Investigating the effect of modifications applied to bio-degradable polyester fibers on the properties of product

In this PhD thesis, textile fibres and compounds from biodegradable polymers, that becoming increasingly important both environmentally and economically, were produced with processes that are applicable to large scale production. Melt-spinning of biodegradable fibres with different properties, along with the incorporation of additives and alterations in the production parameters, were manufactured. Besides, the effect of the compound properties on fibre production was analysed. In the study, at first melt-spinning of solid and hollow neat polyhydroxybutyrate-co-valerate fibres were performed, then constraints on neat fibre production were overcome by incorporation of additives. Extrusion temperatures were reduced by the addition of processing aid and filament flow was also improved. Moreover, poly(hydroxybutyrate-co-valerate)/poly(lacticacid) bicomponent fibres and monofilaments of poly(caprolactone) polymer with a low melting point were successfully melt-spun. In poly(caprolactone) monofilament production, modification in the drawing unit enabled to stabilize the necking point of the fibre. In the extrusion of polyhydroxybutyrate compounds, tributyl citrate and polycaprolactone were used as the plasticizer. Polyhydroxybutyrate-co-valerate compounds including functional additives (alpha-cellulose and titanium dioxide) and plasticizers (polypropylene and tributyl citrate) were also produced. Plasticizers improved the thermal stability and increased the crystallization temperature of biodegradable compounds. The results of the study will contribute to the research and development studies on biodegradable material production and inspire the textile industry for further studies on the biodegradable fibre spinning.