Effect of nano-zirconium oxide modification on flame retardancy of lignocellulose composite

As a common renewable raw material , lignocellulose had the advantages of high carbon content and rich active groups, however its poor flame retardancy limited the application. In this paper, lignocellulose and zirconium oxide (ZrO 2 ) were employed as raw materials, nano-ZrO 2 -lignocellulose flame retardant composites (LCZ) were prepared by mechanical grinding and hot pressing. The friction between lignocellulose and nano-ZrO2 was increased by pretreatment using mechanical grinding. After hot-pressing, the ZrO 2 particles were attached on the lignocellulose. The results showed that LCZ composites had a better flame retardancy and mechanical strength . The mechanical strength of LCZ composite reached 34.9 MPa and improved by 31.2 % while the lignocellulose was 26.6 MPa. Owing to the existence of ZrO 2 , the heat release rate and total heat release rate of LCZ composite were reduced 61 % and 27 % than that of pure lignocellulose material (LC), respectively. The smoke production rate of LCZ composite decreased by 58 % compared with that of LC composite. Thermogravimetric studies showed that ZrO 2 could promoted the charring of lignocellulose, further formed a carbon protective layer on the lignocellulose surface. Therefore, it provided a better modified method for preparing flame retardant lignocellulose composite.