Pine Chips Research Articles

Evaluation of different strategies for pulverization of forest biomasses

The comminution of coarse forest biomass into fine products suitable to feed pulverized fuel burners could be an efficient way to produce usable renewable energy in the short term. However, size reduction of lignocellulosic forest materials is an intensive operation that requires energy. Pulverized fuel burners suitable for biomass usually require that the biomass fuel meet certain particle size specifications. In the present work, the specifications for the comminuted product are set as 95% by weight passing a 1000 μm mesh and 12% weight passing a 125 μm mesh. Three different forest biomasses, namely poplar chips, pine chips and pine bark, have been selected for size reduction study. Four different types of open-circuit processes have been designed and assayed utilizing a pilot plant comprising two hammermills, one screener and one dynamic air separator, in order to obtain the desired fineness for the product. The biomass raw materials and the products obtained have been characterized and the electrical energy requirements recorded. The process consisting of a primary grinding with 4 mm screen size, followed by selection with a dynamic air separator and secondary grinding of the separator reject, has been identified as the process most suitable for obtaining the desired product. The extrapolation to a full-scale plant for processing 10 o.d. t h − 1 gives estimated energy requirements of 120, 150 and 35 kW h o.d. t − 1 for poplar chips, pine chips and pine bark, respectively, with initial moisture contents between 10% and 15% (w.b.).

From forest biomass to chemicals and energy... Biorefinery initiative in New York State

Industrial BiotechnologyVol. 2, No. 2 Feature CommentaryFrom forest biomass to chemicals and energy... Biorefinery initiative in New York StateShijie Liu, Thomas E. Amidon, Raymound C. Francis, Bandaru V. Ramarao, Yuan-Zong Lai, and Gary M. ScottShijie LiuSearch for more papers by this author, Thomas E. AmidonSearch for more papers by this author, Raymound C. FrancisSearch for more papers by this author, Bandaru V. RamaraoSearch for more papers by this author, Yuan-Zong LaiSearch for more papers by this author, and Gary M. ScottSearch for more papers by this authorPublished Online:17 Jul 2006https://doi.org/10.1089/ind.2006.2.113AboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail FiguresReferencesRelatedDetailsCited byWhat is bioprocess engineering?Optimisation and characterisation of bio-oil produced by Acacia mangium Willd wood pyrolysis12 April 2017 | Wood Science and Technology, Vol. 51, No. 5IntroductionRecently Bred Willow (Salix spp.) Biomass Crops Show Stable Yield Trends Over Three Rotations at Two Sites1 April 2016 | BioEnergy Research, Vol. 9, No. 3Influence of hot-water extraction on ultrastructure and distribution of glucomannans and xylans in poplar xylem as detected by gold immunolabeling20 May 2015 | Holzforschung, Vol. 70, No. 3Biorefinery and Possible DeforestationOptimization study on acid hydrolysis of hardwood-derived hemicellulosic extract for alcohol fermentation using response surface methodologyHolzforschung, Vol. 69, No. 2Noble-metal catalyzed hydrodeoxygenation of biomass-derived lignin to aromatic hydrocarbonsGreen Chemistry, Vol. 16, No. 2Polyolefin-Based Plastics from Biomass-Derived Monomers4 October 2013Autohydrolysis Pretreatment of Mixed Softwood to Produce Value Prior to Combustion21 June 2013 | BioEnergy Research, Vol. 6, No. 3Lignin: untapped biopolymers in biomass conversion technologies7 June 2013 | Biomass Conversion and Biorefinery, Vol. 3, No. 3Primary properties of MDF using thermomechanical pulp made from oxalic acid pretreated rice straw particlesIndustrial Crops and Products, Vol. 41Niche Position and Opportunities for Woody Biomass ConversionBiorefinery with Water20 November 2012A sustainable woody biomass biorefineryBiotechnology Advances, Vol. 30, No. 4Mass balances of components dissolved in the pre-hydrolysis liquor of kraft-based dissolving pulp production process from Canadian hardwoodsBiomass and Bioenergy, Vol. 39Hot-water extraction and its effect on soda pulping of aspen woodchipsBiomass and Bioenergy, Vol. 39Increasing the value of a biorefinery based on hot-water extraction: Lignin products1 February 2012 | TAPPI Journal, Vol. 11, No. 1Fractionation of wood polymers by carboxymethylation: Exploring the strategy1 February 2012 | TAPPI Journal, Vol. 11, No. 1Effect of Hot Water Extraction on Hardwood Kraft Pulp fibers (Acer saccharum, Sugar Maple)1 August 2011 | Industrial & Engineering Chemistry Research, Vol. 50, No. 17Oxalic acid pretreatment of rice straw particles and loblolly pine chips: Release of hemicellulosic carbohydrates1 June 2011 | TAPPI Journal, Vol. 10, No. 5Effect of oxalic acid and steam pretreatment on the primary properties of UF-bonded rice straw particleboardsIndustrial Crops and Products, Vol. 33, No. 3Growing Systems for Traditional and New Forest-Based Materials16 March 2011Effect of oxalic acid pretreatment of wood chips on manufacturing medium-density fiberboardHolzforschung, Vol. 65, No. 5Woody biomass: Niche position as a source of sustainable renewable chemicals and energy and kinetics of hot-water extraction/hydrolysisBiotechnology Advances, Vol. 28, No. 5Effect of hot-water extraction on alkaline pulping of bagasseBiotechnology Advances, Vol. 28, No. 5Separation and purification processes for lignocellulose-to-bioalcohol productionOptimization of ethanol production from hot-water extracts of sugar maple chipsRenewable Energy, Vol. 34, No. 11Water-based woody biorefineryBiotechnology Advances, Vol. 27, No. 5Activity and Stability of Perovskite-Type Oxide LaCoO 3 Catalyst in Lignin Catalytic Wet Oxidation to Aromatic Aldehydes Process5 December 2008 | Energy & Fuels, Vol. 23, No. 1Hydrolysis of bamboo fiber cellulose in formic acid1 October 2008 | Frontiers of Forestry in China, Vol. 3, No. 4Utilization of forest derived biomass for energy production in the U.S.A.: status, challenges, and public policiesInternational Forestry Review, Vol. 9, No. 3Genetic Improvement of Willow (Salix spp.) as a Dedicated Bioenergy Crop Volume 2Issue 2Jun 2006 InformationCopyright 2006, Mary Ann Liebert, Inc.To cite this article:Shijie Liu, Thomas E. Amidon, Raymound C. Francis, Bandaru V. Ramarao, Yuan-Zong Lai, and Gary M. Scott.From forest biomass to chemicals and energy... Biorefinery initiative in New York State.Industrial Biotechnology.Jun 2006.113-120.http://doi.org/10.1089/ind.2006.2.113Published in Volume: 2 Issue 2: July 17, 2006PDF download

