Thermal properties of poly(vinyl alcohol)–solute blends studied by TMDSC

Abstract

A thermal analysis study of blends of semicrystalline poly(vinyl alcohol) (PVA) with a pharmaceutical substance, buflomedil pyridoxal phosphate (BPP) is presented. Temperature-modulated DSC (TMDSC) was used to determine the T g as well as the crystallinity of blends with various polymer to drug ratios, for different annealing procedures. Positive deviations from a simple expression for the composition dependence of the glass transition of the blend were found. This result, together with the increased thermal stability of PVA-BPP blends, evidenced by TGA analysis, indicates the existence of specific interactions between the polar groups of the two components. The incorporation of dispersed BPP in the PVA matrix results in a compositiondependent lowering of the polymer's T m and degree of crystallinity. In addition, we found that, while melting of pure PVA is predominantly reversing, its melting in the blends acquires an increasingly higher nonreversing component with increasing BPP content in the blend.

Physically Crosslinked Poly (Vinyl Alcohol)/Kappa-Carrageenan Hydrogels: Structure and Applications

“…In this case, however, a single value for T g is not correlated to the formation of inter-polymer complexes through hydrogen bonding because κ-carrageenan does not show any presence of this type of transition. For the PVA hydrogel, a peak at~75 • C could be ascribed to the glass transition of poly (vinyl alcohol), following the values from the reference literature [64].…”

“…The crystallinity of the PVA matrix in the gels (Cr DSC ) was assessed also based on the DSC data, by dividing the value of the melting enthalpy (∆H m ) to the value of the thermodynamic enthalpy corresponding to the melting of a 100% crystalline PVA (150 J/g), as reported in the literature [64]. The results, presented in Table 3 follow the same trend as the XRD-calculated crystallinity and the FTIR crystallinity index, confirming the semi-crystalline nature of the polymer matrix [40].…”

Nanofeatures affect the thermal transitions of polymer thin films: a microcantilever-based investigation

“…The slope then experiences a slight change that allows the determination of T g at 82 1C, in good agreement with the T g values described in literature. [37][38][39] Despite its atactic configuration, PVA has a relatively significant crystallinity and, as a consequence, we did not observe any cold crystallization process during heating. Differences between PLA and PVA have been attributed to their chemical and physical properties.…”

In Vitro Modulation of Spontaneous Activity in Embryonic Cardiomyocytes Cultured on Poly(vinyl alcohol)/Bioglass Type 58S Electrospun Scaffolds

“…The glass transition (T g ) of PVA depends on the degree of hydrolysis. The T g reported for PVA with a degree of hydrolysis below 98–99% is close to 85 °C [ 43 , 44 , 45 , 46 ]. The melting temperature, T m , of PVA also depends on the degree of hydrolysis.…”