Miscibility, thermal degradation and rheological analysis of epoxy/MABS blends.

The effect of the addition of the methyl methacrylate acrylonitrile butadiene styrene (MABS) copolymer on the miscibility, thermal degradation and rheological properties of epoxy systems is described. Epoxy resin/MABS blends containing 5, 10, 15 and 20 phr MABS were prepared using the solution mixing technique. Homogenous blends obtained using this technique have undergone a polymerization reaction induced phase separation process by the introduction of the curing agent 4,4'-diaminodiphenyl sulfone (DDS). The isothermal rheology at four different temperatures, 150, 160, 170 and 180 °C, was used to examine the effect of MABS on the gelation and vitrification time. The evolution of storage modulus, loss modulus and tan delta was found to be closely related to the evolution of complex phase separation. The increase in the complex viscosity during curing was determined by in situ rheometry and theoretically analysed by fitting with the Williams-Landell-Ferry equation. An exponential increase in complex viscosity was observed, which was induced by cross-linking. The variation of Tg before and after curing was studied using DSC analysis and dynamic kinetic modeling of the curing process was carried out by utilizing dynamic DSC scans. Thermal stability studies of completely cured epoxy/MABS blends using thermogravimetric analysis revealed that all the blends and neat epoxy exhibited single step degradation. Thermal degradation kinetics was calculated using the Coats Redfern equation.

Facile Synthesis of Dihydroquinolines via Palladium Catalyzed Sequential Amination and Cyclisation of Morita-Baylis-Hillman Alcohols.

Quinolines and its derivatives are significant class of heterocyclic compounds which are identified as the key component in many natural products and biologically important molecules. We describe herein a facile method for the synthesis of quinoline derivatives from Morita-Baylis-Hillman (MBH) Alcohols via Palladium Catalyzed intramolecular aryl amination followed by allylic amination pathway. The reaction between a series of MBH alcohols and amino compounds (Tosyl, aliphatic and aromatic amines) under optimized reaction conditions with Pd(PPh3)2Cl2/DPPP catalyst system, afforded the corresponding 1,2-dihydroquinolines upto 95 % isolated yield.

Enantioselective synthesis of 2-methyl indolines by palladium catalysed asymmetric C(sp3)-H activation/cyclisation.

The first example of the enantioselective methyl C-H activation by an intramolecular ArPdX species and subsequent cyclisation was developed. Palladium catalysts using commercially available chiral diphosphines yield good ee's (up to 93% ee) in the synthesis of 2-methyl indolines from 2-halo N-isopropyl anilides. This approach was also employed for the synthesis of enantioenriched cyclohexyl fused indolines with moderate enantioselectivities.