scholarly journals Utilization of enzymatic hydrolysate from corn stover as a precursor to synthesize an eco-friendly adhesive for plywood II: investigation of appropriate manufacturing conditions, curing behavior, and adhesion mechanism

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Zhongyuan Zhao ◽  
Di Wu ◽  
Caoxing Huang ◽  
Min Zhang ◽  
Kenji Umemura ◽  
...  
Keyword(s):  
Heating Temperature ◽  
National Standard ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Pyrolysis Gas ◽  
Adhesion Mechanism ◽  
Enzymatic Hydrolysate ◽  
Curing Behavior

AbstractIn this study, further research on an enzymatic hydrolysate-ammonium dihydrogen phosphate (EHADP) adhesive was carried out. Appropriate hot pressing conditions were clarified by measuring the bond strength of three-ply plywood bonded with EHADP adhesive, and the results indicated that the appropriate fabricate conditions were 170 °C and 5 min. The value of wet shear strength fulfilled the requirements of China National Standard GB/T 9846–2015 when plywood was fabricated by the appropriate conditions. In the research of curing behavior, the insoluble mass proportion promoted significantly as heating temperature and time were ≥ 170 °C and 5 min. Furthermore, a pyrolysis gas chromatography/mass spectrometry analysis indicated that adding ammonium dihydrogen phosphate (ADP) catalyzed the conversion of monosaccharides in the EHADP adhesive. The adhesion mechanism of the EHADP adhesive was studied by Fourier transform-infrared spectroscopy analysis, and the chemical changes indicated that the adhesion mechanism was attributed to both mechanical and chemical bonding between the wood elements and the cured EHADP adhesive.

scholarly journals Investigation of Synthesis Mechanism, Optimal Hot-Pressing Conditions, and Curing Behavior of Sucrose and Ammonium Dihydrogen Phosphate Adhesive

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 216 ◽  
Author(s):  
Zhongyuan Zhao ◽  
Shunsuke Sakai ◽  
Di Wu ◽  
Zhen Chen ◽  
Nan Zhu ◽  
...  
Keyword(s):  
Hot Pressing ◽  
Heating Time ◽  
National Standard ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Synthesis Mechanism ◽  
Pyrolysis Gas ◽  
Curing Behavior ◽  
Pressing Time ◽  
13C Nuclear Magnetic Resonance

In this study, a further investigation was carried out on the synthesis mechanism, optimal manufacturing conditions, and curing behavior of a sucrose-ammonium dihydrogen phosphate (SADP) adhesive. The results of 13C nuclear magnetic resonance (NMR) spectroscopy confirmed that SADP was composed of 5-hydroxymethylfurfural (5-HMF), deoxyfructosazine (DOF), amino compounds, Schiff base, monosaccharides, and oligosaccharide. The optimal hot-pressing conditions were a hot-pressing temperature of 170 °C, a hot-pressing time of 7 min, and a spread rate of 120 g/m2. The wet shear strength of plywood bonded at optimal manufacturing conditions met the requirements of China National Standard (GB/T 9846-2015). Thermal analysis and insoluble mass proportion measurements showed that the main curing behavior of the SADP adhesive occurred at curing temperatures higher than 145 °C, and more than 50% insoluble mass was formed when the heating time was longer than 5 min. Fourier-transform infrared spectroscopy (FT-IR) indicated that cross-linking of the cured adhesive was promoted by prolonging the heating time. In addition, pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) confirmed that the cured SADP adhesive was composed of furan and nitrogen-containing compounds.

scholarly journals Further Exploration of Sucrose–Citric Acid Adhesive: Investigation of Optimal Hot-Pressing Conditions for Plywood and Curing Behavior

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1996 ◽  
Author(s):  
Zhao ◽  
Sakai ◽  
Wu ◽  
Chen ◽  
Zhu ◽  
...  
Keyword(s):  
Citric Acid ◽  
Hot Pressing ◽  
Heating Temperature ◽  
National Standard ◽  
Endothermic Reaction ◽  
Spread Rate ◽  
Pressing Temperature ◽  
Pyrolysis Gas ◽  
Curing Behavior ◽  
Pressing Time

In previous research, sucrose and citric acid were used to synthesize an eco-friendlyplywood adhesive. Herein, further research was performed to determine the optimal hot-pressingconditions and curing behavior of a sucrose-citric acid (SC) adhesive. The results of dry and wetshear strength measurements showed that the optimal hot-pressing temperature, hot-pressing time,and spread rate of plywood samples bonded by the SC adhesive were 190 °C, 7 min, and 140 g/m2,respectively. When plywood was bonded at the optimal hot-pressing conditions, the wet shearstrength met the requirements of the China National Standard GB/T 9846-2015. Thermal analysisshowed that the thermal degradation and endothermic reaction temperatures of the SC 25/75adhesive were lower than either sucrose or citric acid individually. In addition, the insoluble massproportion increased with the heating temperature and time. The Pyrolysis Gas Chromatographyand Mass Spectrometr (Py-GC/MS) analysis confirmed that the SC adhesive was cured by thereaction between furan compounds, saccharide, and citric acid, and the resulting polymer appearedto be joined by ether linkages.

