Sains Malaysiana 30: 177-186 (2001)                                                                           Sains Fizis dan Gunaan /

Physical and Applied Sciences

Properties and Durability of MUF-Bonded Particleboard

Treated with Boron Compound

A. Zaidon, B. Junaidi, M.T. Faridah

Faculty of Forestry

Universiti Putra Malaysia

43400 Serdang, Selangor

M.Y. Nor Yuziah

Malaysian Adhesive & chemicals Sdn. Bhd.

Lot. 9, Jalan Utas 15/7

P.O. Box 7086, 40702, Shah Alam

Selangor D.E. Malaysia

ABSTRAK

Campuran asid borik (H₃BO₃) dan borak (dinatrium tetraborat dekahidrat (Na₂B₄O₇H₂O) pada nisbah 1:1.54 dicampurkan ke dalam papan serpai kayu getah (Hevea brasiliensis) dengan menyemburkan campuran larutan 0.5% dan 1.0% kesetaraan asid borik (BAE, b/b berat kering serpai) kepada adunan serpai semasa proses pengadunan. Resin melamin urea formaldehid (MUF) digunakan sebagai perekat. Ketumpatan sasaran papan serpai adalah 650 kg/m³. Kaedah piawaian titratan MS 955-1986 digunakan untuk menganalisis bebanan borik asid di dalam papan yang telah dirawat. Sifat papan serpai diuji mengikut piawaian JIS 5908 - 1994 dan sifat ketahanan terhadap kulat reput putih diuji mengikut piawaian ASTM D2017-71. Bebanan BAE di dalam papan adalah di antara 0.30% - 0.49% bagi rawatan dengan 0.5% sebatian boron dan 0.63% - 0.86% bagi rawatan dengan 1.0% sebatian boron. Rawatan ini tidak mempengaruhi modulus kekenyalan (MOE) papan yang dirawat, bagaimana pun kekuatan modulus pecah (MOR) menurun sedikit. Ikatan dalaman (IB) papan yang dirawat meningkat apabila bebanan BAE didalam papan meningkat. Pembengkakkan ketebalan (TS) tidak dipengaruhi oleh rawatan tetapi penyerapan air (WA) menurun. Kehadiran sebatian boron di dalam papan meningkatkan ketahanan papan terhadap kulat reput putih, dan ketahanan ini meningkat apabila bebanan bahan kimia di dalam papan meningkat.

ABSTRACT

A mixture of 1:1.54 boric acid (H₃B0₃) to borax, (disodium tetraborate decahydrate (Na₂B₄O₇ H₂O) at 0.5% and 1.0% boric acid equivalent (w/w of oven-dried weight particles) were incorporated in rubberwood (Hevea brasiliensis) particleboards by immediately spraying the boron compounds solution onto the furnish during the blending process. Melamine urea formaldehyde (MUF) resin was used as a binder. The targeted density of the boards was 650 kg/m³. Standard titration method MS 995-1986 was employed to analyse the boric acid loading in the particleboard. The properties and durability against white rot fungus (Pycnoporous sanguineus) of the treated board were evaluated in accordance with JIS-5908-1994 and ASTM D2017–71, respectively.  The boric acid loading in the board was in the range of 0.30–0.49% and 0.63-0.86%, respectively when 0.5% and 1.0% of boron compounds were incorporated in the boards. The treatment did not affect the modulus of elasticity (MOE) of the board, however, modulus of rupture (MOR) was slightly reduced. The presence of boric acid significantly increased the durability of the board against white rot fungus, and the resistance towards the fungus increased as the boric loading increases.

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