Tibertius Agus Prayitno

Improving the Physico-Mechanical Properties of Eco-friendly Composite Made From Bamboo

This research focused on physical and mechanical properties of biocomposite made from bamboo and citric acid as natural binder. Bamboo particles was mixed with citric acid at 0 – 40 wt% resin content based on air-dried particles and each mixture was hot pressed at 180 °C for 10 min. The result showed that addition of citric acid could improve significantly the physical and mechanical properties of particleboard. The thickness swelling was 50 % for bamboo binderless particleboard (0 wt%), whereas it decreased to 7 % under a resin content of 10 wt%. The optimum resin content in this study was 30 wt%, while the modulus of rupture dan the modulus of elasticity were 14 MPa and 4.5 GPa, respectively. The ester linkages were detected by Fourier transform infrared spectroscopy, indicating that carboxyl groups from citric acid reacted with hydroxyl groups from bamboo to produce better properties of particleboard, especially its dimensional stability. Based on these results, it was concluded that citric acid could be as a potential natural binder for bamboo particleboard.

Pengaruh Suhu dan Metode Perlakuan Panas terhadap Sifat Fisika dan Kualitas Finishing Kayu Mahoni

Perlakuan panas dikenal sebagai metode yang dapat digunakan untuk meningkatkan stabilitas dimensi dan menurunkan higroskopisitas. Di sisi lain, perlakuan panas dapat membuat warna kayu menjadi lebih gelap, penurunan sifat mekanika kayu, dan sifat wetabilitas kayu. Oleh karena itu, penelitian mengenai perlakuan panas pada kondisi yang optimum sangat menarik untuk dilakukan agar menghasilkan kayu dengan kualitas yang lebih baik. Tujuan penelitian ini adalah mengetahui pengaruh interaksi suhu dan metode perlakuan panas terhadap sifat fisika dan kualitas finishing kayu mahoni. Contoh uji perlakuan dibuat dari kayu mahoni yang berasal dari industri penggergajian kayu rakyat. Penelitian ini menggunakan 2 metode perlakuan panas yaitu metode oven dan penguapan (steaming) pada variasi suhu 90°C, 120°C, dan 150°C selama 2 jam waktu efektif. Pengujian sifat fisika diuji berdasarkan standar ASTM, yang meliputi : kadar air seimbang, perubahan dimensi, perubahan warna, dan wetabilitas. Pengujian finishing meliputi cross cut test, uji delaminasi, dan uji kekilapan (glossy test). Hasil penelitian menunjukkan bahwa interaksi antara suhu dan metode perlakuan panas berpengaruh sangat nyata terhadap perubahan warna, serta berpengaruh nyata terhadap penyusutan radial, cross cut test, dan uji delaminasi. Metode oven menghasilkan contoh uji dengan kadar air dan pengembangan radial yang lebih rendah, warna yang lebih terang, serta uji delaminasi yang lebih baik dibandingkan dengan metode penguapan. Kata kunci : perlakuan panas, metode oven, metode penguapan, suhu, finishing Effect of temperature and heat treatment on physical properties and finishing quality of mahagony wood Abstract Heat treatment is well known as a method for increasing dimensional stability and reducing hygroscopicity of wood. However, heat tratment can cause the color of wood become darker and reduce the wettability, as well as its mechanical properties. Therefore, the optimum condition of heat treatment is essential to be studied to obtain the high quality of properties treated wood. This research focused on investigating the heating temperature and treatment method on physical properties and finishing quality of mahagony wood. Two treatment methods, i.e. oven method and steaming method, were used in this research. The heating temperatures were set at 90°C, 120°C, and 150°C. The effective heating time was 2 h. The wood physical properties were tested according to ASTM standards and wood finishing quality were tested for its cross cut, delamination, and glossy test. The results showed that interaction between treatment method and heating temperature affected significantly on the change in color, radial shrinkage, cross cut test, and delamination test. Oven method resulted in reducing moisture content and radial shrinkage, light color, and better quality of wood, compared to steaming method.