Controlled Seasoning of Scots Pine Chips Using an Albino Strain of Ophiostoma

Traditional seasoning of wood chips normally results in significant yield losses and brightness reduction due to the uncontrolled action of microorganisms. Techniques for reduction of the amount of wood extractives with minimal yield and brightness loss are therefore of interest for the pulp and paper industry. To study a biotechnological approach for reduction of wood extractives, wood chips from sapwood of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) were treated with a commercial albino strain of the sap stain fungus Ophiostoma piliferum. During 2 weeks of controlled seasoning, the content of wood extractives decreased by approximately 40% for Scots pine and 25% for Norway spruce, where the triglyceride contents were degraded to a greater degree. Thermomechanical pulps were produced from untreated and pretreated pine chips. The properties of these pulps and corresponding laboratory sheets were investigated. The pretreated pulps showed less shortened fibers, lower amounts of triglycerides, and enhanced strength properties. The mechanisms behind these effects are discussed. Furthermore, the ability of the albino Ophiostoma piliferum to displace mould growth from wood chips was investigated in a series of experiments. It was concluded that the fungus should preferably be inoculated on fresh chips in order to repress mould growth.

Concentration of elements in woody and herbaceous biomass as a function of the dry ashing temperature

The main purposes of the study presented in this paper are to select the optimal temperature of dry ashing and to carry out posterior analyses of elements in the ash formed. The concentration of elements from biomass was compared with the concentration of elements in ash obtained at 400, 500, 550, 600 and 800 °C, utilising four woody and herbaceous biomasses: pine chips, poplar chips, thistle and wheat straw. A dry ashing temperature in the 500–550 °C range was found to produce ashes low in organic carbon (less than 1 wt%) and to recover the greatest amount of the element contents present in the original biomass. A slight loss of potassium and sodium is determined in the ashes produced at temperatures as low as 400 °C for herbaceous biomass compared with the potassium and sodium analysed in biomass.

