Miscibility, crystallinity and morphology of polymer blends of polyamide-6 poly (β-hydroxybutyrate)‎

Abstract EN

Polyamide-6 (PA6) with bacterial poly ( β -hydroxybutyrate) (PHB) are typical polyamide and polyester, respectively.

PA6 is known to be high-strength engineering thermoplastic.

Although it is ductile at room temperature, it becomes brittle under severe conditions such as high strain rates and/or low temperatures.

This is due to the low crack propagation resistance of polyamides.

PHB is a biodegradable and biocompatible thermoplastic polymer of high melting temperature (180°C ) and crystallinity.

PHB has attracted much attention as an environmentally degradable resin to be used for agricultural, marine and medical applications.

One of the limitations of PHB for these applications is its brittleness and narrow processing window.

Blending of friendly environmental biopolymers with synthetic polymers has proven to be a suitable tool to produce novel materials with combined characteristics in having both improved application properties and low cost advantages in material performance.

In this study, the segmental interaction parameters, crystallinity, miscibility and morphology of polymer blends (PB) of PA6 and PHB have been studied at different weight fractions and different crystallization temperatures.

The experimental approaches utilized are Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) and Polarized Optical Microscopy (POM).

The interaction parameters were calculated using the Nishi-Wang equation, which is based on the Flory-Huggins theory.

The values of interaction parameters χ12 were negative for all blend compositions suggesting that 12 χ depends on the volume fraction (Φ) of the polymer.

Significant upward shifts of νC=O and νNH are observed with increasing the voume fraction Φ2 of PHB which reflect the miscibility of the blend systems.

Polymer blends show spherulitic morphology and the spherulites exhibit a banded structure.

The band spacing decreases with increasing PHB content.