Tracking the Progress of the Biocompatible Nanocomposites Based on Poly(3-Hydroxybutyrate) With the Hypromellose Nanoadditive by Thermal Analysis and Biological Studies
The poly (3-hydroxybutyrate) (P3HB) was used to prepare biocompatible composites modified by the hypromellose. The aim of the study was to assess the biological properties and selected thermald parametrs together with the phase contents of the obtained biocomposites. The phase transitions of nanocomposites and polymeric matrix were investigated using differential scanning calorimetry. Moreover, the non-equilibrium and equilibrium thermal parameters of composites and the unfilled nanocomposites were established based on thermal history. Based on equilibrium parameters (i.e. the heat of fusion for the fully crystalline materials and the change of heat capacity at glass transition temperature for the fully amorphous composites), the degree of crystallinity, mobile, and rigid amorphous fractions were estimated. The addition of hypromellose to the P3HB matrix caused a decrease in the degree of crystallinity in reference to the unfilled P3HB. Simultaneously, an increase of amorphous phase contents was noted. It was also noted that the rigid amorphous fraction exists only for nanocomposites containing 2% mass of nanofiller. Thermogravimetric analysis of nanocomposites was also carried out and showed that the thermal stability of all nanocomposites is higher than that of the unfilled P3HB. An additional 1% mass of nanofiller increases the degradation temperature of nanocomposites by about 37°C in reference to the unfilled P3HB. The immunosafety of the tested nanocomposites and the absence of, or very low, endotoxin contamination was confirmed by the the Food and Drug Agency Guidance as well as the European Medicines Agency.
Keywords – Poly (3-Hydroxybutyrate), Hypromellose, Nanocomposite, Biocompatible Nanomaterials