Chemical Modification of Wood by Polyglycerol/Maleic Anhydride Treatment

Holzforschung ◽  
2001 ◽  
Vol 55 (1) ◽  
pp. 57-62 ◽  
Author(s):  
C. Roussel ◽  
V. Marchetti ◽  
A. Lemor ◽  
E. Wozniak ◽  
B. Loubinoux ◽  
...  
Keyword(s):  
Maleic Anhydride ◽  
Chemical Modification ◽  
Aqueous Solutions ◽  
Dimensional Stability ◽  
Treated Wood ◽  
Solid Wood ◽  
Reaction Conditions ◽  
Biological Resistance ◽  
Long Time ◽  
And Performance

Summary Polyglycerol (PG), an agricultural by-product of diester industry, was reacted with maleic anhydride (MA) to give heat curable compounds which are useful for impregnating wood to improve biological resistance, dimensional stability and strength. The relationships between reaction conditions of polyglycerol/maleic anhydride (PG/MA) adduct treatment and performance of treated solid wood were investigated. Conditions recommended for producing PG/MA treated wood durable for a long time are vacuum/pressure impregnation of aqueous solutions of PG/MA adduct (30%) in the presence of 2-butanone peroxide (2%) and cobalt naphthenate (2%).

Evaluation of water related properties of birch wood products modified with different molecular weight phenol-formaldehyde oligomers

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Juris Grinins ◽  
Vladimirs Biziks ◽  
Janis Rizikovs ◽  
Ilze Irbe ◽  
Holger Militz
Keyword(s):  
Molecular Weight ◽  
Dimensional Stability ◽  
Phenol Formaldehyde ◽  
Treated Wood ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Solid Wood ◽  
Wood Products ◽  
Birch Wood ◽  
Molecular Weights

Abstract This study investigated the effect of phenol-formaldehyde (PF) resin treatment on the dimensional stability of birch solid wood and plywood. Therefore, three different low molecular weight PF resins with average molecular weights (M w ) of 292, 528, and 884 g/mol were synthesized and used for silver birch (Betula pendula) solid wood (20 × 20 × 20 mm3) and veneer (100 × 100 × 1.4 and 300 × 300 × 1.4 mm3) impregnation to produce plywood. The weight percent gain (WPG) and bulking after curing of resin treated wood specimens were determined. The leaching was performed to evaluate the PF resin fixation stability. All tested resins at all concentrations were similarly fixed in wood blocks after the leaching (1.5–2.0% WPG loss). The dimensional stability of birch wood after treatment with all tested PF resins was significantly improved. The anti-swelling efficiency (ASE) of birch wood blocks treated with PF resins after seven water soaking-drying cycles was in the range of 39–53%, 46–65% and 49–65% using 10, 15 and 20% solution concentrations, respectively. Whereas, the ASE of plywood obtained from veneers treated with 10% of PF solution was improved by 6–20%. The equilibrium moisture content (EMC) and volumetric swelling (VS) of PF treated plywood at 98% of relative humidity (RH) decreased significantly. All PF resin treated plywood surfaces were more hydrophobic compared to untreated plywood.

scholarly journals Dimensional stabilisation of Scots pine (Pinus sylvestris L.) sapwood by reaction with maleic anhydride and sodium hypophosphite

2021 ◽  
Author(s):  
Injeong Kim ◽  
Olov Karlsson ◽  
Dennis Jones ◽  
George Mantanis ◽  
Dick Sandberg
Keyword(s):  
Maleic Anhydride ◽  
Chemical Modification ◽  
Scots Pine ◽  
Dimensional Stability ◽  
Hydrolytic Stability ◽  
Treatment Temperature ◽  
Sodium Hypophosphite ◽  
Cross Linking ◽  
High Concentration ◽  
Weight Percentage

AbstractWood has the ability to absorb and desorb moisture, which can affect its dimensional size when in use. Limiting this can provide products with greater shape stability and less stresses on external coatings. One method that has been investigated for achieving this has been through chemical modification. In this work, the dimensional stabilisation imparted to Scots pine sapwood by chemical modification with maleic anhydride (MA) combined with sodium hypophosphite (SHP) was investigated. The influence of concentration of MA, treatment temperature and treatment period on weight percent gain (WPG) and bulking coefficient (BC) during treatment with MA and SHP of wood was studied. Furthermore, dimensional stability was determined by the water soak/oven dry method (wet-dry cycle) through five cycles in order to determine the hydrolytic stability of the ester bond and any potential cross-linking reactions. Wood blocks (20 × 20 × 10 mm) modified with MA combined with SHP exhibited lower weight loss following water soaking than unmodified blocks or MA-treated blocks. Wood blocks modified with MA and SHP showed the best anti-swelling efficiency and minimum wet-volume (water-saturated). However, as the concentration of SHP increased, dimensional stability was diminished without any increase in weight percentage gain after water soaking. When combined with FTIR results, it appeared that the modification with MA and SHP seemed to form cross-linking between wood constituents, though high concentration of SHP did not seem to result in additional cross-linking.

The 14th Annual AMSE Conference

1988 ◽  
Vol 5 (2) ◽  
pp. 311
Author(s):  
Mozaffar Partowmah
Keyword(s):  
North America ◽  
Nuclear Physics ◽  
Agricultural Research ◽  
Social Scientists ◽  
Electronic Engineering ◽  
Student Paper ◽  
Long Time ◽  
Continuous Support ◽  
And Performance ◽  
Sizable Number

The 14th Annual Conferknce of the Association of Muslim Scientistsand Engineers (ASME) was held during the weekend of qufur 2628,1409/0ctober 7-9, 1988, at the Islamic Center of North America in Plainfield,Indiana. Papers presented at the Conference dealt with a variety of subjectsranging from agriculture and health sciences to car manufacturing tips,computers, industrial, civil and electronic engineering, as well as resourcemanagement and organizational behavior.Members of the AMSS (Association of Muslim Social Scientists) whoattended the AMSE Conference, participated in the sessions with undividedattention. Dr. AbdulHamid AbuSulayman, the AMSS President, in his banquetspeech, stressed the need for an active AMSE that will eventually attracta more sizable number of Muslims in North America and coordinate theirscientific efforts for their common benefit.In a session entitled “Technology Transfer,” the Japanese and Koreanapproaches were contrasted with the Muslim world approach. A highlightof the Conference was the announcement of the A1 Khwarazmi Award thatthe AMSE will award annually to a distinguished Muslim scientist or engineer.The first Al Khwarazmi Award went to Dr. M.A.K. Lodhi of Texas A&MUniversity in appreciation of his continuous support for Muslim studentsand his long-time involvement in the AMSE in addition to his scientific interestand achievements in nuclear physics and field theory.The Best Student Paper Award went to the following: 1) Abdullah M.Elramsisi of Rochester Hill, Michigan for his paper “On Model-based ImageRestoration and Performance Evaluation;” and 2) Khatib Rajab of Morgantown,West Virginia for his paper on “Agricultural Research Needs and Prioritiesin Zanzibar as perceived by Administrators and Extension Workers.”Copies of all of the presented papers were distributed at the Conferenceand will be ppblished in the conference proceedings. Preprints and reprintsmay be obtained by writing to the AMSE office at P.O. Box 38, Plainfield,Indianna, 46168 ...

Study of Chemical Modification of Some Starch Using the Amylographic Method

2008 ◽  
Vol 59 (1) ◽  
pp. 70-73
Author(s):  
Mihai Leonte ◽  
Traian Florea
Keyword(s):  
Chemical Modification ◽  
Heterogeneous Medium ◽  
Reaction Conditions

The amyl graphic behaviour for products like carboxymetil starch obtained in different reaction conditions was looked into. The procedure specific feature is the chemical modification that takes place in a heterogeneous medium though the reaction of the reactant starch particle in indestructible conditions.

Effects of salts on the kinetics of oxidation of alkenes by thallic salts in aqueous solutions

1981 ◽  
Vol 46 (3) ◽  
pp. 693-700 ◽  
Author(s):  
Milan Strašák ◽  
Jaroslav Majer
Keyword(s):  
Aqueous Solutions ◽  
Phase Transfer ◽  
Heterogeneous Reaction ◽  
Qualitative Model ◽  
Kinetic Effect ◽  
Tetraalkylammonium Salts ◽  
Reaction Conditions ◽  
Kinetics Of Oxidation ◽  
Kinetics Of ◽  
Heterogeneous Reaction Conditions

The kinetics of oxidation of alkenes by thallic sulphate in aqueous solutions, involving the two reaction steps-the hydroxythallation and the dethallation - was studied, and the effect of salts on the kinetics was examined; this made it possible to specify more precisely the reaction mechanism and to suggest a qualitative model of the reaction coordinate. It was found that in homogeneous as well as in heterogeneous reaction conditions, the reaction can be accelerated appreciably by adding tetraalkylammonium salts. These salts not only operate as catalysts of the phase transfer, but also exert a significant kinetic effect, which can be explained with a simplification in terms of a stabilization of the transition state of the reaction.

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

scholarly journals On Performance of Sparse Fast Fourier Transform Algorithms Using the Aliasing Filter

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1117
Author(s):  
Bin Li ◽  
Zhikang Jiang ◽  
Jie Chen
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
High Efficiency ◽  
Theory And Practice ◽  
Long Time ◽  
And Performance ◽  
Binary Tree Search ◽  
The One ◽  
Sparse Fast Fourier Transform ◽  
L1 And L2

Computing the sparse fast Fourier transform (sFFT) has emerged as a critical topic for a long time because of its high efficiency and wide practicability. More than twenty different sFFT algorithms compute discrete Fourier transform (DFT) by their unique methods so far. In order to use them properly, the urgent topic of great concern is how to analyze and evaluate the performance of these algorithms in theory and practice. This paper mainly discusses the technology and performance of sFFT algorithms using the aliasing filter. In the first part, the paper introduces the three frameworks: the one-shot framework based on the compressed sensing (CS) solver, the peeling framework based on the bipartite graph and the iterative framework based on the binary tree search. Then, we obtain the conclusion of the performance of six corresponding algorithms: the sFFT-DT1.0, sFFT-DT2.0, sFFT-DT3.0, FFAST, R-FFAST, and DSFFT algorithms in theory. In the second part, we make two categories of experiments for computing the signals of different SNRs, different lengths, and different sparsities by a standard testing platform and record the run time, the percentage of the signal sampled, and the L0, L1, and L2 errors both in the exactly sparse case and the general sparse case. The results of these performance analyses are our guide to optimize these algorithms and use them selectively.

Gas phase oxidation of furfural to maleic anhydride on V 2 O 5 /γ-Al 2 O 3 catalysts: Reaction conditions to slow down the deactivation

2017 ◽  
Vol 348 ◽  
pp. 265-275 ◽  
Author(s):  
N. Alonso-Fagúndez ◽  
M. Ojeda ◽  
R. Mariscal ◽  
J.L.G. Fierro ◽  
M. López Granados
Keyword(s):  
Maleic Anhydride ◽  
Gas Phase ◽  
Reaction Conditions ◽  
Phase Oxidation ◽  
Gas Phase Oxidation
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