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Zenkiewicz M.,University KazimierzaWielkiego w Bydgoszczy | Zuk T.,Instytut Inzynierii Materialow Polimerowych i Barwnikow w Toruniu

The paper is a review of the literature concerning the physical basis of the electrostatic separation of mixed polymers, involving the electrification of polymer particles as a result of the friction between them and/or the friction on the walls of tribocharging unit, followed by separation of the particles in DC electric field. This method can be applied for industrial recycling of plastics wastes. The construction of free-fall separatorwas analyzed and the mathematical formulas describing its operationwere presented. The means of electrification of various materials, in particular tribocharging of polymers, have been described. Source

Zenkiewicz M.,University KazimierzaWielkiego w Bydgoszczy | Moraczewski K.,University KazimierzaWielkiego w Bydgoszczy | Rytlewski P.,Instytut Inzynierii Materialow Polimerowych i Barwnikow w Toruniu

This paper constitutes a review of the literature focusing on the metallization of the surfaces of polymeric materials. The main advantages of this method of polymer surface modification has been discussed and a detailed description of the electroless modification procedure with special consideration on the autocatalytic metallization has been presented (Fig. 1). The role and the possible mechanisms of action of metallization bath components such as reducing and complexing agents as well as stabilizers has been explained (Table 1). The importance of maintaining the stability of the galvanization bath and also the activation of the surface layer of the polymeric material to be metalized has been emphasized. (Figs. 2, 3). The general trend of current research work in the direction of developing new catalysts, their methods of introduction into the polymeric materials and laser activation has been indicated. Source

Polylactide film (50 uμm) was produced by kalendering, irradiated for 200 h at 27°C with UV and visible light and studied for presence of CO, OH, CH2=CH- and CH2= groups and storage modulus. The irradn. resulted in formation of OH groups and unsatd. C=C bonds and in decreasing the storage modulus of the polymer. Source

The effect of the addition of commercial silica aerogel (Table 1) on the mechanical properties of peroxide cured acrylonitrile-butadiene rubber (NBR) was studied. Two series of rubber compounds (NBR1 and NBR2) were prepared, filled respectively with silica (70 phr) and aerogel (76 phr), additionally NBR1 contained novolak resin (50 phr). The aerogel was introduced into the rubber compound in a manner typical for fillers in rubber industry. In spite of the very large surface area of the aerogel in comparison with the silica, the reinforcing effect was significantly weaker than expected. Slight changes in the hardness and tensile strength were observed, the character of these changes was dependent on the presence of novolak resin in the rubber compound (Table 2, 3, Fig. 1). The replacement of silica by aerogel resulted in the increased impact resilience and decreased loss angle in the simple shear dynamic tests as a function of the shear amplitude (Figs. 4, 5) or the aerogel content (Figs. 8, 9). Changes in the dynamic modulus were relatively minor and dependent onthe presence ofnovolak resin in the rubber compound (Figs. 6, 7, 10, 11). The comparable density values for the vulcanizates with the silica and the aerogel may indicate that a part of the porous structure of the aerogel was destroyed during the preparation of rubber compounds and vulcanizates. Source

Zenkiewicz M.,Kazimierz Wielki University in Bydgoszcz | Zuk T.,Instytut Inzynierii Materialow Polimerowych i Barwnikow w Toruniu | Blaszkowski M.,Instytut Inzynierii Materialow Polimerowych i Barwnikow w Toruniu

The results of an investigation of the process of electrostatic separation of binary polymeric blends with different content (10, 20, 30, 40, 50, 60, 70, 80, and 90 wt %) of acrylonitrile-butadiene-styrene terpolymer (ABS) and poly(methyl methacrylate) (PMMA) are presented. The separation was carried out by using a home-made prototype of electrostatic cylindrical separator. It was found that the effects of the tribocharging in fluidized bed dependedon the process duration. Amaximum value of the electric potential (over 22 kV) of the blend containing 50/50 wt % of ABS and PMMA was attained after ca. 20 s of the electrization. Instead, during the mechanical tribocharging, an electric potential increased with the rise of the rotational speed of a stirrer and reached a value of ca. 18 kV. The blend separation was performed in an electrostatic field arising between a high-voltage elliptic electrode and cylindrical ground electrode rotating at a rate of 30 rpm. The dc voltage between the electrodes was 20 kV and the electrostatic field intensity did not exceed 4 kV/cm. It was found that the effects of the separation process, i.e., purity of the particular fractions and yield of the ABS and PMMA recovery, depended on both the tribocharging effects and contents of the individual blend components. A better separation was achieved for the more balanced compositions. The investigations also indicated that the separation of blends containing 20-70 wt % ABS (30-80 wt % PMMA) may result in a purity of the particular fractions above 95 wt % and recovery yield above 97 wt %. Further increase in the purity and yield is possible by application of a multi-step separation. Source

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