1 Sara Pourabbasi IUFRO Division 5 Conference Forest Products IRG/Wood Protection

A. Karimi, M. Tajvidi, D. Parsapajouh, M. Soleymani Sara Pourabbasi* A. Karimi, M. Tajvidi, D. Parsapajouh, M. Soleymani Effect of compatibilizer on the natural durability of wood flour/high density polyethylene composites against the rainbow fungus ( Coriolus versicolor ) Islamic Azad University Of Malayer lecturer at Malayer Islamic Azad University P.O.Box 65718/117, Malayer, Iran. MALAYER IRAN Map

Determining whether or not a compatibilizer can enhance natural durability of wood plastic composites and to what extent the mechanical properties are affected by the fungus in the presence or absence of a compatibilizer... Aim of work and methods Materials NumberCode Fiber Type Fiber content HDPE MAPE Content Content 1 WF-25-0 WF WF-25-1 WF WF-50-0 WF WF-25-2 WF5048 2

 Culture Medium (Malt extract agar)  Purified Rainbow Fungus  Wood flour/high density polyethylene composites METHODS: - Preparation of Composite Specimens - Fungus Culture - Contamination of Composite Specimens with The Purified Fungus Materials

Durability Assessment Apparent Damage ( Willeitner criterion ) No Code Sample size Average mycelium cover (%) Damage class (Willeitner criterion) 1 WF WF WF a 4WF b

The Kolle dishes containing the fungus and the specimens were stored in an incubator for 14 weeks at 25 Ċ and 75% relative humidity. The percentage of the area of the specimens (WF-50-2) and (WF-50-0) covered by fungus mycelium after14 weeks (WF-50-2) (WF-50-0)

Weight Loss Weight loss (%) = dry weight before incubation - dry weight after incubation *100 (1) dry weight before incubation Findlay (1967)method Mechanical Tests  Three-Point Bending  Impact Tests

Instron testing machine Zwick-Material Profong impact tester

Hardness Tests Water Absorption  Shore D hardness tester Water absorption (%) = wet weight - dry weight * 100 dry weight Statistical Analysis Completely randomized design and Duncan’s Multiple Range Test (DMRT)

Comparison of Weight Loss and Natural Durability of the Composites…. RESULTS AND DISCUSSION FIG. 1. Average weight losses of different formulations After 14 weeks incubation

Mechanical Properties FIG. 2. Effect of the compatibilizer on the flexural strength loss of different formulations after 14 weeks incubation.

FIG. 3. Effect of the compatibilizer on the Flexural modulus of different formulations after 14 weeks incubation. Mechanical Properties

FIG. 4. Effect of the compatibilizer on the hardness of different formulations after 14 weeks incubation. Mechanical Properties

FIG. 5. Effect of the compatibilizer on the un-notched impact Strength of different formulations after 14 weeks incubation. Mechanical Properties

Water Absorption FIG. 6. Effect of the compatibilizer on the water absorption of different formulations after 14 weeks incubation.

CONCLUSIONS Compatibilizer has considerable effects on the natural durability of wood flour- high density polyethylene composites. The use of a compatibilizer is inevitable even if improvements in mechanical properties are not of concern.

Weight loss, modulus of elasticity loss, flexural strength loss, and hardness loss were all significantly higher in the absence of the compatibilizer. The main reason for the higher natural durability of the compatibilized formulations is seen in better encapsulation of wood particles by the polymer and less accessibility of the nutrients for the fungus. CONCLUSIONS