Contents Chapter 1 Overview 1 1.1 A brief introduction to wood resources 1 1.1.1 International wood resources 1 1.1.2 China’s wood resources 1 1.2 General drying theory and technology 2 1.2.1 Wood-water relations 2 1.2.2 Wood drying theory 12 1.2.3 Wood drying technology 13 1.3 Drying theory and technology related to wood collapse 16 1.3.1 Fundamental properties related to wood collapse 16 1.3.2 Prediction and assessment of wood collapse 20 1.3.3 Traditional wood collapse theory 22 1.3.4 Novel wood transient collapse theory 23 1.3.5 Drying technology for minimizing collapse 24 1.4 Summary 30 References 31 Chapter 2 Anatomical Characteristics vs. Shrinkage and Collapse 41 2.1 Introduction 41 2.2 Materials and methods 42 2.2.1 Collection of sample woods 42 2.2.2 Preparation of specimens 42 2.2.3 Determination of unit shrinkage (α), total shrinkage and residual collapse 43 2.2.4 Measurement of basic density 43 2.2.5 Determination of microfibril angle (MFA) 44 2.2.6 Determination of both fiber morphology and various tissues proportion 44 2.2.7 Statistics analysis 44 2.3 Results 45 2.3.1 Statistics on various indices 45 2.3.2 Correlation analysis 46 2.3.3 Regression analysis 47 2.4 Discussions 48 2.4.1 Relationship between basic density and unit shrinkage and total shrinkage 48 2.4.2 Relationship between basic density and residual collapse 49 2.4.3 Relationship of anatomical characteristics to unit shrinkage and total shrinkage 50 2.4.4 Relationship between anatomical characteristics and residual collapse 50 2.5 Conclusions 52 References 52 Chapter 3 Colorimetric Characteristics vs. Shrinkage and Collapse 55 3.1 Introduction 55 3.2 Material and methods 57 3.2.1 Preparation of specimens 57 3.2.2 Steaming and drying procedure 58 3.2.3 Non-collapse shrinkage tests 58 3.2.4 Determination of total shrinkage, normal shrinkage and collapse by image analysis technique 59 3.2.5 Measurements of color parameters 59 3.2.6 Regression analysis 60 3.2.7 Measurement of NIR 60 3.3 Results and discussions 60 3.3.1 Effects of drying temperatures on shrinkage and collapse properties 60 3.3.2 Effects of steaming treatments on shrinkage and collapse properties 62 3.3.3 Effects of combination of various heat and steaming treatments on both shrinkage and collapse 63 3.3.4 Shrinkage and collapse properties-colorimetric parameters relationships when subjected to various heat treatments 64 3.3.5 Shrinkage and collapse values-colorimetric parameters relationships when subjected to various steaming treatments 65 3.3.6 Shrinkage and collapse values-colorimetric parameters relationships when subjected to combination of heat and steaming treatments 67 3.3.7 Effect of steaming time on sample coloring 68 3.3.8 Effect of drying process on sample coloring 70 3.4 Conclusions 73 References 74 Chapter 4 Water Vapor Sorption Behavior vs. Shrinkage and Collapse 77 4.1 Introduction 77 4.2 Materials and methods 79 4.2.1 Preparation of specimens 79 4.2.2 Heating and steaming procedure 80 4.2.3 Non-collapse shrinkage tests 81 4.2.4 Determination of total shrinkage, normal shrinkage and collapse by image analysis technique 81 4.2.5 Determination of water vapor sorption behavior 81 4.3 Results and discussion 82 4.3.1 Water vapor sorption behavior 82 4.3.2 Sorption hysteresis 85 4.3.3 Sorption kinetics 87 4.3.4 The applicability of Kelvin-Voigt model 93 4.4 Conclusions 97 References 98 Chapter 5 Drying Conditions vs. Shrinkage and Collapse 102 5.1 Introduction 102 5.2 Materials and methods 103 5.2.1 Preparation of specimens 103 5.2.2 Continuous drying procedures 103 5.2.3 Intermittent drying procedures 104 5.2.4 Measurement of dimension by image analysis technique 104 5.2.5 Determination of total shrinkage and residual collapse 104 5.2.6 SEM observation 105 5.2.7 