Quality Improvement of Oil Palm Trunk Properties by Close System Compression Method

Abstract

ABSTRACT Densification of the inner part of oil palm trunk (OPT) by the close system compression (CSC) method was performed in this study. The effects of the compression temperature and time on the anatomical, physical and mechanical properties of OPT were evaluated. The inner part of OPT with an initial average density of 0.3 g/cm 3 was used as samples. Oven-dried samples were immersed in water and vacuumed until fully saturated andthen compressed by CSC at 120, 140, 160 or 180℃ for 10, 20, 30 or 40 min. The anatomical characteristics of transverse and radial sections before and after compression were compared by optical microscopy. The phys-ical and mechanical properties, including the density, recovery of set (RS), modulus of elasticity (MOE), mod-ulus of rupture (MOR), and compression parallel to grain were examined. It was observed that the anatomical characteristic of the inner part of OPT (i.e., vascular bundles, vessels, and parenchyma tissue) became flattened,fractured, and collapsed after compression by CSC. The RS decreased with increasing compression temperatureand time. The lower RS indicated high dimensional stability. The physical and mechanical properties (i.e., den-sity, MOR, MOE, and compressive strength) of the inner part of OPT increased with increasing compression temperature and time. Compression by the CSC method at 160℃ for 40 min was the optimum treatment. Keywords : close system compression, compressed wood, oil palm trunk, physical and mechanical properties, recovery of set