Aleksandra Heimowska

Degradation of polyurethanes in sea water

Abstract The estimation of degradability of different polyurethanes in the Baltic Sea water and liquid medium containing sea water with sodium azide (NaN3) was the subject of this study. The incubation of polymer samples took place in both environments for a period up to 12 months. The characteristic parameters of sea water are presented and their influence on degradation of polyurethanes is discussed. The changes of weight, tensile strength and morphology of polyurethane samples were tested after particular period of incubation in both environments. It is demonstrated that the degree of degradation of polyurethanes in sea water is dependent on the degree of crosslinking.

Chemical and Enzymatic Hydrolysis of Polyurethane/Polylactide Blends

Polyether-esterurethanes containing synthetic poly[(R,S)-3-hydroxybutyrate] (R,S-PHB) and polyoxytetramethylenediol in soft segments and polyesterurethanes with poly(e-caprolactone) and poly[(R,S)-3-hydroxybutyrate] were blended with poly([D,L]-lactide) (PLA). The products were tested in terms of their oil and water absorption. Oil sorption tests of polyether-esterurethane revealed their higher response in comparison to polyesterurethanes. Blending of polyether-esterurethanes with PLA caused the increase of oil sorption. The highest water sorption was observed for blends of polyether-esterurethane, obtained with 10% of R,S-PHB in soft segments. The samples mass of polyurethanes and their blends were almost not changed after incubation in phosphate buffer and trypsin and lipase solutions. Nevertheless the molecular weight of polymers was significantly reduced after degradation. It was especially visible in case of incubation of samples in phosphate buffer what suggested the chemical hydrolysis of polymer chains. The changes of surface of polyurethanes and their blends, after incubation in both enzymatic solutions, indicated on enzymatic degradation, which had been started despite the lack of mass lost. Polyurethanes and their blends, contained more R,S-PHB in soft segments, were degraded faster.

Biodegradation of the Blends of Atactic Poly[(R,S)-3-hydroxybutanoic Acid] in Natural Environments

The paper presents a part of the results of the biodegradation of the blends of natural poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and atactic poly[(R,S)-3-hydroxybutanoic] acid or natural poly [(R)-3-hydroxybutanoic acid] in natural environments such as a compost containing active sludge and under marine exposure conditions in sea water.

Biodegradation of poly(ε-caprolactone) in natural water environments

Abstract The environmental degradation of poly(ε-caprolactone)[PCL] in natural fresh water (pond) and in The Baltic Sea is presented in this paper. The characteristic parameters of both environments were measured during experiment and their influence on the biodegradation of the samples was discussed. The loss of weight and changes of surface morphology of polymer samples were tested during the period of incubation. The poly(ε-caprolactone) was more biodegradable in natural sea water than in pond. PCL samples were completely assimilated over the period of six weeks incubation in The Baltic Sea water, but after forty two weeks incubation in natural fresh water the polymer weight loss was about 39%. The results have confirmed that the investigated polymers are susceptible to an enzymatic attack of microorganisms, but their activity depends on environments.

Degradability of organic-inorganic cellulose acetate butyrate hybrids in sea water

Degradability of organic-inorganic cellulose acetate butyrate hybrids in sea water Environmental degradability of novel organic-inorganic cellulose acetate butyrate hybrids obtained via solgel process was investigated. The degradation of hybrids was studied under marine exposure conditions in the Baltic Sea for a period of 25 weeks. The influence of characteristic parameters of sea water on the degree of degradation monitored by changes of weight and optical microscopy was discussed. The degraded samples were also examined by FT-IR spectroscopy. It has been established that the CAB/silica hybrids are more susceptible to biodegradation in sea water environment than pure cellulose acetate butyrate.

The influence of chemical structure on thermal properties and surface morphology of polyurethane materials

The surface morphology and thermal properties of polyurethanes can be correlated to their chemical composition. The hydrophilicity, surface morphology, and thermal properties of polyurethanes (differed in soft segments and in linear/cross-linked structure) were investigated. The influence of poly([R,S]-3-hydroxybutyrate) presence in soft segments and blending of polyurethane with polylactide on surface topography were also estimated. The linear polyurethanes (partially crystalline) had the granular surface, whereas the surface of cross-linked polyurethanes (almost amorphous) was smooth. Round aggregates of polylactide un-uniformly distributed in matrix of polyurethane were clearly visible. It was concluded that some modification of soft segment (by mixing of poly([R,S]-3-hydroxybutyrate) with different polydiols and polytriol) and blending of polyurethanes with small amount of polylactide influence on crystallinity and surface topography of obtained polyurethanes.

Environmental Degradability of Polyurethanes

The growing interest in environmental issues and increasing demands to develop materials that do not burden the natural environment significantly are currently observed. In this connection many studies on polymer degradation in different environments are carried out. It is important to consider the influence of synergistic action of various factors in order to understand the environmental degradation of synthetic polymers. This requires understanding of interactions between polymer and living organisms. This paper reviews current authors research on environmental degradation of polyurethanes. The comparison of environmental degradability of polyurethanes in the Baltic Sea water and compost under natural weather depending conditions is presented. The environmental degradation of poly(ester-urethane) based on poly(ethylene-butyleneadipate) and poly(ester-urethane) based on poly (e -caprolactone) was evaluated. The characteristic parameters of sea water (temperature, pH, salt, and oxygen contents) and of compost (temperature, pH, moisture content, and activity of dehydrogenases) were monitored and their influence on degradation of polyur‐ ethanes was discussed. The environmental degradability of polyurethanes was investigated by changes of weight, tensile strength, morphology, and crystallinity of polyurethanes after incubation in environment. The investigated polyurethanes were degradable in both natural environments and their environmental degradability depends on the chemical structure and the kind and conditions of environment.