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

Abstract

When properly compatibilized, the blending of polyethylene (PE) and polyamide (PA) leads to materials that combine low prices, suitable processability, impact resistance, and attractive mechanical properties. Moreover, the possibility of using these polymers without prior separation may be a suitable opportunity for their recycling. In this work, the use of an epoxidized waste vegetable oil (EWVO) was investigated as a green compatibilizer precursor (CP) for the reactive blending of a high-density PE (HDPE) with a polyamide-6 (PA6). EWVO was synthesized from waste vegetable cooking oil (WVO) using ion-exchange resin (Amberlite) as a heterogeneous catalyst. HDPE/PA6 blends were produced with different weight ratios (25/75, 75/25, 85/15) and amounts of EWVO (1, 2, 5 phr). Samples with WVO or a commercial fossil-based CP were also prepared for comparison. All the blends were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), rheology, and mechanical tests. In the case of HDPE/PA6 75/25 and 85/15 blends, the addition of EWVO at 2 phr showed a satisfactory compatibilizing effect, thus yielding a material with improved mechanical properties with respect to the blend without compatibilizer. On the contrary, the HDPE/PA6 25/75 ratio yielded a material with a high degree of crosslinking that could not be further processed or characterized. In conclusion, the results showed that EWVO had a suitable compatibilizing effect in HDPE/PA6 blends with high HDPE content, while it resulted in unsuitable for blends with high content of PA6.

Influence of Strong Shear Field on Structure and Performance of HDPE/PA6 In Situ Microfibril Composites

“…From Figure 10 a,b, it can be seen that after the addition of the PA6 dispersed phase, the tensile strength and tensile modulus of CIM increase to 36.4 MPa and 774.5, respectively. The improvement is very limited, which is due to the incompatibility of the HDPE matrix with the PA6 dispersed phase, although PA6 is much stronger than HDPE [ 44 ]. However, after the introduction of a strong shear field, the tensile strength and tensile modulus of the samples improve significantly and increase with increasing vibration times.…”