THE EFFECT OF COLORANTS ON THE DEGRADATION PERFORMANCE OF WOOD PLASTIC COMPOSITES

The degradation performance of the colorful wood flour/poly (β-hydroxybutyrate valerate) composites (CWPHBVs) in natural outdoor landfill was investigated by some physical, analytical, and microscopic tests. The mass loss rate of the CWPHBVs within 80 days of degradation shows a growth trend and the mass loss rate decreases by more than 20%. With the increase of degradation time, the bending strength of the CWPHBVs continues to decline, the elastic modulus of the CWPHBVs shows a logarithmic decline trend. After 30 days, the bending strength of the CWPHBVs decreases over 50% and tend to be stable. The colorant has a certain inhibitory effect on the degradation. However, with the shedding of the colorant, the effect of the colorant on the degradation is gradually weakened. The addition of colorants reduces the decomposition rate of PHBV and improves the thermal stability of poplar fibers. However, after 20 days, this effect almost disappears

Effects of nano-SiO2/polyethylene glycol on the dimensional stability modified ACQ treated southern pine

Southern yellow pine (Pinus sp.) wood cubes were vacuum-pressure treated with nano-SiO2 solution and different concentrations of ACQ/polyethylene glycol (0.5%, 2.5% and 5.0%) modified solutions. The effects of polyethylene glycol concentrations and nano-SiO2 addition on the water absorption, air drying shrinkage and moisture swelling stability of treated wood were investigated. The results showed that during the whole process of water absorption and air drying shrinkage, the better stability of nano-SiO2 modified ACQ treated wood could only be obtained with the ratio of 2.5% polyethylene glycol addition. However, nano-SiO2 and polyethylene glycol modification could take little effect on the moisture and water swelling resistance of treated wood with different treatments.

Dimensional stability of nano-SiO2/emulsified wax modified CuAz-treated wood after one year outdoor exposure test

Samples were vacuum-pressure treated with nano-SiO2 water solutions with BET specific surface area of 60,150, 200, 380 respectively, and then impregnated with copper azole (CuAz) preservatives or emulsified wax modified CuAz preservatives. The effects of emulsified wax and nano-SiO2 on the dimensional stability were investigated according to standard GB/T 1934 (2009) after one year outdoor exposure test. The results showed that the addition of nano-SiO2 or/and emulsified wax could reduce the water absorption rate of treated wood, and the best water repellent was observed in the samples treated with BET specific surface area of 60 m2.g-1. The addition of wax into nano-SiO2 modified wood was essential to improve the radial and tangential swelling and shrinkage stability of nano-SiO2 treated wood. The bigger BET specific surface area of nano-SiO2 would be adversely affected the dimensional stability of the treated wood.