Recycling cellulosic fibres from waste textile by cellulose carbamate technology (CCA)
Nguyen, Thu Lam (2020)
Nguyen, Thu Lam
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As the new transition of energy is obviously motivated forward which applies technology and constructs closed-loop materials, the textile industry has to confront a massive issue – where solid waste should be administered cautiously. Hence, eco-friendly materials and circular techniques are utilized to improve the performance of the textile industry, whereas cellulose-based fibre and their chemically recycled pathways are concerned. Cellulose carbamate (CCA) technique is especially implemented to recover discarded cotton and dissolving pulp cellulosic fibres. To recover cellulosic fibre in waste cotton or viscose products, the pre-treatments are carried out to withdraw silicate, impurities such as metal and ash by applying alkali, ozone, peroxide and acidic washing prior to the actual carbamation process. The CCA mixture is formed by reacting with urea, small amount of H2O2 and kneader. The cellulose intermediate is soluble in NaOH solution with the aid of ZnO as additive. It is precipitated subsequently into fibres in acidic coagulation baths with Na2SO4 and Al2(SO4)3. The reacted urea attached to cellulose is removed in mild NaOH solution and performed after completing the spinning process. The CCA fibres possess the similar properties but it is more sustainable compares to viscose products. This thesis demonstrated the literature review of CCA production, which has been gradually developed by diverse inventions to acquire the appropriate methods synthesizing CCA fibres from reacting cellulose with urea, or alternative agents to urea aqueous during the CCA formation and dissolution, or alternative baths in the spinning dopes. This thesis also comprised of the mass balance of CCA production by implementing chemical charge and utilized water during the process as the main sources to evaluate GWP, recommending the suitable locations for the factory of CCA and circulation pathway of significant chemicals used to dissolute and regenerate CCA fibres.