Mold resistance of medium density fiberboard panels made from black spruce, hybrid poplar, larch and a mixture of S-P-F chips

Eleven types of medium density fiberboard (MDF) panels were manufactured from fresh-felled trees of black spruce, hybrid poplar, larch and a mixture of spruce, pine and fir (S-P-F) wood chips at a target density of 740 kg/m3 bonded with 10% commercial urea-formaldehyde (UF) resin. Black spruce panels were fabricated from fibers located in three wood age zones (1–20, 21–40 and over 40 annual rings) of bottom logs, as well as top, middle and bottom logs, separately. Hybrid poplar panels were made from three clones with codes 915303, 915311, and 915313. Mold resistance of these panels was tested by exposing panels in an incubation chamber set at favourable temperature and relative humidity (RH) conditions for mold growth for 4 weeks. The results indicate that MDF panels made from black spruce juvenile wood (1–20 annual rings) were more resistant to mold infection comparing to the other types of panels based on Duncan’s multiple-range test at 0.05 of probability. Panels made of fibers taken from black spruce transition zone (21–40 annual rings) and mature wood zone (over 40 annual rings), and top, middle and bottom logs, hybrid poplar clones 915303, 915311, and 915313, larch and S-P-F wood chips were not significantly different, and these panels were severely infected by mold after 4 weeks of incubation. Nine fungal species predominately infected the tested samples. This laboratory experiment indicates that MDF panels made from black spruce transition and mature wood, and top, middle and bottom logs, hybrid poplar, larch and a mixture of S-P-F chips are susceptible to mold growth and protection measures are necessary in order to improve mold susceptibility of those panels when used in humid conditions or for exterior applications.

Chipped Pine Logs: A Potential Substrate for Greenhouse and Nursery Crops

Due to uncertainties of future supplies of pine bark (PB) and peatmoss, ground Pinus taeda logs [pine chips (PC)] were compared to ground PB as a potential container substrate for japanese holly (Ilex crenata Thunb. `Chesapeake'), azalea (Rhododendron obtusum Planch. `Karen'), and marigold (Tagetes erecta Big. `Inca Gold'). Plants were potted in 2.8-L plastic containers 8 Apr. 2004 with either 100% PC, 100% PB, or 75% PC:25%PB (v/v), and glasshouse grown 8 weeks for marigold and 13 weeks for holly and azalea. Plant dry weights were higher for marigold grown in 100% PB compared to 100% PC but not different from plants grown in 75% PC:25% PB. Plant dry weights of azalea were higher in 100% pine bark than both substrates containing chips. There was no difference in shoot dry weight for japanese holly between the three substrates. Root dry weight was higher for 75% PC:25% PB than for 100% PB, but root weight of 100% PB and 100% PC was the same. The percent air space for the PC was higher than the PB substrate but container capacity and available water was not different for the three substrates. Substrate solution electrical conductivity (EC) for PC, was lower than that of PB, possibly due to greater leaching with the more porous PC and nutrient retention by the PC. These factors could account for the cases where larger plants developed with the PB substrate. Nutrient analysis of the substrate solution indicated that there are no toxic nutrient levels associated with PC. The pH of PC is also acceptable for plant culture. As well, there was no apparent shrinkage due to decomposition during the course of this short-term experiment. Pine chips, therefore, offer potential as a container substrate for greenhouse and nursery crops.

A FTIR method for determining the content of hexeneuronic acid (hexA) and Kappa number of a high-yield kraft pulp

Kappa number is a good indicator of chemical demand for bleaching. In the past, it was considered as an indirect measure of residual lignin, but was later realized to depend on both the residual lignin and hexA groups in pulps. Lignin has been characterized by FTIR spectroscopy and the intensity of its characteristic bands has been used to indicate the residual lignin and Kappa number but these previous FTIR methods were not reliable. In the current study, a number of high-yield kraft pulp samples with different Kappa numbers were produced by cooking pine chips in flow-through reactors. Based on the transmission FTIR spectra of dry pulps, a quick and reliable FTIR method was established using a multivariate analysis to take into account all the characteristic bands of lignin and hexA groups for the prediction of Kappa number and hexA content in pulp. The predicted values were found to be highly comparable with the measured values determined in the laboratory.

