Optimizing Effective Factors in Wood Pulp Purification Process Based on the Taguchi Method for Producing the Nitrocellulose

Dissolving pulp or alpha cellulose is one of the most important and valuable biopolymers produced by wood pulp factories. One of the most important applications of dissolving pulp is in military industries to produce of commercial nitrocellulose. In this research, all data of literature about common and developing methods for producing the alpha cellulose are presented. Among the important techniques for purifying wood pulp are cold caustic extraction (CCE) and hot caustic extraction (HCE). These processes were chosen as the best methods for purifying wood pulp owing to their simplicity, low sodium hydroxide consumption and lower production time and optimal energy consumption and these process were investigated precisely in this research. In order to determine the optimal and economic conditions for the caustic extraction process, various experiments were designed by Minitab software and then implemented to determine the contribution of various factors including, concentration of sodium hydroxide, reaction time, speed of stirring and reaction temperature for the purification of industrial wood pulp with 85% alpha cellulose content to 96% dissolving pulp. Based on the experimental data, the concentration of the sodium hydroxide has the highest effect in the purification process. Also this process should be done at low temperature (30 °C). The products were quality controlled by different laboratory methods and equipments including, determination of alpha cellulose content, viscosity value, moisture percentage, ash percentage, extraction with acetone, FT-IR, XRD and ICP spectroscopies along with TGA analysis. These data confirmed that the quality of the produced dissolving pulp sample is same as the linter sample that was used for nitration process and producing of the commercial nitrocellulose.