Chitosan Film Mechanical and Permeation Properties as Affected by Acid, Plasticizer, and Storage

Abstract

The effects of acid (acetic, formic, lactic, propionic) concentrations, plasticizer concentrations, and storage time (up to 9 wk) on mechanical properties, water vapor permeability, and oxygen permeability of solution-cast chitosan films were determined. Measured water vapor permeability coefficients ranged from 5.35 to 13.20 ϫ 10 -1 g/m·day·atm. Oxygen permeated coefficients ranged from 0.08 to 31.67 ϫ 10 -3 cc O 2 / m·day·atm. Neither property was affected by storage time. Tensile strength (6.85-31.88 Mpa) also was not time dependent, but elongation (14-70%) decreased with storage time. Lactic acid solutions produced the lowest oxygen permeability values, formic acid the highest. Films formed with 7.5% lactic acid solutions had uniquely high values for elongation at break.

Development of non-woven nanofibers of egg albumen-poly (vinyl alcohol) blends: influence of solution properties on morphology of nanofibers

“…21,[30][31][32][33][34][35] Furthermore, formic acid is also considered non-toxic and is used in edible chitosan films. 36 The solution viscosity for globular proteins is reported to be higher in formic acid than in water 35 because of the unfolding and swelling of globular proteins. As a result of unfolding and swelling of EA in formic acid, 31 the interactions between EA and PVA in the blends would be enhanced, leading to a homogenous solution for electrospinning.…”

“…Solution properties of polymer compositions and their influence on morphology of nanofibers It was well documented [36][37][38][39][40] that the process of electrospinning is affected or controlled by process parameters such as spinning voltage, solution flow rate, solvent volatility and the distance between the needle tip and the ground electrode. The structure and morphology of electrospun fibers are also influenced or regulated by solution properties, such as polymer content, polymer molecular weight, viscosity, conductivity, dielectric constant and surface tension.…”

“…With an increase in viscosity, the entanglements of polymer chains are increased, which is required to maintain the continuity of the jet during electrospinning. [36][37][38][39][40] Surface tension also has an important role in nanofiber formation. If surface tension is dominant over viscosity, fibers containing beads are formed because of the presence of more solvent molecules and fewer chain entanglements.…”

“…The structure and morphology of electrospun fibers are also influenced or regulated by solution properties, such as polymer content, polymer molecular weight, viscosity, conductivity, dielectric constant and surface tension. [36][37][38][39][40] In electrospinning, one of the conditions required for the formation of nanofibers is that the polymer solution should have an optimum viscosity. Below the optimal viscosity, electrospraying of a solution occurs; above the threshold, the polymer is dried.…”

“…At higher viscosity, the amount of polymer chain entanglements is increased, and the charges on the electrospinning jet allow the polymer solution to stretch with an even distribution of solvent molecules; hence, smooth and continuous nanofibers are formed. [36][37][38][39][40] In our studies, the processing parameters were fixed to study the influences of solution properties on the morphology of formed nanofibers.…”