The feasibility of using DRIFT (diffuse reflectance infrared Fourier transform) spectroscopy combined with a multivariate analysis method (a PLS (projection to latent structures), regression) for predicting the distribution of the main organic constituents (cellulose, glucomannan, xylan, lignin, and extractives) within the Scots pine (Pinus sylvestris) stemwood was examined. PLS calibrations were carried out to establish a mathematical correlation between the data sets of conventional (“wet-chemistry-based”) wood analysis and the DRIFT spectra of the corresponding wood samples. Based on this approach, different surface maps on variations in the content of the main organic constituents within the stemwood matrix were shown.

Variations in the chemical composition within pine ( Pinus sylvestris ) trunks determined by diffuse reflectance infrared spectroscopy and chemometrics

Hydrogen peroxide – a promising oxidizer for rocket propulsion and its application in solid rocket propellants

Chemical additives used in papermaking fall into three groups—general (commodity) and two classes of specialty chemicals—process and functional. Process chemicals are used to optimize the production process by increasing machine speed, runnability, providing deposit control and reducing steam consumption. Retention aids, defoamers, fixative agents, biocides, and defoamers/antifoam additives are some typical examples of process chemicals. Functional chemicals directly affect paper quality and paper properties—color, water repellency, strength, printability, etc. Typical examples of such functional chemicals are dyes, coating binders, and strength and sizing additives. The boundary between process and functional chemicals is not very definite as process chemicals may either significantly influence performance of functional chemicals and/or affect sheet properties directly. About 90% of all chemical additives belong to functional additives. The remaining 10% are process chemicals, with retention aids (including fixatives, coagulants, flocculants and microparticles) representing the biggest and most important part. The in-depth and thorough coverage of chemical additives in the pulp and paper industry are presented. Various sections deal with pulping chemicals, bleaching chemicals, process chemicals, functional chemicals, pigments for fillers, coating pigments, aluminum, starch, chemicals used in paper recycling, and chemicals used for stickies control and tissue and towels.

Pulp and Paper Chemicals

The effects of bleaching of high-yield mechanical pulps (TMP, CTMP) with hydrogen peroxide under acidic and alkaline conditions were studied using different spectroscopic analytical methods. Diffuse reflectance laser flash photolysis (DRLFP) showed the differences in photochemical behavior reflecting transformation of chromophores upon treatment with acidic hydrogen peroxide. FT IR spectroscopic studies allowed to differentiate between the effects of the alkaline peroxide treatment with various stabilizing agents. FT-Raman technique provided additional information on localization of chemical changes after treatment under acidic and alkaline conditions, especially concerning the removal of coniferaldehyde-type groups.

Changes in chromophoric composition of high-yield mechanical pulps due to hydrogen peroxide bleaching under acidic and alkaline conditions

Research progress on design, synthesis and performance of energetic polynitro hexaazaisowurtzitane derivatives: towards improved CL-20 analogues

High energy density materials (HEDM) are the subject of an extensive research effort in relation to the use of these compounds as components of rocket propellants, powders, and formulations of high-performance explosives. Hexanitrohexaazaisowurtzitane (HNIW, i.e., CL-20) has received much attention in these research fields for its specific impulse, burning rate, ballistics, and detonation velocity. In this paper, the development and performances of the explosives from the first to the fourth generation are briefly summarized, and the synthesis status of the fourth-generation explosive, HNIW, is reviewed. The key issues that restrict the development of industrial amplification synthesis of HNIW are analyzed, and the potential directions of development are proposed. It is pointed out that to synthesize new and efficient catalysts is the key to making the cost-effective manufacturing of CL-20 a reality.

/pdf/research-progress-and-key-issues-of-hydrodebenzylation-of-2dlt656x.pdf

Research Progress and Key Issues of Hydrodebenzylation of Hexabenzylhexaazaisowurtzitane (HBIW) in the Synthesis of High Energy Density Material Hexanitrohexaazaisowurtzitane (HNIW)

The performance of phosphonates as additives in kraft pulping of aspen was investigated. Application of 0.1%-0.2% phosphonates in cooking resulted in consider able reduction in kappa number (4-8 points), while pulp yield was increased substantially. The bleaching responses of phosphonate treated pulps to DEDED and OPD sequences were significantly improved, allowing lower chemical application or higher final brightness. In addtion to enhanced lignin removal, the mproved bleachability is likely extended by an appreciable decrease in metal content of pulp fibers. Application: Kraft mills may be able to apply phosphonates as additives in the digester to achieve higher yield, shorter cooking times and better bleaching response.

Phosphonates as additives in kraft pulping - A preliminary investigation

Phosphonates as additives in kraft pulping

Fate of metal cations in the kraft pulping process modified by phosphonates

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Research Progress and Key Issues of Hydrodebenzylation of Hexabenzylhexaazaisowurtzitane (HBIW) in the Synthesis of High Energy Density Material Hexanitrohexaazaisowurtzitane (HNIW)

Phosphonates as additives in kraft pulping - A preliminary investigation

Phosphonates as additives in kraft pulping

Fate of metal cations in the kraft pulping process modified by phosphonates