Effect of alkyl ketene dimer on chemical and thermal properties of polylactic acid (PLA) hybrid composites

Abstract

In this study, the influence of alkyl ketene dimer (AKD) on the chemical and thermal properties of natural fiber (NF) and glass fiber (GF) reinforced poly(lactic acid) (PLA) composites was investigated. The hybrid PLA composites were manufactured by extrusion technique followed by hot press molding. The thermal properties of the composites were evaluated with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), heat deflection temperature (HDT) and thermal conductivity tests. In addition, the hybrid PLA composites were characterized by using Fourier Transform Infrared (FTIR) spectroscopy to determine the relationship between AKD and NF. The crystallinity degree of NF/GF/PLA (10/20/70) was improved to 54.4% with the addition of AKD, which was 18.4% higher than that of the neat PLA. However, the degradation temperatures of the hybrid PLA composites did not change by adding AKD. The HDT of the hybrid PLA composites decreased with the addition of AKD depending on filler type. Although, GF had no a significant influence on thermal conductivity, the thermal conductivity of the GF/PLA (30/70) composites decreased to 0.092 W/mK by adding AKD. In the light of findings, the fact that AKD did not have adversely effect on the thermal and thermo-mechanical properties of biocomposites increased the potential of AKD usage as a compatibilizer in PLA matrix.