SONOCHEMICAL DEGRADATION OF 1,4-CIS-POLYISOPRENE USING PERIODIC ACID-SOLVENT AND TEMPERATURE EFFECT

The influence of solvent and temperature on cleavage of 1,4-polyisopre ne using ultrasonic radiation (40 kHz), chemical degradation with peri odic acid (H5IO6) and sonochemical degradation (H5IO6/40 kHz) was stud ied. The reactions were performed in toluene, n-hexane and chloroform at different temperatures. The results were discussed in terms of diel ectric constants and solvent vapour pressure. Chemical and sonochemica l degradation depend on solvent and temperature. The degradation is mo re efficient in chloroform than in toluene and less efficient in n-hex ane. Increase in temperature causes a significant increase in chemical degradation reaction and decrease in ultrasonic degradation. Ultrason ic irradiation accelerates the chemical degradation process and permit s to obtain products with lower molecular weight. (C) 1997 Elsevier Sc ience Ltd.