Physical Property, Water Repellency, Antibacterial Activity and Ultraviolet Protection of Silk Fabric Treated with Silkworm (Bombyx mori) Sericin-Capped Silver Nanoparticles

Abstract

INTRODUCTION

Negros Occidental produces some of the best quality silks in the world. However, silk absorbs moisture and is easily affected by microorganisms. Making silk resistant to microbes can be achieved using antimicrobial agents such as silver nanoparticles (AgNPs). This motivated the researcher to synthesize AgNPs using sericin from silkworm cocoons and utilized them as a coating agent of silk fabric.

METHODS

Sericin was extracted from silkworm cocoon and was used as a capping and reducing agent in the synthesis of AgNPs. Then, the silk fabrics were coated with AgNPs, dried, and laundered. Silk fabrics with or without AgNPs were tested for various physical properties, water repellency, and protection against UV rays as per standard methods of the Philippine Textile Research Institute. The antibacterial property of the fabrics was also done using the Kirby-Bauer Disc Diffusion Sensitivity Test.

RESULTS

UV visible analysis of sericin-capped samples showed peak absorption at 430 nm, which was used as a monitor for the formation of AgNPs. SEM analysis confirmed the formation of spherical AgNPs. Silk fabric treated with sericin-capped AgNPs had a higher tensile strength (760 N vs. 670 N) piling resistance (Grade 3 vs. Grade 1), colorfastness to laundering (Grade 4 vs. Grade 3.5), rubbing (Grade 4 vs. Grade 3), perspiration (Grade 4.5 vs. 3.5) and light (Grade 7 vs. 4), water repellency and UV Protection than the untreated silk fabric. Moreover, it also exhibited antibacterial activity in terms of the zone of inhibition of S. aureus and E. coli when compared to the untreated fabric, which did not inhibit the growth of the test microorganisms.

DISCUSSIONS

The improved physical property of the fabric with AgNPS is due to its tiny size, which can enter between the polymer molecules and act as filler, thereby contributing to the load sharing phenomenon during load applied to the cloth. The water-repellent property of the treated silk fabric can be attributed to the filling out of AgNPS in the spaces between the fibers, which allows the water to remain on the surface of the fabric. The high UV protection of AgNPs incorporated finished fabrics is due to the large refractive index of AgNPs resulting in very efficient UV scattering while its antibacterial activity is due to the AgNPS destroying the bacterial wall and cause cell damage. The findings of this study could be a breakthrough in the textile industry since sericin-capped AgNPS can be used to make antibacterial, UV protected, and strong silk fabrics.