title: Measurement of the viscosity of irradiated silicone using a differential viscometer
abstract: High-energy electron (2.0 MV) and gamma irradiation (60Co) has been used to modify polymeric silicone fluids of initial viscosities in the range, 90-700 cSt. Doses of electron and gamma radiation were delivered at rates of 0.246 kGy s(-1) and 15 kGy h(-1), respectively, exposure times being adjusted to ensure energy deposition in the range 30-360 kGy. Measurements were made using a differential viscometer based on a Bose Institute design. In line with expectation, samples of greater initial molecular weight (and hence greater viscosity), were observed to be more susceptible to radiation induced cross-linking than those of lower molecular weight. The role of dose rate and oxygen diffusion in determining the extent of change is discussed.
authors.affiliation: Department of Physics, University of Malaya, Kuala Lumpur, Malaysia. D.A.Bradley@exeter.ac.uk
authors.initials: DA
authors.lastname: Bradley
authors.initials: KZ
authors.lastname: Dahlan
authors.initials: SC
authors.lastname: Roy