Polyvinyl alcohol films with different degrees of hydrolysis and polymerization

Abstract

The objective of this work was to manufacture biodegradable films based on polyvinyl alcohol (PVA) and also to evaluate the effect of the different degrees of hydrolysis (DH) and degrees of polymerization (DP) of PVA on the properties of these films. Four different types of PVA with DH ranging from 88.0 to 98.4% and DP ranging from 150 to 2000 were used to produce the films by casting, and glycerol was used as plasticizer. Films based on PVA with lower DH (SelvolTM 540 and 203) showed higher solubility, water vapor permeability and water sorption capacity, and also were less rigid, and had lower glass transition and melting temperatures when compared to films obtained from higher DH PVA (SelvolTM 325 and 107). The DP affected the solubility of the films, the film produced with the higher DP (SelvolTM 325 - DP = 1000????1500) showed lower solubility value. Films based on PVA with higher DP (SelvolTM 540 and 325) showed higher elongation values. Both DH and DP affected PVA films properties, resulting in materials with different possibilities of applications, however, it was observed that however the effect of DH was most important for PVA films properties than DP effect.

Keywords

• biodegradable polymer
• degree of hydrolysis
• degree of polymerization.