Quality enhancement of the inner part of oil palm trunk by close system compression method and by phenol formaldehyde compregnation

Abstract

Improvement of physical and mechanical properties of oil palm trunk could be done by close system compression (CSC) and by compregnation with fenol formaldehida. The aims of these researches were to determine the maximum compression level by studying the density distribution and stress-strain curves of oil palm trunk, to evaluated the fixation of the inner part of oil palm trunk by close system compression, heat treatment and steam treatment, to measured the physical, mechanical, anatomical and chemical of densified oil palm trunk by CSC, and to evaluated the physical and mechanical of phenol formaldehyde (PF)- densified of oil palm trunk. The results showed that density of oil palm trunk was around 0.23-0.74 g/cm3. The density at the outer part was higher, and then decreasing toward the center of trunk. The stress-strain curves showed that water saturated and wet conditions were easier to compress than that of air dry condition. The compression level increased from the outer part to the center. The maximum compression levels of the center park were 67% in air dry condition and 72-73% in wet and water saturated conditions from their initial thickness. Fixation of the trunk by steam treatment method was achieved at 170 oC for 30 min, by CSC at 180 oC for 30 min, while by heat treatment was not yet fixed even at 200 oC for 180 min. Compression by CSC results in the improvement of the physical and mechanical properties of the inner part of oil palm trunk. The density, MOR, MOE and compression parallel to grain of densified-oil palm trunk were improved 3.33-90%, 14.31-192.81%, 43.22-192.74% and 18.93- 123.20%, from the initial samples (control), respectively. The chemical components especially holocellulose was decreased with the increasing of temperature and time of compression, but the other components (lignin, alfa cellulose, extractive by hot water and by alcohol-benzene) were increased. Then, PF compregnation results in the improvement of the physical and mechanical of the inner part of oil palm trunk. The density, MOR, MOE and compression parallel to grain of PF-densified oil palm trunk were improved 94.12–176.47%, 191.7–309.5%, 108.2–287.5%, and 83.72–191.75%, from the initial samples (control), respectively. The last, the inner part of oil palm trunk after treating by CSC and by compregnation PF is suitable for furniture material.

Batang kelapa sawit (BKS) memiliki potensi yang sangat besar untuk dijadikan sebagai pengganti kayu mengingat luas perkebunan kelapa sawit yang terus bertambah. Kendala pemanfaatan dari BKS adalah sifat-sifatnya yang kurang baik, seperti kembang susut yang tinggi, sifat kekuatan dan keawetan yang rendah, serta sifat permesinan yang jelek. Bakar et al. (2000) mengemukakan bahwa hanya 1/3 bagian terluar dari BKS yang memiliki sifat kekuatan yang baik sehingga bisa digunakan sebagai bahan bangunan dan furniture, sedangkan 2/3 bagian dalam kurang baik. Upaya perbaikan sifat-sifat BKS dapat dilakukan dengan modifikasi kayu, salah satunya adalah metode pemadatan. Sifat fisis dan mekanis kayu hasil pemadatan pada umumnya meningkat. Namun jika tanpa perlakuan tertentu, pemadatan yang dilakukan belum menghasilkan fiksasi permanen atau masih terjadi pemulihan tebal (recovery) apabila kayu tersebut terkena air atau kelembaban tinggi. Padahal fiksasi permanen mutlak dibutuhkan untuk penggunaan sebagai bahan bangunan atau furniture. Metode pemadatan dengan close system compression (CSC) yang merupakan modifikasi dari steam treatment adalah metode pemadatan yang menghasilkan fiksasi dalam waktu yang singkat. Recovery of set (RS) pemadatan kayu Sengon suhu 180 oC selama 30 menit menghasilkan RS sebesar 1.6%, sedangkan perendaman contoh uji dalam larutan NaOH 2% mampu menurunkan suhu menjadi 160 oC dengan RS sebesar 1.84% (Amin et al. 2007).