热动力学驱动的涤棉废弃物PET分离与表征研究OA

With the continuous growth in global textile consumption,the issue of recycling and reusing waste textiles has become increasingly prominent.As one of the most widely used blended materials,polyester-cotton blended fabrics present significant challenges in waste management.Traditional methods such as chemical,enzymatic,and physical separation techniques suffer from low efficiency,environmental pollution,or high costs in separating polyester-cotton blended fabrics.Therefore,developing an efficient,environmentally friendly,and industrially scalable separation technology has become a research priority.This study is based on thermodynamic principles and has designed a heating separation technology aimed at achieving efficient separation of polyester-cotton blended textiles.The physical and chemical properties of the separated products are systematically evaluated to provide new pathways for the green recycling and high-value utilization of waste textiles. This study used polyester-cotton blended textiles(65%cotton/35%polyester)as experimental materials and designed a heating separation device.By precisely controlling the temperature,the polyester(PET)was melted,while the cotton fibers decomposed at high temperatures,achieving selective separation.The experiment employed multiple characterization techniques,including thermogravimetric analysis(TGA),infrared spectroscopy(IR),differential scanning calorimetry(DSC),and high-performance liquid chromatography(HPLC),to systematically analyze the thermal stability,functional group composition,melting behavior,and oligomer content of the separated products.Additionally,key process parameters such as heating temperature,time,and sample mass were optimized using experimental design(DOE)and response surface methodology(RSM)to enhance separation efficiency. The results showed that the separated PET components exhibited high consistency with the original PET in terms of thermal stability,functional group composition,and melting behavior.TGA analysis showed that the onset decomposition temperatures of the two were 402℃and 413℃,respectively,with the maximum weight loss rates occurring around 441℃.In the IR spectra,the characteristic absorption peaks of the separated products(such as the C=O bond stretching vibration at 1 710 cm-1)perfectly matched those of the original polyester,indicating that the heating process did not damage the chemical structure of PET.DSC testing revealed that the melting temperature of the separated products(254℃)was slightly lower than that of the original PET(258℃),which may be attributed to partial chain breakage of PET molecules due to high-temperature treatment.HPLC analysis further confirmed that the oligomer content in the separated products was approximately 1%,consistent with the oligomer content range(0.5%-3%)of the original PET. Through response surface optimization,the optimal process parameters were determined:heating temperature of 300℃,heating time of 117 minutes,and sample mass of 2 grams,and a separation efficiency of 68.54%was achieved.Analysis of variance indicated that heating temperature,time,and sample mass all had extremely significant effects on separation efficiency(P<0.000 1).Among these,heating time exhibited a nonlinear relationship with separation efficiency,which is closely related to PET's melting kinetics(Avrami index 2-3)and cumulative thermal degradation effects.Additionally,increasing sample mass prolongs thermal penetration time,leading to increased temperature gradients and thereby affecting separation efficiency. The innovation of this study lies in the first application of thermodynamically driven heating separation technology to the separation of polyester-cotton blended textiles.The high purity of the separation products was verified through multiple characterization methods,and process parameters were optimized through experimental design,providing a reliable basis for industrial application.This technology offers advantages such as simple operation,environmental friendliness,and efficient separation,opening new avenues for the resource utilization of waste textiles.Future research could further explore the separation patterns of large-scale samples,optimize device design to enhance separation efficiency,and assess the economic viability and scalability potential of this technology.