Selective Oxidation Of Bamboo Pulp Fiber And Research On Modified Structure And Properties By Silk Fibroin

Bamboo pulp fiber is a kind of regenerated cellulose fiber and the modification for it has become the most important study.It can be widely used in the production of underwear,bedding,hygiene materials.In addition,China is rich in bamboo resources which laying a good foundation for the development and production of bamboo pulp fiber.But the breaking strength of bamboo pulp fiber would decrease after moisture absorption and bamboo pulp fiber fabric has larger washing shrinkage,wrinkles easily and has poor shape retention,etc.Therefore,the use of a variety of chemical or physical methods to bamboo pulp fiber for functional modification and the study of supramolecular structure and physicochemical properties of bamboo pulp fiber before and after modification,would be a great significance for the potential function,the further development of bamboo fiber and to the increase value and expand of bamboo pulp fiber applications.However,the traditional modified technology would have a negative impact on the ecological environment and human health while modify the performance of bamboo pulp fiber,it is difficult to meet the requirements of modern green eco-textiles.Therefore,the green technology used in modern textile will be an effective way to achieve sustainable development and improve the competitiveness of China’s textile products.This article used the HNO₃/H₃PO₄-NaNO₂ oxidation system oxidized bamboo pulp fiber selectively,the C6 position hydroxyl on the cellulose glucose units was oxidized to be reactive carboxyl,and study the oxidant concentration and oxidation time on the carboxyl content and yarn weight loss,breaking strength.The active carboxyl make bamboo pulp fiber can be have an amide cross-linking reaction directly with other organic or inorganic chemicals which containing amino reactive groups.Then use the silk fibroin solution to soak the oxidative bamboo pulp fiber and silk fibroin cross-linked oxidized bamboo pulp fiber were prepared successfully.While optimizing the modification process and optimum modification conditions.In the entire modification process we do not use any chemical cross-linking agents or additives,the silk fibroin cross-linked oxidized bamboo pulp fiber is a natural material and the preparation process is simple,which were both in line with people’s environmental protection requirements.The results show that the primary hydroxyl on oxidation bamboo pulp fiber macromolecular chain is oxidized to be lively carboxyl,and oxidized bamboo fibers were prepared successfully.The increase of oxidant concentration and extension of oxidation time will improve the carboxyl content of bamboo pulp fiber,but the breaking strengthdecreases and weight loss increases.In order to maintain the breaking strength of oxidized bamboo pulp fiber yarns and preparing a sufficient amount of carboxyl for the next reaction with silk fibroin,we selected oxidation process and the oxidant concentration is1.0%,oxidation time is 60 min and oxidation temperature is 25 ℃.The weight gain of oxidation bamboo fiber yarns increase with the increasing concentration of silk fibroin solution after being modified by silk fibroin,and when the concentration of silk fibroin solution is more than 30g/L,the weight gain of oxidation bamboo yarns is leveled off;when the modification temperature at 40 ℃-70 ℃,the weight gain of yarns changed little,but once the temperature exceeds 70 ℃,the weight gain of yarns decreased;when modified time is 1h,the weight gain of yarns is the biggest,once exceeds 1h,the weight gain of yarns decreases.The concentration of silk fibroin solution has little influence on the yarn,but too high modified temperature and too long modified time make the breaking strength of yarns decrease.The result of orthogonal experiment shows that the optimum modified process is the concentration of silk fibroin solution is 30g/L,modified temperature is 40℃,modification time is 90 min.The analysis of Scanning electron microscopy,infrared spectroscopy,X-ray diffraction and solid-phase test show that the C6 primary hydroxyl group in the macromolecules of bamboo pulp fiber is oxidized to be carboxyl group,but the structure of cellulose macromolecules is not changed,the amino on silk fibroin react with the carboxyl and form a C-N covalent bond.