Effect of compatibilizer on mechanical, thermal and morphological study of pbs/phbhhx blends
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Date
2019-05
Authors
Tan Siew Mian
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Abstract
Poly(butylene succinate) (PBS), which has excellent processability, was blended with Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) to improve its processability, thermal stability and mechanical properties, especially brittleness and toughness. However, the properties of polymer blends can be affected by blend ratio and compatibility between the polymer components. Thus, this study was aimed to investigate the effect of blend ratio and compatibilizer on the mechanical, thermal, and morphological properties of PBS/PHBHHx blends. PBS/PHBHHx blends with ratio of 20/80, 40/60, 60/40, and 80/20 wt%, and PBS/PHBHHx (20/80) blends with 4,4’- methylene diphenyl diisocyanate (MDI) contents of 0, 2, and 4 wt% were melt blended in an internal mixer at 165°C. The properties of the blends were evaluated through tensile and impact tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscope (SEM). Tensile strength, elongation at break, and impact strength of the blends decreased when PBS content increased up to 40 wt%, but increased back when PBS content reached 60 wt% and higher. The modulus of the blends decreased gradually with increasing PBS contents. There was no significant changes in the melting temperatures and thermal stability of PHBHHx in the blends as PBS content increased. With addition of MDI, the tensile and impact properties of the PBS/PHBHHx blends were increased. The compatibilized blends achieved the highest tensile properties at 2 wt% MDI. Melting temperature and thermal stability of the blends were remain unchanged after adding MDI. SEM micrographs displayed reduction in PBS phase size and increase in interfacial adhesion between the PBS and PHBHHx phases. xviii Fourier transform infrared (FTIR) spectroscopy revealed that chemical interaction had taken place between the polymers and MDI.