Strategies for implementation and validation of on‐line models for multivariate monitoring and control of wood chip properties

AbstractHere we present an approach for on‐line control and monitoring of pulpwood chip properties based on near infrared (NIR) spectroscopy and multivariate data analysis. In addition, this paper suggests how to deal with large multivariate data sets in order to extract information which can be used as a basis for changes in raw material or process conditions in the drive towards more optimal intermediate or end product properties within the pulp and paper industry. The pulpwood chips used as raw material in a pulp and paper making process were characterized at‐ and on‐line using NIR spectroscopic measurements. Collected NIR spectra were used in multivariate calibration models for prediction of the moisture content as well as the between‐ and within‐species variation in the studied raw material. Statistical experimental design was used to form a calibration data set including most of the variation occurring in a ‘real’ on‐line situation. NIR spectra for all designed samples were measured at‐line and the estimated calibration models were used for carrying out predictions on‐line. Predictions of the moisture content (% dry weight) as well as the percentage contents of pine and sawmill chips in the raw material were carried out using partial least squares projections to latent structures (PLS) methodology. NIR spectra were collected subsequently on‐line once every minute, and, to reduce the problem with noise in the time series predictions, the measured signals were filtered using a moving average of 100 predicted values. This provided smoother predictions more suitable for process monitoring and control. To validate the quality of the predictions, wood chips from the studied process were sampled and analysed in the laboratory before being subjected to predictions in the on‐line model. Comparison of the filtered on‐line predictions with the results obtained from the laboratory measurements indicated that moisture and pine chip contents could be well predicted by the on‐line model, while predictions of sawmill chip content showed less promising results. Copyright © 2004 John Wiley & Sons, Ltd.

Effect of organic mulches on soil bacterial communities one year after application

The application of organic mulches as a soil cover is effective in improving the quality of soil. However, very little information is available on the effect of mulches on the soil microbial community. In this study, we investigated the effect of various organic mulches on soil dehydrogenase activity (DHA) and microbial community structures in the top 1 cm and 5 cm below the soil surface 1 year after application of the mulches. DHA was stimulated at both depths in plots mulched with grass clippings (GC), but was not significantly different from the control for the other mulch treatments. Fatty acid methyl ester (FAME) analysis and denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction-amplified 16S rDNA fragments were used to assess changes in the soil microbial community structure. Cluster analysis and principle component analysis of FAME profiles showed that only soil mulched with pine chips distinctively clustered from the other treatments. At the soil surface, bacterial DGGE profiles revealed that distinct shifts in several bacterial populations occurred in soils mulched with GC and eucalyptus yardwaste (EY), while DGGE profiles from soil at the 5 cm depth revealed no distinct changes. Changes in bacterial diversity at the soil surface under different mulches were calculated based on the number of bands in the DGGE profile using the Shannon-Weaver index of diversity ( H). Compared to the control ( H =0.9), the GC- and EY-treated soils showed slightly increased bacterial diversity, with an H of 1.1 and 1.0, respectively. These results indicate that the long-term effect of organic mulches on the soil microbial activity and community structure is highly dependent upon the type of mulch and is mostly exerted in the top few centimeters of the soil profile.

Counter pressure on ventilation of different types of wood chip and chunkwood

The pressure resistance to airflow during ventilation was measured for different types of wood chips and chunk and one type of wood pellet made from sawdust. The influence of the air velocity and particle size was determined and the results described by a mathematical equation. The measured pressure resistance correlated very well with the size distribution of the different chip and chunk types. The lowest pressure resistance was found in a 100 mm long chunk produced with a Sasmo chunker from Sitka spruce whole trees at only 14 Pa m −1 at an airflow rate of 0.1 m s −1 . The highest resistances were found in 35 mm long chip produced with a Sasmo chipper from Norway spruce logging residue, and for long-pole Contorta pine chip produced with a TP 960 chipper. These measured 61 and 68 Pa m −1 , respectively, at an air flow rate of 0.1 m s −1 . If the chip is stored, the pressure resistance during ventilation will increase considerably. Drying of the chip will only reduce the pressure resistance slightly. The pressure resistance to airflow was a factor of 6–60 lower for the wood chip tested than for agricultural crops like rape seed and grain.

Detoxification of semisolid olive-mill wastes and pine-chip mixtures using Phanerochaete flavido-alba

Semisolid olive-mill residues, pine chips, and mixtures of both residues contain phytotoxic components capable of inhibiting germination and vegetative growth in plants. Solid-state cultures of Phanerochate flavido-alba on pine chips or mixtures of both residues reduce these phytotoxic effects in fermented substrates. The phenol and lipid contents in cultures detoxified by this fungus also decreases.

