IN THIS WORK, THE IMPREGNATION QUALITY AND MECHANICAL PROPERTIES OF PINUS RADIATA D.DON TREATED WITH DIFFERENT COPPER NANOPARTICLES (CUNP) SOLUTIONS (NAMED K1 AND K2) AND A COMMERCIAL PRESERVATIVE (M) WERE STUDIED. THE IMPREGNATION QUALITY OF RADIATA PINE WOOD WAS ANALYZED BY TWO INDICATORS, PENETRATION AND RETENTION. THE MICRO-DISTRIBUTION OF PRESERVATIVE IN THE TREATED WOOD WAS QUALITATIVELY EVALUATED BY SEM-EDS, BOTH IN THE SAMPLES CONTAINING CUNP AND IN THOSE TREATED WITH THE COMMERCIAL PRESERVATIVE. IN ADDITION, SOME MECHANICAL PROPERTIES WERE STUDIED IN THE PRESERVED WOOD INCLUDING MOE, MOR AND HARDNESS. THE RESULTS INDICATED VALUES BY ED XRF RETENTION OF 0.96 KG/M3 AND 0.86 KG/M3 FOR K1 AND K2, RESPECTIVELY, AND 1.01 KG/M3 FOR M WOOD IMPREGNATED. IN THE PENETRATION DETERMINED BY COLORIMETRIC TEST, THE WOOD SAMPLES IMPREGNATED (WITH K1, K2 AND M) SHOWED 100% PENETRATION. THE DISTRIBUTION OF CUNP AND MICRONIZED COPPER WITHIN THE WOOD NSTRUCTURE WAS CONFIRMED BY SEM EDS MAPPING. IN MECHANICAL PROPERTIES, A REDUCTION IN MOE WAS REFLECTED IN ALL WOOD TREATED. THE CONTROL SAMPLES WERE FAR SUPERIOR TO THE K1 AND M TREATED SAMPLES AND SLIGHTLY SUPERIOR TO THE K2 SAMPLES, WITH NO STATISTICALLY SIGNIFICANT DIFFERENCES. ON THE OTHER HAND, SAMPLES IMPREGNATED WITH K1 AND K2 SHOWED THE HIGHEST VALUES IN HARDNESS PARALLEL AND PERPENDICULAR TO THE GRAIN, REVEALING THAT THESE PRESERVATIVE SOLUTIONS TEND TO INCREASE HARDNESS. OVERALL, WHEN IT COMES TO THE SAMPLES IMPREGNATED WITH MICRONIZED COPPER (M), THE MECHANICAL PROPERTIES WERE CONSIDERABLY LOWER COMPARED TO THE CUNP TREATED AND CONTROL WOOD. THEREFORE, THE CUNP-BASED PRESERVATIVE DID NOT STRONGLY AFFECT THE MECHANICAL PROPERTIES OF THE PRESERVED WOOD.

THE YIELD OF EUCALYPTUS REGNANS LOGS FOR LUMBER PRODUCTION WAS EVALUATED. CRACK WIDTH AND LENGTH AT EACH LOG END WERE MEASURED. TWO LOG-CUTTING PLANS WERE USED TO OBTAIN SAWN LUMBER. THE FIRST PLAN (PA) CONSIDERED LOGS WITH DIAMETERS VARYING FROM 28 TO 40 CM, AND IN THE SECOND PLAN (PB), THE LOG DIAMETERS RANGED FROM 42 TO 56 CM (PB). LUMBER YIELD WAS DETERMINED USING TWO LOG VOLUME METHODS: THE JAPANESE AGRICULTURAL STANDARDS (JAS) AND SMALIAN

THE MAIN OBJECTIVE OF THIS STUDY WAS TO DEVELOP CELLULOSE NANOFIBERS FROM THE THERMOME- CHANICAL PULP (TMP) OF RADIATA PINE (PINUS RADIATA D. DON), AND FOR THIS, A ONE-STEP MICRO-GRINDING PROCESS WAS USED. THE NEWLY DEVELOPED MATERIAL WAS CALLED THERMOMECHANICAL PULP NANOFIBERS (TMP-NF). IN THE FIRST INSTANCE, A DETERMINATION OF THE CONSTITUENTS OF THE TMP WAS CARRIED OUT THROUGH A CHEMICAL CHARACTERIZATION. THEN, TMP-NFS WERE COMPARED WITH CELLULOSE NANOFIBERS (CNF) BY MORPHOLOGICAL ANALYSIS (SCANNING ELECTRON MICROSCOPY, SEM, AND ATOMIC FORCE MICROSCOPY, AFM), X-RAY DIFFRACTION (XRD) AND FOURIER-TRANSFORM INFRARED SPECTROSCOPY WITH ATTENUATED TOTAL REFLECTION (FTIR-ATR). IN ADDITION, FILMS WERE DEVELOPED FROM TMP-NF AND CNF USING A VACUUM FILTRATION MANUFACTURING METHOD. FOR THIS STUDY, 0.10, 0.25, 0.50, AND 1.00% DRY WEIGHT OF CNF AND TMP- NF WERE USED AS CONTINUOUS MATRICES WITHOUT ORGANIC SOLVENTS........

