STUDIES ON EVALUATION OF COTTON STALKS AS A CELLULOSIC FIBROUS RAW MATERIALS

Abstract

Many of the developing countries of the world like Egypt do not have adequate supplying of wood. Egypt has large quantities of fibrous agricultural residues, which represent another renewable source for wood. Many of these lignocellulosic fibrous can be used for manufacture of pulp, paper and paperboard products. Cotton stalk is one of the agricultural waste presents in Egypt in large quantity about 1.9 million tons.

The aim of the present work is to study the utilization of cotton stalks as fibrous source for pulp and paper manufacture. Chemical and chemimechanical pulping processes were studied. For chemical pulping methods, the alkaline sulphite pulping (ASP) process of the undebarked (the whole raw material) cotton stalks was investigated. The effect of total alkali, kind of alkali source (NaOH and Na2C03) and its ratio were studied. From the results, it is observed that the ASP process with NaOH as alkali source gives slightly lower yield with higher paper properties than ASP method with Na2 C03 . Some modifications on ASP process were carried out as follows:

( l) The presence of AQ as additive in ASP liquor with NaOH or Na2 C03 as alkali source increases the yield and improves paper properties.

(2) The effect of other additives, e.g. methanol on ASP process was investigated at different concentrations (0-50% based on liquor) and 20% total alkali. The optimum methanol concentration is 25% at which low lignin content and better strength properties were obtained.