Bio-Based Poly(3-hydroxybutyrate) and Polyurethane Blends: Preparation, Properties Evaluation and Structure Analysis.

Area of Science:

• Materials Science
• Polymer Science

Background:

• Poly(3-hydroxybutyrate) (P3HB) is a biodegradable polymer with potential applications but limitations in thermal and mechanical properties.
• Polyurethane (PU) is a versatile polymer known for its elasticity and toughness.

Purpose of the Study:

• To develop and characterize polymer blends of P3HB and synthesized linear PU.
• To investigate the effect of varying PU content (5, 10, 15 wt. %) on the thermal, mechanical, and surface properties of P3HB.
• To determine the optimal PU composition for enhanced material performance.

Main Methods:

• Synthesis of linear polyurethane (PU) via reaction of polypropylene glycol with 4,4'-diphenylmethane diisocyanate.
• Melt-blending of P3HB and PU using a twin-screw extruder.
• Characterization using differential scanning calorimetry (DSC), Fourier transformation infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX).
• Evaluation of mechanical properties (impact resistance, hardness, tensile, flexural) and surface topography.

Main Results:

• FTIR confirmed hydrogen bonding interactions between PU and the P3HB matrix.
• Increased PU content led to improved surface regularity and homogeneity.
• P3HB/PU blends showed reduced hardness, enhanced impact strength, and greater relative elongation at break compared to pure P3HB.
• DSC indicated decreased glass transition, melting, and crystallization temperatures with increasing PU content.
• Blends with 10 wt. % PU demonstrated the best overall mechanical and thermal properties.

Conclusions:

• Polyurethane incorporation significantly modifies the properties of P3HB.
• The P3HB/PU blend containing 10 wt. % PU offers a promising balance of improved mechanical performance, enhanced processability due to lower melting point, and better thermal stability.
• These findings suggest potential for P3HB/PU blends in applications requiring enhanced biodegradability and tailored mechanical characteristics.