Jun Wen Pu

Paper and Board Pigment Coating Raw Materials – A Review of some Recent Innovative Novelties

The intention of this paper is to review of some recent innovative novelties about paper and board pigment coating raw materials. First an overview is given of “traditional” coating raw materials and the coating process. Then new starch based pigments and binders as well as novel plastic pigments are reviewed regarding their effect on coated paper properties. Finally it is concluded that further innovations and research are needed.

Chemical and Physical Changes for Dimensionally Stability of Compressed Wood

The objective of this study was to determine the chemical and physical changes of chemical modified on poplar wood. The chemical modifier was impregnated into cell lumen space by pulse-dipping machine to improve the dimension stability and mechanical property of timber. The timbers were compressed and dried by the multilayer hot-press drying to produce the modified timber. The modified timber had better dimension stability than the natural wood when they were immerged water continuous eight-hour. Characteristics of Fourier Transform Infrared Spectroscopy (FTIR) for modified were studied by the FTIR spectrometer. The intensity of hydroxyl absorption peak in the infrared absorption spectrogram decreased significantly, and that of carbonyl decreased lightly, which due to the bond of the function groups of -NHCH2OH of urea-formaldehyde prepolymer react with the wood carboxyl (C=O) and hydroxyl(-OH). The morphologic models of chemical within wood were discovered by SEM.

Synthesis and Application of a Modifier with Low Formaldehyde Emission to Enhance General Wood Properties

A preparation method of Urea-formaldehyde performed polymer(UFP) with low molecular weight and high reactivity is presented. The UFP can impregnate into wood along trachea from the ends with pressurized impregnation method. In the following heating and pressing processes of the wood, the UFP polymerizes, and it enhances stability and strength of the wood. The impregnating-pressing-drying method avoiding the disadvantage of dealing with the large specimens using vaccum-pressing method is suitable for industrial production. Results from test showed the degree of crystallinity tested by XRD were 30%, 32% in different dosage of the modifier. Utilizing a combination of low molecular weight resin impregnation and pressing resulted in a density increase of UFP treated wood from 0.214 to 0.268g/cm3. At the same time, the Young’s modulus and bending strength increased from 1.407GPa to 1.759GPa and 64MPa to 74.5MPa, respectively. But the formaldehyde emission is great reduced from 0.5% to 0.008%. It can be concluded that the effective utilization of UFP impregnated in wood is a promising technique for the production of high-strength in the drying and pressing processing.

Modified Nanocrystalline Cellulose Used for Improving Formaldehyde Emission and Bonding Strength of Urea Formaldehyde Resin Adhesive

Nanocrystalline cellulose (NCC) was used for improving the formaldehyde (HCHO) emission and bonding strength of urea formaldehyde (UF) resin adhesive in fiberboard and plywood. The original NCC was modified by 3-aminopropyltriethoxysilane (APTES) and the wetting property with UF resin adhesive was improved by 26.4%. The UF resin adhesive with modified NCC was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared (FT-IR). The crystal region of UF resin adhesive was influenced by NCC and the diffraction intensity of the peak at 2θ = 22.82° was enhanced significantly. The thermal stability of UF resin adhesive with 1.0% modified NCC increased by 4.9%. And modified NCC led hydroxyl groups into the UF resin adhesive. HCHO emission and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standards GB/T 17657-1999 and GB/T 9846-2004. The HCHO emission of fiberboard and plywood with 1.5% modified NCC decreased by 13.0% and 53.2%, respectively. The bonding strength of fiberboard increased by 158.3% (from 0.12 MPa of control group to 0.31 MPa of fiberboard with 1.5% modified NCC), while 1.5% modified NCC led to a 23.6% increase in the plywood.

The research of chemical modification on fast-growing wood

The aim of this study was to describe a chemical modification on fast-growing woods. After modification, it was found that the bending strength increased 42.7%, the compressive strength parallel to grain increased 37.8%. Moreover, the characteristics of the unmodified and modified samples were studied by X-Ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). The XRD analysis showed the degree of crystallinity changed from 35.49% to 37.31%, and the FTIR results revealed clear changes in the molecular structure. Finally, the SEM micrographs of modified and unmodified samples demonstrated strong and firm bonding between the inner wood cell and the wood modifier.

