Effect of electron beam irradiation on dynamic mechanical, thermal and morphological properties of LLDPE and PDMS rubber blends

The effect of electron beam irradiation on the blends of linear low-density polyethylene (LLDPE) and poly dimethyl siloxane rubber (PDMS) prepared over a wide range of compositions starting from 70:30 to 30:70 (LLDPE: PDMS) by varying the radiation doses from 50 to 300 kGy has been studied. The dynamic modulii and dielectric strength of the blends increase on irradiation at 100 kGy as compared to that for the unirradiated blends. Degree of crystallinity and melting behaviour remain unchanged upon irradiation upto a dose of 100 kGy, beyond which it decreases. Thermal stability increases with increase in the proportion of PDMS rubber in the blend as well as on irradiation at 100 kGy. The phase morphology of the blends examined under the SEM exhibit two phase morphology before electron beam irradiation, whereas single phase morphology is observed after electron beam irradiation due to intra- as well as inter-molecular crosslinking leading to a miscible system.

► Immiscible blends of LLDPE and PDMS rubber becomes miscible after electron beam irradiation (EBR).
► The gel content and cross link density of the blends increase on EBR, upto a dose of 100 kGy.
► Dielectric strength of the blends increase with increase in LLDPE proportion in the blends after EBR.
► Dielectric constant of the blends increase with proportion of silicone rubber in the blend after EBR.
► Thermal stability of the blends increase on exposure to EBR.