THE INFLUENCE OF DRYING MEDIUM, TEMPERATURE, AND TIME ON THE RELEASE OF MONOTERPENES DURING CONVECTIVE DRYING OF WOOD CHIPS

ABSTRACT The release of volatile organic components (VOC) during the drying of wood chips was studied experimentally. The drying medium was hot dry air with a pressure of 1 bar and velocity of 1 m/s. Four different temperature levels of the drying medium, i.e., 120, 140, 160 and 180°C, and two different materials, Scots Pine and Norway Spruce, were investigated. It was found that the main components released consist of various types of monoterpenes, with α-pinene dominating in each of the two materials. The amount released is time-dependent, showing a maximum at shorter times. The release rate is more intensive at higher drying temperatures. The mass-balance for α-pinene was checked by comparing the amount present in the wood chip before and after drying with the amount obtained by integrating the release curve. A good agreement was obtained. Environmental Scanning Electron Microscope pictures were taken of both the spruce and pine chip in order to investigate differences in the wood structure before and after drying with air at 160°C. No obvious structural change could, however, be observed. The influence of the drying medium on the release rate of monoterpenes (air and superheated steam) was also studied. The results showed that the release rate was faster when drying with superheated steam.

Pyrolysis of Pine ( Pinus Brutia Ten.) Chips: 2. Structural Analysis of Bio-oil

Fixed-bed pyrolysis liquid products of pine chips ( Pinus Brutia Ten.) have been identified for their structures. The solid and liquid products were analyzed to determine their elemental composition and calorific values. In particular, the liquid products were identified in detail to determine their composition and characteristics. Chemical fractionation of liquids showed that the oxygenated and polar fractions were dominant. The empirical formula of bio-oils obtained in a static pyrolysis atmosphere and in a nitrogen atmosphere are CH 1.32 O 0.54 N 0.0014 and CH 1.38 O 0.37 N 0.002 , respectively. The heating value of liquid varies from 23.1 MJ/kg to 25.4 MJ/kg in the range of 300 to 500°C pyrolysis temperature. The H/C and O/C molar ratios were 1.38 and 0.37, respectively.

Pyrolysis of Pine ( Pinus Brutia Ten.) Chips: 1. Effect of Pyrolysis Temperature and Heating Rate on the Product Yields

In this work, bark-free chips of Turkish red pine ( Pinus Brutia Ten.) were pyrolyzed in a laboratory-scale fixed bed reactor. The influence of final pyrolysis temperature, heating rate, and pyrolysis atmosphere on the product yields were investigated. Pyrolysis runs were performed using reactor temperatures ranging between 300 and 550°C with heating rates of 7 and 40°C/min. The char, gas, and liquid yield obtained ranged between 23 and 36 wt%, 11 and 23 wt%, and 21 and 30 wt%, respectively, at different pyrolysis conditions. The highest liquid yield was obtained at 500°C pyrolysis temperature with a heating rate of 40°C/min and the sweep gas flow rate of 50 cm 3 /min. The results from the pyrolysis of pine chips showed that the clear increments of the pyrolysis conversion in the temperature interval 450 to 500°C is due to the rapid devolatilization of cellulose and hemicellulose.

Bacterial Biodegradation of Extractives and Patterns of Bordered Pit Membrane Attack in Pine Wood

Wood extractives, commonly referred to as pitch, cause major problems in the manufacturing of pulp and paper. Treatment of nonsterile southern yellow pine chips for 14 days with Pseudomonas fluorescens, Pseudomonas sp., Xanthomonas campestris, and Serratia marcescens reduced wood extractives by as much as 40%. Control treatments receiving only water lost 11% of extractives due to the growth of naturally occurring microorganisms. Control treatments were visually discolored after the 14-day incubation, whereas bacterium-treated wood chips were free of dark staining. Investigations using P. fluorescens NRRL B21432 showed that all individual resin and fatty acid components of the pine wood extractives were substantially reduced. Micromorphological observations showed that bacteria were able to colonize resin canals, ray parenchyma cells, and tracheids. Tracheid pit membranes within bordered pit chambers were degraded after treatment with P. fluorescens NRRL B21432. P. fluorescens and the other bacteria tested appear to have the potential for biological processing to substantially reduce wood extractives in pine wood chips prior to the paper making process so that problems associated with pitch in pulp mills can be controlled.

