Journal of Applied Chemical Research, 6, 34-44 (2008) Feasibility of Utilizing Corn Stalk Residues in Chemi- Mechanical Pulping (CMP) and Papermaking A. J. Latibari *1 , M. Roohnia 1 , A. Tajdini 1 , F. Darvishghadema 2 , A. Moradback 2 1 Agricultural Research Center, Islamic Azad University, Karaj Branch, Karaj, Iran. 2 Department of Wood and Paper Science and Technology, Islamic Azad University, Karaj Branch, Karaj, Iran. * latibari_24@yahoo.com (Received 10 Aug. 2008; Final version received 16 Nov. 2008) Introduction  When paper making was invented, non-wood fibers were utilized as the main source of the raw material and the first major paper mill in North America used wheat straw [1]. However, this situation did not last too long and very soon, wood fibers replaced non- wood fibers. However, not all countries in the world possess suitable and sufficient quantities of wood to fulfill their fiber requirements [2, 3]. Consequently, these countries are forced to use non-wood fibers and research on this aspect of pulping was foreseen and most efforts were concentrated on this issue [4]. Even though, the share of non-wood pulping is only 6.5% of the total pulp production, there Abstract  The influence of pulping conditions on properties of CMP pulp from corn stalks is investigated. Pulps were prepared from undepithed and depithed corn stalks, utilizing different pulping variables. Presence of pith lowered both yield and strength. Therefore different pulping conditions using sodium sulfite and sodium hydroxide were selected and applied on depithed corn stalks. Sodium sulfite charge varied between 8-14% and sodium hydroxide charge was kept constant at 8%. Pulping time varied at 30, 45, and 60 minutes. Total yields after impregnation were measured between the minimum of 70.8% and minimum of 87.2%. However, the yield after defibration was lower than the above mentioned values and varied between 53.1% and 68.7%. Based on the measured yields, different sodium sulfite charges at constant amount of the sodium hydroxide, time, and temperature were selected for pulp strength evaluation. The results of hand sheet evaluation revealed that the strength of the pulp produced using 10% Na 2 S 2 O 3 , 8% NaOH, during 30 minutes time and at 95ºC with a breaking length of 1.98 km, 8.28 mN.m2/g tear index and 20.40 N.m/g tensile index was superior to that obtaind under other pulping conditions. Keywords:  Cornstalks, CMP, Yield, Tear index, Tensile index.