The paper addresses the properties of glassforming melts in an attempt to predict the dependence of viscosity on temperature and on pressure. A review on the main viscosity models (free volume model, the Adam & Gibbs model etc.) is given. It is demonstrated that the activation energy can be expressed through the glass transition temperature Tg. The main attention is concentrated on the jump fre...

The glass transition of supercooled fluids is a particular challenge for computer simulation, because the (longest) relaxation times increase by about 15 decades upon approaching the transition temperature Tg. Brute-force molecular dynamics simulations, as presented here for molten SiO2 and coarse-grained bead-spring models of polymer chains, can yield very useful insight about the first few de...

We report a dynamical-mechanical study of stress relaxation at small deformation in a natural (polyisoprene) rubber well above its glass transition temperature Tg. We find that an almost complete relaxation of stress takes place over very long relaxation periods, even though the elastic network is retained. The relaxation rate and the long-time equilibrium modulus are sensitive functions of tem...

Under optimal freeze-drying conditions, solutions exhibit a cake-like porous structure. However, if the solution temperature is higher than the glass transition temperature of the maximally freeze-concentrated phase (Tg') during drying phase, the glassy matrix undergoes viscous flow, resulting in cake collapse. The purpose of the present study was to investigate the effect of cake collapse on t...

A system consisting of aggregated nonstoichiometric zinc ferrite nanoparticles has been studied using AC and DC magnetization measurements. A superparamagnetic– super-spin-glass phase transition at Tg has been identified. The relaxation time diverges at Tg and the nonlinear susceptibility shows an abrupt increase. The critical behavior vanishes when the nanoparticles are not in close contact. T...

The epoxy/glass fiber/organo-montmorillonite (OMMT) nanocomposites were prepared by hand lay up method. In the previous work, the flexural and morphological properties of the epoxy/glass fiber/OMMT were studied. In this work, the epoxy nanocomposites were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and water absorption tests. The exfoliation of OMMT in epox...

Using a simple three-dimensional lattice copolymer model and Monte Carlo dynamics, we study the collapse and folding of protein-like heteropolymers. The polymers are 27 monomers long and consist of two monomer types. Although these chains are too long for exhaustive enumeration of all conformations, it is possible to enumerate all the maximally compact conformations, which are 3×3×3 cubes. This...

This research has been carried out in order to demonstrate the use of differential scanning calorimetry (DSC) in detecting and measuring αand β-relaxation processes in amorphous pharmaceutical systems. DSC has been employed to study amorphous samples of poly (vinylpyrrolidone) (PVP), indomethacin (InM), and ursodeoxycholic acid (UDA) that are annealed at temperature (Ta) around 0.8 of their gla...

– We have computed the time-dependent susceptibility for the finite-size meanfield random orthogonal model (ROM). We find that for temperatures above the mode-coupling temperature, the imaginary part of the susceptibility χ′′(ν) obeys the scaling forms proposed for glass-forming liquids. Furthermore, as the temperature is lowered the peak frequency of χ′′ decreases, following a Vogel-Fulcher la...

Novel cyclic olefin polymers (COPs) derived from bulky cyclic olefins, tricyclodipentadiene (TCPD) and tricyclo[6.4.0.19,12]-tridec-10-ene (TTE), with high glass transition temperature (Tg), excellent thermal stability, and high transparency, have been synthesized by ring-opening metathesis polymerization (ROMP) and subsequent hydrogenation. ROMP of TCPD and TTE was carried out successfully wit...