Speaker
Description
Polymers are inevitably used for many medical applications and devices. Development of the polymeric materials over the recent decades provided valuable commodity materials to be used in different medical applications such as single-use medical devices, implants, drug delivery and packaging systems because of their versatility and economic advantages and their ability to withstand sterilization processes. Irradiation is a widely used technology for sterilizing medical products. Gamma irradiation is one of the most common sterilization techniques which has controlled doses penetrating deeply into many materials. Although its widespread usage, it has some drawbacks due to the safety and security considerations.
Rubbers are widely used in medical applications due to their unique physical and mechanical properties. This study focuses on to investigate the radiation effects on natural rubber (NR) and silicone rubber (SR) by comparing the results obtained from gamma and e-beam irradiations. Rheological analyses were carried out to determine appropriate vulcanization parameters. The prepared NR and SR test samples were subjected to gamma irradiation at 2 different dose rates (High-dose: 213 kGy/h and Low-dose: 10 kGy/day) and 6 different doses of 10, 20, 30, 40, 60 and 80 kGy., and to e-beam irradiation at a single dose rate (1 kGy/sec) and 7 different doses of 10, 20, 30,40, 60, 80 and 120 kGy.
Mechanical tests were carried out for non-irradiated and irradiated test samples for both irradiation modalities. Swelling ratios were determined and crosslink densities were calculated by Flory-Rehner equation. Gel content of the samples was tested by Soxhlet extraction. TGA, DSC, DMA, FTIR and SEM analysis were carried out to investigate the changes in thermal, dynamic-mechanical and morphological properties. The degree of change of samples with e-beam and gamma irradiation were compared to determine the degradation and modification pathways.
Keywords: Gamma irradiation, e-beam irradiation, radiation sterilization, natural rubber, silicone rubber
Acknowledgements: This study is a Coordination Research Project (CRP) supported by International Atomic Energy Agency (IAEA) (Project # F24701).
