Effect of Organo-Modified Montmorillonite on Thermal Properties of Bacterial Poly(3-hydroxybutyrate)

Abstract

Nanocomposites based on biodegradable poly(3-hydroxybutyrate) (PHB) and two types of organically modified layered silicates, cloisite 30B (C30B) and montmorillonite grafted-poly(ϵ-caprolactone) (MPCL), were prepared through solution intercalation technique. The thermal properties of PHB/nanocomposites at different organoclay contents (5 and 10%) were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC results showed that the dispersed MPCL enhanced the rate of crystallization of PHB from glassy and molten states, whereas C30B retarded the crystallization of PHB from glassy state and enhanced its crystallization from molten state. Kinetics of thermal degradation was studied using Ozawa and Kissinger methods.

Keywords:

• Kinetics
• Nanocomposites
• Poly(3-hydroxybutyrate)
• Thermal properties

ACKNOWLEDGMENT

Special thanks to Cairo University for supporting this research through Graduate Research Challenge Fund (GRCF) for distinguished young researchers.

Notes

^a Determined from the DSC second run (Run II).

^b Cold crystallization exothermic peak determined from Run II.

^c Melt crystallization exothermic peak determined from the DSC cooling scan from melt.

^d Normalized heat enthalpy of fusion of 1.0 g PHB determined from the DSC Run II.

^e Crystallinity percentage according to the following equation: where is the heat enthalpy of fusion of completely crystallized PHB with reference value 146 J/g.