Study On The Influence Of Recycling Processes Of Densified Post-consumer Polyester Fabric

In recent years,waste polyester textiles of high value-added chemical recycling problems become the focus in the people.However,the volume of crushed waste polyester textiles is fleeciness,it is difficult to contact with liquid degradation of reagent effectively.So the waste polyester textiles must be treated with densification.While,what happens in the structure of different densification process and whether these changes will affect the subsequent polymerization process,the quality of final product and spinning process are problems that must study and solve.Firstly,post-consumer fabrics undergone four different densification processes were used as raw materials(namely:textile fabric scraps,semi-thermal densified textiles,melt extrusion material,loose granulating textiles)to study the effect of densification level on the structure and properties of recycled PET.The Soxhlet extraction was conducted on the above raw materials with o-cresol as solvent.The structure of the extracts obtained was characterized using DSC,FTIR and 1HNMR.The recycled PET chips were prepared with a so-called partial degradation plus re-polymerization process.The structure of the PET thus obtained were characterized using DSC,GPC,Potentiometric Titration and GC respectivelyThe results showed that varying degrees of thermal degradation of the post-consumer fabrics occurred after the densification process.Among them,hydrolyzation of loose granulating textiles occurred after the densification process.Semi-thermal densified textiles can minimize the thermal degradation.Using semi-thermal densified textiles as raw material,the recycled PET chips have high intrinsie viscosity,good molecular weight distribution and thermal stability;have low content of carboxyl groups and diethylene glycol.The studies on the rheological properties of different density forms of post?consumer fabrics were done in this paper.The recycled fibers were prepared with model-scale melt spinning and single screw small spinning machine.The morphology,crystallization behavior and mechanical properties of the recycled fibers were characterized using SEM,XRD and tensile tester respectively.The results showed that the densification of waste polyester textiles have no essential effect on the rheological behavior.They are all showed non-Newtonian pseudo-plastic fluid behavior.The result of melt spinning with different density form of recycled PET chips shows that semi-thermal densified textiles has better spinnability than melt extrusion material and loose granulating textiles.The recycled fibers of melt extrusion material and loose granulating textiles have“bulge,in the longitudinal surface,and the thickness of the fibers are uneven,so the drafting cannot go smoothly.The highest breaking strength of recycled fiber obtained from semi-thermal densified textiles has reached 2.96cN/dtex with 19.21%of breaking elongation in the condition of 1000 m/min of spinning speed and 3.5 times of the draft.This recycled fiber basically meets the requirements for the conventional apparel fibers.