Modification of NCC for Improving the Wetting Property with Polyurethane

In this study, different lipophilic groups from 3-aminpropyltriethoxysilane (APTES) and 3-glycidoxypropyltrimethoxysilane (GPTMS) were used to alter the surface structure of nanocrystalline cellulose (NCC). The diversifications of NCC surface resulted from modifiers improved the wetting property between NCC and polyurethane significantly. The modified NCC was characterized by X-ray powder diffraction (XRD). And the wetting property was indicated by contact angle (CA). Epoxy groups from 6% GPTMS led to a 47.6% decline of CA, while the improvement of wetting property from APTES was inconspicuous.

Determination of Holocellulose and Alpha-Cellulose Contents in Triploid Clones of Populus tomentosa Using NIRS

The aim of this work was to study the ability of NIR spectroscopy to determine holocellulose and alpha-cellulose contents in triploid clones of Populus tomentosa. For this purpose 90 trees with five families in different planting density grown in Shandong were analyzed. Calibration models were developed from wet chemical and NIR data using partial least squares (PLS) regression. High coefficients of determination (R2) and low root mean square errors of cross-validation (RMSECV) were obtained for holocellulose (R2 = 0.7805, RMSECV =0.652) and alpha-cellulose (R2 = 0.8702, RMSECV = 0.548) from wood meal. Prediction produced high correlation coefficients between laboratory and predicted values for holocellulose and alpha-cellulose contents, which R2 values are 0.7467 and 0.8505, and RMSEP are 0.993 and 0.553, respectively. This study showed that NIR analysis can be reliably used to predict holocellulose and alpha-cellulose contents in triploid clones of Populus tomentosa.

Study on Compressed Wood with Urea-Formaldehyde Prepolymer

In this research, the urea-formaldehyde prepolymer and multilayer hot-press drying was used to obtain modified wood. The timbers were compressed and dried by the multilayer hot-press drying kiln. The combination of chemical modification and hot-press drying can improve the drying rate, which can also enhanced the physical and mechanical properties. Based on the findings, the basic density of modified wood improved 25.2 %, the bending strength and the bend elastic modulus improved 15.6 % and 25.0 % respectively. The dimensional stability of the treatment appeared to be slightly higher than that of untreated samples under the same conditions for processing temperatures and times. The improving dimensional stability of wood mainly was attributed to the prepolymer that changes wood cell wall components such as the degradation of the hemicelluloses and cellulose during hot-press drying treatment. The XRD results indicated that the degree of crystallinity increased to 35.45 %from 31.25 %. The TGA results show that the degradation of the samples can be divided into two step, both of the maximum weight loss velocity temperature of the two step increased to 266 °C, 355 °C from 244 °C and 341 °C.

Synthesis and Application of a Modifier to Enhance General Properties of the Polar Wood

A preparation method of modifier with low molecular weight and high reactivity is presented. This modifier （called KFK in lab）can impregnate into polar wood along trachea from the ends with pressurized impregnation method. In the following heating and pressing processes of the polar wood, the KFK polymerizes, and it enhances stability and strength of the wood. It showed that the favorable conditions for synthetic reaction of the KFK are: molar ratio of U and F, 1:1; reaction temperature, 20°C; reaction time, 3 hours; dosage of ignition primer A: 5%. Results from test showed the degree of crystallinity tested by XRD were 30%, 32% in different dosage of the modifier. Utilizing a combination of low molecular weight resin impregnation and pressing resulted in a density increase of KFK resin-treated wood from 0.214 to 0.268g/cm3. At the same time, the Young’s modulus and bending strength increased from 1.407GPa to 1.759GPa and 64MPa to 74.5MPa, respectively. It can be concluded that the effective utilization of KFK resin impregnated in polar wood is a promising technique for the production of high-strength in the drying and pressing processing.

Impregnation and Drying Schedule of Eucalyptus Wood

The aim of this research was to define a rapid and simple test that would indicate the probable performance of a pretreated wood species in a hot-press drying process and the kiln schedule. The drying rate (mass/time) and the remaining mass of water were measured at different moisture intervals. The moisture of timber decreased rapidly and the drying rate was 3.7% per day in the early five days. The timbers were B grade after drying used the hot-press drying kiln in 16 days. The moisture content of timber reached 9.20% after the drying process with the standard deviation of 0.92%. The gradient of the moisture content was 3.40%. The moisture content standard deviation in the thickness of timber was 2.70% and the residual stress was 1.38%. The mechanical properties of impregnation wood improve significantly compared to the untreated wood. The basic density of impregnation wood improved by 17.1%, the over-dried density increased to 0.55 g·cm-3 from 0.49 g·cm-3. The scanning electron microscopy explained the wood modifier has been permeated into the wood fiber which reacted with the wood composition.