Amit Biswas

Development and Properties of Novel Thermoplastic Elastomer Based on Poly (Phenylene Ether)

Abstract A series of novel thermoplastic elastomers (TPEs) based on poly (phenylene ether)(PPE), which is an engineering thermoplastic with a glass transition temperature >200 °C, has been developed. The resulting blend based on PPE, Polystyrene (PS), Ethylene Vinyl Acetate (EVA) and a tri-block copolymer, Styrene-Ethylene-Butylene-Styrene (SEBS), met all the key performance criteria for thermoplastic elastomers in terms of melt processability, tensile elongation, tension set and recyclability. Depending on Florys interaction parameter and critical surface tension value, the elastomeric components of the blends were selected. Morphological analysis of the blend using Transmission Electron Microscopy indicated a unique microstructure, wherein EVA domains were dispersed in a mainly co-continuous matrix comprising of the blend of PPE-PS/SEBS. Differential Scanning Calorimeter and Dynamic Mechanical Analysis were done to evaluate the thermal transitions of the blend and to throw light on the interactions bet...

HIGH STRENGTH -LOW HARDNESS THERMOPLASTIC ELASTOMERS FROM ETHYLENE-BUTENE COPOLYMERS AND LOW DENSITY POLYETHYLENE

Abstract A thermoplastic elastomer (TPE) is a rubbery material with final properties and functional performance similar to those of a conventional vulcanized rubber at ambient temperature, yet it can be processed as a thermoplastic at elevated temperature. The main objective of the present investigation was to prepare novel olefinic thermoplastic elastomers based on blends of a thermoplastic i.e. low density polyethylene (PE) and new ethylene-butene copolymers (PEB), which would have higher strength and lower hardness compared to the existing TPEs. The 70:30 PEB: PE blend exhibited the best properties. Ethylene vinyl acetate was found to work as compatibilizer at lower loadings in these blends. The resultant blends were of low hardness (60–80 Shore A) and high strength (26–33 MPa). The interaction parameter and the morphology of the blends were the key parameters, which governed the final properties of blends.

Micro/Nano Indentation and Micro-FTIR Spectroscopy Study of Weathering of Coated Engineering Thermoplastics

A novel combination of depth-sensing nano-indentation, micro-indentation and micro-FTIR techniques is employed towards understanding the durability of coating layers used on engineering thermoplastics upon exposure to harsh weathering environments. This combination of techniques enables study of changes in surface-to-bulk properties in the clearcoat-substrate system upon weathering; typically observed as a degradation starting from the surface and then proceeding inwards to the bulk of the material. Nano-indentation measurements carried out to understand the mechanical properties of the coating layer provide insights into the changes in hardness and modulus upon prolonged weathering exposure. Depth-sensing micro-indentation and micro-FTIR spectroscopy studies performed to evaluate mechanical performance and chemical changes, respectively, explain the influence of the substrate on the coating layer, especially at the interface upon weathering. This unique combination of depth-sensing indentation and micro-FTIR spectroscopy has led to an understanding of the properties of the coating layer and the substrate individually as well as an integral system as a function of weathering exposure time. Finally, the physico-chemical properties of the coating and substrate are linked to performance prediction, enabling optimization of coating-substrate combinations.