Comparison of Properties of Pine Scrim Lumber Made from Modified Scrim

In this study southern pine scrim was treated with low molecular weight melamine formaldehyde (MF), phenolic formaldehyde (PF), and furfuryl alcohol (FA) at different loadings and formed into 25-mm thick panels. Mechanical, dimensional and biological properties were evaluated. Results showed that samples treated with 5 percent MF had the highest MOE, MOR and work to maximum load values (15.3 GPa, 54.2 MPa and 25.4 KJ/m3, respectively), while those treated with 10 percent MF had the highest internal bond and edgewise toughness values of 390 kPa and 12 N•m, respectively. With respect to dimensional stability, samples treated with 20 percent FA had the lowest swelling value (ASE = 36.8 percent), and the lowest water absorption value (27.5 percent). Dynamic swelling test revealed much higher ASE value (\u3e 45 percent) for furfurylated samples. As for termite resistance, both untreated and treated samples had little weight loss (1.10-1.56 percent), high visual rating (8-9.3/10), and 100 percent mortality in laboratory test

Synthesis, Characterization, and Mechanism Study of Carbon-Encapsulated Copper Nanoparticles

In this project, the synthesis of carbon encapsulated copper nanoparticles using sustainable bioproducts as raw material was systematically studied. The synthesis mechanism, process parameters, and functionalization of carbon encapsulated copper nanoparticles were well established. In a preliminary study, carbon encapsulated copper nanoparticles were successfully synthesized at 1000 ºC, 1h, 20 ºC/min, and 1800 sccm argon gas flow rate using BCL-DI lignin as the carbon source. Carbon encapsulated copper nanoparticles were mainly located at defect sites. Copper was found not tightly encapsulated by graphene shells. The carbon encapsulated copper nanoparticles were uniformly distributed. The conversion of copper ions into copper atoms occurred at above 300 ºC, with the company of decomposition of BCL-DI lignin into CO, CO2, and hydrocarbon gases. The growth of graphene layers was proposed to start above 300 ºC. TEM images illustrated the onset of growth of graphene at the edge of the surface at 400 ºC, and the formation of graphene bands at 500 ºC. Copper catalyst continued to facilitate the decomposition of lignin functional groups at 600 ºC. Further increasing the temperature retarded the degradation of lignin, while assisted the reconstruction of the defective sites of the graphene layers, producing higher quality products. Plastic film phase of lignin dominated on the synthesis of carbon encapsulated copper nanoparticles, while gaseous phase had little impact. The orthogonal experiment revealed that temperature played the most important role in the growth of graphene: high temperature was preferred in order to obtain less defective sites. The optimum synthesis parameters were suggested as 1000 °C, 30 min duration time, 20 °C/min temperature rising ramp, and 1200 sccm argon gas flow rate. Post heat treatment was proved to be a feasible way to improve the crystallinity of graphite. Amorphous carbon was removed or converted into crystalline graphite under heat and oxygen. FTIR spectra confirmed the covalent linkages between carbon encapsulated copper nanoparticles and N-methyl-2-pyrrolidone and polyvinylpyrrolidone, indicating a successful functionalization. This study has presented a homogeneous carbon encapsulated copper nanoparticles solution in water and ethanol, and paved ways for further functionalization of CECNs

Thermal Insulating and Mechanical Properties of Cellulose Nanofibrils Modified Polyurethane Foam Composite as Structural Insulated Material

Cellulose nanofibrils (CNF) modified polyurethane foam (PUF) has great potential as a structural insulated material in wood construction industry. In this study, PUF modified with spray-dried CNF was fabricated and the physical and mechanical performance were studied. Results showed that CNF had an impact on the foam microstructure by increasing the precursor viscosity and imposing resistant strength upon foaming. In addition, the intrinsic high mechanical strength of CNF imparted an extra resistant force against cells expansion during the foaming process and formed smaller cells which reduced the chance of creating defective cells. The mechanical performance of the foam composite was significantly improved by introducing CNF into the PUF matrix. Compared with the PUF control, the specific bending strength, specific tensile strength, and specific compression strength increased up to three-fold for the CNF modified PUF. The thermal conductivity of PUF composite was mainly influenced by the closed cell size. The introduction of CNF improved thermal insulating performance, with a decreased thermal conductivity from 0.0439 W/mK to 0.02724 W/mK

