Research On Recovery Technology Of Nylon/polyester/cotton Blend Fabrics

This paper introduces the recovery technology of the polyester/cotton/nylon textile fabrics.The purpose of this paper is to separate the three components of polyester/cotton/nylon textile fabric by using chemical method.Firstly,the N-methyl morpholine-N-oxide?NMMO?was used to dissolve the cotton fiber to obtain the spinning solution of cellulose/NMMO/H₂O;secondly,the polyester fiber is dissolved by alcohol-alkali combination method to achieve the terephthalic acid?TPA?powder;finally,the undissoluted nylon fiber is filtered,washed,dried and recovered.The experimental process is divided into four stages,and the specific process was as follows:In the first stage,the blended fabrics are activated.As the result of the high degree of crystallization and the crystalline region of cotton fibers,it is necessary to activate the cellulose fiber before the dissolve of cellulose fiber.The concentration of sodium hydroxide and the activation time were taken as the influencing factors.The orthogonal experiment showed that the main factor of influencing the activation of cotton fiber was the concentration of sodium hydroxide,and the secondary factor was the activation time.In order to ensure the fabric loss rate as small as possible,the activation parameters were as follows:the concentration of sodium hydroxide concentration was 10%,activation time was 12h.The structure and properties of activated cotton fiber were tested,analyzed,and the XRD showed that the crystallinity of activated cotton fiber decreased obviously.The purpose of the second stage is to dissolute the cotton fiber.The effects of mass fraction of NMMO,dissolution temperature,swelling time of dimethyl s ulfoxide?DMSO?and the ratio of solute to solvent on the dissolution of cotton fiber were analyzed by single factor experiment.The orthogonal experiment was used to optimize the process conditions,it was found that the optimum dissolution conditions of cotton fiber were as follows:the temperature was 95?,the mass fraction of NMMO was 87%,the swelling time of DMSO was 60min,the ratio of solute to solvent was 3:100.The best dissolving process was used to dissolve the cotton fiber,and the cellulose/NMMO/H₂0 solvent system was obtained.The cellulose film was prepared by electrostatic spinning and its properties were tested and analyzed.The third stage,the dissolution of polyester technology was studied.Alcohol-alkali method was used to dissolve the polyester fiber,and the effects of alkali metal compound and alcohol species,dissolution time,reaction temperature and the volume fraction of dioxane?DX?on the dissolution of polyester fiber were analyzed by single factor experiment.The results showed that the dissolution of polyester was better with potassium hydroxide?KOH?.The higher the reaction time,the higher the yield of terephthalic acid?TPA-K₂?.The higher the volume fraction of DX,the higher the yield of TPA-K₂.The yield of terephthalic acid?TPA-K₂?increased firstly and then decreased when the reaction temperature increased,and when the reaction temperature was 170?and the dissolution of polyester is the best.From the aspect of economy and resource utilization,KOH was used as the alkali metal compound,ethanol?C₂H₅OH?as the hydrolyzed alcohol,the temperature was 170?,the dissolution time was 40min and the volume fraction of DX was 20%better.The fourth stage,structural and performance testing of the terephthalic acid.The target product after PET recovery was identified as terephthalic acid by elemental analysis and infrared spectroscopy.The purity,acidity,surface structure,crystallinity and thermal properties of TPA were measured and analyzed respectively.Finally,the remaining nylon fiber was washed and dried to be used for subsequent spinning or non-woven fabric production.52 figures,23 tables and 118 references.