Relationships between Moisture Content and Physical Properties of Korean Honeys

2010 ◽  
Vol 6 (6) ◽  
Author(s):  
Mi-Jung Kim ◽  
Jun-Hwan Oh ◽  
Byoungseung Yoo
Keyword(s):  
Glass Transition ◽  
Moisture Content ◽  
Loss Modulus ◽  
Thermal Characteristics ◽  
Small Deformation ◽  
Rheological Parameters ◽  
Subzero Temperature ◽  
Physical Parameters ◽  
Transition Temperatures ◽  
Glass Transition Temperatures

Dynamic rheological and thermal characteristics of ten Korean acacia honeys with different moisture contents (18.4 to 20.4 percent) were evaluated as a function of moisture content using both a controlled stress rheometer for small-deformation oscillatory measurements and a differential scanning calorimeter (DSC). The honey samples displayed a liquid-like behavior at a subzero temperature (-5°C) with loss modulus (G") predominating over storage modulus (G'), showing a high dependence on frequency. Plots of dynamic moduli (G' and G") and complex viscosity (?*) versus moisture content gave better exponential relationships (R2 = 0.95-0.97) than the tan delta values (R2 = 0.89). Glass transition temperatures at onset (To) showed a better linear relationship (R2 = 0.87) with moisture content compared to those at midpoint (Tm) (R2 = 0.84) and endpoint (Te) (R2 = 0.81). The dynamic rheological parameters more closely correlated with moisture content as compared to the glass transition temperatures, indicating that dynamic rheological measurements at a subzero temperature are better physical parameters to estimate the quality of honeys.

Glass Transition Temperature, Mechanical Properties of Rice and their Relationships with Milling Quality

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Kobra Tajaddodi Talab ◽  
Mohd. Nordin Ibrahim ◽  
Sergey Spotar ◽  
Rosnita A. Talib ◽  
Kharidah Muhammad
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Moisture Content ◽  
Bending Strength ◽  
Bending Test ◽  
Transition Line ◽  
Transition Temperatures ◽  
Drying Process ◽  
Glass Transition Temperatures ◽  
Grain Moisture

Abstract Glass transition temperatures (Tg) of MR219 rice variety were measured by differential scanning calorimeter (DSC). State diagram was developed and used to evaluate drying process in this study. Glass transition temperatures range of 9.65- 61.79°C were observed for gains with moisture content of 26.8 – 7.4% (w.b.). For mechanical properties and milling test, statistical analysis was performed by using a two factor experiment in completely randomized design (CRD). Two selected factors were drying temperatures at 5 levels (40, 45, 50, 55, and 60°C) and final moisture content (FMC) at 4 levels (10-10.5, 11-11.5, 12-12.5 and 13-13.5%). Three–point bending test was applied to measure the mechanical properties of rice kernel. Generally, bending strength, apparent modulus of elasticity and fracture energy of brown rice kernel increased with decreasing the grain moisture content. Maximum bending strength was 35.69 and 33.64 MPa for 55, and 60°C, respectively. All samples that were dried at 55 and 60°C experienced to go through the glass transition line after reaching their temperature to the room temperature at the end of drying process. The effect of drying temperature, paddy FMC and their interactions on whole kernel percentage (WKP) and mechanical properties were significant (α = 0.05). An inverse relationship was observed between WKP and the percentage of strong kernels for all treatments.

MULTIPLE GLASS TRANSITION TERPOLYMERS OF ISOPRENE, BUTADIENE, AND STYRENE

2010 ◽  
Vol 83 (4) ◽  
pp. 380-390 ◽  
Author(s):  
Adel F. Halasa ◽  
Bill B. Gross ◽  
Wen-Liang Hsu
Keyword(s):  
Glass Transition ◽  
Loss Modulus ◽  
Rolling Resistance ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Transition Temperatures ◽  
Wear Properties ◽  
Glass Transition Temperatures ◽  
The One ◽  
Butadiene Styrene

Abstract Novel polymers that will contribute to a better combination of traction and tread wear in tire applications, which is historically difficult to achieve, have been developed. In this work, multiple viscoelastic polymers possessing multiple glass transition temperatures terpolymers of isoprene/butadiene/styrene were synthesized containing 45/45/10, 40/40/20, and 35/35/30 polymer ratios in 5-gallon laboratory reactors using tetramethylethylenediamine or bis(dipiperdino) ethane as a modifier. These polymers show two glass transition temperatures (Tg's); the one that occurs at higher temperatures (–25 to –10 °C) is known to contribute to good wet traction properties, while the lower Tg is known to contribute to better tread wear properties. These terpolymers were characterized by the fact that their multiviscoelastic loss modulus has narrow molecular distribution for better rolling resistance. In a standard ASTM D31912 carbon-black-filled tread compound recipe, the polymers having all three terpolymers of isoprene/butadiene/styrene polymerized showed excellent values of loss tangent at 0 and 60 ºC, which is a laboratory predictor for both wet traction and rolling resistance. These terpolymers when evaluated in the same ASTM D3191 delivered better properties in a tread compound recipe than either solution or emulsion styrene-butadiene rubber in a formulation that has natural rubber or polybutadiene.

Properties of Random PSF/PES Copolymers as High-Performance Polymers

2011 ◽  
Vol 217-218 ◽  
pp. 1606-1610
Author(s):  
Dong Jiang ◽  
Xiao Ran Zhang ◽  
Yan Mei Ma ◽  
Cheng You Ma
Keyword(s):  
Weight Loss ◽  
Tensile Strength ◽  
Glass Transition ◽  
High Performance ◽  
Molar Ratio ◽  
Transition Temperatures ◽  
Elongation At Break ◽  
Glass Transition Temperatures ◽  
High Performance Polymers ◽  
Diphenyl Sulfone

A series of random polysulfone/polyethersulfone (PSF/PES) copolymers were synthesized by the polycondensation of 4, 4'-isopropylidendiphenol, 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-dichlorodiphenyl sulfone in the presence of K2CO3. We obtained a series of copolymers by changing the molar ratio of 4, 4΄-dihyolroxy diphenyl sulfone and 4, 4'-isopropylidendiphenol (it was marked as the ratio of S:A). The copolymers have the similar solubility with polyethersulfone. They also have high glass transition temperatures (Tg: 199°C~229°C) and 5% weight loss temperatures (4, 4'-isopropylidendiphenol: 4, 4΄-dihyolroxy diphenyl sulfone=1:1, Td5=497°C). At the same time the elongation at break is much higher than that of PES, while the tensile strength is a little lower than that of PES.

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