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Abstract:
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The braids studied in this thesis were manufactured from biodegradable lactic acid stereocopolymer P(L/D)LA 96/4. Two sizes of monofilament fibres were used, 0.16 and 0.25 mm in diameter, and a 8-multifilament yarn, each filament 0.09 mm in diameter. The braids made of monofilament fibres consisted of 16, 24 and 32 fibres, while the multifilament braids had 12 and 14 yarns, thus having 96 and 192 single filaments. All brains were tested using tensile testing and the changing of the properties in vitro was studied with some braiding batches. The 24-multifilament braid performed well in the tensile test; its maximum load was 453 N, and the strain increased to 54%. After six weeks in hydrolysis the maximum load decreased to 253 N and the strain was 41%. Monofilament braids had a maximum load of 273 N (32 x 0.25 fibre) with a strain of 35%. The specimens of monofilament braids were 9 weeks in hydrolysis and the tensile properties changed only slightly: a 5-9% decrease in maximum load and 2-14% increase in strain.Multifilament braid was also braided over the various mandrels: monofilament and multifilament braids and Polyactive tube. These braids were tested with the compression test. The two-layered multifilament braid found back its rounded shape in hydrolysis and hardened slightly. The multifilaments braided over the Polyactive mandrel kept the swollen Polyactive well inside the braid in vitro. /Kir10 |