The Effect of Modifier on Properties of Bamboo Powder/High-Density Polyethylene Composites

Abstract

Abstract The focus of this study was to observe the properties of bamboo plastic composites modified with a self-made modifier, 18 acyl-dopamine (0, 0.25, 0.50, 0.75, 1.00, and 1.25 weight percent [wt%] based on the dry weight of bamboo powder). The effects of the modifier were demonstrated by measures of mechanical properties, water absorption, thermal stability, and scanning electron microscopy (SEM). The results revealed that 18 acyl-dopamine could be used as an effective modifier of bamboo powder/high-density polyethylene composites. When the modifier was increased, the toughness of the composite deteriorated, and the strength and rigidity improved. This indicated that when the dosage became higher, the compatibilization became stronger, and the toughening effect became worse. Based on the experimental data, a small dosage modifier acted as a toughening agent; as the dosage increased to 1.0 wt%, the compatibility began to appear. The modifier reacted with the hydroxyl groups on the surface of the bamboo powder, which caused the bamboo powder to absorb less water, so the thickness expansion rate was lowest at 1.25 wt%. The pyrolysis peak of bamboo powder and plastic showed a tendency to be close to each other, indicating that the interface was improving. Based on the equation of Flynn-Wall-Ozawa, as the dosage of the modifier increased from 0.50 to 1.25 wt%, the apparent activation energy also increased. The SEM analysis showed the binding between bamboo powder and the plastic matrix was strongest when the modifier dosage was 1.25 wt%.