Properties of Pine Scrim Lumber Made From Modified Scrim

In this study, scrim from small-diameter southern pine bolts was treated with melamine formaldehyde (MF), phenol formaldehyde (PF), and furfuryl alcohol (FA) at different loadings and formed into 25-mm-thick pine scrim lumber (PSL) panels. MOE, MOR, work to maximum load (WML), internal bond (IB), toughness, water absorption, thickness swelling, 5-h tangential dynamic swelling, and termite resistance were evaluated. Results showed that samples treated with 5% MF resin had the highest MOE, MOR, and WML values (15.3 GPa, 54.2 MPa, and 25.4 kJ/m3, respectively), whereas those treated with 10% MF resin had the highest IB and edgewise toughness values of 390 kPa and 12 N m, respectively. With respect to dimensional stability, samples treated with 20% FA had the lowest swelling values after 24-h submersion in water (anti-swelling efficiency [ASE] . 36.8%), and the lowest water absorption value (27.5%). Five-hour tangential dynamic swelling test revealed much higher dimensional stability for furfurylated samples (ASE >45%). As for termite resistance, both untreated and treated PSL had little weight loss (1.10-1.56%), high visual rating (8-9.3/10), and high mortality (100%) in laboratory tests. MF and FA impregnation proved to be feasible modification methods in this study.

Synthesis and Characterization of Cellulose Nanofibril-Reinforced Polyurethane Foam

In this study, traditional polyol was partially replaced with green, environmentally friendly cellulose nanofibrils (CNF). The effects of CNF on the performance of CNF-reinforced polyurethane foam nanocomposites were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and a compression test. The results showed that the introduction of CNF into the polyurethane matrix not only created stronger urethane bonding between the hydroxyl groups in the cellulose chain and isocyanate groups in polymethylene polyphenylisocyanate, but also developed an additional filler–matrix interaction between CNF and polyurethane. With the increase of the CNF replacement ratio, a higher glass transition temperature was obtained, and a higher amount of char residue was generated. In addition, an increase of up to 18-fold in compressive strength was achieved for CNF-PUF (polyurethane foam) nanocomposites with a 40% CNF replacement ratio. CNF has proved to be a promising substitute for traditional polyols in the preparation of polyurethane foams. This study provides an interesting method to synthesize highly green bio-oriented polyurethane foams

Vertical Density Profile and Internal Bond Strength of Wet-Formed Particleboard Bonded with Cellulose Nanofibrils

In this study, the effects of cellulose nanofibrils (CNFs) ratio, press program, particle size, and density on the vertical density profile (VDP) and internal bond (IB) strength of the wet-formed particleboard were investigated. Results revealed that the VDP was significantly influenced by the press program. Pressing using a constant pressure (CP) press program produced panels with flat-shaped profile. Panels made from a constant thickness (CT) press program produced U-shaped profile. The CNF ratio and density also influenced the VDP especially for the CT panels. As the CNF ratio increased, there were noticeable increases in face density, while the core density slowly increased. The CT panels had the lowest core density compared with the CP counterparts, thus significantly lowering the IB. The IB of CP panels increased with the increase of CNF ratio, but the trend for CT panels was different. For the 10% CNF ratio, the IB increased as the core density increased. For the 15% and 20% CNF ratios, the IB decreased as the core density increased. For CP panels, the minimum core densities were higher and thus the IB was significantly higher. None of the panels met the IB values for high-density standard particleboard. All CP panels met some of the medium-density standard IB values and all the low-density standard IB values. However, for the CT panels, only those with 15% and 20% CNF ratio marginally met the low- and medium-density particleboard standard. Trends show that increased CNF ratio and higher pressure could improve IB properties for the high-density particleboard

