Effect of the molecular structure of the polymer and nucleation on the optical properties of polypropylene homo- and copolymers.

Two soluble nucleating agents were used to modify the optical properties of nine PP homo- and random copolymers. The ethylene content of the polymers changed between 0 and 5.3 wt%. Chain regularity was characterized by the stepwise isothermal segregation technique (SIST), while optical properties by the measurement of the haze of injection molded samples. Crystallization and melting characteristics were determined by differential scanning calorimetry (DSC). The analysis of the results proved that lamella thickness and change in crystallinity influence haze only slightly. A model was introduced which describes quantitatively the dependence of nucleation efficiency and haze on the concentration of the nucleating agent. The model assumes that the same factors influence the peak temperature of crystallization and optical properties. The analysis of the results proved that the assumption is valid under the same crystallization conditions. The parameters of the model depend on the molecular architecture of the polymer. Chain regularity determines supermolecular structure and thus the dependence of optical properties on nucleation

Structure-property relations of heterophasic ethylene-propylene copolymers based on a single-site catalyst

The target of the present study was to investigate the structure-property relationships of heterophasic ethylenepropylene (EP) copolymers based on a single-site (metallocene) catalyst (SSC) supported with an emulsion technology developed by Borealis. The structure of these copolymers, their morphology evolution, as well as resulting mechanical properties were studied by varying the composition of the dispersed phase, i.e. the amorphous ethylene-propylene copolymer or rubber (EPR), in a systematic series of bench-scale products. Next to composition effects, an attempt was made to understand the key differences between products based on Ziegler-Natta catalysts (ZNC) and single-site catalysts (SSC) in terms of polymer structure and property profile. A remarkably different phase morphology with very good phase coupling to the matrix PP and the absence of crystallizable polyethylene in the ethylene-rich copolymers (EPR) was observed for the SSCbased grades, resulting in a high level of impact strength over a wide composition range

Scientific research complex for the study of human operator in extreme conditions

In paper is presented a research complex which will recreate as closely as possible the diversity of the real working environment with appropriate incentives and will register the necessary examination of physical, physiological signals and parameters. Apparatus complex will simulate close to real work situations, will include tests necessary to assess the psychological status of the research subject. Further ahead in the complex algorithm will monitor the overall conduct of the experiment will record and process information from all physiological channels: electro miograma, electrocardiogram, blood pressure, pulse wave, respiration rate, galvanic skin response. The operator will receive visual and auditory information from the computer complex and will communicate with him through a special keyboard, standard optical mouse, track ball, stick and pedal controls. It is proposed methodology for conducting comprehensive studies of operator in extreme conditions. The developed complex will contribute to enhancing the skills of operators of mission-critical systems - pilots, pilots, operators of unmanned aerial vehicles, astronauts, heads of air traffic, nuclear operators and drivers of public transport

Use of technology virtual reality for the study of human - Operator in extreme conditions

Astronaut's training includes self-forming a mental model of the upcoming flight. In fact, this model consists of images of the