scholarly journals The Mechanical Properties and Molecular Dynamics of Plant Cell Wall Polysaccharides Studied by Fourier-Transform Infrared Spectroscopy

2000 ◽  
Vol 124 (1) ◽  
pp. 397-406 ◽  
Author(s):  
Reginald H. Wilson ◽  
Andrew C. Smith ◽  
Marta Kačuráková ◽  
Paul K. Saunders ◽  
Nikolaus Wellner ◽  
...  
2010 ◽  
Vol 129-131 ◽  
pp. 837-841 ◽  
Author(s):  
Sheng Hua Lv ◽  
Yan Fen Ma ◽  
Rui Gong ◽  
Xiao Liang Yan ◽  
Ming Ming Hou

Degraded starch was reacted with 4-phenolsuflonate (PHS) in water in the presence of horseradish peroxidase (HRP) catalyst/H2O2/acetylacetone (ACAC) to give starch and PHS graft copolymers. The structure and properties of the graft copolymer are characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR). The retanned leather exhibits excellent increased thickness and softness, good dyeing ability and eligible mechanical properties.


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 268
Author(s):  
Carmen-Mihaela Popescu ◽  
Magdalena Broda

The goal of the study was to characterise chemical interactions between waterlogged archaeological wood and organosilicon compounds applied for its conservation to shed lights on the mechanism of wood dimensional stabilisation by the chemicals. Two alkoxysilanes (methyltrimethoxysilane and (3-mercaptopropyl) trimethoxysilane) and a siloxane (1,3-bis(diethylamino)-3-propoxypropanol)-1,1,3,3-tetramethyldisiloxane) were selected for the research since they already have been proven to effectively stabilise waterlogged wood upon drying. Fourier transform infrared spectroscopy was used for structural characterisation of the degraded wood and evaluation of reactivity of the applied chemicals with polymers in the wooden cell wall. The results obtained clearly show much stronger interactions in the case of alkoxysilanes than the siloxane, suggesting a different mechanism of wood stabilisation by these compounds. The results of this study together with other data obtained in our previous research on stabilisation of waterlogged archaeological wood with organosilicon compounds allow the conclusion that the mechanism of waterlogged wood stabilisation by the used alkoxysilanes is based on bulking the cell wall by silane molecules and wood chemical modification, while in the case of the applied siloxane, it builds upon filling the cell lumina.


The aim of this work is to study the influence of pro oxidant agents on the natural ageing of polypropylene (PP). For that purpose, two formulations containing, respectively, 5 wt % of Ca stearate and Ca/Zn complex as pro oxidant agents were prepared and exposed during 18 months to exterior natural conditions of Mediterranean climate. For comparison, a control formulation based only on PP was prepared. Samples were taken off every three months and characterized. The evolution of mechanical properties was followed by tensile test and Shore D hardness while the chemical modifications were analysed by Fourier transform infrared spectroscopy (FTIR). The results showed that all the considered formulations were affected but those containing the pro oxidant agents were the most affected. Moreover, Ca stearate is more effective than Ca/Zn complex as pro oxidant agent.


2021 ◽  
Vol 15 (5) ◽  
pp. 45
Author(s):  
Abeer Shmait ◽  
Nour El Ghouch ◽  
J. Al Boukhari ◽  
A. M. Abdel-Gaber ◽  
R. Awad

ZnO and ZnAl2O4 nanoparticles (NPs) were successfully prepared by the co-precipitation method and characterized by x-ray powder diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The prepared NPs were incorporated into epoxy (EP) coating with mass ratios 200  800 mg/kg of ZnO NPs/EP and ZnAl2O4 NPs /EP. The prepared coatings were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, and their mechanical properties were investigated, at room temperature, after 5, 10, 15, and 20 days of preparation. Tensile tests showed an improvement in the tensile properties, with the best improvement in ultimate tensile strength (93.2%) for 800 mg/kg ZnAl2O4 NPs/EP coating after 15 days of preparation. The ZnO NPs/EP and ZnAl2O4 NPs/EP coatings exhibited noticeable sensitivity to the stretching rate. Vickers microhardness (Hv) investigations showed normal indentation size effect behavior for all the samples. The best improvement in Hv was attained after 5 days of preparation, for all coatings, with the best improvement (9.15%) for 700 mg/kg ZnO NPs/EP.


2018 ◽  
Vol 37 (23) ◽  
pp. 1402-1417 ◽  
Author(s):  
M Bassyouni

The incorporation of sisal fiber as reinforcement materials for polymers will be advantageous if it is synthesized and manufactured perfectly. In this study, surface modification using polymeric diphenylmethane di-isocyanate and gamma-aminopropyltriethoxysilane was applied for further amelioration of polypropylene–sisal bonding. Surface morphology, thermomechanical properties, thermal stability, and chemical bonding were investigated using scanning electron microscopy, dynamic mechanical analysis, thermogravimetric analysis, and Fourier transform infrared spectroscopy, respectively. A number of mathematical models were studied for predicting the effect of untreated and modified sisal fiber loadings on the mechanical properties of biocomposites. Polymeric diphenylmethane di-isocyanate showed a significant improvement on the thermal and mechanical properties of polypropylene biocomposites. Fourier transform infrared spectroscopy analysis of polypropylene–sisal biocomposite showed the formation of urethane group at 3333 cm−1 in the presence of polymeric diphenylmethane di-isocyanate. Glass transition temperature of polypropylene–sisal was slightly increased to 6.8°C by chemical modification with polymeric diphenylmethane di-isocyanate. Yield strength of polypropylene–sisal (30 wt%) was enhanced by more than 50% with polymeric diphenylmethane di-isocyanate chemical treatment. Halpin–Tsai and Nielsen theoretical mathematical models showed a good agreement with experimental results of polypropylene–untreated sisal and polypropylene–treated sisal, respectively.


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