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Keywords:

  • wood-flour/HDPE;
  • composite;
  • pigment;
  • UV weathering;
  • color;
  • photodegradation

Abstract

The effects of different color pigments on the durability of wood-flour/high-density polyethylene composites (WF/HDPE) were evaluated by UV-accelerated weathering tests. WF/HDPE composites were dyed using three different color inorganic pigments, which were added at 2% based on the weight of the composite. Samples were weathered in Q-panel UV aging equipment for 1500 h. All samples showed significant fading and color changes in exposed areas. Changes in surface chemistry were studied using spectroscopic techniques. X-ray photoelectron spectroscopy (XPS) was used to verify the occurrence of surface oxidation. Changes in carbonyl groups (C[DOUBLE BOND]O), PE crystallinity, cellulose C[BOND]O, and lignin aromatic C[DOUBLE BOND]C were detected by Fourier transform infrared (FTIR) spectroscopy. The results indicate that surface oxidation occurred immediately within exposure 250 h for all samples; the surface of the control WF/HDPE composites was oxidized to a greater extent than that of the dyed WF/HDPE. This suggests that the addition of pigments to the WF/HDPE composites results in less weather-related damage. The surface configuration observed by scanning electron microscopy revealed that WF/HDPE composites degraded significantly on accelerated UV aging, with dense cracking apparent on the exposed surface. Carbon black had a more positive effect on color stability than the other pigments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010