Degradation of PVC/HC blends. II. Terrestrial plant growth test.

UNLABELLED: The behavior at degradation by soil burial of some plasticized polyvinyl chloride (PVC) based blends with a variable content of hydrolyzed collagen (HC) has been followed. MATERIAL AND METHOD: The modifications induced in the environment by the polymer systems (pH variation, physiologic state of the plants, assimilatory pigments) were studied. Using the growth test of the terrestrial plants, we followed the development of Triticum (wheat), Helianthus annus minimus (little sunflower), Pisum sativum (pea), and Vicia X hybrida hort, during a vegetation cycle. After the harvest, for each plant, the quantities of chlorophyll and carotenoidic pigments and of trace- and macroelements were determined. RESULTS: It was proved that, in the presence of polymer blends, the plants do not suffer morphological and physiological modifications, the products released in the culture soil being not toxic for the plants growth.

Degradation of polyvinyl chloride (PVC) / hydrolyzed collagen (HC) blends active sludge test.

UNLABELLED: Biodegradable polymers represent a solution for the environment protection: they decrease the landfill space, by declining the petrochemical sources, and offer also an alternative solution for the recycling. MATERIALS AND METHODS: The behavior during degradation in the presence of active sludge of some polyvinyl chloride (PVC) based blends with variable content of hydrolyzed collagen (HC) has been followed. Some samples were subjected to UV irradiation, for 30 hours. The modifications induced in the environment by the polymer systems (pH variation, bacterial composition), as well as the changes of the properties of the blends (weight losses, aspect etc.) were studied. RESULTS: During the first moments of degradation in active sludge, all the samples absorbed water, behavior which favored the biodegradation. The bacteriological analysis of the sludge indicates the presence of some microbiological species. Generally, the populations of microorganisms decrease, excepting the sulphito-reducing anaerobic bacteria, the actinomycetes and other anaerobic bacteria. CONCLUSIONS: PVC/HC blends are degraded with a significant rate in active sewage sludge. More susceptible for the degradation are the UV irradiated blends. After the migration of the components with a small molecular mass in the environment, the natural polymer is degraded. The degradation effect increases with the content in the natural polymer.