Effect of conventional degumming methods on Eri silk fibers produced in Kenya

Purpose This paper aims to determine the best conventional degumming technique for use by rural farmers practicing Eri silk fiber production in Kenya. Design/methodology/approach Three conventional silk degumming methods (water, soap and alkali) were analyzed under the factors, namely, time, pressure and degumming media, following the multilevel factorial design of experiments. The effect of variables on degumming weight loss was determined. The effects of the conventional degumming methods that produced complete sericin removal on chemical structure, surface morphology, thermal properties, crystallinity and fiber strength on Eri silk fibers produced in Kenya were then determined. The optimal degumming condition was then evaluated. Findings Soap and water degumming led to incomplete sericin removal. Alkali degumming media had the most effect, especially when pressure cooked at 103 kPa. Increasing time during alkali degumming beyond 30 min did not to have any major difference on degumming loss (at p 0.05). There were no major changes in chemical and thermal properties after degumming. However, the tensile strength and elongation deteriorated especially on alkali medium. Decreasing degumming time in alkali medium from 120 min to 30 min reduced the strength loss from 45% to 33%. Optimal degumming was found to be in an alkali media at 103 kPa for 30 min. Originality/value There is very little information available on Eri silk fibers produced in Kenya. Results of this study provide an optimized conventional degumming procedure suitable for small scale farmers in rural areas practicing Eri silk fiber production.