Viscoelastic properties of green wood across the grain measured by harmonic tests in the range of 0\degree C to 95\degree C. Hardwood vs. softwood and normal wood vs. reaction wood

The viscoelastic properties of wood have been investigated with a dynamic mechanical analyser (DMA) specifically conceived for wooden materials, the WAVET device (environmental vibration analyser for wood). Measurements were carried out on four wood species in the temperature range of 0\degree C to 100\degree C at frequencies varying between 5 mHz and 10 Hz. Wood samples were tested in water-saturated conditions, in radial and tangential directions. As expected, the radial direction always revealed a higher storage modulus than the tangential direction. Great differences were also observed in the loss factor. The tan\delta peak and the internal friction are higher in tangential direction than in radial direction. This behaviour is attributed to the fact that anatomical elements act depending on the direction. Viscoelastic behaviour of reaction wood differs from that of normal or opposite wood. Compression wood of spruce, which has higher lignin content, is denser and stiffer in transverse directions than normal wood, and has lower softening temperature (Tg). In tension wood, the G-layer is weakly attached to the rest of the wall layers. This may explain why the storage modulus and the softening temperature of tension wood are lower than those for the opposite wood. In this work, we also point out that the time-temperature equivalence fits only around the transition region, i.e. between Tg and Tg + 30\degree C. Apart from these regions, the wood response combines the effect of all constitutive polymers, so that the equivalence is not valid anymore

Central Kalimantan's Fast Growing Species: Suitability for Pulp and Paper

Recent studies of fast growing species grown in PT. Sari Bumi Kusuma, Central Kalimantan, show that based on their fiber dimensions there are five species, namely Endospermum diadenum, Dillenia spp., Adinandra dumosa, Adiandra sp., and Nauclea junghuhnii with good potential for pulp and paper production. The fiber length of those five wood species are was more than 2,200 µm on average. This paper studies the physical properties, fiber dimensions and their chemical contents to predict the paper and pulp quality. The result shows that all of the species were classified in the medium to high density category. All species were classified into the first class quality for pulp and paper. Based on chemical contents, Dillenia sp. is the most suitable species due to its high value of holocellulose and a-cellulose, low lignin content, and its fiber length is about 3,119 µm on average. A. dumosa also has good opportunities because it had the longest fiber lengths (3,137 µm on average) and high value of holocellulose, even though it has the highest lignin content. While Nuclea junghuhnii is less suitable due to low values of holocellulose and a-cellulose

Pengaruh Suhu Dan Tekanan Uap Air Terhadap Fiksasi Kayu Kompresi Dengan Menggunakan Close System Compression Temperature and Steam Pressure Dependency on the Fixation of Compressed Wood by Close System Compression

It is known that compression wood by heat treatment needs approximately 20 hours at 180ºC to attempt the permanent fixation of compressive deformation. On the other hand, even the permanent fixation of compressive deformation by steam treatment is reached in 10 minutes at the same temperature, this method needs expensive apparatus and inapplicable for large wood dimensions. These both problems can be solved by Close System Compression (CSC) method. CSC is a method to press the wood inside an airtight seal chamber, which is placed between the two hot press plates. Wood moisture contents, which evaporate due to heat from hot press, are trapped inside the CSC and produce steam. The wood species used in this research was Randu (Bombax ceiba. L) with dimensions of 2 cm (L) x 2 cm (T) x 3 cm (R). The wood specimens were compressed into 2 cm in radial direction inside the CSC at 140ºC, 160ºC, and 180ºC for 10 min, 20 min and 30 min. They were compressed in air-dried, water saturated and steam saturated conditions, because it was predicted that moisture content of wood and steam pressure, which was produced inside the CSC has significantly effects on the fixation of wood, beside the temperature.The result shows that moisture content of the wood has an effect on the decreasing of recovery of set. However, it was needed 180ºC temperature and 10 kg/cm2 steam pressure to attempt the permanent fixation. Therefore, it was necessary to add water to produce the steam pressure besides that was produced from the evaporation of wood moisture content

Sifat Ketahanan Api Lima Jenis Kayu Dengan Pelapisan Carbon Phenolic Spheres (CPS) Yang Diuji Dengan Cone Calorimeter Fire Resistance Properties of Five Wood Species Laminated with Carbon Phenolic Spheres (CPS) Tested by Cone Calorimeter

In all aspects of wood utilization their fire resistance properties are very important; therefore efforts to enhance those properties are needed. In the previous study, graphite phenolic spheres (GPS) laminated on woods and plywood enhanced their fire properties. Carbon phenolic spheres (CPS) is a new material made from a mixture of wood char and phenolic resin, this material is cheaper than GPS. In the present experiment, CPS sheet was laminated on five wood species and their fire resistance properties were evaluated using cone calorimeter.　The five wood species are randu (Bombax ceiba L.), angsana (Pterocarpus indicus Jacq.), mindi (Melia azedarach L.), puspa (Schima wallichii DC Korth), and mahoni (Swietenia mahagony L. Jacq). The specimen was 100 mm x 100 mm with thickness of 30 mm tested with cone calorimeter in accordance with ISO 5660 standard. Using cone calorimeter a homogenous heat was exposed to the surface of wood specimen, and ignited with igniter. About 1 mm thick of CPS sheet was laminated on the wood surface (100 mm x 100 mm). Specimen was tested at horizontal position and at heat flux of 40 kW/m2. On the unexposed wood surface, thermocouple was attached to measure increases of temperature. Results showed that five species of wood laminated with CPS have higher fire properties compared with control wood, however compared with woods laminated with GPS those results were lower

