This second in a series of articles deals with studies on the structure and physical properties of five varieties of Indian silk: two mulberry (bivoltine and crossbreed) and three nonmulberry (tasar, muga, and eri). A detailed analysis of the microstructural parameters and mechanical properties was reported. Significant differences between and within the varieties with respect to microstructural parameters (crystallinity, density, birefringence, dichroic ratio, sonic modulus, etc.), as well as the effect of microstructural parameters on mechanical properties, were discussed. Some of the observations made on the inverse stress relaxation behavior of the different silk varieties were also reported. The extent of variation of these morphological parameters was found to correlate well with the mechanical properties.

If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. ABSTRACTSilk is a natural protein fibre. It is the only natural fibre available in continuous filament form. Earlier research studies on physical structure and mechanical properties of silk have indicated that the physical and chemical architecture varies between different varieties of silk and a substantial variation of these properties was observed within the cocoon. The amino acid composition and even the dyeing behaviour are different in different silk. Silk is considered as a non-thermoplastic fibre and is generally not expected to undergo significant morphological changes as a result of thermal shrinkage like synthetic fibres, viz., polyester and nylon. Needless to mention, silk fibres do undergo several kinds of heat treatments either in dry or wet state in the course of textile processing. Hence, an attempt has been made in this paper to deal with the response of different silk varieties (mulberry and non-mulberry) to thermal inputs. Five varieties of silk, two mulberry (bivoltine and crossbreed) and three non-mulberry (tasar, muga and eri) were subject to thermal treatments using TGA and DTA techniques. It was found that both mulberry and non-mulberry varieties behave differently to thermal inputs. Non-mulberry varieties show lower weight loss of 35-37% at 400 o C as compared to about 41-44% for mulberry varieties. They also exhibit a higher decomposition temperature. Interestingly, an additional transition at around 290 o C is clearly observed with all the nonmulberry silks. The DTA results indicate higher stability of non-mulberry silks towards thermal treatments.