| Bombyx mori silk fiber has lots of advantages, such as light texture, feel full, good strength and elongation, easy processing, shiny, soft and comfortable, and harmless to the human body, etc, and is considered as an excellent natural protein fiber materials. Particularly, silk fibers have some unique properties such as excellent mechanical properties, good biocompatibilities, and slow degradation, and have been widely used as materials for the biomedical, health and cosmetic applications. However, silk fibers have also some natural defects such as low water absorption rate, easy to turn yellow discoloration, and easy to wrinkle, etc. Moreover, the current process of silk fiber requires degumming, dissolution, dialysis, film forming and other operational processes, which is very complicated and will destroy some excellent properties of natural silk, and those processes seriously restricts the improvement of the quality of silk, silk products and its application. It has been proved that the better the surface hydrophilic, the better the proliferation of cell adhesion. Direct surface modification of the raw silk can help to improve its hydrophilicity, biocompatibility and adsorption capacity of cells, promote the application of silk fiber as a new kind of green biomaterials in higher-end products and more fileds, and enhance the practicality of silk fiber and its products. The object of this study is processes to modify the raw silk by using the PEG-400and PEG4000-etherified DMDHEU reagents, to develope a method of improving the water absorption of raw silk and explore novel silk materials with good water absorption.The main research contents and results are as follows: 1. Main process and characterization of the grafted raw silkUsing the grafting monomer of PEG-400and PEG-4000and the catalyst MgCl2ยท6H2O, several raw silk samples with different improved absorbency degrees was obtained after the Second Baptist Second rolling process, indicating the feasibility and effectiveness of this method. We also developed a testing method of characterizing and silk, including the methods of testing the contact angle, water absorption, mechanical properties, thermal stability and structural stability, which provide a good assessment tools for comparing the characterization of the raw silk with the grafted raw silk.2. Processing, structure and properties of the PEG-400etherified DMDHEU grafted raw silkThrough orthogonal experiment, we obtained a series of different levels of absorbency increased raw silk after grafted by PEG-400etherified DMDHEU. After characterizing its structure and performance, combining with SPSS analysis results, we concluded the optimum combination of PEG-400etherified DMDHEU to grafted raw silk. In the best grafted raw silk, the water absorption was improved about177.35%, and the heat and structural stability was also improved.3. Processing, structure and properties of the PEG-4000etherified DMDHEU grafted raw silkSimilarly, through orthogonal experiment, we obtained a series of different levels of absorbency increased raw silk after grafted by PEG-4000etherified DMDHEU. After characterizing its structure and performance, combining with SPSS analysis results, we concluded the optimum combination of PEG-4000etherified DMDHEU to grafted raw silk. In the best grafted raw silk, the water absorption was improved about92.27%, and the heat and structural stability was also improved.4. Comparative analysis of the PEG-400and PEG-4000etherified DMDHEU grafted raw silkBy using two different monomers etherified DMDHEU to grafting raw silk, we characterized the water absorption, morphology, mechanical properties, thermal stability and structural stability of the grafted raw silk. The results showed that the water absorption of PEG-400etherified DMDHEU grafted raw silk was higher than the PEG-4000etherified DMDHEU grafted raw silk, which was consistent with the nature of the PEG, namely, the larger molecular weight, the stronger absorbent. |
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