The effect of using willow wood on the optical and mechanical properties of newsprint paper obtained from chemi-mechanical pulp

In this study, the effect of mixing willow wood species with other wood species used in Mazandaran wood and paper industry on the optical and mechanical properties of newsprint paper made from chemi-mechanical pulp (CMP) was investigated. CMP pulp was made under condition of efficiency of 85 %, cooking time of 60 min, temperature of 170° C, and L:W = 7, sulfite percentage of 20 % based on the dry weight of the willow wood species in 6 levels. After handmade papers (60 g/cm2, gsm) were prepared, optical and mechanical properties of papers were evaluated. Results showed that the best optical properties were related to papers obtained from the factory pulps (control pulp), and only the opacity of papers obtained from willow paper pulp mixed with factory pulps has been in acceptable level (45:55, 45 % willow pulp to 55 % of the factory pulp). The best strength properties were observed in the incorporation of 100 % factory CMP pulp and in second priority 60:40 mixture (include 60 % of willow pulp with 40 % of factory CMP pulp). Due to the importance of strength properties compared to the optical properties in newsprint paper, incorporation of 60 % of willow pulp with 40 % of factory CMP pulp is suggested for newsprint paper.