Determination of The Optimum Use of Cationic Starch on the Basis of the Mechanical Strengths of Mixed OCC and Virgin NSSC pulps

This study was carried out to optimize of cationic starch use for improvement of the mechanical properties of mixed OCC & NSSC pulps. NSSC pulps were mixed with the OCC pulps by following weight ratios: 80/20، 70/30 and 60/40، respectively. Cationic starch was used in different charges of 0. 5، 1. 25، 2 and 3 %. The produced paper strength properties were measured according to Tappi standard. The results obtained from normalized equation showed that treatment of C4 (60% NSSC+ 40% OCC using 3% Cationic starch) is the best suitable samples. Also، by increasing the OCC proportion in mixed pulps، tensile، Tear، burst strengths increases، but Concora medium test (CMT) and Ring crush test (RCT) decreased. In general، by increasing of the cationic starch dosage، mechanical strengths has increased and its improved use had determined by 3% cationic starch.