Fluidized-bed co-gasification of residual biomass/poor coal blends for fuel gas production

Experiments involving the co-gasification of residual biomass/poor coal blends and gasification of individual feedstocks used in the blends were performed in a bench scale, continuous fluidized-bed working at atmospheric pressure. Two types of blends were prepared, mixing pine chips (from Valcabadillo, Spain) with black coal, a low-grade coal from Escatrón, Spain, and Sabero coal, a refuse coal from Sabero, Spain, in the ratio range of 0/100–100/0. Experimental tests were carried out using as a gasification agent mixtures of air and steam with dew points of 74–85°C at gasification temperatures of 840–910°C and superficial fluidized gas velocities of 0.7–1.4 m/s. Feasibility studies were very positive, showing that blending effectively improved the performance of fluidized-bed co-gasification of the low-grade coal, and the possibility of converting the refuse coal to a low-Btu fuel gas. This study indicates that a blend ratio with no less than 20% pine chips for the low-grade coal and 40% pine chips for the refuse coal are the most appropriate. The dry product gas low heating value augments with increasing blend ratio from 3700 to 4560 kJ/N m 3 for pine chips/low-grade coal, and from 4000 to 4750 kJ/N m 3 for pine chips/refuse coal. Dry product gas yield rises with the increase of the blend ratio from 1.80 to 3.20 N m 3/kg (pine chips/low-grade coal), and from 0.75 to 1.75 N m 3/kg (pine chips/refuse coal), respectively. About 50% co-gasification process overall thermal efficiency can be achieved for the two types of blend.

Studies on Impact Fracture Properties of Wood-Polymer Composites

Composite plates containing pine wood chips and high density polyethylene (HDPE) matrix were prepared and studied for their impact fracture behavior using an instrumented drop weight tester. Maximum load sustained, deflection to maximum load, energy to maximum load and energy for total penetration of the test specimens were determined for the above-mentioned wood-polymer composites. Effects of pine chip concentration in composites and its particle size on impact damage resistance were analyzed. Large size wood chips in the 50 to 60 vol.% concentration range increased the energy to fracture and damage resistance considerably. This is attributed to the internal friction forces encountered between such large sized chips restricting the deformation and contributing to uneven perforation. On the contrary, specimens with small sized wood chips in similar composition range perforated evenly consuming less energy than needed to perforate even the polymer alone.

Sorption of Monoaromatic Hydrocarbons to Wood

The sorption of benzene, toluene and o-xylene to wood, a common subsurface fill material, was characterized. Sorptive equilibrium was attained within 24 h for water-saturated Douglas fir and Ponderosa pine chips of centimeter-sized dimensions, consistent with predictions of retarded diffusive transfer into the wood. Sorption to the chips exhibited linear sorption isotherms. When wood−water partition coefficients were normalized to the wood's lignin content, the resulting lignin−water partition coefficients, Klignin, agreed to within a factor of 2 with literature values reported for chemically isolated lignins. Wood sorption was substantially overpredicted by an organic carbon-based model (i.e., Koc). Wood−water partition coefficients for nonionic sorbates (10 < Kow < 104) can be predicted as the product of the wood's fractional lignin content, flignin, and a Klignin estimated from the linear free energy relationship: log Klignin = (0.74 ± 0.09) log Kow − (0.04 ± 0.25).

Studies on Impact Fracture Properties of Wood-Polymer Composites

Composite plates containing pine wood chips and high density polyethylene (HDPE) matrix were prepared and studied for their impact fracture behavior using an instrumented drop weight tester. Maximum load sustained, deflection to maximum load, energy to maximum load and energy for total penetration of the test specimens were determined for the above-mentioned wood-polymer composites. Effects of pine chip concentration in composites and its particle size on impact damage resistance were analyzed. Large size wood chips in the 50 to 60 vol.% concentration range increased the energy to fracture and damage resistance considerably. This is attributed to the internal friction forces encountered between such large sized chips restricting the deformation and contributing to uneven perforation. On the contrary, specimens with small sized wood chips in similar composition range perforated evenly consuming less energy than needed to perforate even the polymer alone.

Einfluß der Imprägnierung von Kiefernspänen ( Pinus silvestris L.) mit Harnstoff- und Harnstoff-Ammmoniumsulfatlösungen auf die Formaldehydabgabe und den pH-Wert unter variierenden thermohydrolytischen Bedingungen

The formaldehyde release of pine chips before and after impregnation with urea and urea-ammonium sulphate solutions was determined according to the flask-method at 40°C and 103°C after 24 h, 48 h, 72 h and 144 h. Also the pH-values were measured in the aqueous solution. The results reveal: (1) The formaldehyde release of untreated chips was much higher than that of the impregnated ones. (2) The pH-values in the aqueous solution were slightly acidic for unimpregnated chips. The impregnated chips showed a different behaviour: the pH-values measured at 103°C were in the alcaline region. (3) There was no distinct difference between the chips impregnated with urea solution and those impregnated with urea-ammonium sulphate solution.