Synergy of CMC and modified chitosan on strength properties of cellulosic fiber network

Previously, the application of modified chitosan (MCN) and carboxymethyl cellulose (CMC) in a dual polymer system showed promising results in increasing the strength of fiber networks. This work evaluates the influence of CMC molecular weight (MW) and of CMC/MCN ratio on the characteristics of formed CMC/MCN complexes in polymer solutions and on the properties of cellulosic fiber networks. The results showed that the application of MCN and the high MW CMC (HCMC) (1:1 charge ratio) enhanced the tensile, burst, and tear indices, but reduced the light scattering coefficient of the fiber network more significantly than that of MCN and the low MW CMC (LCMC). Increasing the ratio of HCMC/MCN marginally affected the tensile index, the burst index, and the light scattering coefficient of the fiber network, even though the ratio significantly affected the characteristics of the CMC/MCN complexes in polymer solutions. The tear index and brightness were improved by increasing the HCMC/MCN ratio. These results were explained based on the retention of HCMC/MCN complexes and the layer-by-layer assembly of HCMC and MCN on the fiber surface.