Improvement in strength and vapor barrier properties of cellulose composite sheets with chitosan and carboxymethyl cellulose

Improvement in the dry strength, wet strength, and vapor barrier properties of paper sheets has been shown through the sequential addition of chitosan (CS) and carboxymethyl cellulose (CMC) to the pulp solution. Examination of pulp solutions revealed the formation of aggregates due to electrostatic interaction between the unabsorbed CS and CMC. Tensile test results revealed 64% improvement in the dry modulus for sheets with 50% CS and 50% CMC with respect to the control sheet. The wet tensile test results showed that the control pure pulp sheet broke immediately, whereas the composite sheet with 50% CS and 50% CMC exhibited a wet modulus value of 39.5 MPa. The specific water vapor transmission rate (SWVTR) was also found to be the lowest for this particular composite, with a 32% decrease with respect to the control sample, which was again attributed to the formation of agglomerates that filled the void spaces. © 2014 ASABE.