scholarly journals Long-term watershed management is an effective strategy to reduce organic matter export and disinfection by-product precursors in source water

2019 ◽  
Vol 28 (10) ◽  
pp. 804 ◽  
Author(s):  
Hamed Majidzadeh ◽  
Huan Chen ◽  
T. Adam Coates ◽  
Kuo-Pei Tsai ◽  
Christopher I. Olivares ◽  
...  
Keyword(s):  
Organic Matter ◽  
South Carolina ◽  
Watershed Management ◽  
Management Practices ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Long Term Effects ◽  
Pyrolysis Gas ◽  
Water Extracts

Watershed management practices such as prescribed fire, harvesting and understory mastication can alter the chemical composition and thickness of forest detritus, thus affecting the quantity and quality of riverine dissolved organic matter (DOM). Long-term effects of watershed management on DOM composition were examined through parallel field and extraction-based laboratory studies. The laboratory study was conducted using detritus samples collected from a pair of managed and unmanaged watersheds in South Carolina, USA. Results showed that dissolved organic carbon (DOC), total dissolved nitrogen (TDN) and ammonium (NH4+-N) concentrations were higher in water extracts from the unmanaged watershed than from the managed watershed (P<0.01). Pyrolysis gas chromatography–mass spectrometry analysis showed that water extracts from the unmanaged watershed contained more aromatic compounds than extracts from the managed watershed. For the field study, monthly water samples were collected for 1 year (2015) from the paired watersheds. DOC and TDN concentrations, as well as DOM aromaticity, were significantly higher in the unmanaged watershed than in the managed watershed for most of the year (P<0.05) and were linked to detrital thickness, precipitation and flow patterns. The formation potential of two regulated disinfection by-products was lower in the unmanaged watershed for most of 2015 (P<0.05). From this study, it appears that long-term watershed management practices may alter detrital mass and chemistry in ways that improve water quality.

TMAH-pyrolysis – gas chromatography – mass spectrometry analysis of residual lignin changes in softwood kraft pulp during oxygen delignification

2004 ◽  
Vol 82 (7) ◽  
pp. 1197-1202 ◽  
Author(s):  
Shiyu Fu ◽  
Lucian A Lucia
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Residual Lignin ◽  
Oxygen Delignification ◽  
Pyrolysis Gas ◽  
Spectrometry Analysis ◽  
Pyrolysis Gas Chromatography ◽  
Chromatography Mass Spectrometry

The residual lignins from pulps and effluent lignins from oxygen delignification effluents were characterized using pyrolysis – gas chromatography – mass spectrometry in the presence of tetramethylammonium hydroxide. The results indicated that oxidation under alkali oxygen conditions can induce fragmentation in lignin and produce more acid groups, but the lignin maintains most of its C6–C3 units. Oxygen delignification also led to a decrease in diphenyl structures in the residual lignin and an enrichment in concentration of lignin carbohydrate complex structures.Key words: residual lignin, pyrolysis, oxygen delignification.

Effect of Ammonium Dihydrogen Phosphate (ADP) Addition as Catalyst on the Curing Maltodextrin Adhesives Properties

2020 ◽  
Vol 840 ◽  
pp. 551-557
Author(s):  
Greitta Kusuma Dewi ◽  
Ragil Widyorini ◽  
Ganis Lukmandaru
Keyword(s):  
Heat Treatment ◽  
Water Resistance ◽  
Heating Temperature ◽  
High Water ◽  
Dihydrogen Phosphate ◽  
Ammonium Dihydrogen Phosphate ◽  
Ftir Analysis ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Endotherm Peak

Ammonium dihydrogen phosphate (ADP) is expected to be an effective catalyst to increase the water-resistance and hasten the curing speed of maltodextrin as wood adhesives. This research investigated the effect of ADP addition on the curing maltodextrin properties. The ratio of maltodextrin/ADP was 100/0 and 90/10 wt%. The heat treatment was 180-220 °C for 10 min. The water-resistance improvement and the chemical changes were analyzed using insoluble matter rate against boiling water and Fourier Transform Infrared (FTIR) analysis, respectively. The thermal behavior of the dried mixture of adhesives was also analyzed through differential scanning calorimetry (DSC) analysis at room temperature until 400 °C. The results showed that the water-resistance properties of maltodextrin increased with the addition of 10 wt% ADP and increasing the heating temperature. FTIR analysis detected a high water-resistant substance of furan in the adhesives with maltodextrin/ADP ratio 90/10 wt% and heat treatment of 220 °C for 10 min. DSC analysis showed that ADP addition can hasten the reaction of maltodextrin as the endotherm peak temperature was shifted from 272 to 204 °C.

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