Studium degradace polyesterových mikro a nanovlákenných materiálů
Loading...
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Cílem práce je studium degradace a sledování vlivu degradace na mechanické vlastnosti polyesterových mikro a nanovlákenných materiálů, se zaměřením na polykaprolakton. V teoretické části jsou rešeršní formou popsány technologie výroby nanovlákenných vrstev, materiály využívané v tkáňovém inženýrství, mechanismus degradace a testování mechanických vlastností. V experimentální části jsou popsány metody a materiály použité při experimentech. V části výsledky a diskuze je popsána charakteristika vstupních materiálů, optimalizace enzymatické degradace (použitým enzymem byla Lipáza z Pseudomonas Cepacia) a měření mechanických vlastností v závislosti na stupni degradace. Během degradace se sledoval a hodnotil hmotnostní úbytek materiálu, změna morfologie, změna molekulové hmotnosti polymeru a změna krystalinity. Dále se sledovaly mechanické vlastnosti v průběhu degradace pomocí tahových zkoušek. Z výsledků vyplývá, že při vhodně zvolené koncentraci enzymu, je možné prodloužit dobu degradace a tím i déle provádět mechanické testování. Při koncentraci 5 U/10 mg vzorku bylo možné měřit mechanické vlastnosti až do 6. dne. V průběhu degradace dochází ke zhoršení mechanických vlastností všech testovaných materiálů. Zásadní vliv na degradaci má molekulová hmotnost polymeru. Materiál s vyšší molekulovou hmotností (PCL80) degraduje pomaleji a má lepší mechanické vlastnosti ve srovnatelné fázi degradace než materiály s nižší molekulovou hmotností (PCL45_A, PCL45_B).
The main aim of this thesis is to study the degradation and monitoring of degradation effect on the mechanical properties of polyester microfibrous and nanofibrous materials. The work is focused on matherials made from polycaprolactone. The theoretical part describes the technologies of nanofibrous layers production, materials used in the tissue engineering, the mechanism of polymer degradation and testing of mechanical properties. The experimental part describes the methods and materials used in the experiments. The results and discusion section describes the characteristics of the input materials, the optimalization of enzymatic degradation (the enzyme used was Lipase from Pseudomonas Cepacia) and the measurement of mechanical properies depending on the degree of degradation. During the degradation were monitored and evaluated the weight loss of the material, the change in morphology, the change in molecular weight of polymer and the change in rystalinity. Selected mechanical properties of materals during degradation were studied. The results show that with appropriately enzyme concentration the degradation time can be extended and the mechanical testing can be perfomed longer. At the concentration 5 U/10 mg of the sample was possible to measure the mechanical properties till day 6. During the degradation the mechanical properties of all tested materials deteriorate. The material prepared from the higher molecular weight polymer (PCL80) degrades significantly lower than those prepared from the polymer of the lower molecular weight (PCL45_A, PCL45_B). This material also exhibits better mechanical properties in a comparable degradation phase.
The main aim of this thesis is to study the degradation and monitoring of degradation effect on the mechanical properties of polyester microfibrous and nanofibrous materials. The work is focused on matherials made from polycaprolactone. The theoretical part describes the technologies of nanofibrous layers production, materials used in the tissue engineering, the mechanism of polymer degradation and testing of mechanical properties. The experimental part describes the methods and materials used in the experiments. The results and discusion section describes the characteristics of the input materials, the optimalization of enzymatic degradation (the enzyme used was Lipase from Pseudomonas Cepacia) and the measurement of mechanical properies depending on the degree of degradation. During the degradation were monitored and evaluated the weight loss of the material, the change in morphology, the change in molecular weight of polymer and the change in rystalinity. Selected mechanical properties of materals during degradation were studied. The results show that with appropriately enzyme concentration the degradation time can be extended and the mechanical testing can be perfomed longer. At the concentration 5 U/10 mg of the sample was possible to measure the mechanical properties till day 6. During the degradation the mechanical properties of all tested materials deteriorate. The material prepared from the higher molecular weight polymer (PCL80) degrades significantly lower than those prepared from the polymer of the lower molecular weight (PCL45_A, PCL45_B). This material also exhibits better mechanical properties in a comparable degradation phase.
Description
Subject(s)
degradace, biodegradace, nanovlákna, polyestery, polykaprolakton, mechanické testování, degradation, biodegradation, nanofibers, polyesters, polycaprolactone, mechanical testing