The effect of solvent mixture on the properties of solvent cast polylactic acid (PLA) film

The objective of this study was to investigate the effects of various solvents on the crystallinity and thermal expansion stability of PLA film. Three different PLA films were produced by the solvent casting technique; PLA in chloroform (PLA‐C), PLA in methylene chloride (PLA‐M), and PLA in methylene chloride: acetonitrile = 50: 50 (PLA‐MA). The PLA‐MA had higher % crystallinity, 46.15, than the PLA‐C, 24.03, and the PLA‐M, 14.25. With this increase in crystallinity, the PLA‐MA had improved thermal expansion stability as shown by very low accumulated dimensional changes at 20 to 100°C. Wide‐angle X‐ray diffraction identified multiple crystalline structures for the PLA‐MA. Film barrier properties were also measured. PLA‐MA had the lowest oxygen permeability. However, there was no significant difference in water vapor permeability among the three PLA films. The mechanical property tests revealed that the PLA‐C and PLA‐M were ductile while the PLA‐MA was brittle in behavior. The PLA‐MA was very hazy as compared with the PLA‐C and PLA‐M. This work has shown that the PLA‐MA had increased % crystallinity and, more importantly, it had improved thermal expansion stability which can be very beneficial for the flexible packaging industry. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

In Vivo Evaluation of Pindolol Multi-Unit Dosage Forms

Pindolol, a beta adrenoceptor agent, is effective in the treatment of hypertension in daily doses ranging from 10 to 45 mg. The drug shows pH dependent solubility and a modified multi unit controlled release formulation was assessed for efficacy in vivo in healthy male human volunteers. An open blind comparative crossover study of the controlled release formulation was carried out with a conventional formulation. The treated quotients and the ratio between the maximal plasma concentration were calculated to assess the efficacy of the formulations.     

Thermophoresis and Brownian motion effects on Williamson nanofluid flow past a stretching surface with thermal radiation and chemical reaction

The heat transfer mechanism of nanofluids has numerous industrial applications owing to the non-Newtonian behavior and has been exercised as a thermophysical phenomena in presence of thermal radiation. The present paper deals with the thermal transfer characteristics of time-independent magnetohydrodynamics Williamson fluid past a stretching surface in presence of the reaction of chemical equilibrium is dealt. The flow constitutive nonlinear partial differential coupled equations are transmitted into ordinary differential equalities by employing relevant similarity transmutations. These deduced equations are determined by using the Runge–Kutta numerical technique with a shooting approach with the aid of MATLAB software. Influences of distinct pertinent flow parameters like an inclined uniform magnetic field, Soret number, heat generation/absorption, and Schmidt number constrained to convective boundary condition is displayed through graphs with relevant physical interpretations. Computed numerical values for the friction factor coefficient, local Nusselt parameter, and Sherwood number are tabulated.