Search Results

1 - 10 of 82 items :

  • "plastic material" x
Clear All

Abstract

It is justified thatproblems related to the changes in structural and mechanical properties of plastic material and influence of structural elements of equipment and modes of implementation of the for-mation process on them are considered detail, taking into account empirical data, theoretical dependencies and results of physical experiments. It was established that during the mechanical influence of rollers with grooves on a structured dispersion plastic material in the node of injection of the molding machine, internal shear, and shearing deformation have a preponderant value. Accordingly, the productivity of machines is determined mainly by the structural parameters of the working bodies geometry, kinematics, and contact area. It is shown that increasing the pressure in the plastic material causes a decrease in its volume, but the relationship between pressure and volume has a nonlinear character. It has been established that regardless the variety of flour from which the plastic material was prepared for bagels, its moisture content and the duration of fermentation reduced viscosity of the effective plastic material along with the increase of the shear stress. The paper describes the refined rheological model of the Bingham body deformation, which develops instantaneously, and the velocity of the common elastic deformation in the dough is a simultaneous function of stresses and temperatures, which are close to exponential ones.

References Sivan A. New perspectives in plastic biodegradation. Curr Opin Biotechnol. 2011;22(3):422-426. Iovino R, Zullo R, Rao MA, Cassar L, Gianfreda L. Biodegradation of poly(lactic acid)/starch/coir biocomposites under controlled composting conditions. Polym Degrad Stab. 2008;93:147-157. Mohee R, Unmar G. Determining biodegradability of plastic materials under controlled and natural composting environments. Waste Manage. 2007;27:1486-1493. Leejarkpai T, Suwanmanee U, Rudeekit Y, Mungcharoen T. Biodegradable kinetics of plastics under controlled composting

studies of poly(b-hydroxybutyrate-co-b-hydroxyvalyrate).Polym Degrad Stab. 1996;51:205-210. [8] Kyrikou I, Briassoulis D. Biodegradation of agricultural plastic films: A critical review. J Polym Environ. 2007;15(2):125-150. DOI 10.1007/s10924-007-0053-8. [9] Sarasa J, Gracia JM, Javierre C. Study of the biodisintegration of a bioplastic material waste. Bioresour Technol. 2009;100(15):3764-3768. DOI: 10.1016/j.biortech.2008.11.049. [10] Mohee R, Unmar G. Determining biodegradability of plastic materials under controlled and natural composting environments. Waste Manage

materials for single edge notch plate in tension . – Archives of Civil and Mechanical Engineering, vol.11, No.2, pp.301-319. [22] Graba M. (2012): The influence of material properties and crack length on the Q-stress value near the crack tip for elastic-plastic materials for centrally cracked plate in tension . – J. Theor. Appl. Mech., vol.50, No.1, pp.23-46. [23] Graba M. (2008): The influence of material properties on the Q-stress value near the crack tip for elastic-plastic materials . – Journal of Theoretical and Applied Mechanics, vol.46, No.2, pp.269-290. [24

the Functional Properties of Parts Made from Thermoplastic Materials, Mach. Dyn. Res. , 36(1), 82-89. 9. Jałbrzykowski M., Nachimowicz J. (2009), The problems of reliability and durability of tools for the injection of plastic materials, Acta Mechanica et Automatica , 3(1), 49-53. 10. Kayvon M. (2014), Sina Ebnesajjad and all: Handbook of Polymer Applications in Medicine and Medical Devices , William Andrew Inc., Elsevier, Oxford. 11. Laurence W. McKeen (2007), Effect of Temperature and other Factors on Plastics and Elastomers , William Andrew Inc

of Plasticity, 16(1-8), 723-748. 16. Fisher F.D., Reisner G. (1998), A criterion for the martensitic transformation of a microregion in an elastic-plastic material, Acta Materialia 46, 2095-2102. 17. Garion C., Skoczeń B. (2003), Combined Model of Strain – Induced Phase Transformation and Orthotropic Damage in Ductile Materials at Cryogenic Temperatures, International Journal of Damage Mechanics, 12(4), 331-356. 18. Hallberg H., Hakansson P., Ristinmaa M. (2010), Thermo-mechanically coupled model of diffusionless phase transformation in austenitic steel

tvárnenie plastov . (Moulding tools for forming plastic materials). Žilina: ŽU, 155 p. ISBN 9788055401911. 4. AKAY, M., 1992. Jetting and fibre degradation in injection moulding of glass-fibre reinforced polyamides. Journal of materials science , 1992, 27 (21), 5831-5836. ISSN 0022-2461. 5. WANG, X., ZHAO, G., WANG, G., 2013. Research on the reduction of sink mark and warpage of the molded part in rapid heat cycle molding process. Materials & Design , Volume 47, 779-792. ISSN 0261-3069.

  ( n , θ ) \font\mtmib=MTMIB${\mtmib \tilde u}_i \left( {{\mtmib n}, {\bf \theta} } \right)$ , d n ( n ) and I n ( n ) Functions in Hutchinson-Rice-Rosengren solution and its 3d generalization . – Journal of Theoretical and Applied Mechanics, vol.44, No.1, pp.19-30. [4] Graba M. (2008): The influence of material properties on the Q-stress value near the crack tip for elastic-plastic materials . – Journal of Theoretical and Applied Mechanics, vol.46, No.2, pp.269-290. [5] Graba M. (2012): The influence of material properties and crack length on the Q-stress value

Abstract

Nowadays, wide applications of plastics result in plastic waste being present in the water environment in a wide variety of sizes. Plastic wastes are in water mainly as microplastics (the size range of 1 nm to < 5 mm). Microplastics have been recognized as an emerging threat, as well as ecotoxicological and ecological risk for water ecosystems. In this review are presented some of the physicochemical properties of plastic materials that determine their toxic effect on the aquatic environment. Wastewater treatment plants (WWTPs) are mentioned as one of main sources of microplastics introduced into fresh water, and rivers are the pathways for the transportation of the pollutants to seas and oceans. But, effluents from tertiary wastewater treatment facilities can contain only minimally microplastic loads. The issue of discharge reduction of plastic pollutants into water environment needs activities in the scope of efficient wastewater treatment, waste disposal, recycling of plastic materials, education and public involvement.

Abstract

Additive technology uses a wide range of materials. Beginning from plastic material, different types of resin but also steel material. Presented paper deals with Fused Deposition Modeling technology which is focused to processing of plastic materials based on polymers. Mostly used are ABS plastic (Acrylonitrile Butadiene Styrene), Nylon, Polycarbonate (PC), or composites based on different polymers. New devices designed for the production of plastic parts are able to work also with environmentally friendly and biodegradable materials as Polylactic acid (PLA). The aim of this paper is to show the possibility of using materials based on organic polymers whose properties are comparable to conventionally used polymers. Presented are measured and statistically evaluated data related to basic properties of PLA material.