Tinjauan Hasil-hasil Penelitian Faktor-faktor Alam Yang Mempengaruhi Sifat Fisik Dan Mekanik Kayu Indonesia Review of Researches on Natural Factors Affecting the Physical and Mechanical Properties of Indonesian Wood

This review deals with several topics concerning natural factors affecting physical and mechanical properties of wood, i.e. (1) wood species; (2) age and location of growing; (3) position of wood sample in the stem; (4) diameter; (5) humidity, moisture content, and temperature; (5) weathering and fungi; (6) forest fired; that have been done by researchers who are members of Indonesian Wood Research Society. The purposes of this review are (1) to evaluate the research results that have been done, (2) to promote the applicable and feasible utilization of research results to the users, (3) to provide information concerning previous researches that might be useful for further researches.More than 60 wood species have been reported in this review. Besides the major and minor commercial wood species; lesser known species, i.e. Balsa (Ochroma spp.), Randu (Ceiba pentandra Gaertn.), Merkubung (Macaranga sp.), Cengkeh (Eugenia aromatica L.), Afrika (Maesopsis eminii), Kisereh (Cinnamomum porrectum (Roxb) Kosterm), Kibawang (Melia excelsa Jack.), Pulai Konggo (Alstonia Kongoensis Engl.), Sengon Buto (Enterolobium cyclocarpum Griserb.), Salamander (Grevillea robusta A.Cunn.), Kilemo (Litsea cubeba Pers.), Tahongai (Kleinhovia hospita Linn.), Sukun (Arthocarpus altilis), Arang (Diospyros borneensis), Berumbung (Adina minutifolia), Tisuk/Waru (Hibiscus macrophyllus), Urograndis (Eucalyptus urograndis), Kelapa (Cocos nucifera L.), Kelapa Sawit (Eleais guineensiis Jacq.), Laban (Vitex Pubescens Vahl.), Rambai (Baccaurea motleyana Muell.), Ki Sampang (Evodia latifolia DC.), Nangka (Artocarpus integra Merr.), Kalapi (Kalappia celebica), Gofasa (Vitex coffasus), Ketileng (Vitex glabrata), Cemara (Gymnostoma sp.), and Lamtoro (Leucaena glauca (Willd) Benth). have also been observed. The researches were generally done in relation to the utilization prospect of lesser known species, crops estate species, Fast growing species, timber estate species, rural forest species, commercial species, for contruction/structural materials, handy-craft, musical instruments, or out-door exposures.Wood properties were interaction between specific gravity or density, moisture content, shrinkage and mechanical properties of wood. However, the values of those physical and mechanical properties in the papers could not directly compared to each other, because there were various testing standard and strength classification used. And unfortunately, researches on acoustic, thermal, electrical, creep, relaxation, and fatigue behaviour of Indonesian wood species were very rare or almost none

Hubungan Sifat Berat Jenis Dengan Sifat Higroskopisitas Melalui Pendekatan Nilai Rerata Kehilangan Air [Relationship Between Specific Gravity and Hygroscopicity Through Average Water Loss Approach]

. Sifat higroskopisitas kayu diduga berhubungan dengan nilai berat jenis (BJ) kayu. Penelitian ini bertujuan untuk mengetahui pengaruh perbedaan nilai BJ kayu sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes), jati (Tectona grandis L. f.), merbau (Instia bijuga (Colebr.) Kuntze) dan mahoni (Swietenia mahagoni (L.) Jacq.) terhadap nilai kehilangan air saat diberi perlakuan pengeringan pada suhu 60ºC selama beberapa waktu. Sengon dan jati yang berusia muda mewakili kayu dengan BJ rendah, sedangkan mahoni dan merbau mewakili kayu dengan BJ tinggi. Hasil penelitian menunjukkan massa awal setelah perendaman dengan air selama 24 jam untuk sengon, jati, mahoni dan merbau berturut-turut adalah 5,346 g; 7,356 g; 7,366 g dan 7,469 g. Nilai BJ sengon, jati, mahoni dan merbau berturut-turut sebesar 0,294; 0,511; 0,625 dan 0,733. Pengukuran kehilangan air yang dilakukan selama 7,5 jam menunjukkan nilai rerata kehilangan air total untuk sengon, jati, mahoni dan merbau berturut-turut adalah 2,431 g; 2,440 g; 2,363 g dan 1,560 g. Uji lanjut Tukey menunjukkan bahwa nilai BJ antar keempat spesies tersebut berbeda nyata. Uji lanjut Tukey untuk nilai rerata kehilangan air selama 7,5 jam tidak berbeda nyata antara sengon, jati dan mahoni namun berbeda nyata antara sengon, jati dan mahoni dengan merbau