| As a major textile and garment country,China has a large demand for textile raw materials.Due to the shortage of resources,a large amount of imported textile raw materials are required every year.At present,most of the waste textiles are mainly burned and landfilled,or limited to some physical recycling,to produce some products with lower added value.This not only wastes resources,but also causes problems such as environmental pollution.The recycling and recycling of used textiles can further help solve the problem of insufficient textile raw materials and reduce environmental pollution.Therefore,it is of great significance to recycle the recycling of waste textiles.This paper takes the recycling of textiles from elastic cotton-polyester blended textiles as a technical route.The elastic cotton-polyester blended textile is subjected to a low alkali treatment and a DMAC(N,N-dimethylacetamide)solution to obtain a recycled cotton fiber.The structure and properties of cotton fibers were studied.At the same time,the structure and properties of spandex under various process conditions were discussed.The effects of alkali treatment on the properties of spandex under different treatment conditions were studied.The dissolution process of spandex and the recycled cotton fiber obtained after alkali dissolution and spandex dissolution of elastic textiles were explored by controlling the experimental parameters such as reaction time,reactant concentration and temperature.Research.The following conclusions were obtained:(1)The effect of low alkali on the structure and properties of spandex was discussed.,and the spandex breaking strength and elasticity test were used as indicators.The effects of treatment temperature,treatment time and alkali solution concentration on the properties of spandex were investigated,and the optimal treatment conditions were obtained.It was found that the decrease in the breaking strength of spandex was positively correlated with the treatment time,treatment temperature and alkali solution concentration.(2)The effects of DMAC solution treatment time,temperature and DMAC concentration on the breaking strength and elasticity of spandex were discussed.In addition,the performance changes of spandex were analyzed by infrared spectroscopy and crystallinity test.It wasconcluded that the strength of spandex under non-DMAC pure solution treatment conditions increases with raising treatment temperature,time and solution concentration.The crystallinity analysis was found to be because the crystallinity of the treated spandex filament was positively correlated with the treatment time,temperature and concentration,which results in an increase of the breaking strength.The spandex after the DMAC pure solution treatment will dissolve.It was found that the treatment time was at least 15 min at a reaction ratio of 1:30 and a reaction temperature of 30 °C.(3)The properties of the cotton fibers treated with the DMAC pure solution and the alkali solution were analyzed.The mass loss rate and the breaking strength of the cotton fiber were tested.In addition,the reasons for the change in cotton fiber properties were analyzed by infrared spectroscopy and crystallinity tests.It has been found that the reduce in the breaking strength of the cotton fiber decreases as the ratio of the reactants,the treatment temperature and the treatment time increase.Moreover,the quality of cotton fibers will also decrease after being treated.It was found by infrared spectroscopy and crystallinity test that the chemical composition of cotton fiber did not change.Only the amorphous and crystalline regions inside the fiber have changed,and the crystallinity of the treated cotton fiber has decreased,which is one of the reasons why the breaking strength of the cotton fiber decreases after being treated. |
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