Robin N. Santra

Thermogravimetric studies on miscible blends of ethylene-methyl acrylate copolymer (EMA) and polydimethylsiloxane rubber (PDMS)

Abstract Thermogravimetric and derivative thermogravimetric analysis of blends of ethylenemethyl acrylate copolymer and polydimethylsiloxane of different compositions have been investigated. Curves of weight loss and derivative weight loss against temperature show that degradation takes place in two steps with peak maxima, at T 1max and T 2max , both proportional to the components in the blends. Kinetic studies show that the degradation of the blends and that of the single components follow first order reaction kinetics. Activation energies of the degradation have been determined using Freeman and Carrolls method and the thermal stability of the blends has been investigated.

Kinetic investigation on the curing of ethylene methyl acrylate—Polydimethyl siloxane rubber blends by differential scanning calorimetry

Curing reactions of ethylene methyl acrylate (EMA) polydimethyl siloxane (PDMS) rubber blends have been investigated by differential scanning calorimetry (DSC) and by Rheometry. The curing exoterms obtained from DSC curves have been analysed to derive the kinetic parameters associated with the curing process. Crosslinking of EMA-PDMS rubber blends follow first order kinetics. The effect of blend ratio and peroxide concentration on the crosslinking characteristics of the blends have also been investigated.ZusammenfassungMittels DSC und Rheometrie wurden die Härtungsreaktionen Gummigemischen aus Ethylenmethylacrylat (EMA) und Polydimethylsiloxan (PDMS) untersucht. Die Ableitung der kinetischen Parameter ist mit dem Härtungsprozeß verbunden. Die Vernetzung von EMA-PDMS Gummigemischen verläuft in einer Reaktion erster Ordnung. Der Einfluß von Gemischverhältnis und Peroxidkonzentration auf die Eigenschaften der Vernetzungsreaktion der Gemische wurde ebenfalls untersucht.

Studies on Reaction Mechanism Between Ethylene-Methyl Acrylate Copolymer and Poly Dimethyl Siloxane Rubber Processed Under High Shear and Temperature

Abstract Blending of ethylene–methyl acrylate (EMA) copolymer and polydimethyl siloxane (PDMS) rubber led to miscibility of the two components under the processing conditions of 180°C and 100 rpm rotor speed, and the miscibility was assumed to be due to reaction between EMA and PDMS rubber. A plausible mechanism has been suggested. The mechanism has been confirmed by infrared and solid-state MAS nuclear magnetic resonance spectroscopy, which show a reduction in the vinyl group concentration of PDMS rubber and an increase in the[sbnd]CH2[sbnd]bridge concentration of EMA in the vicinity of the α-carbon atom in the blend.

Studies on Reactive Blending of Epoxidized Natural Rubber and Ethylene–Acrylic Acid Copolymer

Abstract Melt blending of epoxidized natural rubber (ENR) and ethylene—acrylic acid (EAA) in the proportion 90:10 was carried out in a Brabender Plasticorder at 150°C for 10 min to improve the processing characteristics of ENR. IR spectrophotometric study revealed the presence of a characteristic ester band at 1742 cm−1, and dynamic mechanical analysis showed the formation of a new tan δ peak at −70°C. Die swell and flow characteristics of the ENR improved significantly. These observations strongly support the occurrence of a chemical reaction between ENR and EAA. A mechanism of the possible reaction is also suggested.