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Polystyrenes with pendent diquaternary 4,4-bipyridinium groups are polystyrenes containing pendent viologen groups. They were obtained by the reaction of chloromethylated polystyrene with N-monoquaternary-4,4’- bipyridinium bromides as: N-(p- H, NO2, Cl) phenacyl-4,4’-bipyridinium bromides and N-carbomethoxymethyl/ethyl-4,4’-bipyridinium bromides (2a-e). Thermal stabilities of polystyrene with pendent viologen groups were investigated. The influence of the chemical structure of pendent viologen groups on the thermal stability was performed by thermogravimetric analysis in the dynamic conditions of temperature and atmospheric air. The substituted compounds undergo a thermal degradation process that took place by a complex mechanism in three steps. These steps are disscused from both kinetic parameters and thermogravimetric characteristics points of view. The thermostability of low molar mass compounds 1a-e decreases in the following order: 1c > 1a > 1e > 1d > 1b and the same thermostability order was found in the case of chloromethylated polysulfone derivatives (2c > 2a > 2e > 2d > 2b). Keywords: Thermal behaviour, thermal stability, chemical modificated polystyrene, N-phenacyl and N- carbomethoxymethyl/ethyl- 4,4’-bipyridinium groups, viologen group

This paper presents the influence of styrene-butadiene block-copolymers on the modification of high density polyethylene wastes. The modification of this polyolefine is a means of improving the mechanical properties, especially the impact strength, in order to increase the posibilities of recycling high density polyethylene wastes. Keywords: styrene-butadiene block-copolymers

The residence time distribution at the exit of mixing zone in a fully intermeshing, corotating twin screw extruder was determined with a stimulus-response technique. The operating parameters investigated were screw speed and feed rate. The residence time decreases with increasing screw speed and feed rate. Keywords: residence time distribution, corotating twin screw extruder

A solvent and catalyst-free synthesis of a polyphosphate was accomplished. The reaction involved a gas-liquid polycondensation between phenylphosphoric dichloride and phenolphthalein. The polyphosphate was characterized by IR, 1H-NMR, inherent viscosity, thermal analysis and molar mass. Polyphosphate was stable up to 260oC. Keywords: gas-liquid polycondensation, polyphosphate

The structural characteristics of polymeric composites based on EPDM, (ethylene-propylene-dien monomer) rubber, which have various percentages of high density polyethylene, were studied by IR spectroscopy and optical microscopy, evidencing the influence of processing parameters. The EPDM rubber was vulcanized using either sulphur and accelerators or peroxides. The influence of the dynamic conditions (rotation rate during the mixing of rubber with polyethylene) on the solvent retaining by maintaing 1-24 hours in benzene, chloroform and MEC (methylethylcetone) was shown by weighing the samples. The results of research could be used for choosing the suitable compositions, processing conditions as well as the fields for application of these composites. Keywords: EPDM (ethylene-propylene-dien monomer) rubber, polyethylene,IR spectroscopy, microscopy

In the paper, a stress strain analysis in the area of central ligament of a cruciform glass-epoxy specimen is presented. Investigation was done experimentally, using strain gauges technique, by application of six gauges in the stress concentration area. The validation of a theoretical model (a special type of a finite element), which was created by authors for analysis of the laminate composite structures, was the aim of this study. A good agreement between numerical calculus and experimental results was observed. Keywords: experimental validation, finite element method, epoxy resin, lamina, cruciform specimen, strain gauges technique

The transport process of charged polymer, through a nanopore in a biological membrane is studied. An expression for the polymers flow in terms of the free energy and the friction coefficient is obtained. Keywords: polymer translocation, polymer flow, nanometric pores, biological membrane

The paper presents the experimental results obtained in processing rubber waste armed with metallic insertions. The experimental results were obtained appliyng a new technology for processing rubber waste reinforced with metallic insertions. The technology presented in this paper, is based on changes of rubber mechanical properties, at temperatures in criogenic domain. Keywords: rubber, waste, processing, cryogenic domain

The Wittig reaction is amongst the most popular methods for regiospecific introduction of carbon-carbon double bonds in organic synthesis. The paper deals with the synthesis of copolymers functionalized with olefin groups by Wittig type polymer-analogous reactions in phase transfer catalysis. The copolymer bond aldehyde was reacted with phosphonium salts to give olefin groups grafted on macromolecular support. Keywords: polymer-suported Wittig reagent, phase transfer catalysed, styrene-divinylbenzene copolymers

The exposure of ethylene-propylene elastomers to the action of gamma-radiation causes the modification of chemical state of polymer matrix by the formation of oxygenated products. The accumulation of these dipoles modifies the electrical behaviour of materials, the value of resistance more than three times at increasing dose up to 200 kGy. The absorbtion/resorbtion current measurements demonstrates the wrong consequence of the inversion of polarity for applied voltages. Differences between the two sorts of synthetic elastomers (ethylene-propylene copolymer and ethylene-propylene terpolymer) were pointed out. Keywords: synthetic elastomers, EPDM, EPR, electrical properties