Kirkwoodsche Korrelationsfaktoren von binären Systemen mit Alkoholen und Diäthyläther

Kirkwood Correlation Factors of Binary Systems with Alcohols and Diethylether The KIRKWOOD theory allows the calculation of a correlation factor for describing the association of polar substances. For the systems n-hexane + diethylether cyclohexane + 1-propanol cyclohexane + 1-butanol benzene + methanol benzene + ethanol benzene + 1-propanol benzene + 1-butanol benzene + 1-hexanol benzene + 1-octanol the experimental values of dielectric constant and the calculated correlation factors are presented. From the concentration dependence of the correlation factors, calculated by use of the KIRKWOOD -FRÖHLICH -equation for mixtures, the existence of widely ramified associations of methanol and the formation of clusters of ethanol, propanol-(1), butanol-(1), hexanol-(1) and octanol-(1) is deduced. In the systems benzene + alcohol in most of the cases some specific interactions between the two components are supposed to exist.     

Untersuchung des einflusses molekularer parameter auf morphologie und eigenschaften von polyethylenen niedriger dichte

Based on the example of PE-LD grades and on model substances obtained by preparative fractionation (fractions in the molecular weight range M?_w = 1.2 ? 390·10⁴ g/mol), comprehensive investigations regarding the problems of structure/properties have been carried out. The correlations of M?_w with 15 physical and application technological perameters have been investigated taking into account the reaction mechanism during the manufacturing of PE-LD in the tubular and agitated autoclave reactor, resulting in the formation of so-called primary structure perameters M?_n, M?_w, molar mass distribution, short chain branching and long chain branching. For the interpretation of the results, among other factors, also the morphological conditions have been taken into consideration, which in connection with the molecular parameters reveal — for specific M?_w-ranges — strong changes and saturation ranges, resp., for the physical and application technological properties.     

Modell zur beschreibung der glasübergangstemperaturen binärer und ternärer mischungen von poly(styrol-co-n-butylmethacrylat)en

Glass transition temperatures of binary and ternary blends of chemically uniform poly(styrene-co-n-butyl methacrylate)s with a mean content of 30.8 wt.-% of n-butyl methacrylate and number-average molar masses in the range of 4900 and 67000 g/mol have been investigated in relation to their composition. The blends showed significant deviations from an ideal behaviour with reference to a linearity between glass transition temperature and composition. This phenomenon is described by a mathematical model where polynoms are particularly well suited to represent the glass transition temperatures of the blends, partly exceeding those of the pure components. Finally, various reasons of these deviations were discussed. Here, energetical interactions seem to be of considerable importance combined with a nonadditivity of volumes.     

Beiträge zur galvanisierung von polymeren, 11. Metallisierung von mischungen aus epoxidharzen und acrylnitril-butadien-copolymeren

The metallization of mixtures containing epoxy resins and acrylonitrile-butadiene copolymers depends on taking the suitable ratio of components and on the hardener, which was brought to reaction with the epoxy prepolymer in presence of the copolymer. Using triethylenetetramine as curing agent the highest values of peel strength have been reached and have been increased up to 150 N/25 mm by short-time-treatment with ozone. Longer ozonization times lead to lower values of peel strength and impairment of the material. Caverns occur only in mixtures which are rich on epoxy resin, and increase in size with increasing time of ozone treatment. These samples have relatively low values of peel strength.