Solvent effect in grafting of liquid polybutadienes with maleic anhydride

The maleinization of liquid polybutadienes with different microstructures was studied in two solvents: o-xylene and decahydronaphtalene. The concentration of maleic anhydride versus time was determined by gas chromatographic analysis. The results obtained in o-xylene were processed according to a first-order model, hence the kinetic constants and estimated activation energy values showed a solvent effect with respect to the bulk reaction. Moreover, the model was improved by taking into account that at 140 degrees C, the kinetic curves reached after some time a final constant yield depending on microstructure and maleic anhydride concentration. On the other hand in decahydronaphtalene at 130 degrees C, the reaction was very fast with very high yields. Nevertheless, in the range from 150 to 180 degrees C, the amount of linked anhydride in the final products did not exceed 11% (w/w) probably because of a decarboxylation of the maleinized products favoured by decahydronaphtalene. (c) 2005 Elsevier B.V. All rights reserved.