Table of Contents
ISRN Polymer Science
Volume 2012 (2012), Article ID 630642, 9 pages
Research Article

Optimization of PET Glycolysis Process by Response Surface Methodological Approach: A Two-Component Modelling Using Glycolysis Time and Temperature

1Department of Chemical Technology, Sant Longowal Institute of Engineering & Technology, Punjab, Sangrur 148106, India
2RM & CD, Corporate Research & Development Centre, Apollo Tyres Ltd., Limda, Gujarat, Vadodara 391760, India
3Department of Polymer Science & Technology, University of Calcutta, 92, A. P. C. Road, Kolkata 700009, India
4Department of Food Engineering and Technology, Sant Longowal Institute of Engineering & Technology, Punjab, Sangrur 148106, India

Received 30 January 2012; Accepted 26 February 2012

Academic Editors: A. Granville, A. Varesano, and S. Yamazaki

Copyright © 2012 Sunain Katoch et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Response surface methodology (RSM) was used for predicting the optimal condition of glycolysis time and temperature in the recycling of PET scrap. Central composite rotatable design (CCRD) for two variables at four levels was chosen as the experimental design. The data obtained from measurement of properties were fitted as a two variable second-order equation and were plotted as 3D surface plots using programme developed in MATLAB v.5. Analysis of variance (ANOVA) was used to evaluate the validity of model. The optimum operating conditions for glycolysis time and temperature were 6.5 h and 180°C, respectively. Under these optimal conditions, the hydroxyl value and glycolysis conversion percentage was 38.14 mgKOH/g and 95%, respectively, at the 0.97 desirability level, whereas the acid value and number average molecular weight ( 𝑀 𝑛 ) at the same desirability level were 12.2 mgKOH/g and 695 g/mol, respectively.