This article presents the results from investigations of tensile tests, absorbency test and degradation test of biodegradable and non- or partly biodegradable yarns produced from pure poly hydroxybutyrate-co-valerate (PHBV), poly (lactide acid) (PLA), isotactic polypropylene (iPP) polymers and their blends. The results indicate that mechanical-physical properties of PHBV are improved by adding PLA and iPP to PHBV. The main results indicate that the PHBV/PLA and PHBV/iPP (70/30) blends had better mechanical properties than pure PHBV, as well as improved immiscibility and the same or lower degradation in sodium chloride solution, respectively. The PHBV/PLA and PHBV/iPP blends showed a tendency for lower crystallinity and stiffness of the yarns, rendering them less stiff and fragile. The absorption tests showed that absorption dynamic process depends on the structure and raw materials of the yarns. The disinfectant in all samples is absorbed faster than blood. Research results showed that pure PHBV yarns have good hydrophobic properties, compared with pure PLA and iPP yarns. The use of additional PLA and iPP polymers changed the wetting behaviour of yarns. Absorption time of blended yarns in disinfectant liquid decreases and absorption time in the case of blood significantly increases in comparison with PLA and iPP yarns and decreases compared with PHBV yarns. The degradation tests (within 90 days in a solution of sodium chloride) showed that pure PHBV and PHBV/PLA blends degraded at different rates but with the loss of the same weight, while pure PHBV and PHBV/iPP blends degraded at the same rate, but PHBV/iPP blends had worse destruction results. Such improvements are expected to be important for the practical application of PHBV in some fields
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