THE INFLUENCE OF LOAD ON THE CELLULOSE MICROFIBRILS OF SINGLE CELLS OR THIN WOOD FOILS IS KNOWN. IT CAN DECREASE THE CELLULOSE MICROFIBRIL ANGLES AND, IN TURN, INCREASE THE STIFFNESS. HOWEVER, THIS MODIFICATION OF A PIECE OF WOOD, WHICH IS MADE UP OF MULTIPLE CELLS, IS UNKNOWN. THE AIM OF THIS RESEARCH WAS TO STUDY THE EFFECT OF TENSILE CREEP ON THE LONGITUDINAL STIFFNESS OF RADIATA PINE WOOD. THE MODULUS OF ELASTICITY OF EACH SPECIMEN WAS DETERMINED BEFORE AND AFTER BEING SUBJECTED TO TENSILE CREEP. THE SAMPLES WERE LOADED AT 1170 N AND 1530 N FOR 20 MIN AT 70 °C. THE LOAD WAS DETERMINED AS A FUNCTION OF A PERCENTAGE OF THE FORCE AT THE PROPORTIONAL LIMIT. THE MODULI OF ELASTICITY BEFORE AND POST-TENSILE CREEP SHOWED NO EFFECT ON THE STIFFNESS OF WOOD AT THE MACROSCOPIC LEVEL, BUT NEITHER WERE THERE DAMAGE TO THE CELL STRUCTURE. IT CAN BE ASSUMED THAT THERE ARE CHANGES AT THE MICROSCOPIC LEVEL, BUT THEY ARE NOT ENOUGH TO BE REFLECTED AT THE MACRO SCALE. IT IS ALSO CHALLENGING TO ACHIEVE THE MODIFICATIONS THAT OCCUR AT THE LEVEL OF A SINGLE CELL OR IN THIN WOOD FOILS; HOWEVER, THE IMPLICATIONS OF THIS WOULD BE FAVORABLE FOR THE DEVELOPMENT OF STRONGER WOOD-BASED PRODUCTS.

QUASISTATIC NANOINDENTATION IS A PROVEN TOOL THAT PROVIDES INFORMATION ON THE MICROMECHANICAL BEHAVIOR OF WOOD CELL WALLS. HOWEVER, QUASISTATIC TESTS CANNOT PROBE THE TIME-DEPENDENT MECHANICAL BEHAVIOR SHOWN BY WOOD. NANOINDENTATION DYNAMIC MECHANICAL ANALYSIS (NANODMA) CAN MEASURE THE VISCOELASTIC PROPERTIES OF WOOD CELL WALLS. THIS RESEARCH AIMED TO STUDY THE QUASISTATIC AND VISCOELASTIC PROPERTIES OF INDIVIDUAL RADIATA PINE WOOD (PINUS RADIATA D. DON) CELL WALL LAYERS. TO MINIMIZE VARIABILITY AND RETRIEVE BOTH PROPERTIES AT THE SAME LOCATIONS, A LOAD FUNCTION COMPOSED OF A MULTILOAD-QUASISTATIC FUNCTION FOLLOWED BY DYNAMIC REFERENCE FREQUENCY SEGMENTS WAS DEVELOPED. NANOINDENTATIONS WERE THEN PERFORMED ON THE S2 LAYER AND COMPOUND CORNER MIDDLE LAMELLA (CCML) OF UNEMBEDDED LATEWOOD CELLS. BECAUSE THE S2 LAYER IS ANISOTROPIC, BOTH TRANSVERSE AND LONGITUDINAL?TANGENTIAL WOOD PLANES WERE STUDIED. IN THE TRANSVERSE PLANE, THE AVERAGE RESULTS OF THE QUASISTATIC ELASTIC MODULI (??) FOR THE S2 LAYER AND CCML WERE 15.7 GPA AND 4.6 GPA, RESPECTIVELY. IN THE LONGITUDINAL?TANGENTIAL PLANE, THE ?? WAS 3.9 GPA. IN THE TRANSVERSE SECTION, THE HARDNESS (?) OF THE S2 LAYER AND CCML WERE 331 MPA AND 277 MPA, RESPECTIVELY, AND IN THE LONGITUDINAL?TANGENTIAL SECTION H WAS 244 MPA. TO ACQUIRE THE VISCOELASTIC PROPERTIES, MEASUREMENTS WERE MADE OVER MORE THAN THREE DECADES OF FREQUENCY. AN INCREASE OF THE STORAGE MODULUS (??), AND A REDUCTION OF THE LOSS MODULUS (??) AND LOSS FACTOR (TAN?) AS FREQUENCY INCREASED WERE FOUND IN BOTH WOOD ORIENTATIONS. THE QUASI-STATIC AND DYNAMIC INDENTATIONS EQUIVALENT AT 0.1 HZ SHOWED SIMILAR VALUES FOR ?? AND E?. THIS STUDY CONTRIBUTES TO OUR KNOWLEDGE OF WOOD CELL WALL MICROMECHANICAL PROPERTIES.