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Rheological behaviour of some products based on chemical modified starch, with characteristics proper to retarding additives for concrete designed for cementation of the big depth wells, was investigated. With that end in view, rheological tests of several pastes obtained from products of the hydroxypropylstarch type were carried out. Maintaining, at pastes preparation, the concentration of 10% additive, proved as being the most efficient in use, shearing strain tests were performed at 20°C, 40°C and 60°C versus keeping time of pastes, namely, 24 h and 48 h from preparation time. At the same time, influence of the disodicphosphate and urea additions over rheological pastes was investigated versus the same parameters. Based on the experimental results obtained, the mathematical models describing rheological behaviour of the tested additives, within a large range of external stress and temperature, were elaborated.

This paper presents data concerning the capacity of a bismaleinimide (BMI) to protect elastomers with different structures and unsaturated degree and the copolymers EVA submitted to thermooxidative destruction at 80 - 200ºC. The main structural changes were followed in the IR domain and the kinetic parameters of the processes were determined.

The research investigated the compatibility between the styrene-butadiene rubber mix and wastage materials of finite cromated leather in order to obtain products necessary in various industries or specifically in the leather and shoes industry. The researchers immersed multiple composite samples containing rubber and various proportions of leather-wastage in three solvents: benzene,carbon-tetrachloride and cloroform. The samples where then monitored during their expansion in time and the changes that occurred in the IR spectra. The studies have demonstrated the material compatibility confirmed also by mechano-physical determinations.

Five commercial products, based on acrylic polymers, have been used for cotton coating. The structures of the polymers have been established based on their IR spectra of the active compound from the acrylic dispersion. The properties of the coated materials have been discussed in connection with the structure of the acrylic polymer.

New poly(succinimide-ether)s with maleimidic rings in the side chain were synthesized by a chemical modification reaction on the polymers containing hydroxylic pendant groups. The polymers were obtained in good yields and they were characterized by elemental analysis, infrared and proton nuclear magnetic resonance spectroscopy, gel permeation chromatography, dynamic thermogravimetric analysis and solution viscometry.

A simple, efficient and general one-pot method has been developed for the synthesis of aminophosphonates grafted on styrene-divinylbenzene copolymers from benzaldehyde grafted on styrene-divinylbenzene copolymer with amines and diethyl phosphite in tetrahydrofuran. The aminophosphonates grafted on insoluble macromolecular supports were characterized by infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Keywords: aminophosphonate groups, stirene-divinylbenzene copolymers

Coating powders are finely grounded polymeric materials containing binders, pigments, extenders and special additives, used to obtain decorative and protective organic coatings. There are two major categories: thermoplastic and thermoreactive coating powders, based on thermoplastic and on thermoreactive binders, respectively. This paper presents the classes of thermoplastic coating powders, and their main characteristics.

Two compounds containing mesogenic cores based on dithiophene and dithienothiophene or fluorene units and hexyl end groups have been synthesized and their thermotropic properties were studied. The mesomorphic behaviour has been analyzed in the thermal stability range, by three complementary methods: polarized light microscopy, differential scanning calorymetry and variable temperature wide angle X ray diffraction. It was established that both compounds form a mesophase at low temperature, whose architecture depends by the mesogen molecular structure. By thermal treatment of the compounds in the mesophase stability range continuous ordered films have been obtained. Keywords: liquid crystal, internal plasticizer, ordered film

Assuming that the “structural” elements of a multiphase fluid (hydrogel, drug or fluid particles) move on continuous and non-differentiable curves (fractal curves), a new theoretical model that describes the drug release processes from polymeric hydrogels is established. This model, namely fractal hydrodynamic model, is based on two equations: the momentum and probability density conservation laws. The fractal potential, from the momentum conservation law, is a measure of the non-differentiability of the movement curves and controls the drug release processes. The model allows us to evaluate some characteristics of the hydrogel network, such as a distribution parameter for drug particle inside hydrogel. The novelty of this approach is that the system complexity is replaced by fractality, eliminating thus the whole classical “arsenal” of quantities from the standard physics based on the assumption of continuity and differentiability of physical quantities (differentiable physics). Keywords: fractal hydrodynamic, drug release, polymer, hydrogel