Research On Antheraea Pernyi Cocoon Microstructure:A Bionic Study Of Thermal Insulated Textile Composite

In recent years,it has been paid more attention and concern on the development of new bionic textiles by combining the bionics with textile technology with the development of bionic technology.The application of bionic technology in the textile industry is gradually increased,in which the research on the bionic insulation composite textile is the focus of long-term concern and the development of the object.It is widely used in ordinary clothing,shoes,military uniforms,tents and many other areas,due to the fact that the insulation effect of bionic warm composite textile is excellent.We studied the micro-structures of two kinds of Antheraea pernyi silkworm cocoons,one is from Dandong,Liaoning Province and another is from Nanyang,Henan Province.The results illustrated that the two kinds of cocoon layers had special nonwoven fabric structure with the attachment of calcium oxalate crystals.Additionally,the content of calcium ion in the cocoon was calculated by ICP-AES method and it was demonstrated that the content of calcium oxalate crystals in the cocoon of Dandong was about 1.3 times of that of Nanyang,Henan Province.Furthermore,the thermal insulation performance of Antheraea pernyi silkworm cocoon from the Liaoning Province was better in comparison with the one from the Henan Province tested by self-made devices.The experimental analysis of the thermal properties of the special calcium oxalate crystal attached to the cocoon layer of the Antheraea pernyi silkworm cocoons can provide a theoretical basis for the study of the bionic structure design of the internal microstructure.Therefore,this structure can be a biological prototype of the bionic composite insulation textile design.The porous nonwoven structure,like the Antheraea pernyi silkworm cocoons layers formed by filamentous silk,was imitated by polypropylene nonwoven fabric,and the sericin structure was simulated by mixture of gelatin and calcium oxalate crystals for bio-mimetic composite textiles with the similar structure of the Antheraea pernyi silkworm cocoon.The results showed that the bio-mimetic composite insulation textiles have certain permeability,hygroscopicity and heat preservation performance with the distribution of internal micro climate irregularly.Compared with the permeability of SMMS/gelatin composite fabric,with theincrease of granular calcium oxalate crystals,the thickness of bionic composite textiles did not change significantly.Besides,the air permeability decreased significantly,which was about 40.86% lower and heat preservation rate and the CLO value increased obviously,namely,the insulation rate increased by 147%,the CLO value increased by 157%,while the heat transfer coefficient decreased apparently,that was 67.9%.It was indicated that the bionic composite textile had a good thermal insulation performance.The results of this research can provide a reference of basic theoretical and design direction for the development of new bionic composite textiles in the follow-up work.