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.

Sulfonated Polystyrene Ionomers Neutralized with Mixtures of Various Cations Studied by Dynamic Mechanical and Small-Angle X-Ray Scattering Techniques

2003 ◽  
Vol 778 ◽  
Author(s):  
Ho Seung Jeon ◽  
Ju-Myung Song ◽  
Joon-Seop Kim
Keyword(s):  
Glass Transition ◽  
Dynamic Mechanical Properties ◽  
The Other ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Dynamic Mechanical ◽  
The Matrix ◽  
Cluster Phase ◽  
The One ◽  
Zinc Cations

AbstractThe effects of the addition of mixed cations, i.e. Na+/Cs+, Ba2+/Cs+, and Ba2+/Zn2+, to the acid form sulfonated styrene copolymers on their dynamic mechanical properties and morphology were investigated. It was found that the matrix glass transition temperatures did not change with the ratio of the one cation to the other. As expected, however, the ratio of one cation to the other in the mixed cations affected cluster glass transition temperatures significantly. It was also found that the activation energies for the glass transitions for the matrix phase remained constant, while those for the cluster phase changed with the ratio of the two cations. In addition, the position of the SAXS peak was found to be affected by the type of cations. From the results obtained above, the decrease in the cluster Tg with increasing the amount of cesium and zinc cations in Na/Cs, Ba/ Cs, and Ba/Zn mixtures, were explained on the basis of the considerations of the size, charge, and type of cations, which alter the degree of clustering as well as ion-hopping mechanism.

LC Polyimides 29. Non-Crystalline Cholesteric Copoly(Ester-Imide)s Derived from Adipic Acid and Isosorbide

1997 ◽  
Vol 9 (2) ◽  
pp. 91-104 ◽  
Author(s):  
Hans R Kricheldorf ◽  
Thorsten Krawinkel
Keyword(s):  
Glass Transition ◽  
Adipic Acid ◽  
The Other ◽  
Molar Ratio ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Molar Ratios ◽  
Melting Temperatures ◽  
Low Concentrations ◽  
The One

Numerous cholesteric copoly(ester-imide)s were prepared from mixtures of isosorbide and tert.-buthylhydroquinone (or other diphenols), on the one hand, and mixtures of adipoylchloride and N-(4-chlorocarbonylphenyl) trimellitimide chloride on the other. When the molar ratio of isosorbide/diphenol was varied, Grandjean textures were only observed for low concentrations of isosorbide (5/95 or 10/90). In the case of adipoylchloride/imide dichloride molar ratios of 30/70–50/50 favoured the formation of Grandjean textures. Most copoly(esterimide)s were non-crystalline with glass transition temperatures ( Tgs) between 90 and 190 °C. In several cases the Grandjean textures were frozen in by cooling below Tg. Such copoly(esterimide)s may be useful as pigments. All copoly(ester-imide)s containing methylhydroquinone were semicrystalline with melting temperatures in the range of 240–270 °C.

LC Polyimides 30. Non-Crystalline Cholesteric Poly(Ester-Imide)s Based on Isosorbide and 1, 6-Bis(4-Carboxyphenoxy)Hexane

1997 ◽  
Vol 9 (2) ◽  
pp. 105-120 ◽  
Author(s):  
Hans R Kricheldorf ◽  
Thorsten Krawinkel
Keyword(s):  
Glass Transition ◽  
Dicarboxylic Acid ◽  
The Other ◽  
Molar Ratio ◽  
Transition Temperatures ◽  
Acid Chlorides ◽  
Glass Transition Temperatures ◽  
The One

Numerous cholesteric copoly(ester-imide)s were prepared from tert.-butylhydroquinone and isosorbide, on the one hand, and from the acid chlorides of N-(4-carboxyphenyl)trimellitimide and 1, 6-bis(4-carboxyphenoxy)hexane on the other. Two polycondensation methods were applied and compared. The molar ratio of the diols was varied and also the molar ratio of hot dicarboxylic acid chlorides. The copoly(ester-imide)s formed Grandjean textures with a low content (5–10 mol%) of isosorbide and relatively high content of the flexible dicarboxylic acid. The glass transition temperatures ( Tgs) varied in the range of 160–180 °C.

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.

Effect of Carbon Black Structures towards Heat Build-Up Measurements and its Dynamic Properties

2015 ◽  
Vol 1134 ◽  
pp. 131-137 ◽  
Author(s):  
Mohd Ismail Rifdi Rizuan ◽  
Mohammad Azizol Abdul Wahab ◽  
Ahmad Zafir Romli
Keyword(s):  
Carbon Black ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Rolling Resistance ◽  
Testing Procedure ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
High Carbon ◽  
Heat Build Up ◽  
Styrene Butadiene

The aim of this study is to investigate the effect of different carbon black structures towards heat build-up measurements and its dynamic properties such as tangent delta, loss modulus and storage modulus on the industrial rubber compounds containing Natural Rubber (NR) and Styrene Butadiene Rubber (SBR). Different carbon black structures were used and characterised with respect to their rheological and physical properties. Heat Build-up test is a testing procedure which is used to measure the rate of heat generated by the rubber vulcanisates when subjected to rapidly oscillating compressive stresses or strain under controlled conditions. It was found that NR compound containing low and high carbon black structures; N375 and N339 produced lower heat generation compared to NR/SBR blends that filled with the same type of carbon black fillers. It shows that NR with low and high carbon black structures exhibits low heat build-up (surface and intrinsic) with a balance of good traction and low rolling resistance for application in tyre.

INTERPRETATION OF THE TANδ PEAK HEIGHT FOR PARTICLE-FILLED RUBBER AND POLYMER NANOCOMPOSITES WITH RELEVANCE TO TIRE TREAD PERFORMANCE BALANCE

2018 ◽  
Vol 91 (3) ◽  
pp. 577-594 ◽  
Author(s):  
Nuthathai Warasitthinon ◽  
Christopher G. Robertson
Keyword(s):  
Glass Transition ◽  
Polymer Nanocomposites ◽  
Volume Fraction ◽  
Loss Modulus ◽  
Viscoelastic Model ◽  
Peak Height ◽  
Dynamic Strain ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Filled Rubber

ABSTRACT The aim of this research is to clarify the meaning of the peak height for the viscoelastic loss tangent (tanδ) in the glass transition region of particle-filled rubber, polymer nanocomposites, and polymer systems in general. Filler, oil, and curative loadings were systematically varied in a model styrene-butadiene rubber formulation with carbon black as the reinforcing filler. The dynamic mechanical responses of these compounds enabled a detailed study of the glass-to-rubber softening transition, which is known to play an important role with respect to the balance of traction, handling, and rolling resistance characteristics of tire treads. From the temperature-dependent viscoelastic results that were acquired at fixed frequency and small dynamic strain, it was demonstrated that a higher peak value for tanδ was correlated with a lower dynamic modulus in the rubbery state. Adjusting filler volume fraction was found to be an effective way of changing the rubbery modulus and hence the tanδ peak height. It was furthermore verified that such a correlation is a universal material-independent viscoelastic effect by mathematically producing a similar trend by varying the rubbery modulus parameter in the Havriliak–Negami viscoelastic model. This investigation also showed why glass transition temperature should be determined from the position of the loss modulus peak and not the tanδ peak. Cure behavior, tensile stress–strain properties, and extent of filler networking (Payne effect) for these rubber compounds will additionally be discussed.

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