Effect of Adsorption on Reinforcement of Filled Polyurethane

1977 ◽  
Vol 50 (2) ◽  
pp. 333-341 ◽  
Author(s):  
J. Seto
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Physical Adsorption ◽  
Random Coil ◽  
Chain Formation ◽  
Network Chain ◽  
Effective Network

Abstract The effective network chains, ns formed at the polyurethane-particle interface are brought about by physical adsorption of the polymer from solution. The relation between ns and adsorption, Γs, is given as Equation (3). The coefficient K is evaluated as 10. This value supports multicontact adsorption and agrees with random coil dimensions. The pretreating of powder by a surfactant (oleate) brings about neither adsorption nor network chain formation. The glass transition temperature increases with increasing amount of adsorption.

The role of molecular volume and the shape of the hole transport molecule in the morphology of model charge transport composites

2010 ◽  
Vol 88 (3) ◽  
pp. 247-259 ◽  
Author(s):  
Ferdous Khan ◽  
Shalini Khanna ◽  
Ah-Mee Hor ◽  
P. R. Sundararajan
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Charge Transport ◽  
Small Molecules ◽  
Small Molecule ◽  
Hole Transport ◽  
Random Coil ◽  
Molecular Volume ◽  
Van Der Waals Volume

We present a study of the morphology and molecular interactions in a model charge transport composite with 1,1-bis(di-4-tolylaminophenyl) cyclohexane (TAPC) as the hole transport molecule in bisphenol-A polycarbonate (BPAPC) and cyclohexyl polycarbonate, also known as bisphenol-Z polycarbonate (PCZ). Solution NMR shows that while there is aromatic interaction between the phenyl groups of the polycarbonate and TAPC, the broadening of the peaks corresponding to the latter indicates a decrease in the rotational motion. FTIR spectroscopy also exhibits frequency shifts of the aromatic C–H absorption peaks, which parallels the extent of the depression of the glass transition temperature (Tg) of the polycarbonate. These are compared with the previous results for N,N-diphenyl-N,N-bis(3-methylphenyl)-[1,1-biphenyl]-4,4-diamine (TPD) and tri-p-tolylamine (TTA), and the differences are rationalized on the basis of the molecular shape and van der Waals volume of the small molecules. It is proposed that when the polycarbonate is in a random coil conformation, spherical small molecules (e.g., TAPC and TTA) reduce the glass transition temperature much more than a rodlike small molecule (e.g., TPD). Annealing at a temperature just below the Tg of the polycarbonate was used as a means of simulating accelerated ageing. Upon annealing, phase separation and crystallization of TAPC occurs and leads to a recovery of the Tg of the polymer significantly. The Tg recovery in this case is much more significant than in the case of TPD. The average crystal sizes are about ten times smaller than the crystals obtained in the case of TPD for the same temperature of annealing. To enhance the charge mobility, it might actually be advantageous to induce submicron crystals of the small molecule, while keeping the film transparent.

A Novel Poly(Ionic Liquid) as the Thermal Insulating Material

2020 ◽  
Vol 13 (3) ◽  
pp. 241-247
Author(s):  
Wenxin Wei ◽  
Guifeng Ma ◽  
Hongtao Wang ◽  
Jun Li
Keyword(s):  
Thermal Conductivity ◽  
Ionic Liquid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Flame Resistance ◽  
Insulating Material ◽  
Low Thermal Conductivity ◽  
Thermal Insulating ◽  
Poly Ionic Liquid

Objective: A new poly(ionic liquid)(PIL), poly(p-vinylbenzyltriphenylphosphine hexafluorophosphate) (P[VBTPP][PF6]), was synthesized by quaternization, anion exchange reaction, and free radical polymerization. Then a series of the PIL were synthesized at different conditions. Methods: The specific heat capacity, glass-transition temperature and melting temperature of the synthesized PILs were measured by differential scanning calorimeter. The thermal conductivities of the PILs were measured by the laser flash analysis method. Results: Results showed that, under optimized synthesis conditions, P[VBTPP][PF6] as the thermal insulator had a high glass-transition temperature of 210.1°C, high melting point of 421.6°C, and a low thermal conductivity of 0.0920 W m-1 K-1 at 40.0°C (it was 0.105 W m-1 K-1 even at 180.0°C). The foamed sample exhibited much low thermal conductivity λ=0.0340 W m-1 K-1 at room temperature, which was comparable to a commercial polyurethane thermal insulating material although the latter had a much lower density. Conclusion: In addition, mixing the P[VBTPP][PF6] sample into polypropylene could obviously increase the Oxygen Index, revealing its efficient flame resistance. Therefore, P[VBTPP][PF6] is a potential thermal insulating material.

High-temperature carbon plastics based on thermoreactive polyimide binder

2020 ◽  
pp. 89-102
Author(s):  
M. I. Valueva ◽  
I. V. Zelenina ◽  
M. A. Zharinov ◽  
M. A. Khaskov
Keyword(s):  
Glass Transition ◽  
High Temperature ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Strength Properties ◽  
High Glass Transition Temperature ◽  
Reinforced Plastics ◽  
Carbon Plastics ◽  
Fundamental Possibility ◽  
Fiber Reinforced Plastics

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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