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Effect of mould speed on selected properties of moulded parts and energy consumption in rotational moulding

Głogowska Karolina, Longwic Filip, Ludziak Krzysztof

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 5

art. no. e143106

EN

This paper deals with rotational moulding. The relationship between mould speed and wall thickness in the upper, middle and lower areas of rotational moulded parts is investigated. Young’s modulus of moulded parts is determined via static tensile testing. A static compression test is performed to determine the maximum compressive force causing strain. The test is conducted on the wall of moulded parts, parallel to the main axis of rotation. Also, energy consumption in rotational moulding is investigated for different rotational speeds of the mould. Moulded parts are made of DOWLEX®2629UE linear low-density polyethylene (LLDPE). Experimental results are statistically analysed using STATISTICA 13. Non-parametric statistical tests are used for results analysis. The ANOVA method is employed to determine if there are any significant differences between obtained results. The statistical tests show that the range is much narrower for a speed ratio of 4:1. The narrowest range value is obtained for 12\3 rpm. The highest Young’s modulus values are obtained for the parts moulded at 12\3 rpm (1263.33 MPa) and 16\4 rpm (1263.67 MPa). The highest maximum compressive force is obtained for the parts moulded at 12\3 rpm (10 400 N). An analysis of the results demonstrates that the part moulded at 12\3 rpm has the most advantageous properties. For this mould speed, the power consumption amounts to 8.28 kWh. Experimental results and statistical analyses demonstrate that mould speed affects both moulded part quality and energy consumption in the rotational moulding process.

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Impact of Intensive Mixing and Shearing Elements on the Effectiveness of Extrusion of Wood Polypropylene Composites

Głogowska Karolina, Sikora Janusz W., Ludziak Krzysztof

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 4

231--242

EN

The objective of this study was to determine the effect of various design solutions for intensive mixing and shearing elements located at the end of a single-screw plasticizing system on the effectiveness of wood polypropylene composite extrusion. Four types of such elements were used in the study: a pineapple mixer, a Maddock mixer, a ring mixer, and a helical mixer. For the purpose of the study, 4 blends were prepared containing 5, 10, 15 and 20% of wood fibre, respectively. Direct and indirect resulting factors as well as variable, constant and disturbing factors were investigated. The effectiveness of extrusion of wood polypropylene composites was determined based on results of parameters characterizing this process, such as extrudate temperature, unit consumption of energy supplied to the extruder, mass flow rate, and extrusion speed. It has been shown that the effectiveness of the extrusion process can be improved by using different mixing and shearing elements. Such screw design solutions make it possible to affect rheological phenomena occurring during melt flow in the plasticizing system, without modifying the extrusion process parameters such as screw rotation speed and polymer temperature. The literature review shows that there exist very few and general studies investigating the effect of screw design geometry, especially that of mixing and shearing elements, on the efficiency of extruding and mixing wood polypropylene materials.

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Characteristics of Polymer Materials with New Smart Utilities

Głogowska Karolina, Klepka Tomasz, Dulebova Ludmila

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 4

96--103

EN

Modern technologies increasingly often rely on the use of intelligent (also known as “smart”) materials exhibiting unique utilities and properties. The state of knowledge on intelligent polymers ranges from diagnostic research to a more extensive body of knowledge, combined with the knowledge of the practical methods for manufacturing these materials. On the basis of a review of the subject literature, this paper describes the existing smart polymer materials. It also presents the examples of applications for these new materials. In the further part of the paper, an example of how the concept of smart materials can be used in new polymeric products to influence the selected mechanical properties when the surrounding temperature changes. The new material or the acquisition of different properties was created by undercutting or selecting the correct thickness and type of polymer layer from which the new product is made. The example of own research, apart from their analysis, ends with the conclusions of an applicative nature.

4

Studium wytłaczania polietylenu z dodatkiem nanorurek haloizytowych. Cz. 1, Charakterystyka procesu wytłaczania

Głogowska Karolina, Majewski Łukasz

Przemysł Chemiczny

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2019

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T. 98, nr 8

1313--1315

PL

Polietylen o małej gęstości napełniono haloizytowymi nanorururkami (średnica 30–70 nm, długość 1–3 μm) o udziale masowym 2–6% w stosunku do osnowy oraz bez dodatków, proces wytłaczania przeprowadzono w laboratoryjnej wytłaczarce jednoślimakowej przy prędkościach obrotowych ślimaka 50 rpm i 150 rpm. Zbadano wpływ składnika chemicznego i prędkości obrotowej ślimaka na parametry wytłaczania. Największą wydajność procesu (ponad 39,6%) osiągnięto podczas wytłaczania polimeru nienapełnionego przy prędkości ślimaka 150 rpm. Wydajność nieznacznie spadała (do 39,1%) wraz ze wzrostem zawartości nanorurek. Najmniejszą wartość jednostkowego zużycia energii osiągnięto przy wytłaczaniu (150 rpm) materiału zawierającego 2% haloizytu. Zastosowanie prędkości obrotowej ślimaka 50 rpm spowodowało znaczne zmniejszenie wydajności wytłaczania oraz znaczny wzrost jednostkowego zużycia energii dla badanych materiałów.

