Sensitivity to the physical and chemical structure of hard-segment-reinforced polyurethane elastomers with variable percentage of hydrogen bonding

2011 ◽  
Vol 122 (6) ◽  
pp. 3544-3550 ◽  
Author(s):  
C. Prisacariu ◽  
E. Scortanu
Keyword(s):  
Hydrogen Bonding ◽  
Chemical Structure ◽  
Hard Segment ◽  
Polyurethane Elastomers ◽  
Physical And Chemical

scholarly journals Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1801
Author(s):  
Rafał Oliwa ◽  
Joanna Ryszkowska ◽  
Mariusz Oleksy ◽  
Monika Auguścik-Królikowska ◽  
Małgorzata Gzik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Structure ◽  
Oxygen Index ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Ftir Analysis ◽  
Limiting Oxygen Index ◽  
Peak Heat Release Rate ◽  
Physical And Chemical ◽  
Scanning Electron

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this composite was characterized by the highest char yield (m600 = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.

scholarly journals Analysis of oxidation degree of graphite oxide and chemical structure of corresponding reduced graphite oxide by selecting different-sized original graphite

RSC Advances ◽  
2018 ◽  
Vol 8 (31) ◽  
pp. 17209-17217 ◽  
Author(s):  
Lu Shen ◽  
Lihua Zhang ◽  
Kui Wang ◽  
Lijing Miao ◽  
Qiaofeng Lan ◽  
...  
Keyword(s):  
Graphite Oxide ◽  
Chemical Structure ◽  
Chemical Properties ◽  
Thermal Reduction ◽  
Physical And Chemical Properties ◽  
Oxidation Degree ◽  
Reduced Graphite Oxide ◽  
Physical And Chemical ◽  
And Chemical Properties

The thermal reduction of GO is the most commonly used strategy for preparation of rGO, and the oxidation degree of GO would influence the chemical structure of prepared rGO, thereby affecting its physical and chemical properties.

Investigation of the physical and chemical structure of NSC from sucrose

2022 ◽  
pp. 1-9
Author(s):  
Jingguang Liu ◽  
Shao Luo ◽  
Hao Yang ◽  
Yanzhi Tao ◽  
Guangzai Nong
Keyword(s):  
Chemical Structure ◽  
Physical And Chemical

Spatial and Temporal Variability of Surface Snowfall and Snowpack Chemistry in Central Ontario

1985 ◽  
Vol 7 ◽  
pp. 185-190 ◽  
Author(s):  
R.S. Schemenauer ◽  
P.W. Summers ◽  
H.A. Wiebe ◽  
K.G. Anlauf
Keyword(s):  
Chemical Composition ◽  
Chemical Structure ◽  
Precipitation Chemistry ◽  
Spatial And Temporal Variability ◽  
Vertical Variation ◽  
Ph Values ◽  
Pollutant Concentrations ◽  
The One ◽  
Physical And Chemical ◽  
Annual Deposition

The physical and chemical structure of the snowpack near North Bay, Ontario was examined during the winter of 1984. precipitation chemistry measurements were also made. A marked areal uniformity was noted in the layered structure of the snowpack and in the vertical variation of the chemical composition. In late January, pH values of the snowpack varied from ∼4.1 at the surface to ∼4.8 near the ground. After rain and a major thaw in February the pH was near 4.8 throughout. Nitrate concentrations exceeded those of sulfate in the snowpack. The molar concentration ratio of / was typically 0.5. Samples of precipitation from six sites had pH values ranging from 3.4 to 5.2. to equivalent ratios were <1 in snow and near 1 or >1 in rain. The chemical composition of the precipitation was closely related to the airmass trajectory. Southerly trajectories yielded the lowest pH values and highest pollutant concentrations. The one-month period from 20 January to 21 February had a deposition of 0.2 g m−2 and a deposition of 0.35 g m−2. For , this deposition would be about one-twelfth the expected annual deposition and for about one-fifth.

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