From Waste Vegetable Oil to a Green Compatibilizer for HDPE/PA6 Blends

Area of Science:

• Polymer Science and Engineering
• Materials Science and Engineering
• Sustainable Chemistry

Background:

• Blending polyethylene (PE) and polyamide (PA) offers cost-effective materials with desirable properties.
• Recycling PE/PA blends without separation is an attractive sustainable approach.
• Green compatibilizers are sought to improve PE/PA blend performance and processability.

Purpose of the Study:

• To investigate epoxidized waste vegetable oil (EWVO) as a green compatibilizer precursor (CP) for high-density polyethylene (HDPE)/polyamide-6 (PA6) reactive blending.
• To evaluate the effect of EWVO on the morphology, thermal properties, rheology, and mechanical performance of HDPE/PA6 blends.
• To compare EWVO with virgin waste vegetable oil (WVO) and a commercial fossil-based CP.

Main Methods:

• EWVO synthesized from waste vegetable oil (WVO) using ion-exchange resin catalysis.
• HDPE/PA6 blends prepared at various ratios (25/75, 75/25, 85/15) with different EWVO concentrations (1, 2, 5 phr).
• Blend characterization via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), rheology, and mechanical testing.

Main Results:

• EWVO demonstrated a satisfactory compatibilizing effect in HDPE/PA6 blends with high HDPE content (75/25 and 85/15 ratios) at 2 phr.
• Improved mechanical properties were observed in EWVO-compatibilized blends compared to uncompatibilized counterparts.
• High polyamide-6 (PA6) content blends (25/75 ratio) exhibited excessive crosslinking, hindering processing and characterization.

Conclusions:

• EWVO is an effective green compatibilizer for HDPE/PA6 blends with a majority of HDPE.
• The compatibilizing efficiency of EWVO is dependent on the blend composition.
• EWVO shows potential for enhancing the recyclability and performance of specific HDPE/PA6 formulations.