摘要:

Oxidative pretreatment of Southern pine wood with alkaline hydrogen peroxide increased its rate of delignification during subsequent kraft and soda-AQ pulping. Effective pretreatment required the removal of transition metals prior to oxidation at high pH (12), low teaperature (50°C) and short reaction time (<45 min.). Compared with reference pulping, pretreatment with 1.4% H2O2 and 3.3% NaOH on wood reduced pulping time to 35 kappa number by 30 minutes (at 170°C). Pre-oxidation resulted in pulp with yield-kappa number and viscosity-kappa number relations equal to or greater than those of corresponding reference pulp.

ISSN:0277-3813    

DOI:10.1080/02773818708085269

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Unbleached kraft pulp containing 4.7% Klason lignin has been found to dissolve completely in several nonaqueous cellulose solvents. Extraction of the residual lignin in the unbleached kraft pulp from these solutions was attempted using several kinds of solvents for kraft lignin and hemicellulcoes.

ISSN:0277-3813    

DOI:10.1080/02773818708085270

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Five 1,1-diarylethanes were detected in three industrial alkali pulping spent liquors. Of these, two were novel compounds. The methylmethine linkages present in these compounds is expected to have formed during pulping. The degraded lignin and residual lignin in the pulp can therefore also be expected to contain methylmethine linkages.

ISSN:0277-3813    

DOI:10.1080/02773818708085271

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The constituents of the essential oil extracted from the needles and twigs of white spruce -Picea glauca(Moench) Voss -by steam distillation are analyzed by GC-MS and GC with authentic samples. The analysis allows for the Identification of 39 constituents.

ISSN:0277-3813    

DOI:10.1080/02773818708085272

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Eight tropical hardwoods (Malaysian) were subjected to autohydrolysis at 195°C for 10 – 100 Min, followed by extraction with 90% dioxane. A linear relationship was obtained between the % of water soluble extract, after autohydrolysis, and the % of hemicellulose present in the respective woods. Comparison of the different woods for their response to autohydrolysis was made, based on the % of maximum extractable lignin obtained. It was found that the effectiveness of autohydrolysis was not related to the density of the wood, or to the taxonomic type, but to a certain extent to the content of lignin present in the wood.

ISSN:0277-3813    

DOI:10.1080/02773818708085273

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Rapid hydrothermolysis at 350°C of poplar sapwood, heartwood and bark, as well as the lignin extracted from the sapwood and heartwood, gives oil and water soluble fractions whose chemical analysis is correlated with the nature of the feed stock. Results from cellulose and Douglas fir are included, and the poplar bark and heartwood lignin are shown to give an ether soluble oil that consists mainly of guaiacyl units while the sapwood product is mainly syringyl. However, the chloroform soluble oil from both sapwood and heartwood was mainly syringyl with the additional presence of carbohydrate derived material in the heartwood oil. The acetone-only soluble residue from sapwood was shown by pyrolysis mass spectrometry to be mainly cellulose derived while that from heartwood was mainly from lignin. Thus there is a fundamental difference in the behaviour of the poplar sapwood and heartwood that may arise from different distributions of the guaiacyl and syringyl units, and of the binding to the cellulose. The origin of the rapid hydrothermolysis products with respect to the major wood components is discussed. An empirical approach to the calculation of the lignin content based on the rapid hydrothermolysis fractions is presented.

ISSN:0277-3813    

DOI:10.1080/02773818708085274

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An experimental optimisation procedure has been used to investigate steam explosion ofPinusradiata. Enzymatic digestibility of this softwood is enhanced by steam explosion and addition of sulphur dioxide greatly Improves effectiveness of the process. The effects of the variables time, temperature, and sulphur dioxide level have been described by empirical models. The response parameters modelled are: dry-matter yield; water-insoluble fibre yield; water- soluble sugar yield; enzymatic-hydrolysis sugar yield; and total sugar yield. Near optimal total sugar yields were obtained with the conditions: 3 minutes; 215°C; and 2.55% sulphur dioxide. Under these conditions the steam-exploded fibre was 82% digestible (cellulose to glucose) by the cellulase enzymes used, and a total sugar yield of 57 g./100 g o.d. wood was obtained. This study has shown that softwoods, of whichPinus radiatais typical, can be made as amenable to hydrolysis by cellulase enzymes as hardwoods, which have previously been considered the only viable substrates for such processes.

ISSN:0277-3813    

DOI:10.1080/02773818708085275

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Preparation of hydroxyethylated wood-phenol resin adhesives has been attempted. The steam-explosion pretreatment or the phenolysis of the chemically modified wood was found to enhance its solubility making it feasible to prepare adhesives with good properties and workability. Thus, water soluble hydroxyethylated wood-phenol resin adhesives, comparable in gluability with the commercial resol type phenol resin adhesives could be obtained. The JIS specification for the dry adhesive strength was easily surpassed in case of these adhesives. By setting the glue line temperature at 130–150°C, which is necessary for three-dimensional curing of resol adhesive, and using other suitable gluing conditons, water-proof adhesion was also attainable. The water-proof adhesion could be enhanced by the addition of crosslinking agent (polymeric MDI) into the hydroxyethylated wood-phenol resin adhesives, resulting in fulfilment of the JIS specification for both the dry and water proof adhesive bond strength.

ISSN:0277-3813    

DOI:10.1080/02773818708085276

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Standard soil block tests can be used for southern pine and aspen flskeboards made with phenol-formaldehyde adhesive if the boards are first leached to remove toxic residual chemicals which inhibit fungal attack. Standard fungal cellar and termite tests can be applied directly without leaching. Flakeboards made from flakes acetylated by a new simplified dip acetic anhydride procedure are resistant to attack by brown-, white-, and soft-rot fungi and tunneling bacteria at acetyl weight gains above 15%. Acetylated flakeboards at 18 to 21% acetyl weight gains are not completely resistant to attack by subterranean termites.

ISSN:0277-3813    

DOI:10.1080/02773818708085277

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0277-3813    

DOI:10.1080/02773818708085268

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor