Silk has always been associated with making clothes, but its uses are incredibly diverse, thanks to its strength and elastic properties. Silk is a natural fiber that exists as a continuous thread, and this unique feature contributes to the diversity of uses of silk fibers.
Uses of silk
The silkworms spit the protein fibroin (silk) through small holes in their jaws (two salivary glands) in the form of a continuous thread. The fibroin consists of the leaves of the digested trees and the protein that the silkworms feed on.
Currently, interest is increasing in advanced technologies used in silk processing and engineering with the aim of producing a wide range of new practical tools. The silk fibers extracted from silkworms have remarkable bio-compatibility and bio-absorbability. Therefore, they are widely used in the medical field due to the low risk of inflammatory reactions. .
Therefore, researchers have been studying ways to harden silk, such as treating the silk threads extracted from silkworms by using chemicals during the spinning process. However, these chemicals are toxic and harmful to human health and the environment.
Researchers have been studying different methods of strengthening silk, such as treating it with chemicals (Getty Images)
A natural diet solves the dilemma
Cellulose nanofibers are plant-derived fibers that are refined to a micro level, and are promising environmentally friendly nanomaterials that can be used to form low-cost, lightweight, high-strength, renewable and sustainable nanocomposites.
Tohoku University researchers in Japan produced nano-cellulose (CNF) silk naturally by modifying the silkworms' diet, and published their research findings in Materials and Design on February 1.
According to a report by Scitech Daily published on March 21, the purpose of this study is to develop fibers containing silkworm silk and nanocellulose, by directly feeding the silkworm with nanomaterials.
The nanofibers were added to the regular diet of silkworms in order to improve the tensile strength of the silk produced, then they conducted a tensile test to understand the mechanical properties of the silk fibers. They also studied the surface of the silk fibers to confirm the presence and alignment of the nanofibers.
The researchers' findings demonstrate an environmentally friendly way to produce stronger silk (Getty Images)
Better fiber alignment
Composite materials based on cellulose nanofibers, which were synthesized in previous studies, showed little mechanical improvement, despite the use of advanced equipment, due to the lack of good alignment of the nanofibers.
"The idea of our research came when we realized that the flow-focusing method by which silkworms produce silk are optimal for the alignment of the nanofibers of cellulose," said Dr. Fumio Narita, a materials science engineer at Tohoku University, who is involved in the research.
The observed nanofibre alignment is attributed to the natural mechanism that occurs inside the silkworms during the spinning process, whereby the silkworms produce silk in a flow-enhancing method.
Tohoku University researchers of Japan produced nanoscale cellulose silk naturally (Getty Images)
In this recent study, the silkworm larvae were divided into 3 groups, and fed to food containing different amounts of cellulose nanofibers, then the research group conducted strength tests on the pulled silk fibers, which were found to be about twice stronger than the silk produced from the silkworm that does not It feeds on cellulose nanofibers.
"Our findings illustrate an environmentally friendly way to produce sustainable biomaterials by using cellulose nanofibers as food (silkworm)," said Dr. Fumio Narita.