The impact of plasticizer and degree of hydrolysis on free volume of poly(vinyl alcohol) films
Date
2018-05
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
ENGLISH ABSTRACT: The effect of plasticizer species and the degree of hydrolysis (DH) on the free volume
properties of poly(vinyl alcohol) (PVA) were studied using positron annihilation lifetime spectroscopy.
Both glycerol and propylene glycol caused an increase in the free volume cavity radius, although
exhibited distinct plasticization behavior, with glycerol capable of occupying existing free volume
cavities in the PVA to some extent. The influence of water, normally present in PVA film under
atmospheric conditions, was also isolated. Water added significantly to the measured free volume
cavity radius in both plasticized and pure PVA matrices. Differences in plasticization behavior can
be attributed to the functionality of each plasticizing additive and its hydrogen bonding capability.
The increase in cavity radii upon plasticizer loading shows a qualitative link between the free volume
of voids and the corresponding reduction in Tg and crystallinity. Cavity radius decreases with
increasing DH, due to PVA network tightening in the absence of acetate groups. This corresponds
well with the higher Tg observed in the resin with the higher DH. DH was also shown to impact
the plasticization of PVA with glycerol, indicating that the larger cavities—created by the weaker
hydrogen bonding acetate groups—are capable of accommodating glycerol molecules with negligible
effect on the cavity dimensions.
Description
CITATION: Fong, R. J. et al. 2018. The impact of plasticizer and degree of hydrolysis on free volume of poly(vinyl alcohol) films. Polymers, 10(9):1036, doi:10.3390/polym10091036.
The original publication is available at https://www.mdpi.com
The original publication is available at https://www.mdpi.com
Keywords
Poly(vinyl alcohol), Hydrolysis, Plasticizers, Crystalline polymers
Citation
Fong, R. J. et al. 2018. The impact of plasticizer and degree of hydrolysis on free volume of poly(vinyl alcohol) films. Polymers, 10(9):1036, doi:10.3390/polym10091036.