Early causes for biodegradation of PVA/PVC tapes for audio recording

Catégorie : Biodégradation
Date :6 novembre 2020
Da Costa Ribeiro, Ana Paula; Rosa, Teresa; Bressan, Federica.
146th Aes Convention
The degradation of magnetic tapes is one of the main threats to the survival of our collective audio heritage. Archives around the world, big and small, are all concerned with the same challenge, that of counteracting the natural decay of plastic compounds. This study investigates the biodegradation of poly(vinyl alcohol)/poly(vinyl chloride) (PVA/PVC) blends tapes, namely audio magnetic tapes, using the spectrophotometry (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The tapes (both sides) were studied in the light of their degradation in special conditions. The objective is to obtain more information regarding the polymer degradation of magnetic tapes for audio recording and how it affects the structural composition of the tapes. This study contributes to the long-term goal of building a structured knowledge base about diagnostic tools and recovery methods for magnetic tapes. Biodegradation generally allows for cheaper final disposal of plastic waste through composting and returns the polymer into the natural carbon cycle. By definition, biodegradable polymers are those that are degraded into carbon dioxide, water, and biomass as a result of the action of living organisms, special conditions or enzymes. The rate of degradation and polymer crystallinity are important factors affecting the biodegradability, with degradation taking place preferentially in the polymer amorphous domains [1]. Some of these biodegradable polymers are poly(vinyl alcohol) (PVA) and poly(vinyl chloride) (PVA/PVC), which are the main constituents of most of the magnetic tapes for audio recording from the 1970s and 80s (Figure 1). Poly (vinyl alcohol) (PVA), a water soluble synthetic polymer prepared by the hydrolysis of polyvinyl acetate, is widely used in adhesives, chemicals, coatings and paints.