Enhanced Water Resistance and Mechanical Properties of Thermo-Compressed Konjac Glucomannan Xerogel Films by Ammonia-Vapor Treatment

Konjac glucomannan (KGM) is a hydrophilic polysaccharide with film- and gel-forming properties. This study investigated the effects of ammonia-vapor treatment on the structural, physicochemical, morphological, and mechanical properties of thermo-compressed KGM xerogel films. KGM was mixed with water and glycerol, thermo-compressed into xerogel films, and exposed to ammonia vapor for 6, 12, 24, or 48 h. Ammonia-vapor treatment progressively increased the degree of deacetylation. The water contact angle increased, whereas moisture content, water-induced mass loss, water vapor permeability, and swelling degree decreased. The swelling degree decreased from 1072% in untreated films to 538%, 477%, 437%, and 422% after 6, 12, 24, and 48 h, respectively. Surface pits and pores became more pronounced with increasing treatment duration, while the cross-sections remained dense and continuous. A treatment duration of 12 h provided the best combined mechanical performance, with tensile strength, elongation at break, and tensile toughness increasing by 1.58-, 1.77-, and 3.58-fold, respectively, compared with untreated films. These findings demonstrate improvements in water resistance and mechanical performance. However, further evaluation of residual ammonia content, hydrated mechanical properties, fluid management, and biological safety is required before the films can be considered suitable for wound-dressing applications.