Dissertations in Forestry and Natural Sciences

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Taneli Väisänen: Effects of Thermally Extracted Wood Distillates on the Characteristics of Wood-Plastic Composites A pendulum strikes the middle of the specimen that may be unnotched or have a U-notch or V-notch. In the Izod impact test, the dimensions of the specimen are 4.1 mm × 10.1 mm × 75 mm. The specimen is placed vertically on the support, and it can be unnotched or have only a V-notch. In the Izod test, the notch is facing the pendulum whereas in the Charpy test the notch side of the specimen faces away from the pendulum. The Charpy impact test determines the amount of energy absorbed by a material during the fracture. The measurement apparatus consists of a pendulum of a known mass and length. The pendulum is dropped from a known height so that it strikes the specimen. The amount of energy absorbed by the material at the impact can be determined by comparing the heights of the hammer before and after the fracture. The energy absorbed in the breaking is expressed as impact energy (J/m). It is calculated by dividing the energy by the thickness of the sample. In ISO 179-1, the Charpy’s impact strength is reported in kJ/m 2 , which is derived by dividing the impact energy by the area under the notch. In ASTM D6110-10, the results are reported as J/m. Notching has a considerable effect on the results of the impact test. Thus, the exact geometries and dimensions of notches have been determined in ISO 179-1. In addition, the size of the sample can affect the results. The differences between ISO and ASTM impact tests are related to the type of pendulum hammer used in the tests. In ISO 179-1, the pendulum hammer may be used in the range from 10 to 80% of its nominal potential energy whereas the maximum value in ASTM D6110-10 is 85%. In addition, according to ISO 179-1, the largest possible hammer must be used because the speed loss at the impact must be kept as low as possible. ASTM D6110-10 defines that the standard pendulum hammer has a rated initial potential energy of 2.7 J, and the hammer size is increased by doubling its dimensions. However, unlike ISO 179-1, the smallest hammer in the range has to be used in the tests. 54 Dissertations in Forestry and Natural Sciences No 222
Characterization of wood-plastic composites 3.2 WATER ABSORPTION Water absorption of WPCs is typically evaluated using the standard methods developed for plastics, wood, and WPCs. However, the time to reach the moisture equilibrium is longer for WPCs than for plastics or wood (Defoirdt et al. 2010); wood reaches an equilibrium in hours or weeks, plastics in weeks and WPCs in months. Therefore, the testing methods used for WPCs may not allow the material to reach the moisture equilibrium and this may affect the results obtained. This, however, does not mean that the test methods described in these standards could not be used to investigate the differences between various WPC types; considerable differences in the water resistance can be observed even with only two hours of water immersion. Guidelines for the determination of water absorption of WPCs are given in BS EN 15534-1. ISO 62 can also be used because it applies to the reinforced plastics, to which WPCs belong. Similarly, ASTM D570-98(2010)E1 can also be used to determine the moisture absorption of WPCs. According to the standards, the water absorption of the material can be determined by completely immersing the samples in water at 23 °C or in boiling water. Before the immersions, the samples must be dried in an oven at 50 ± 2 °C for at least 24 h and then cooled to room temperature in a desiccator before weighing. After the immersion, water absorption, c (%), of the materials can be determined by using the following formula: c = m 2-m 1 m 1 100% , (3.5) where m1 is the mass of the test specimen after initial drying and before the immersion, and m2 is the mass of the test specimen after the immersion. There are some differences in these standards. In BS EN 15534-1, the immersion period in the water bath (23 °C) is 28 ± 1 days whereas the immersion period in ISO 62 should be at least 24 hours. In addition, the immersion time in boiling test is 5 h ± 10 min in BS EN 15534-1, but in ISO 62 the immersion Dissertations in Forestry and Natural Sciences No 222 55
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PUBLICATIONS OF THE UNIVERSITY OF E
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Grano Oy Jyväskylä, 2016 Editors:
Page 7 and 8: ABSTRACT The use of raw materials d
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Page 12 and 13: Finally, I am grateful to my wife A
Page 14 and 15: TD-GC-FID/MS Thermal desorption/gas
Page 17 and 18: LIST OF ORIGINAL PUBLICATIONS This
Page 19 and 20: Contents 1 Introduction ...........
Page 21 and 22: 1 Introduction The finiteness of cr
Page 23 and 24: Introduction A new and environmenta
Page 25 and 26: 2 Wood-plastic composites By defini
Page 27 and 28: Wood-plastic composites additives u
Page 29 and 30: Wood-plastic composites Cellulose i
Page 31 and 32: Wood-plastic composites The propert
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Page 35 and 36: Wood-plastic composites of lubrican
Page 37 and 38: Wood-plastic composites roughness a
Page 39 and 40: Wood-plastic composites Hosseinaei
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Page 43 and 44: Wood-plastic composites However, WP
Page 45 and 46: Wood-plastic composites A typical s
Page 47 and 48: Wood-plastic composites to fill the
Page 49: Wood-plastic composites absorption.
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Page 63 and 64: 4 Thermal processing of wood Therma
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Page 67 and 68: Thermal processing of wood counterp
Page 69 and 70: Thermal processing of wood and the
Page 71 and 72: Thermal processing of wood and Miet
Page 73 and 74: 5 Aims and significance Despite the
Page 75 and 76: 6 Materials and methods Two types o
Page 77 and 78: Materials and methods heat energy f
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Page 81 and 82: Materials and methods 6.2.1 Tensile
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Page 85 and 86: Materials and methods The emissions
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Taneli Väisänen: Effects of Therm
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9 Summary and conclusions In the pr
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Bibliography Abdolvahaba E, Lashgar
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Bibliography Ayrilmis N, Jarusombut
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Bibliography Cernansky R. State-of-
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Bibliography polypropylene composit
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Bibliography with odor assessments
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Bibliography La Mantia FP, Morreale
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Bibliography Mohan D, Pittman CU, a
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Bibliography Rinne J, Taipale R, Ma
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Bibliography Stark NM and Rowlands
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Bibliography Yeh S and Gupta RK. Im
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