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This study aimed to investigate the impact of including teak wood in recycled high-density polyethylene wood plastic composites (WPC) with pine wood on their resistance to degradation caused by termite attack and accelerated weathering. A 23 factorial experimental design was conducted with three repetitions in the center to analyze the weight loss and termite mortality during the experiments. The factors studied were the days of exposure to accelerated weathering, days of exposure to termite attack, and the concentration of teak wood in the composite. Surface characterizations (SEM and FTIR) were carried out to analyze the exposed surfaces and determine the chemical modification of the composite components. The results showed that the WPC manufacturing process promotes a heterogeneous distribution of the wood particles, being greater within the center of the samples than on the surface. Specimens exposed to both accelerated weathering and termite attack resulted in a certain weight loss and termite mortality, depending on the material, conditions of exposure, and the content of teak wood in the WPC. When those compounds were subjected to accelerated weathering followed by termite attack they exhibited a higher termite attack. The presence of teak wood in the WPC produced a reduction in the effects of termite attack and accelerated weathering on weight loss and an increase in termite mortality compared to the WPC with only pine wood, as teak wood contains extractables with termiticidal action. The lowest value of weight loss (0.06%) was observed for the WPC with the highest amount of teak wood with termite attack, resulting in a termite mortality rate of 100% after 17 days of exposure. [ABSTRACT FROM AUTHOR]

It has been reported that pinewood residue/recycled high density polyethylene composites with 40 wt% of wood were attacked by termites native to the Yucatan Peninsula (Nasutitermes nigriceps). Thus, this article gives account of how effective environmentally friendly borates are (i.e. borax and zinc borate) to protect this kind of composites. Before biotic exposure, composites’ samples were subjected to 1000 and 2000 h of accelerated weathering, using a ultraviolet-type accelerated tester equipped with UVA-340 fluorescent lamps and respectively impregnated with 1, 2, and 3% aqueous solutions of both borates, following the ASTM D 1413 standard test method as reference. A reduction in the treated samples’ weight loss was observed, which indicated that they increased their resistance to termite attack. No weight losses occurred when the solutions with 3% of both borates were respectively used. Additionally, scanning electron microscopy revealed that these solutions did not damage the composites’ surface. The results show that both borates experimented with have the potential to be used as termiticides for wood–plastic composites without damaging the environment. [ABSTRACT FROM AUTHOR]

Although wood–plastic composites (WPCs) are materials widely used in the construction industry, their durability constitutes a serious issue especially when used for outdoor applications. Therefore, this work gives account on the effect of biotic and abiotic degradation agents on two different WPCs prepared from recycled high-density polyethylene (HDPE) and pinewood residues. Two aspects were evaluated, namely mechanical properties and aesthetics. Compression-molded samples obtained from two different formulations based on 40% of wood and 60% of HDPE, containing 0 and 5% of coupling agent with respect to wood content, were subjected to 0, 1000 and 2000 h of accelerated weathering (AW), using an ultraviolet-type accelerated tester equipped with UVA-340 fluorescent lamps. Afterward, the aged specimens were exposed to attack by termites (TA) of the species Nasutitermes nigriceps for 15 and 30 days. Tensile properties after AW and TA were assessed using an Instron 5500R (1125) universal tester. Similarly, the aesthetic aspect was studied to evaluate the color changes on the specimens’ surfaces using a Minolta CR-200 Chroma Meter. The results of this work show drops in the mechanical properties of both composites that were not significant, even after being exposed to 2000 h of AW in combination with 30 days of TA. However, their aesthetics was seriously affected by both degradation agents, as reflected by the variations registered on the total color change and relative lightness of the tested samples. [ABSTRACT FROM AUTHOR]