Preparation of phenol formaldehyde resin from phenolated wood

The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp) wood meal was liquefied by phenol in the presence of sulfuric acid as a catalyst. After the liquefied products were cooled, alkaline catalyst and formaldehyde were added. The mixture was kept at (60±2)°C for 1h and then was heated to (85±2)°C for 1h. The influence of molar ratio of formaldehyde to phenol (F/P) was investigated. The results showed when the molar ratio of formaldehyde to phenol was over 1.8, the PWF adhesives had high bond quality, bond durability and extremely low aldehydes emissions. Foundation item: The research was supported by Sino-Japanese Technical Cooperation Project (2-1-b) and the key technologies R & D Program for the 10th Five-Year Plan (325-11). Biography: LI Gai-yun (1974-), female, Assistant professor in Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P. R. China Responsible editor: Zhu Hong     

Penetration of urea–formaldehyde resins with different formaldehyde/urea mole ratios into softwood tissues

In order to understand the impact of formaldehyde/urea (F/U) mole ratio on penetration characteristics of urea–formaldehyde (UF) resin into softwood tissues, a quantitative measurement of UF resin penetration into radiata pine (Pinus radiata) tissues from the bond-line was undertaken. Four different F/U mole ratios (1.6, 1.4, 1.2, and 1.0) of UF resins with different viscosities and two levels of hardener (NH₄Cl) for two extreme F/U mole ratios (1.6 and 1.0) were studied. Firstly, field emission scanning electron microscope and confocal laser scanning microscopy were used to localize UF resins in the bond-line for the qualitative evaluation of resin penetration. Then light microscopy was employed to quantitatively measure the resin penetration and bond-line thickness. A decrease in the F/U mole ratio of UF resin that proportionately decreased the resin viscosity resulted in an increase in the average resin penetration and a decrease in the bond-line thickness. Higher hardener level provided a greater resin penetration with all F/U mole ratio UF resins. These results demonstrated that F/U mole ratio had an impact on the penetration and bond-line thickness of UF resins, owing to differences in the reactivity of resins, with higher F/U mole ratio resins being more reactive.     

Phenol–formaldehyde impregnation of densified wood for improved dimensional stability

To produce a highly stable wood-based product with increased mechanical properties, phenol formaldehyde (PF) resin impregnation was combined with the viscoelastic thermal compression (VTC) process. Dimensional stability and bending stiffness were evaluated. Two PF resins with weight average molecular weights of 172 and 780 were studied at three different concentrations, 5, 10 and 20%. After 24-h room temperature water soak and 2-h boil, both PF treatments at all concentration levels showed high levels of dimensional stability compared to non-impregnated VTC processed controls. The higher molecular weight PF provided greater stability with an average thickness swell value of 12% compared to 20 and 37% for the lower molecular weight PF resin treatment and control, respectively. High anti-swelling efficiency values were recorded for both low and high molecular weight resins, implying these modifications were effective at reducing the volumetric swelling which occurred in the unmodified control. PF treatments were also extremely effective at reducing irreversible swelling. The low and high molecular weight resin treatments had 1/5th and 1/7th the irreversible swelling than the unmodified VTC processed controls, respectively. All dimensional stability values improved as resin concentrations increased. Both resin types at all concentration levels reduced Young’s modulus.     

Shear strength development of the phenol–formaldehyde adhesive bond during cure

The development of the shear strength of the phenol–formaldehyde (PF) adhesive bond during curing was investigated. Five different PF adhesive mixtures and 1.1 mm thick peeled beech (Fagus sylvatica L.) veneer were used to produce lap-shear specimens, which were cured at a pressing temperature of 160°C. Dielectric analysis (DEA) and modified ABES (automated bonding evaluation system) were used to evaluate the physical–chemical and mechanical aspects of PF adhesive cure in a miniature hot-press. The degree of cure, which was calculated from conductivity data, was dependent on pressing time and the composition of the PF adhesive. An addition of rye flour to the PF adhesive significantly postponed the curing process as determined by DEA. It was found that the adhesive bond started to develop in the last stage of the curing (vitrification), by which time most of the physical–chemical conversion of the adhesive had been completed.     

Curing kinetics study of melamine–urea–formaldehyde resin/liquefied wood

The objective of this research was to investigate the effect of liquefied wood (LW) on the cure kinetics and network properties of melamine–urea–formaldehyde (MUF) resins by differential scanning calorimetry. The MUF/LW compounds exhibited two distinct cross-linking processes. It can be assumed that there did not appear to be a coreaction of the MUF with the LW. The overall apparent activation energies (E _a) of the curing reactions were calculated using the Kissinger equation. An nth-order kinetic model was used to describe the cross-linking of MUF/LW compounds, of various compositions, cured at different heating rates. The E _a values for the cross-linking process of the MUF/LW compounds predominantly tended to be approximately 80 and 71 kJ mol^?1 for MUF and LW, respectively. The apparent reaction orders of the MUF cross-linking process of the MUF/LW compounds were in the range 1–2, whereas the n values of the LW were approximately unity or less, which hints to there being a more complex mechanism of this process.     

