Effects of UV-accelerated weathering and natural weathering conditions on anti-fungal efficacy of wood/PVC composites doped with propylene glycol-based HPQM

This work studied the mechanical, physical and weathering properties and anti-fungal efficacy of polyvinyl chloride(PVC) and wood flour/polyvinyl chloride composites(WPVC). 2-hydroxypropyl-3-piperazinyl-quinoline carboxylic acid methacrylate (HPQM) in propylene glycol was used as an anti-fungal agent. Propylene glycol-based HPQM was doped in neat PVC and in WPVC containing 50 and 100 pph wood (WPVC-50 and WPVC-100). The flexural properties of PVC decreased when propylene glycol-based HPQM was added. However, adding this component did not affect the flexural properties of WPVC. Fungal growth inhibition test and dry weight technique were used for evaluation of anti-fungal effectiveness. Aspergillus niger was used as a testing fungus. Adding propylene glycol-based HPQM to WPVC-100 led to the most effective anti-fungal performance. Wood flour acted as an anti-fungal promoter for the WPVC composites. The optimal dosages of propylene glycol-based HPQM in PVC, WPVC-50, and WPVC-100 were 50000, 15000, and 10000 ppm, respectively. UV-accelerated weathering aging and natural weathering conditions were found to affect the flexural properties of PVC and WPVC. The change in the anti-microbial performance of WPVC under natural weathering were slower than those under UV-accelerated weathering aging. The anti-microbial evaluation indicated that the samples doped with less than 20000 ppm propylene glycol-based HPQM had a more pronounced effect than the ones doped with higher dosages