Utjecaj nanočestica cinkova oksida na vatrootpornost drvno-plastičnih kompozita

The interest in wood plastic composites (WPCs) has increased in recent years. The utilization of environmentally friendly materials has been of great significance due to the overwhelming pressure on nature. As a widely used material, plastic is, however, easily combustible due to its structure. In this study, WPCs were reinforced with zinc oxide (ZnO) nanoparticles. The effect of higher content of ZnO nanoparticles (1, 3, 5, 10 %) on WPCs thermal stability and fire performance was investigated. Thermogravimetric analysis (TGA) clearly demonstrated that nanoparticles acted as a shield, which inhibited heat transfer and increased the degradation temperature thanks to covering the surface of materials. Free radicals accelerated the thermal degradation of neat-HDPE (high-density polyethylene) by oxidative reactions, while ZnO nanoparticles reduced the degradation velocity. Moreover, the increase in nanoparticle content significantly affected the residue. The fire performance of WPCs was also investigated by the limit oxygen index (LOI) test. While neat-HDPE flamed with dripping, ZnO nanoparticles made flaming difficult for WPCs. Therefore, the LOI values increased with increasing nanoparticle content up to 28.5 %, which indicated the need for more oxygen. The improvement reached up to 54 % compared to neat HDPE. Moreover, the char forming was also improved, which helped enhance the fire resistance. The scanning electron microscope (SEM) investigation indicated that nanoparticles were well dispersed in the matrix. However, the tendency to agglomerate increased with the increase of concentration. The ability of carbonization of wood fiber surface during the combustion also contributed to improving thermal stability and fire performance. Zanimanje za drvno-plastične kompozite (WPC) posljednjih je godina poraslo. Upotreba ekološki prihvatljivih materijala ima veliko značenje zbog golemog pritiska na okoliš. Plastika je široko rasprostranjen i vrlo često upotrebljavan materijal, ali je zbog svoje strukture lako zapaljiva. U ovom su istraživanju drvno-plastični kompoziti ojačani nanočesticama ZnO. Istraživan je utjecaj većeg udjela nanočestica cinkova oksida (ZnO) (1, 3, 5 i 10 %) na toplinsku stabilnost i vatrootpornost WPC-a. Termogravimetrijska analiza (TGA) jasno je pokazala da nanočestice djeluju kao štit koji inhibira prijenos topline i povećava temperaturu razgradnje. Nadalje, slobodni radikali u reakcijama oksidacije ubrzali su toplinsku razgradnju čistog HD