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Dielectric spectroscopy, heat capacity spectroscopy (HCS), and differential scanning calorimetry (DSC) investigations in the αβ relaxation splitting region of a series of random copolymers of n-butyl methacrylate with styrene are reported. A separate onset of the α relaxation is dielectrically observed, about one frequency decade below a continuous local aβ component in the Arrhenius diagram. This splitting scenario shifts to higher frequencies and temperatures for increasing styrene content and does not qualitatively change from homo PnBMA up to 54 mol % styrene. The logarithms of onset frequency, log ωon, and of WLF asymptotic frequency, log Ω, change linearly with the styrene content, but their ratio is constant and remains large, log10(Ω/ωon) = 3.8 ± 1. The log Ω ≈ 7 (rad/s) values for small styrene content are unusually low. Ω is explained as the frequency of local cooperativity chances in the concept of kinetic molecular randomness for the dynamic glass transition. The α dielectric intensity, Δεα, the caloric intensity, Δc p , and the square root of cooperativity from a fluctuation formula, N α 1/2, are linearly proportional to the temperature difference to the onset, e.g. Δεα ∼ (T on − T). The dielectric activities of the α process and a hypothetical γ process (beyond the Johari Goldstein β process) increase with increasing styrene content although the styrene unit is almost nonpolar. This is interpreted by dipole decompensation for the α and γ relaxation modes caused by the random styrene units.

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The main transition of amorphous polymers is analyzed with respect to a fine structure by means of new experimental dynamic shear, dielectric, and heat capacity data for the following polymers:  poly(n-alkyl methacrylate)s with alkyl = methyl, ethyl, propyl, butyl, and hexyl, polystyrene, poly(vinyl acetate), a series of weakly vulcanized natural rubbers, a series of butyl rubbers with different carbon black content, polyisobutylene, and bromobutyl rubber. The components of the fine structure are assumed to be a proper glass transition at short times, followed by a confined flow zone, and, at large times, a hindering zone caused by entanglements at large times. Two lengths are assumed to correspond to the first and third components, respectively, the characteristic length to the proper glass transition and the entanglement spacing to the hindering zone. The confined flow will be described by a dispersion law (general scaling) across the main transition. The characteristic length of the glass transition for the poly(n-alkyl methacrylate)sonly of order 1 nm as determined by calorimetryis confirmed by backscaling from the entanglement spacing by means of a Rouse dispersion law for shear. The fate of the Rouse modes below the αβ splitting of the glass transition is discussed for the other amorphous polymers. Finally, a speculative molecular picture of the different modes in the main transition is described. The new element is a low-viscosity longitudinal motion of individual chain parts in the confined flow zone. A simple rheological model for the confined flow is also presented.

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The study aimed to evaluate the effects of selected protein isolates and concentrates on quality and staling of gluten-free bread, in the absence of other structure-forming agents such as guar gum and pectin. The applied preparations included albumin, collagen, pea, lupine and soy. Their addition had various effects on rheological properties of the dough and volume of the bread. Volumes of the loaves baked with soy and pea protein were smaller, while those with albumin significantly larger than control. Presence of non-gluten protein caused changes in crumb structure (higher porosity, decrease in cell density, higher number of pores with a diameter above 5 mm) and its color, which was usually darker than of unsupplemented starch-based bread. The least consumer's acceptance was found for bread baked with soy protein. The presence of pea and lupine preparations improved sensory parameters of the final product, providing more acceptable color and smell in comparison to control, while soy caused a decrease of all analyzed consumer's scores. The addition of protein caused an increase in bread hardness and in enthalpy of retrograded amylopectin, during bread storage.