Structure and properties of flat cocoon silk after silk reeling

Silk is obtained mostly from oval cocoons. In this paper, the flat cocoons were obtained by changing the silking environment of Bombyx mori silkworms. Then the appropriate method was used to reel the flat cocoons. The structure, thermal and mechanical properties of flat cocoon silk (FCS) after silk reeling and degumming were studied. The experimental results have shown that flat cocoon silk has the same main composition and similar thermal performance as that of common cocoon silk (CCS), but the sericin distribution on the surface of FCS is more uniform, the crystallinity degree of the FCS (53.77%) is slightly higher than that of the CCS (50.02%), and the cross-sectional areas of the FCS before and after degumming are smaller than those of the CCS. Before degumming, the stress of FCS is about 1% higher than that of CCS, the initial modulus is about 4.7% higher, and the strain is about 10.7% lower. After degumming, the stress of FCS is about 2.7% higher than that of CCS, the initial modulus is about 7.8% higher, and the strain is about 31.3% lower. The results have shown that FCS after silk reeling has application performance close to or even better than that of CCS.