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 °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 °C, the reaction was very fast with very high yields. Nevertheless, in the range from 150 to 180 °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.