Byla zkoumána oxo-biodegradabilita polyetylenových mulčovacích fólií lišících se v množství stabilizátorů, antioxidantů a prooxidantů. Degradace způsobená kombinovaným účinkem ultrafialového záření, tepla, vody a vlhkosti byla sledována pomocí změn v infračerveném spektru, dynamické viskozitě a prodloužení při přetržení. Byl potvrzen předpokládaný rozdíl v kinetice mezi fotooxidací a termooxidací. Dále bylo zjištěno, že voda silně urychlovala fotooxidaci zkoumaných mulčovacích fólií. Naproti tomu vlhký vzduch termooxidaci inhiboval. Zoxidovaný povrch vzorků byl doložen pomocí stereomikroskopie.
Anotace v angličtině
Oxo-biodegradation of blown polyethylene mulching films differed in the level of stabilizers, antioxidants and pro-oxidants has been studied. The degradation was followed by changes in infrared spectrum, dynamic viscosity and elongation at break during exposure of samples to the combination of ultraviolet light, heat, water and humidity. Different kinetics of degradation between photo-oxidation and thermo-oxidation was found. Significantly, water had an accelerating effect on the photo-oxidation of mulching films under study. In contrast, humid air during thermo-oxidation was found to be an inhibitor. Oxidised surface of the specimens was documented by stereomicroscopy.
Byla zkoumána oxo-biodegradabilita polyetylenových mulčovacích fólií lišících se v množství stabilizátorů, antioxidantů a prooxidantů. Degradace způsobená kombinovaným účinkem ultrafialového záření, tepla, vody a vlhkosti byla sledována pomocí změn v infračerveném spektru, dynamické viskozitě a prodloužení při přetržení. Byl potvrzen předpokládaný rozdíl v kinetice mezi fotooxidací a termooxidací. Dále bylo zjištěno, že voda silně urychlovala fotooxidaci zkoumaných mulčovacích fólií. Naproti tomu vlhký vzduch termooxidaci inhiboval. Zoxidovaný povrch vzorků byl doložen pomocí stereomikroskopie.
Anotace v angličtině
Oxo-biodegradation of blown polyethylene mulching films differed in the level of stabilizers, antioxidants and pro-oxidants has been studied. The degradation was followed by changes in infrared spectrum, dynamic viscosity and elongation at break during exposure of samples to the combination of ultraviolet light, heat, water and humidity. Different kinetics of degradation between photo-oxidation and thermo-oxidation was found. Significantly, water had an accelerating effect on the photo-oxidation of mulching films under study. In contrast, humid air during thermo-oxidation was found to be an inhibitor. Oxidised surface of the specimens was documented by stereomicroscopy.
The work will focuse on a novel class of polymeric materials, so-called oxo-degradable polyethylene, intended for agricultural applications. The main attention will be paid to the interrelation between the durability and formulation of these systems. Two grades of polyethylene doped by various pro-degrading additives will be processed into films via extrusion blow moulding. Films will be exposed to UV light under the condition of accelerated ageing. Durability will be studied by both chemical analysis (spectroscopy analysis, carbonyl index determination) and viscoelastic and mechanical analysis to obtain the profound knowledge of the evolution in material properties upon the degradation process.
Zásady pro vypracování
The work will focuse on a novel class of polymeric materials, so-called oxo-degradable polyethylene, intended for agricultural applications. The main attention will be paid to the interrelation between the durability and formulation of these systems. Two grades of polyethylene doped by various pro-degrading additives will be processed into films via extrusion blow moulding. Films will be exposed to UV light under the condition of accelerated ageing. Durability will be studied by both chemical analysis (spectroscopy analysis, carbonyl index determination) and viscoelastic and mechanical analysis to obtain the profound knowledge of the evolution in material properties upon the degradation process.
Seznam doporučené literatury
Raff, RAV. Polyethylene. New York: Interscience Publishers, 1956.
Geuskens, G. Degradation and Stabilization of Polymers. London: Applied Science Publ., 1975.