The fire-retardant properties of the melamine-modified urea–formaldehyde resins mixed with ammonium polyphosphate

Fire retardancy of melamine-modified urea–formaldehyde resin (MUF) containing intumescent fire-retardant ammonium polyphosphate (APP) (MUF/APP) was conducted by cone calorimeter with surface treatment of medium density fiberboard (MDF). The results showed that the six MUF resins synthesized with different F/(M + U) and M/U molar ratios containing APP significantly improved the fire retardancy of the MDF by prolonging ignition time, reducing heat release rate and total heat release, and decreasing mass loss rate. The fire-retardant properties of the six synthesized MUF/APP acted differently even though each MUF resin containing the same mass ratio of APP. The melamine content in the MUF should not be too high, otherwise it would decrease the fire-retardant properties of MUF/APP. Based on this study, the higher the APP amounts, the better the fire-retardant performance of the resin was. The fire retardancy of MUF/APP increased with the increase in the amount of glue that spread on the material surface. However, only the amount of glue spread exceeded 250 g/m², whereas the ability of MUF/APP in inhibiting heat release did not increase significantly any longer.     

Effect of the addition of <Emphasis Type="Italic">Acacia mangium</Emphasis> bark on thermosetting of phenol–formaldehyde resin

The effect of addition of Acacia mangium bark powder on the thermosetting processes of two commercial phenol resins, PF-A and PF-B, was examined by bond strength test, torsional braid analysis, and differential scanning calorimetry. When the bark powder was added to PF-A, the bond strength of plywood pressed at 110°C increased and was comparable to that of plywood pressed at 120 and 130°C. However, when the bark powder was added to PF-B, the bond strength of plywood pressed at 110°C was still lower than that of plywood pressed at 120 and 130°C. The relative rigidity and loss tangent of PF-A cured with the bark powder obtained by heating at 100°C were comparable to those at 120 and 140°C, and the reaction enthalpy was increased by bark powder addition. In contrast, chemical reactions for cured PF-B were not enhanced by bark powder addition.     

Study of the Digestive Rate of Coarse Cellulose of Giant Pandas

IntroductionBal11booisl11ainfoodoftl1cgial1tpal1daint`.ildal1dman-fedgiantpandattasfCd111ucl1bal11boobcsldcsconccntratestl1atx`erel11adcofgrainPOwdcrtokccpltsfeedingl1abitsinwiId,buttl1cdigestivcratcofcoarsccclluloseisvery'low,il1botl1ttilda11d111a11-fcdpa11das.Wecanfindthattl1eba111boot'asall11ostl1otdigcstcdfrolllthefCccsthatcol1tai11edl11ucI1bal11boosticks.CI1cl1Yucllulletc.(l993)rcPortedt1lattl1edigcstit'eratcil1bal11boocoarsecelluloscisabout25%ol1lv.Tl1cautl1orsdesiglledthiscxPCrilll…     

Analysis of Nutrition Composition of Schisandra Fruits

IntroductionSchiSandraisadeciduousvineofMopohaceae.ItsthetStaSteofsWed,sour,bitter,PepPeryandsalty.ItisoneOfthetfadihonalChineseherbalmedicine.Schisan-for(Mopohaceae)hasbeenusedasprecioustonicandastriopntdrugforalleviahngcoughsinceanc1enthme.Modemmedicine…     

Evaluation of the sustainability of participatory management of forest plantations: the case study of Wari-Maro Forest Reserve,Republic of Benin§

This study assessed ecological and socio-economic impacts of a participatory forest management project in the Republic of Benin. The study focused on the Wari-Maro Forest Reserve and the ‘Projet d’Aménagement des Massifs Forestiers’ five years after its completion. A forest inventory was carried out using 37 square plots of 729 m² each to characterise the population structure of two types of plantations established: plantations with exotic species and plantations with native species. In addition, individual surveys were conducted with local households, organs of joint forest management and forestry officers to evaluate their perceptions about the participatory management of the plantations. Finally, the sustainability of the participatory management was assessed with an established rating system. Results showed that plantations with exotic species were more successful than plantations with native species. Local communities argued that they have not been involved in the plantations design but only in the implementation step and that their standards of living have decreased after the project completion. The rating system used showed that the participatory management of plantations had a short-term sustainability. The findings suggest that future projects should be designed and implemented with better participation of local communities as full partners.     

