Effect of Polyalumium Chloride and Nano-Chitosan Bio-polymeric System on the Optical and Mechanical Properties of Chemi-mechanical Pulp (CMP)

This study was aimed to investigate the effect of polyalumium chloride and ‎nano-chitosan on optical and mechanical properties of chemi-mechanical pulp. For this purpose, some of the bleached CMP pulp of Mazandaran Wood and Paper Industries (MWPI) were randomly selected as a control sample. In addition, the polyalumium chloride were used as a white powder at 4 levels of ‎0, 0.5, 1, and 1.5%. The nano-chitosan was then added to the CMP pulps suspensions at 3 levels of 0, 1, and 2%, as well. Hand-sheets with a basis weight of 60 gr/m2 were prepared from the mentioned pulps. The optical and mechanical properties were then measured and compared using TAPPI standard test methods. The results showed that by adding polyalumium chloride and nano- chitosan(separate) to the CMP pulps, brightness, opacity, greenness,tear, tensile, burst strengths, air resistance‎ ‎increased , but Cobb 60 and a* factor ‎decreased. On the other hand, with the addition of nano-chitosan and polyalumium chloride to CMP pulp, the brightness and greenness increased, but tensile, burst, tear strengths, air resistance, Cobb 60 and opacity low decreased and then suitable increased. Moreover, the findings showed that by simultaneous adding 1% polyalumium chloride and 2% nano-chitosan(separate) and 2% nano-chitosan with 1.5% polyalumium chloride to the CMP pulp, most of the paper properties were improved. Therefore, ‎it can also be introduced as the best treatment.