Advancement of novel concepts of both transient collapse and maximum transient collapse 106 5.3 Results and discussion 107 5.3.1 Characteristics of wood tissue structure changes in the drying process under the continuous and intermittent drying regimes 107 5.3.2 Comparison of collapse-shrinkage characteristics under the continuous and intermittent drying regimes 108 5.3.3 Analyses of radial variation characteristics in collapse-shrinkage properties under the continuous and intermittent drying regimes 110 5.4 Conclusions 111 References 112 Chapter 6 Morphological Study of Collapsed Wood Cells in Intermittent Drying 114 6.1 Introduction 114 6.2 Materials and methods 115 6.2.1 Materials 115 6.2.2 Drying conditions 115 6.2.3 Collapse-type shrinkage curve 116 6.2.4 Preparation of micro section and SEM observation 117 6.3 Results and discussion 117 6.3.1 Effects of different drying schedule on drying progression 117 6.3.2 Shrinkage curves of different drying process 120 6.3.3 Distribution of moisture content in continuous and intermittent drying 122 6.3.4 Morphological study of collapse in continuous and intermittent drying 126 6.4 Conclusions 130 References 130 Chapter 7 Intermittent Drying for Minimizing Shrinkage and Collapse in Wood 133 7.1 Introduction 133 7.2 Materials and methods 134 7.2.1 Sample woods collection 134 7.2.2 Specimens preparation 135 7.2.3 Procedures of continuous and intermittent drying regimes 135 7.2.4 Collapse-free shrinkage tests 137 7.2.5 Measurements of transversal section areas by using image analysis technique 137 7.2.6 Determination of total shrinkage, normal shrinkage and collapse ..137 7.3 Results and conclusions 137 7.3.1 Effects of intermittent duration on total shrinkage and collapse 137 7.3.2 Effects of drying duration on total shrinkage and collapse 139 7.3.3 Effects of drying temperatures on shrinkage and collapse 140 7.3.4 Effects of alteration of high-low relative humidity on total shrinkage and collapse 142 7.4 Conclusions 143 References 144 Chapter 8 Quantitative Assessment of Moisture Sorption in Wood Cell Walls 147 8.1 Introduction 147 8.2 Materials and methods 149 8.2.1 Sample preparation 149 8.2.2 Micro-FTIR spectrometer 149 8.2.3 DVS apparatus 151 8.2.4 Micro-FTIR data processing 152 8.3 Results and discussion 152 8.3.1 Qualitatively analyzing moisture sorption 152 8.3.2 Quantitative analysis of moisture sorption 155 8.4 Conclusions 157 References 158 Chapter 9 Spatial Distribution of Moisture in Wood Cell Wall 162 9.1 Introduction 162 9.2 Materials and methods 164 9.3 Results and discussion 167 9.3.1 μ-FTIR spectra associated with water molecules 167 9.3.2 Assignment of Raman spectral peaks 169 9.3.3 Spatial distribution of lignin and cellulose 170 9.3.4 Spatial distribution of adsorbed water 172 9.4 Conclusions 173 References 174 Chapter 10 Molecular Association of Water with Wood 178 10.1 Introduction 178 10.2 Materials and methods 180 10.2.1 Sample preparation 180 10.2.2 Microscopic Fourier transform infrared (micro-FTIR) spectroscopy equipment 180 10.2.3 Data processing 181 10.3 Result and discussion 182 10.3.1 Micro-FTIR spectra of wood associated with water molecules 182 10.3.2 Analysis of difference spectra 183 10.3.3 Molecular association of adsorbed water with wood during the adsorption process 184 10.4 Conclusions 191 References 191 Chapter 11 Molecular Association of Adsorbed Water with Main Chemical Components in Wood 195 11.1 Introduction 195 11.2 Materials and methods 197 11.2.1 Materials 197 11.2.2 Micro-FTIR spectrometer 197 11.2.3 Data processing 199 11.3 Results and discussion 200 11.3.1 Effective sorption sites in lignin during water adsorption process 200 11.3.2 Molecular association of adsorbed water with lignin 201 11.4 Conclusions 206 References 206