Preparation and characterisation of blends of poly(ethylene oxide) and functionalised epoxidised natural rubber

Abstract

Blending of polymers has been a popular technique for making new materials with improved properties or processability. The synergistic properties in the blends are related to the miscibility of the components when there are significant interactions between the constituents. This paper reports the preparation of reactive blends of poly(ethylene oxide) (PEO) and acetic acid-modified epoxidised natural rubber (ENR50, which contains 50% of the isoprene units converted to epoxide groups) by solution casting. The carboxylic acid modification of ENR50 was carried out by reacting the ENR50 dissolved in toluene with excess acetic acid at 100°C. Ring-opening of epoxide group by acetic acid has led to an increase in the Tg. The effects of blend ratio of the acetic acid-modified ENR50 and PEO on the thermal properties were studied. The initial ENR50 has a Tg of −29°C and the acetic acid-modified ENR50 has led to a new Tg of 10°C. FTIR results showed that there was no chemical reaction between the acetic acid-modified ENR50 and PEO in the blends. This is in agreement with the DSC results where two distinct Tgs were observed in the blends.