Optimization of viscose process to improve fiber properties

Abstract

Viscose process has been widely used in the world to synthesize viscose rayon from the cellulose present in the pulp. The optimization of this process has been of keen interest to the textile industry in order to maximize the profit. The purpose of this thesis is to determine the best process parameters and conditions to optimize the process and identify maximum possible wet strength of the fibre. The thesis can be split in to two major objectives: (a) Method development for determining filterability constant using small Kw (100 g) and (b) optimizing the spinning parameters such as spin bath composition, temperature, etc. Filterability is one such important parameter which is measured in terms of kW value at a big setup. In order to avoid wastage of prepared dope, a small kW (100 gm capacity) equipment was standardized w.r.t. the previously existing 2 kg set up. It was observed that despite the use of a correction factor, the flowrate of the two setup were not matching. The flowrate of the small setup was decreasing faster than the flowrate of big setup. However, this difference of flowrate did not prove to be an obstacle towards the standardization. As a part of spinning parameter optimization, several trials were conducted with varying spinbath composition. These trials had to be conducted at a constant temperature, by means of an indigenously designed heat exchanger in the spin bath trough. Based on experiments related to parametric study, a mathematical model was formulated to predict the tenacity of the fiber at any spinbath composition and stretch. It was then optimized using Genetic Algorithm to get the best condition.