Temperature and Copper Concentration Effects on the Formation of Graphene-Encapsulated Copper Nanoparticles from Kraft Lignin

The effects of temperature and copper catalyst concentration on the formation of graphene-encapsulated copper nanoparticles (GECNs) were investigated by means of X-ray diffraction, Fourier transform infrared spectroscopy-attenuated total reflectance, and transmission electron microscopy. Results showed that higher amounts of copper atoms facilitated the growth of more graphene islands and formed smaller size GECNs. A copper catalyst facilitated the decomposition of lignin at the lowest temperature studied (600 °C). Increasing the temperature up to 1000 °C retarded the degradation process, while assisting the reconfiguration of the defective sites of the graphene layers, thus producing higher-quality GECNs

Modification of Poplar Wood via Polyethylene Glycol Impregnation Coupled with Compression

Wood permeability and compressibility are affected by cell wall structure and chemical composition. These properties can be improved by appropriate wood pretreatments. Low-density poplar wood was converted to a more dense structure by the following steps: First, lignin and hemicellulose were removed using a mixture of NaOH and Na2SO3. Second they were impregnated with polyethylene glycol (PEG, mean molecular weight of 1200), nano-SiO2, and a silane coupling agent at atmospheric temperature and pressure. Finally, impregnated wood was compressed at 150 °C. Results showed that the tracheid lumens on the transverse section of the compressed wood almost vanished. Specifically, the lumens in the wood cells, especially those that were compressed, were almost completely filled with PEG. In FTIR, the asymmetric absorption peaks of Si–O–Si at 1078–1076 cm−1 were clearly observed, which confirms the existence of bonding between nano-SiO2 and wood. The highest melting enthalpy and crystallization enthalpy showed a heat storage capacity of modified wood, which were 20.7 and 9.8 J/g, respectively. Such phase change capabilities may have potential applications in regulating the rate of change of room temperature. In summary, the modified wood could be utilized as material for construction to conserve energy

Modification of Poplar Wood via Polyethylene Glycol Impregnation Coupled with Compression

Wood permeability and compressibility are affected by cell wall structure and chemical composition. These properties can be improved by appropriate wood pretreatments. Low-density poplar wood was converted to a more dense structure by the following steps: First, lignin and hemicellulose were removed using a mixture of NaOH and Na2SO3. Second they were impregnated with polyethylene glycol (PEG, mean molecular weight of 1200), nano-SiO2, and a silane coupling agent at atmospheric temperature and pressure. Finally, impregnated wood was compressed at 150 °C. Results showed that the tracheid lumens on the transverse section of the compressed wood almost vanished. Specifically, the lumens in the wood cells, especially those that were compressed, were almost completely filled with PEG. In FTIR, the asymmetric absorption peaks of Si–O–Si at 1078–1076 cm−1 were clearly observed, which confirms the existence of bonding between nano-SiO2 and wood. The highest melting enthalpy and crystallization enthalpy showed a heat storage capacity of modified wood, which were 20.7 and 9.8 J/g, respectively. Such phase change capabilities may have potential applications in regulating the rate of change of room temperature. In summary, the modified wood could be utilized as material for construction to conserve energy

EFFECT OF PROCESSING PARAMETERS ON THE SYNTHESIS OF LIGNIN-BASED GRAPHENE-ENCAPSULATED COPPER NANOPARTICLES

 Graphene-encapsulated copper nanoparticles (GECNs) can be applied in the wood protection industry. In this study, a simple thermal treatment was applied to a mixture of kraft lignin and copper sulfate for the synthesis of GECNs. The effect of temperature, duration time, temperature rising ramp, and argon gas flow rate were investigated on the quality of the GECNs. Temperature was found to be the most important factor in the growth of graphene; high temperature was preferred to obtain less defective graphene shells. Gas flow rate, duration time, and temperature rising ramp had less effect. The optimum synthesis parameters were proposed as 1000C, 30-min duration time, 20C/min temperature rising ramp, and 1200-sccm argon gas flow rate. Results showed that postheat treatment was a feasible way to improve the crystallinity of graphite.