Density and glass transition temperature

Table 1. Volume expansion change at Tg density and glass transition temperature of amine hardened TGDDM-based resins...

Table 2-2 Abbreviations, densities and glass transition temperatures of some important thermoplastics.

Control of the EB cured film properties through formulation is the key to meeting specific end use properties. A wide range of hardness and flexibility can be produced by adjustment of crosslink density and glass transition temperature. Studies on the effects of formulation variables on the tensile elongation properties of free films have proven especially valuable in development of coatings for flexible substrates. 

Molecular dynamics calculations have been carried out to simulate a conformational model and vibrational spectra of poly(dichlorophospha-zenes). Molecular dynamics similations for [NP(OCH2CF3)2] and the isomers [NP(OBu")2] , [NP(OBu )2] and [NP(OBu )2] show a reasonable agreement between the calculated and experimental values of density and glass transition temperature as well as for gas transport parameters in these polymers.Small molecule models have been used for a theoretical approach of poly(thionylphosphazenes). ... 

Properties for several TFE/PDD copolymers and PTMSP are compared in Table IV. Density and glass transition temperatures for the TFE/PDD copolymers were obtained from Buck and Resnick (44), and the density and glass transition temperature for PTMSP are from the study of Nakagawa et al.(l). Among the fluoropolymers in this table, PTFE homopolymer exhibits 5ie lowest glass transition temperature, the lowest oxygen permeability coefficient, and the lowest fractional free volume. In the polymers in Table IV, the PALS results suggests a bimodal distribution of free... 

Fedderly, J., Compton, E., and Hartmaim, B. Additive group contributions to density and glass transition temperature in polyurethanes. Polymer Engineering and Science, 38(12), 2072-2076 (1998). 

The coatings can be applied to steel substrates. A commercial soybean oil polyol was used and was found to have a lower modulus and a lower crosslink density and glass transition temperature compared to coatings formulated with sucrose soyate polyols (16). 

PPE/PS ratio of 75/25. The expansion of the SAN phase is less restricted, and the PPE/PS phase tends to foam even at lower foaming temperatures as a result of the lower viscosity and glass transition temperature. By increasing the foaming time to 30 s, again a shift of the minimum density to lower temperatures can be detected. 

The most significant differences in performance properties between a two-component, room temperature curing epoxy adhesive and a one-component, heat-curing type are the heat and chemical resistance. These differences are due primarily to the lower crosslink density or glass transition temperature of the room temperature curing types. 

Many properties of pure polymers (and of polymer solutions) can be estimated with group contributions (GC). Examples of properties for which (GC) methods have been developed are the density, the solubility parameter, the melting and glass transition temperatures, as well as the surface tension. Phase equilibria for polymer solutions and blends can also be estimated with GC methods, as we discuss in Section 16.4 and 16.5. Here we review the GC principle, and in the following sections we discuss estimation methods for the density and the solubility parameter. These two properties are relevant for many thermodynamic models used for polymers, e.g., the Hansen and Flory-Hug-gins models discussed in Section 16.3 and the free-volume activity coefficient models discussed in Section 16.4. 

Classical methods are designed to obtain thermodynamic and transport information, for example molar volume, density, viscosity, and surface tension. The effects of pressure and temperature on these properties can also be evaluated, and thus phase transition information such as melting points and glass transition temperatures. If molecular dynamics (in contrast to Monte Carlo) is used, data relating to reorientation of molecules, self-diffusion and residence times are all available. Information can also be obtained from the simulation equations on the contribution made by kinetic, coulombic, intramolecular and dispersion energies to the total potential energy. However, because the charges are fixed and there is no explicit wavefunction included in the classical methods, no electronic information can be obtained. 

Polymer Synthesis. All polymers were prepared in dimethylacetamide at the temperature of 85°C for 20 - 30 min in nitrogen atmosphere. Table I summarizes the reduced specific viscosity, density (p), and glass transition temperature (Tg)... 

Table I. Reduced Specific Viscosity ijiJC), Density (/9), and Glass Transition Temperature (Jg)...

Unlike UF, AESO resin cannot be sprayed on straw particles because of its high viscosity. In order to reduce AESO viscosity, styrene, which also increases the strength, stiffness and glass transition temperature due to an increase in cross-link density of the cured resin, was blended with AESO in the amount of 33 wt% [7,12]. Since the polymerization process of AESO is addition type, a free radical initiator should be used for the curing. Benzoyl peroxide was used as free radical initiator in the amount of 5 wt% of the AESO + styrene mixture. 

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