Abstract

In order to realise the re-use of waste yak hair, in this research, keratin was extracted from yak hair by urea and sodium sulfide. During extraction, the hydrogen bonds and hydrophobic interaction in keratin from yak hair was destroyed using urea and the disulfide bonds were reduced to mercapto groups using sodium sulfide. Moreover, the strong alkalinity of sodium sulfide could also decompose the chemical bonds in the keratin and promote the dissolution of yak hair. The FTIR spectrum confirmed this view.

The recycling of the urea and sodium sulfide liquid reduced the cost of extraction and solved the environmental problems. The extracted keratin from yak hair using urea and sodium sulfide had high molecular weight, good thermal stability and high crystallinity based on GPC, TG, DTG, DSC and XRD. The re-use of waste yak hair as a raw material and the development of new keratin from the hair were conducive to the high value conversion of waste yak hair, in line with the strategic direction of sustainable development. This research laid a foundation for the development of keratin based biomaterials with unique functions.