Influence of biological factors in aging of polymeric materials under natural environmental conditions

Abstract

Two copolymers were investigated for long-term influence of environmental factors. The polymers were exposed in the open air, in a special containers kept in the open air and in damp cellar. Microbiological evaluation of the exposed materials showed that these copolymers were contaminated by micromycetes. Scaning electron microscopy allowed to observe abundant fungal growth with well developed hypha, spore producing structures and formed colonies. As these polymers are hardly available for fungi, their development was possibly determined by outer nutritional and energy sources – pollutants settled on the materials. The heaviest contamination of the materials was noticed in cellar conditions where constant high humidity prevailed. IR spectroscopy of the materials showed that tetrafluorine ethylene and hexafluorine propylene copolymer kept in the open air and containers did not undergo structural changes. Meanwhile, IR spectrum of the sample exposed in cellar, showed high changes in structure. The results allow to conclude that microorganisms could have an effect on materials deterioration and destruction processes.Structural changes of the copolymer of tetrafluorine ethylene and vinylidene fluoride were observed after exposure of its samples in the open air, where all environmental factors influenced, and in the cellar, where combined effect of humidity and microorganisms took place.

Medžiagų struktūros pokyčių tyrimas IR spektroskopijos metodais leidžia teigti, kad tetrafluoretileno ir heksafluorpropileno kopolimero bandinių, laikomų atviroje lauko aikštelėje ir mikologiniame namelyje, struktūra nepasikeitė. Tuo tarpu rūsio sąlygomis laikytos šios medžiagos struktūroje pastebėta ryškių pakitimų. Galima teigti, kad tokius pokyčius galėjo sukelti gausiai besivystantys mikromicetai, kuriems būdingas intensyvus metabolizmas. Tetrafluoroetileno ir vinilidenfluorido kopolimero bandinių, laikytų lauko aikštelės ir rūsio sąlygomis, IR spektruose rasta struktūrinių pokyčių,. kuriuos galėjo sukelti kompleksinis aplinkos veiksnių poveikis.