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Publikācija: Expanded Polystyrene Heterogeneity Research Using Raw Material with Different Granulometry

Publication Type Publications in RTU scientific journal
Funding for basic activity Unknown
Defending: ,
Publication language Latvian (lv)
Title in original language Pētījumi par putu polistirola bloku neviendabīgumu izmantojot izejmateriālu ar dažādu granulometrisko sastāvu
Title in English Expanded Polystyrene Heterogeneity Research Using Raw Material with Different Granulometry
Field of research 2. Engineering and technology
Sub-field of research 2.4 Chemical engineering
Authors Olita Medne
Iljo Dreijers
Līga Bērziņa
Līga Bērziņa-Cimdiņa
Keywords polystyrene, heterogeneity, granulometry
Abstract pētīta divu dažādu veidu polistirola daļiņu granulometrija, kā arī izejmateriāla daļiņu sakārtojuma ietekme, uz lielizmēra bloku viendabīgumu. Saražoto bloku mehānisko īpašību pārmērīga neviendabība var radīt mehānisko deformāciju un defektīvu gala produktu. Saražoto lielizmēra polimēra bloku viendabību raksturoja ar spiedes spriegumu pie 10% deformācijas, tilpummasu un mikrofotogrāfiju paraugiem, kas tika ņemti no saražotajiem blokiem noteiktās vietās telpiskajā režģī
Abstract in English The granulometry of polystyrene particles of two different raw material brands (material B - Styropor from BASF and material C - NF from StyroChem) and the impact of the raw material particle distribution on the uniformity of the intermediate product were studied for large size blocks. Spatial uniformity of polystyrene blocks is important characteristic of product quality. Excess non-homogeneity of mechanical properties of produced blocks leads to mechanical deformation and defective end product. The uniformity of produced large size polymer blocks were characterized by the compression stress at relative compression strength of 10%, density, and microphotography of samples taken over produced block volume at defined places of spatial lattice. Block dimensions are 1000x1200x4000mm; 315 probes of 50x50x50mm from each block were cut according with regular lattice 250x200x500mm. Average diameter of raw material B particles is 0.7-1.0mm, but for raw material C – 0.5-0.7mm. Material C contains higher percentage of small particles than material B. In the preheating stage both material particles are expanding proportionally to particle diameter. Mass of blocks are 157.6 and 152.5kg respectively for material B and C. Density of block B probes are higher with higher values of density at the central part of block (32-35kg/m3). Densities of block C probes are lower and distributed very asymmetrically – left side of the block is with very low density (26-28kg/m3) compared with the right side 30-32kg/m3). Compression stress is positively correlated with probe density and the compression stress distributions resemble the distribution of density. Apparently, larger amount of small particles of the raw material C are jamming steam flow to the central parts of block form, causing inconsistency of temperature field, and resulting in lower inter-particle melting degree. Considering investigated raw materials preference must be given to material B
Reference Medne, O., Dreijers, I., Bērziņa, L., Bērziņa-Cimdiņa, L. Expanded Polystyrene Heterogeneity Research Using Raw Material with Different Granulometry. Materials Sciences and Applied Chemistry. Vol.22, 2010, pp.118-121. ISSN 1407-7353.
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