Glass transition temperature of polybutadiene and polyisoprene from high temperature segmental relaxation correlation using molecular dynamics

The article presents results of studies of experimental carbon plastics based on thermosetting PMRpolyimide binder. Сarbon fiber reinforced plastics (CFRPs) are made from prepregs prepared by melt and mortar technologies, so the rheological properties of the polyimide binder were investigated. The heat resistance of carbon plastics was researched and its elastic-strength characteristics were determined at temperatures up to 320°С. The fundamental possibility of manufacturing carbon fiber from prepregs based on polyimide binder, obtained both by melt and mortar technologies, is shown. CFRPs made from two types of prepregs have a high glass transition temperature: 364°C (melt) and 367°C (solution), with this temperature remaining at the 97% level after boiling, and also at approximately the same (86–97%) level of conservation of elastic strength properties at temperature 300°С.

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Viscoelastic Behavior of Segmented Elastomers

Rubber Chemistry and Technology ◽

10.5254/1.3539120 ◽

1967 ◽

Vol 40 (4) ◽

pp. 1105-1110 ◽

Cited By ~ 1

Author(s):

Stuart L. Cooper ◽

Arthur V. Tobolsky

Keyword(s):

Hydrogen Bonding ◽

Glass Transition ◽

High Temperature ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Viscoelastic Behavior ◽

Temperature Transition ◽

Hydrogen Bonding Interactions ◽

Structural Nature ◽

Hard Segments

Abstract Viscoelastic behavior of linear segmented elastomers was examined. The unusual properties found in spandex systems are also observable in hydrocarbon block co-polymers, indicating that hydrogen bonding interactions are perhaps not essential. Low temperature properties of segmented systems are governed by the structural nature of the associated flexible segments, which determines the value of the major glass transition temperature (Tg). It appears that an association of the hard segments provides a broad temperature range of enhanced rubbery modulus. This occurs between the major Tg and a secondary high temperature transition.

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Experimental Research on Mechanical Behavior of GFRP Bars under High Temperature

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.3591 ◽

2011 ◽

Vol 71-78 ◽

pp. 3591-3594 ◽

Cited By ~ 6

Author(s):

Xiao Lu Wang ◽

Xiao Xiong Zha

Keyword(s):

Glass Transition ◽

High Temperature ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Epoxy Resin ◽

High Temperatures ◽

Glass Fibers ◽

Ultimate Tensile Stress ◽

Gfrp Bars ◽

Tensile Test Result

Experimental results on tensile mechanics properties of GFRP bars at high temperatures are present in this paper. Thirty commercially produced GFRP tensile specimens of 8mm diameter were tested at high temperature ranging from 10°Cup to 500°C. Tensile test result indicates that, the ultimate tensile stress has significant reduction at two temperature zones, one is glass transition temperature of epoxy resin (80-120°C), with strength degradation 22%, the second is the soften temperature of glass fibers(about 400°C), the strength decrease drastically with almost linear rate and remained 33% residual strength at 500°C. The elastic modulus remained unchanged until glass transition temperature of epoxy resin, and the modulus declined linearly with the temperature elevating. Stress-strain relationships of GFRP bars exhibit liner performance even at high temperatures.

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Influence of Carbon Nanotube Aspect Ratio on Glass Transition Temperature of Polymers: A Molecular Dynamics Simulation Study

Materials Science Forum ◽

10.4028/www.scientific.net/msf.817.797 ◽

2015 ◽

Vol 817 ◽

pp. 797-802 ◽

Cited By ~ 2

Author(s):

Cai Jiang ◽

Jian Wei Zhang ◽

Shao Feng Lin ◽

Su Ju ◽

Da Zhi Jiang

Keyword(s):

Molecular Dynamics ◽

Glass Transition ◽

Carbon Nanotube ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Aspect Ratio ◽

Epoxy Resin ◽

Md Simulations ◽

Diglycidyl Ether ◽

Dynamics Simulation

Molecular dynamics (MD) simulations on three single walled carbon nanotube (SWCNT) reinforced epoxy resin composites were conducted to study the influence of SWCNT type on the glass transition temperature (Tg) of the composites. The composite matrix is cross-linked epoxy resin based on the epoxy monomers bisphenol A diglycidyl ether (DGEBA) cured by diaminodiphenylmethane (DDM). MD simulations of NPT (constant number of particles, constant pressure and constant temperature) dynamics were carried out to obtain density as a function of temperature for each composite system. The Tg was determined as the temperature corresponding to the discontinuity of plot slopes of the densityvsthe temperature. In order to understand the motion of polymer chain segments above and below the Tg, various energy components and the MSD at various temperatures of the composites were investigated and their roles played in the glass transition process were analyzed. The results show that the Tg of the composites increases with increasing aspect ratio of the embedded SWCNT

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