Vicinity Of Melting Point Research Articles

Thermoanalytical studies of a cytotoxic derivative of carbamazepine: iminostilbene

Iminostilbene is an organic compound, being a precursor of some active pharmaceutical ingredients including well-known anti-epileptic drug carbamazepine as well as substance exhibiting toxic properties and posing threat to natural environment itself. Although its derivatives are commonly studied, there is a lack of thorough investigation of that compound itself, especially concerning its properties at temperatures close to the melting point. Herein, thermodynamic and structural properties of iminostilbene as well as its vibrational and dynamic properties were studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). DSC measurements suggests that in the vicinity of melting point, some enantiotropic transition takes place. TGA measurements reveal that strong sublimation of examined substance is observed at temperatures even tens of degrees lower than melting point. Finally, all measurements indicate that the applied heat treatment induces an irreversible phase transition in the studied sample.

Thermal expansion of solids: review on theories

The coefficient of thermal expansion of a solid can be derived from (1) anharmonicity of atomic vibrations; (2) lattice dynamics; (3) equation of state by G. Mie; (4) equation of state by E. Gruneisen; and (6) potential of interatomic interaction. Only the last theory in this list provides us with the equation describing correctly all features in the thermal expansion: (1) proportionality between thermal expansion and heat capacity; (2) various values of “plateau” for the coefficient of thermal expansion at temperatures close to Debye temperature; and (3) acceleration of the thermal expansion in the vicinity of melting point.

Hot-melt adhesion and wettability between polyethylene and other polymers in the vicinity of the adherend melting point

The effect of bonding temperature on the bonding strength of polyethylene to polypropylene or other polymers was investigated. It became clear that the interfacial bonding strength reached maximum strength at a bonding temperature in the vicinity of the melting point of the adherend (i.e., the polymer having the higher melting point). The effect of temperature on the contact angle of the molten polymer having the lower melting point on the adherend surface was also investigated. The wettability of the adherend by the molten polymer drop was considerably reduced at the temperature near the melting point of the adherend. The relationship of increasing adhesiveness to decreasing wettability was found out.