Investigation of the effect of colour masterbatch addition on the physical, mechanical and thermal properties of recycled polyethylene terepthalate fibers

Polyethylene terephthalate (PET) is a recyclable thermoplastic polymer. However, after several recycling processes of PET, degraded PET (d-PET) waste is formed. In order to utilize this d-PET waste and discover new useful form for it, the formation of by-products from d-PET waste was studied. In this regard, thermal, molecular, structural and chemical analyzes of d-PET were initially compared with virgin fiber grade PET, recycled PET (r-PET) flake, and r-PET granules. In order to obtain new useful carbonized materials and chemicals from d-PET, carbonization was carried out and optimum processing parameters were determined. As a result, the carbonization material yield of over 20% and the chemical yield of over 17% were achieved from the carbonization of d-PET. With using different milling speeds and time particle sizes of the carbonized material were reduced to nanometer scale and recycled carbon powders (r-CPs) were obtained. Fully recycled colour masterbatch (frc-MB) composites were also formed by using this r-CPs in different ratios. Lastly, fully recycled and coloured PET (frc-PET) filaments and fibers were formed with using varying amounts of frc-MB. Physical, mechanical and morphological properties of frc-PET fibers were investigated. Fully recycled products of frc-MB and frc-PET fibers were successfully developed from the d-PET waste.