Miscibility

About: Miscibility is a research topic. Over the lifetime, 5521 publications have been published within this topic receiving 133547 citations. The topic is also known as: miscible.

Chitosan and Poly(vinyl pyrrolidone): Compatibility and Miscibility of Blends

Abstract: The miscibility of chitosan and poly(vinyl pyrrolidone) -PVP- has been studied by viscosity measurements, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). For chitosan/PVP blends in solid state (thin films) interaction were found by FTIR and DSC methods. After blending PVP with chitosan the glass transition temperature Tg was altered, this may be a result of hydrogen bonds between the synthetic and biological component. It was found that solution of chitosan and PVP are immiscible, viscosimetry methods showed that interactions between chitosan and PVP are to small for the predictions of miscibility, due to the high affinity of the two polymers for the solvent. The study of blends with bespoke structural and properties will be essential for the development of a new generation of biocompatible stimuli-sensitive hydrogels.

Molecular Modeling as a Predictive Tool for the Development of Solid Dispersions

Abstract: In this study molecular modeling is introduced as a novel approach for the development of pharmaceutical solid dispersions. A computational model based on quantum mechanical (QM) calculations was used to predict the miscibility of various drugs in various polymers by predicting the binding strength between the drug and dimeric form of the polymer. The drug/polymer miscibility was also estimated by using traditional approaches such as Van Krevelen/Hoftyzer and Bagley solubility parameters or Flory–Huggins interaction parameter in comparison to the molecular modeling approach. The molecular modeling studies predicted successfully the drug–polymer binding energies and the preferable site of interaction between the functional groups. The drug–polymer miscibility and the physical state of bulk materials, physical mixtures, and solid dispersions were determined by thermal analysis (DSC/MTDSC) and X-ray diffraction. The produced solid dispersions were analyzed by X-ray photoelectron spectroscopy (XPS), which confirmed not only the exact type of the intermolecular interactions between the drug–polymer functional groups but also the binding strength by estimating the N coefficient values. The findings demonstrate that QM-based molecular modeling is a powerful tool to predict the strength and type of intermolecular interactions in a range of drug/polymeric systems for the development of solid dispersions.

Miscibility, morphology and tensile properties of vinyl chloride polymer and poly(ε‐caprolactone) blends

Abstract: The miscibility, morphology and tensile properties of three blend systems of poly(e-caprolactone) (PCL) with poly(vinyl chloride) (PVC) and with two chlorinated PVCs (CPVCs) with different chlorine contents (63 wt% and 67 wt% of Cl) have been studied Based on the shifts of single glass transition temperature, the Gordon–Taylor K parameter is calculated as a measurement of interaction strength between PCL and (C)PVCs Higher K values are found for blends of (C)PVCs with higher chlorine content, together with the interaction χ parameters estimated from the melting point depression results The morphology observed with polarized light microscopy shows that spherulites exist in blends rich in PCL (≥50 wt%) only Wide angle X-ray diffraction studies indicate that the crystal structure of PCL is independent of the Cl content of (C)PVCs The tensile properties of various blends exhibit a minimum as the PCL content increases The elongation at break increases with increasing PCL content © 2000 Society of Chemical Industry