Volume 3 Issue 3

Beech sawdust was reacted with phthalic (PA) and maleic (MA) anhydrides for chemical modification. The influence of reaction time and anhydride amount was investigated. IR spectra gave evidence of wood esterification. Thermogravimetric investigation of chemically modified wood indicated a better thermal stability (mainly for wood treated with phthalic anhydride) in comparison with the untreated wood.

The effect of xylanase treatment of eucalyptus wood chips on chip refining and fiber properties was investigated. The fiber separation region and fiber surface structure were observed with SEM, TEM, and AFM. The fiber length and fines were analyzed with a Bauer-McNett classifier and optical image analysis of flowing suspensions (FQA). The results showed that xylanase degraded and hydrolyzed some xylan in the fiber wall, thus loosening the fiber wall structure. Therefore, in the subsequent refining process, fiber separation occurred in the secondary wall. This resulted in fibers with less lignin and extractives on the surface, which will benefit the interfiber bonding.

The thermal degradation of cellulose is an important process in several fields such as the paper industry, biomass combustion, fire retardation, etc. Paper consists mostly of cellulose fibres. Although the fibre source has changed continiously from cotton or linen rags to wood, its nature is still vegetal. Pyrolysis in combination with gas chromatography and mass spectrometry has been used to identify the structures of thermal degradation products with the aim to characterize papers used in different centuries. Pyrolysis of cellulose has also been studied in the presence of the methylating reagent tetramethylammonium hydroxide (TMAH).

This paper presents a preliminary study for the production of dissolving pulp from Trema orientalis (Nalita). Water prehydrolysis kraft and soda-ethylenediamine (EDA) pulping for the production of dissolving pulp from T. orientalis was investigated. Prehydrolysis at 150 and 170 oC did not produce pulp with high α-cellulose content when using the kraft process. But addition of 0.25 % H2SO4 in prehydrolysis liquor increased the purity of the pulp with the sacrifice of pulp yield and viscosity. The soda-EDA process produced better pulp yield, kappa number, viscosity, and α-cellulose content as compared to the kraft process. Increasing EDA charge in the soda liquor increased pulping selectivity and α-cellulose content. Degraded cellulose (R18-R10) in soda-EDA pulp was lower than kraft pulp. But the bleachability of soda-EDA pulp was inferior as compared to kraft pulp in DED bleaching.

Wear patterns were analyzed for High Speed Steel (HSS) SKH51 cutting tools after milling wood of four wood species having very different High Temperature Tribochemical Reactions (HTTR), wood density and very low hard mineral contamination (HMC). The experimental results showed that the HTTR can be an important factor influencing acceleration of cutting tool wear.

A new type of binder for wood particles or fibres was developed using a recycled polyol from polyurethane or PET wastes and a polyisocyanate as raw materials. The binders developed with various ratios of hydroxyl and isocyanate groups are solid at room temperature with melting points between 40 and 60°C. Between 5 and 20% of these were mixed with the wood products and compression-moulded at temperatures between 80 and 100°C and 0.75 to 2.05 kp/mm² pressure to give composites of tensile strength up to 47 N/mm2 or flexural strength up to 58 N/mm2.

The purpose of this work was to improve the quality of jack pine TMP long fibers, particularly with respect to the strength properties, by alkaline peroxide treatment. This paper reports the chemical characteristics of the treated long fibers and the spent liquors originating from various treatments. It was observed that, in comparison with hydrogen peroxide, the alkalinity of the treatment solutions had a greater influence on most fibre characteristics and spent liquor properties.

Molybdenum catalyzed peroxide bleaching (PMo Stage) consists of pulp treatment with hydrogen peroxide under acidic conditions in the presence of a molybdenum catalyst. Molybdenum is applied in catalytic doses (50-200 mg/kg pulp) and may originate from various sources, including (NH4)6Mo7O24.4H2O, Na2MoO4.2H2O, siliconmolybdate, etc. This work is aimed at optimizing the PMo stage and evaluating its industrial application in the OAZDP sequence. Optimum PMo stage conditions for bleaching eucalyptus pulp were 90 ºC, pH 3.5, 2 h, 0.1 kg/adt Mo and 5 kg/adt H2O2. The PMo stage was more efficient to remove pulp hexenuronic acids than lignin. Its efficiency decreased with increasing pH in the range of 1.5-5.5, while it increased with increasing temperature and peroxide and molybdenum doses. The application of the PMo stage as replacement for the A-stage of the AZDP sequence significantly decreased chlorine dioxide demand. The PMo stage caused a decrease of 20-30% in the generation of organically bound chlorine. The quality parameters of the pulp produced during the PMo stage mill trial were comparable to those obtained with the reference A-stage.

The thermostable enzyme systems produced by the thermophilic ascomycete fungus Talaromyces emersonii cultivated on various carbon sources were investigated for the production of high value products from sugar beet. A broad range of enzymatic activities relevant to cellulose, hemicellulose, and pectin hydrolysis were identified in T. emersonii culture filtrates. In hydrolysis experiments conducted at 71ºC, the enzyme cocktails generated sugar-rich syrups from untreated sugar beet plants. Maximal levels of sugar beet hydrolysis were obtained with T. emersonii enzyme cocktails induced with sorghum/ beet pulp (68%) and sugar beet plant (56%). The principle monosaccharides released were glucose, xylose, and arabinose with minor amounts of galactose and galacturonic acid. Northern analysis of RNA isolated from T. emersonii when sugar beet plants were used as the sole carbon inducing source showed that genes required for polysaccharide hydrolysis and five carbon monosaccharide metabolism were co-ordinately expressed.

Resource assessment is a necessary step for any project, plan, or future energy prospectus involving renewable energy sources. The assessment of biomass and, in particular, the so-called forest and agricultural field residues, faces particular methodological difficulties due to the scarcity and heterogeneity of the data sources. For agricultural residues such as cereal straw, bagasses, etc., the residue to product ratios (RPR) are the key data needed for the estimations. In the present work the values of these product ratios reported in the literature are surveyed and are seen to vary greatly, depending on the reporting source. Some methodological procedures for obtaining RPR values are considered, and guidelines for conducting the resource evaluation are indicated. For the estimation of forest field biomass resources a methodological procedure based on the different stand stages along a forest rotation is presented. The main steps of this methodology are based on the availability of basic quantitative data from forest stands and the assumption of different silvicultural operations during the stand rotations. Environmental constraints should be observed in biomass resource assessments. However, the lack of clear recommendations concerning biomass removal in different forest soil and climate conditions suggest that more research is required to assess the sustainability of biomass harvest. Chemical characterization of some of the most representative biomass materials is also presented.