Preparation of a maleated Fischer-Tropsch paraffin wax and FTIR analysis of grafted maleic anhydride

Grafting of maleic anhydride (MA) onto Fischer-Tropsch paraffin wax was performed by a melting process in the presence of dibenzoyl-peroxide (DBP). It was confirmed that suitable reaction conditions can give a product which does not contain unbound maleic anhydride. Washing of the final product in boiling water is not suitable in this case, due to the relatively high solubility of the final product in water. A simple method, using Fourier transform infrared spectroscopy (FTIR), was developed for the determination of the grafting degree of MA. The method is based on the evaluation of the ratio of the C-H wax vibration absorbance to that of the carbonyls of the grafted succinic anhydride ring. The identification of the main peaks was done and suitable peaks were chosen for FTIR analysis. The concentration of grafted maleic anhydride was calculated by an iteration technique based on a function derived from the Lambert-Beer law. The regression and statistical parameters of the calculated function, as well as the accuracy of the determined grafted anhydride content, were computed.