Thermal Conductivity of Oil Palm Fibre - Polyethylene Hybrid Composite 23 Thermal Conductivity of Oil Palm Fibre - Polyethylene Hybrid Composite Ridzuan Ramli*; Mohd Ariff Jamaludin** and Semsolbahri Bokhari** Ridzuan Ramli*; Mohd Ariff Jamaludin** and Semsolbahri Bokhari** Ridzuan Ramli*; Mohd Ariff Jamaludin** and Semsolbahri Bokhari** Ridzuan Ramli*; Mohd Ariff Jamaludin** and Semsolbahri Bokhari** Ridzuan Ramli*; Mohd Ariff Jamaludin** and Semsolbahri Bokhari** * Malaysian Palm Oil Board, P. O. Box 10620, 50720 Kuala Lumpur, Malaysia. ** Faculty of Forestry, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. ABSTRACT Hybrid composite boards were manufactured from oil palm trunk (OPT), frond (OPF), empty fruit bunch (EFB) and polyethylene. The objective of this study was to measure the thermal conductivity of hybrid composite boards. The thermal conductivity of the boards was measured using Quick Thermal Conductivity Meter (QTM-D3). In this study, hybrid boards with different types of oil palm fibres and plastic content (5%, 12% and 20%) were used as the samples for experiment. Statistical analysis showed that the fibre types did not affect thermal conductivity values significantly. However, fibre types did influence the density of the boards. The correlation between density and thermal conductivity showed that density affected the value of thermal conductivity but it was not significant. The results showed that the values of thermal conductivity for this type of hybrid board were very low. Therefore, the hybrid composite boards are suitable for use as insulating boards. ABSTRAK ABSTRAK ABSTRAK ABSTRAK ABSTRAK Papan komposit hibrid diperbuat daripada batang (OPT), pelepah (OPF), tandan kosong (EFB) dan polietilena. Tujuan kajian ini untuk menentukan konduktiviti terma papan komposit hibrid. Konduksian terma bagi sampel ditentu- ukurkan dengan menggunakan Quick Thermal Conductivity Meter (QTM-D3). Sampel yang digunakan dalam kajian ini adalah daripada papan gentian sawit yang dicampurkan dengan plastik mengikut peratusan kandungan yang ditentukan (5%, 12% dan 20%). Dari analisis statistik, didapati jenis gentian tidak mempengaruhi nilai konduktiviti terma tetapi ia mempengaruhi nilai ketumpatan papan tersebut. Korelasi di antara ketumpatan dengan konduktiviti terma menunjukkan bahawa ketumpatan papan hibrid sedikit sebanyak mempengaruhi nilai konduktiviti terma tetapi Oil Palm Bulletin 45 (November 2002) p. 23 – 26 Keywords: Keywords: Keywords: Keywords: Keywords: composite hybrid board, poly- ethylene, thermal conductivity, density. tidak memberikan kesan yang bererti. Keputusan kajian menunjukkan nilai konduktiviti terma bagi bahan biojisim sawit ini adalah rendah. Oleh itu, papan hibrid ini sesuai digunakan sebagai papan penebat. INTRODUCTION INTRODUCTION INTRODUCTION INTRODUCTION INTRODUCTION Thermal conductivity (K) is one of the thermal- physical characteristics of a material. The unit for K is Watt per metre Kelvin, (W m -1 T -1 ). Under room conditions, K is very high for conductors, such as metals, but for gases, K is very low, less than 0.01 W m -1 T -1 . Materials with K < 1 W m -1 T -1 are classified as insulators (Parrot, 1975). The K of a material (Table 1) depends on its chemical composition, phase situation and crystal structure (Siau, 1984). For example, metals are known to have good K and are classified as conductors. However, wood and cellulose materials such as oil palm residues are insulators. In wood or oil palm residues, there are vessels in their structure with entrapped air which is a poor conductor. The insulating properties of wood have numerous advantages and contribute greatly to the fire-resistant properties of wood as compared with the highly conducting metals, which soften at high temperatures. In this study, experiments and analyses were performed on hybrid composites of oil palm residues (trunk, frond, EFB) and plastic. The residues were mixed with adhesive and plastic at different contents. The influence of the plastic content on the K of the hybrid boards was investigated.