The use of an Experimental Design method to evaluate the influence of process parameters in the graft polymerization of acrylic acid onto cassava starch.
Chemical Product Design and Engineering (CPD&E)
Chemical Product Design & Engineering - Poster (CPD&E - P)
Keywords: add on, cassava starch, experimental design, Fe2+/H2O2, grafting.
Grafting of acrylic acid onto starch offers the prospect of replacing many current applications of polyacrylic acid, by more biodegradable products based on renewable raw materials. We have investigated the influence of reaction and process variables on the grafting of acrylic acid onto gelatinized cassava starch, with Fe2+/H2O2 as initiator system. These experiments were conducted at laboratory scale using a batch reactor in order to collect the data needed for the set up of a continuous reactor system at a larger scale.
The number of potential variables is large however, and their interrelation can be complex. The use of an Experimental Design method is not very common in this field but has been found useful in evaluating which of these variables have the largest influence on the grafting results, with a limited number of experiments. Also, within the selected ranges, optimal values could be elucidated for these variables.
Intermediate temperatures (40-50°C) and the mol ratio of Fe2+ to AGU in the order of 1:50 were found optimal for grafting efficiency, add-on and monomer conversion. A high monomer-to-starch ratio favoured add-on but decreased graft selectivity, i.e. much homopolymer was then formed. Monomer conversion was favoured also by excess H2O2 with respect to Fe2+. For an efficient process, starch concentration should be high but will be limited by the handling feasibility of the highly viscous gelatinized starch and its graft copolymer. This aspect needs further study.
Presented Wednesday 19, 13:30 to 15:00, in session Chemical Product Design & Engineering - Poster (CPD&E - P).
