Polyhydroxyalkanoates (PHAs) are a family of naturally-occurring thermoplastic polyesters, biologically derived by bacterial fermentation. PHAs are fully biodegradable by microorganisms and a viable substitute for most plastic applications such as packaging and textiles. Several research studies have investigated the production of PHA textile filaments with melt spinning, which is the most cost-effective fibre production method. However, poor thermal stability and slow crystallization of PHAs limits the melt-spinning of fibres and results in inadequate mechanical properties. Therefore, in this study, we tried to establish different conditions and parameters for melt spinning of PHA filaments with improved properties. Consequently, the aim of our study is focused on the development of PHA melt-spun filaments with improved properties by an economically viable process and to investigate the role of production parameters on processability in the melt-spinning line.
Since PHAs are thermoplastic in nature, melt spinning under reasonable conditions is feasible. In this study, PHA multifilaments were produced on an industrial-scale melt-spinning plant. During extrusion, PHAs have nonhomogeneous melt due to the low process temperature that is preferred to prevent thermal degradation. Besides, melt strength is low and crystallization rate is slow which leads to the polymer sticking to the godets. We could overcome such processing limitations of these biodegradable polymers with the improvements/modifications in the melt-spinning line. Tensile test results suggest that PHAs can be melt-spun into filaments with decent mechanical properties in an industrial-scale melt-spinning line.