Thermal and Mechanical Performance of Maleic Anhidride/Benzoyl Peroxide-Modified PLA/PCL Biocomposites

Area of Science:

• Polymer Science
• Materials Science
• Composite Materials

Background:

• Poly(lactic acid) (PLA) and poly(caprolactone) (PCL) are biodegradable polymers with complementary properties.
• Improving the compatibility and performance of PLA/PCL blends is crucial for advanced applications.
• Maleic anhydride (MA) is a potential compatibilizer for immiscible polymer blends.

Purpose of the Study:

• To investigate the compatibilizing effect of maleic anhydride (MA) grafted onto PLA in PLA/PCL blends.
• To evaluate the influence of varying MA content on the thermal, mechanical, and morphological properties of PLA/PCL blends.
• To determine the optimal MA concentration for enhancing the properties of PLA/PCL systems.

Main Methods:

• Preparation of PLA grafted with MA (PLA-g-MA) using benzoyl peroxide (BPO) initiator.
• Fabrication of PLA/PCL blends with different formulations of PLA-g-MA.
• Characterization using Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Fourier-Transform Infrared Spectroscopy (FTIR), goniometry, Scanning Electron Microscopy (SEM), and mechanical testing (tensile, impact, hardness).

Main Results:

• PCL addition improved PLA ductility but decreased tensile strength and hardness.
• MA grafting enhanced phase compatibility, increasing elongation at break and impact resistance, particularly at 1-3% MA.
• Higher MA concentrations (≥5%) resulted in heterogeneous phase dispersion, leading to variable thermal and mechanical properties.
• FTIR confirmed residual BPO below 0.1 phr; TGA showed slight thermal stability improvement at 5% MA.

Conclusions:

• Controlled maleic anhydride grafting effectively improves the compatibility and performance balance of PLA/PCL blends.
• Intermediate MA concentrations (1-3%) offer the most significant improvements in ductility and impact resistance.
• Further optimization of grafting and processing conditions is needed to mitigate heterogeneity at higher MA levels.