EN

Low d. polyethylene doped with halloysite nanotubes (diam. 30–70 nm, length 1–3 μm) in concns. 2–6% by mass as well as without additives was extruded in a single-screw lab. extruder at 50 rpm or 150 rpm. The effect of chem. compn. of obtained materials and rotational speed of the screw on the parameters of the extrusion process was tested. The highest efficiency of the process (over 39.6%) was achieved during extrusion at screw speed of 150 rpm of non-doped polymer. The efficiency slightly decreased to 39.1% with the increase of the nanotube content. The smallest value of unit energy consumption was achieved for the extrusion (at 150 rpm) of a material contg. 2% halloysite. The screw rotating at 50 rpm resulted in a significant redn. in the efficiency of the process as well as in significant increase in the unit energy consumption for the tested materials.

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Studium wytłaczania polietylenu z dodatkiem nanorurek haloizytowych. Cz. 3, Właściwości strukturalne

Majewski Łukasz, Sikora Janusz W., Głogowska Karolina

Przemysł Chemiczny

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2019

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T. 98, nr 8

1319--1322

PL

Intensywny rozwój nauk z obszaru inżynierii materiałowej sprawił, że modyfikując właściwości materiałów kompozytowych coraz częściej konieczne jest sterowanie strukturą materiału na poziomie skali nano aby uzyskać pożądane właściwości użytkowe. Zmiany właściwości nanokompozytów polimerowych są ściśle związane z jakością rozprowadzenia fazy wzmacniającej w osnowie polimerowej. Badano mikrostruktury kompozytów polimerowych na osnowie polietylenu małej gęstości z dodatkiem nanorurek haloizytowych (HNT) wytworzonych w procesie wytłaczania jednoślimakowego przy różnych prędkościach obrotowych ślimaka. Na podstawie otrzymanych fotografii mikroskopowych ze skaningowego mikroskopu elektronowego dokonano analizy struktury badanych kompozytów oraz oceny jakości zdyspergowania HNT w osnowie z polietylenu. Przeprowadzono badania z wykorzystaniem skaningowego kalorymetru różnicowego, na podstawie których określono wpływ zawartości HNT na temperaturę zeszklenia, temperaturę topnienia, temperaturę krystalizacji oraz stopień krystaliczności polietylenu małej gęstości.

EN

Low d. polyethylene prepd. by K. Głogowska and Ł. Majewski (2019)¹⁾ was studied for dispersion of nanotubes in polyethylene matrix by using a scanning electron microscope. Redn. of the rotational speed of the screw in composites with a constant content of nanotubes resulted in an increase of the no. of small sized agglomerates. Increasing the content of nanotubes in composites resulted in an increase of the the no. of agglomerates and their size. The melting, glass transition and crystn temps. were detd. by differential scanning calorimetry. Melting points and glass transition temps. of composites were slightly lower than the corresponding values of polyethylene, while an inverse relationship was obsd. for the crystn. point value.

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Studium wytłaczania polietylenu z dodatkiem nanorurek haloizytowych. Cz 2, Właściwości mechaniczne i przetwórcze

Sikora Janusz W., Majewski Łukasz, Głogowska Karolina

Przemysł Chemiczny

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2019

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T. 98, nr 8

1316--1318

PL

Określono wpływ parametrów wytwarzania oraz zawartości masowej nanorurek haloizytowych HNT (halloysite nanotubes) na wybrane właściwości mechaniczne oraz przetwórcze wytłoczyny z polietylenu o małej gęstości. Próbki pomiarowe wytłoczono z wykorzystaniem wytłaczarki jednoślimakowej przy zmiennej prędkości obrotowej ślimaka. Dokonano pomiarów masowego i objętościowego wskaźnika szybkości płynięcia oraz oceniono wpływ wybranych czynników zmiennych na intensywność pojawiającego się podczas wytłaczania efektu Barusa. Przeprowadzono analizę zmian podstawowych właściwości mechanicznych otrzymanych wytłoczyn na podstawie wyników ze statycznej próby rozciągania.

EN

Low d. polyethylene prepd. by K. Głogowska and Ł. Majewski (2019) was studied for mech. properties (Young modulus, tensile strength) as well as processability (melt flow rate indexes and material swelling behind the extruder head). The increase in the content of halloysite in the tested materials resulted in the redn. of their Young modulus and tensile strength and in an increase of the melt flow rates. The 2% addn. of halloysite resulted in decreasing the material swelling. The increase in the swelling value was obsd. for higher additive contents and higher rotational speeds of the extruder screw.

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The Effect of Ageing on Selected Properties of Polylactide Modified with Blowing Agents

Głogowska Karolina, Majewski Łukasz, Garbacz Tomasz, Tor-Świątek Aneta

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 4

204--213

EN

The modification of processing and functional properties of polymeric materials is widely used in polymer processing. The current progress in this field involves the introduction of new ways of modifying polymers, often by changing their structure from homogeneous to porous. As a result, these polymers have lower density, and thus modified processing and functional properties. The paper presents the results of a study on the selected properties of the injection-molded specimens of polylactide (PLA) modified with blowing agents, before and after thermal ageing. Blowing agents with exothermic (Hydrocerol 530) and endothermic decomposition (Hydrocerol ITP-810, Expancel 951 MB 120 and LyCell F-017) were used. The mass content of the blowing agents was changed in the range from 0.5% to 3%. The study involved examination of the changes in properties such as Young’s modulus, tensile strength, tensile stress, strain at maximum tensile stress, Vicat softening temperature and impact strength depending on the mass content and type of blowing agent before and after the ageing process.