Analysis of Sediment Source of Watershed in Western Shanxi of the Loess Plateau

1 INTRODUCTIONThe Loess Plateau is the most drastic soil erosion regionin China, with the most severe water erosion. Thedistribution of types and intensity of erosion not onlyhave regional diversity but also have perpendicularvariation. In the small watershed, there are differencesin erosion characters among its upper, middle and lowerreaches. It is very significant for taking rationalmeasures of soil and water conservation and forpreventing soil and water loss to analyze the relationbe…     

Evaluation of Strength Performance of Finger-jointed Lumbers Using Three Kinds of Nondestructive Techniques

Resonance flexural vibration（Fast Fourier Transform, FFT）, ultrasonic wave（Pundit） and stress wave（Metriguard） techniques were examined as means of evaluating the static modulus of elasticity （MOE） and predicting the modulus of rupture （MOR） of finger-jointed lumber specimens made with four kinds of Eucalyptus （Eucalyptus. citriodora, E. exserta, E. grandis x E. urophylla and E. grandis）. Dynamic MOE was calculated from frequency and time obtained from forced vibrations and sounds induced in the four species of finger-jointed specimens. It was found that correlation coefficients between density and static MOE and dynamic MOE were statistically significant at the 0.01 level. And it was also found that the three nondestructive techniques can provide rapid and accurate means to determine the MOE, and the dynamic MOE was more accurate to predict static MOE than density. But the correlation coefficient between dynamic MOE, static MOE and MOR were lower than results reported by other researchers for solid wood, and were not statistically significant. It can be concluded that the three nondestructive techniques are useful for evaluating the MOE, but not suitable for predicting the MOR of finger-jointed.     

Ultrasound-associated extraction of seed oil of Korean pine

Experiment on ultrasound- associated extraction of seed oil of Korean pine (Pinus koraiensis) was conducted in Northeast Forestry University, Harbin, China. The factors affecting extraction yield, such as ultrasonic frequency, extracting temperature, extracting time and the ratio of material to liquid (ratio of Korean pine seed to absolute alcohol), were analyzed under specific condition and the optimal extracting parameters were obtained as the ultrasonic frequency 32 000 Hz, the extracting temperature 80℃, the extracting time 50 rain, and the ratio of material to liquid 1: 30. The study demonstrates that ultrasound is a reliable and great efficiency tool for the fast extraction of Korean pine seed oil。     

A Study of Eco-service Valuation of Saihanba Forest

The study made a monetized valuation of eco-service provided by forests at Saihanba Mechanic Forest Farm in terms of water conservancy, soil conversation, carbon sequestration, micro-climate adjustment, air quality improvement, protection for agriculture, biodiversity maintenance, and landscape recreation. The results revealed that the total value of various eco-services is 3.061 billion yuan/a, while the eco-services of unit area forest values at 42 300 yuan/(ha·a).     

A Study of Collecting Robot of Conifer Cone

IntroductionIntheforeStp~tion,thecollectionofconifcrconeisalmpsadifficultProblem.AlthoughmanykindsofconecoleCtinmachinehavebeenresearchedandmanufac-~athomeandabroad,forexample,elevator,vibra-tionmachineoftrdetrunkandsoon.ThesemachincshavcnotbeenaPPliedwid…     

A Survey of Laoshan Experimental Station of Plantation

GeneralInf0rmati0nLaoshanExperimentalStationofPlantation,knownasakeyexperimentalbaseofplantationofNortheastForestryUniversity,wasestablishedinl958.ItislocatedonShangzhiCountyof'HeilonaiiangProvince,45"20,-45"25'in1atitudeand'l27o30,-l27o34'inlongitude.Themeanelevationisabout300In-ThehighestpeaknamedMaoershanis800minelevationralativeheight.Thes1opeinthisregionrangesfroml0"to15",andtheterrainisachainofundu1atedhills.Vegctati0nThezonalvegetationofthisregionisbroadleavedandkoreanpinemixedfO…     

Simulation of Landscape Pattern of Old Growth Forests of Korean Pine By Block Kriging

IntroductionLandscapecanbeconsideredaspatiaI1yheterogeneousarea,andspatialpatter11referstothearra11gementofstructurall1eterogeneityofenvironments,resourceandbiologicalsysteInsinspace(Formanetall986,Tur11erl987,l989-Risserl987,TurneretaI199l).Turner(1987,1…     

Evaluation of nutrient value of seabuckthorn in north China

Five minerals or elements, crude protein, lysine, methionine cystine, calcium and phosphorus, were selected for evaluation of the food value of seabuckthorn (Hippophae rhamnoides ssp. sinensis) using the method of "food analysis". The decision values (δi) of seabuckthorn seeds, leaves and fruit residues rank in the fifth, sixth and ninth position among the 16 types of fodder. Seeds, leaves and fruit residues of seabuckthorn are suitable for livestock and poultry fodder. The weights of livestock and poultry are considerably increased after feeding with seabuckthorn. The development of seabuckthorn should have great potentials as food, pre-food and food additives for livestock and poultry in north China. Processing facilities should pay more attention to seabuckthorn food development methods and strategies and the seabuckthorn fodder industry should be promoted.     

To Authors and Readers of Journal of Forestry Research

DearcolleagueScientificperiodicalisamainkindofmediumforpublishingscientificresearchresutts.Aboutseventypercentofresearchresultsarepublishedindifferentformsofperiodicals.Thereareabout260kindsofforestryjournalsinChina.Thesejournalsareplayinganimportantroleinadvancingacademicexchangesandflourishingforestryresearch.Mostofthesejoumals,however,arepublishedinChinese,somewithEnglishabstracts,veryfewpublishedinEnglish.SothescopeofacademicexchangesofforestryresearchislimitedinChina.NortheastForestry…