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 WPCs. There are several ways to modify wood fibers, e.g., heat treatment (Ayrilmis et al. 2011), the extraction of hemicelluloses (Hosseinaei et al. 2012) and the treatment with coupling agents (Müller et al. 2012); these modifications can considerably increase the water resistance of the WPCs. On the other hand, in some instances, the mechanical properties of WPCs can be enhanced by using recycled polymers instead of virgin material (Adhikary et al. 2008a). Moreover, the mechanical durability of WPCs can be improved by incorporating additives, such as maleated polypropylene or polyethylene (MAPP or MAPE) (Pérez et al. 2012, Ndiaye et al. 2013), waste charcoal (Li et al. 2014, Das et al. 2015a), nanoclay (Abdolvahaba et al. 2014), or inorganic fillers (Gwon et al. 2012), into the composite. WPCs are also increasingly used in indoor applications, such as window frames and furniture. However, the impact of WPCs on the quality of the indoor air has not been studied widely. Volatile organic compounds (VOCs) are chemicals that have a high vapor pressure at room temperature, allowing a great number of molecules to evaporate from the material and enter the surrounding air. VOCs include chemical compounds that occur in nature, and compounds that originate from human activity. Some VOCs exert harmful effects on human health and the environment, and therefore, their release and maximum concentrations in indoor air are regulated. Several studies have examined the effects of organic wastes and residues on WPCs (Ashori and Nourbakhsh 2010, Hamzeh et al. 2011, Madhoushi et al. 2014, Das et al. 2015b). When organic waste is added to WPCs, typically there is an emphasized need for coupling agents to improve the bonding between the fibers and the polymer matrix. The choice, acquisition and application of the right coupling agent for WPCs is neither straightforward nor inexpensive, and the whole process requires time. Therefore, there is a desire to minimize the use of coupling agents and other additives with similar challenges, especially if they can be substituted with more affordable bio-based filler materials that can confer similar benefits. 20 Dissertations in Forestry and Natural Sciences No 222
Introduction A new and environmentally friendly approach to improve the properties of WPCs is to add the thermal degradation products of wood into the composites (Das et al. 2015b). Wood can be converted into charcoal, liquids, and non-condensable gases in pyrolytic processes (Klass 1998). The yields of these products vary depending on the process type (Nachenius et al. 2013). Since it is the primary product which is sought, the secondary products of the processes are commonly considered simply as waste. The potential of biochar as an additive in WPCs has been investigated previously, and the positive effects of incorporation of biochar into WPCs were evident (Li et al. 2014, Das et al. 2015a). Even though the liquid components of wood have multiple applications, e.g., as biocides, pesticides, material coating, and medicine (Bridgwater 1996, Fagernäs et al. 2012a), their effects on the characteristics of WPCs have not been studied earlier. Nonetheless, since wood distillates have a rather versatile nature, one could speculate that they could be utilized in WPCs as ecological additives, coupling agents, lubricants, biocides or stabilizers after proper processing. The present thesis project investigated the effects of liquid components of wood on the properties of WPCs. It was hypothesized that the utilization of liquid components of wood in WPCs could provide many advantages. First, the content of rather expensive and petroleum-derived polymers in WPCs could be reduced. Second, the raw materials would be exploited more effectively as these liquids would otherwise be treated as waste and therefore, not be further utilized. The focus of this thesis was also on the determination of the VOC characteristics of WPCs. Proton-transfer-reaction time-of-flight massspectrometry (PTR-TOF-MS) was used to analyze the levels of VOCs emerging from WPCs. The effects of hardwood and softwood distillates were evaluated in mechanical tests, water absorption studies, and VOC analyses. The working hypothesis was that WPC granules could be effectively impregnated with hardwood or softwood distillates to increase the water resistance of WPCs and to strengthen the materials. The VOC Dissertations in Forestry and Natural Sciences No 222 21
Page 1: PUBLICATIONS OF THE UNIVERSITY OF E
Page 4 and 5: 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: 1 Introduction The finiteness of cr
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
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Page 39 and 40: Wood-plastic composites Hosseinaei
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Page 49: Wood-plastic composites absorption.
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Page 63 and 64: 4 Thermal processing of wood Therma
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5 Aims and significance Despite the
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6 Materials and methods Two types o
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Materials and methods heat energy f
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Materials and methods with the untr
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Materials and methods 6.2.1 Tensile
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Materials and methods 6.3 WATER ABS
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Materials and methods The emissions
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Materials and methods where Evoc is
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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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