Biopolyester-based nanocomposites: Structural, thermo-mechanical and biocompatibility characteristics of poly(3-hydroxybutyrate)/montmorillonite clay nanohybrids

In this work, the structural, thermal, mechanical, and biocompatibility characteristics of biopolyester-based nanocomposites with phyllosilicate clays, namely those of poly(3-hydroxybutyrate) (PHB) with octadecylamine-modified montmorillonite (C₁₈MMT), are reported. PHB/clay nanocomposites with various loadings were prepared by melt mixing. X-ray diffraction measurements and transmission electron microscopy images revealed the coexistence of intercalated and exfoliated states in the produced nanocomposites. Atomic force microscopy imaging also shed light to the morphological characteristics of the pure PHB and the prepared nanocomposites. The thermal stability of the nanohybrid materials was improved with the 5 wt % loading nanocomposite to show the best improvement. In addition, the nanohybrids have lower melting point compared to pure PHB and enhanced storage modulus (E′). Finally, the biocompatibility of pristine PHB and the 5 wt % nanocomposite was assessed by studying the morphology and proliferation of osteoblast cells attached on their surfaces. The results after 3 and 7 days of cell culturing indicate the incorporation of nanoclays does not change the cell adhesion and spreading as compared to those on pure PHB.