s modulus represented at 40 ${}^{\circ }$C; (d) Rule of mixture models predicting effectiveness of stress transfer between fibre–matrix. Reprinted (adapted) with permission from [111]. Copyright 2021 American Chemical Society.