BazTech - Yadda

1

The changes of LD-PE films after exposure in different media

Kojnoková Tatiana, Markovičová Lenka, Nový František

Production Engineering Archives

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2020

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Vol. 26, Iss. 4

185--189

EN

This work deals with the study of polymers, and, in particular, polyethylene; its production, types, properties, and usage. The experimental part evaluates the changes of properties of the polyethylene film to be reused under various exposure conditions and selection of the most suitable medium for its application. The film made of low-density polyethylene (LD-PE) was influenced by aggressive media with different pH, specifically Savo for the disinfection, Savo as a Saponate for dish washing and Coca-Cola. On LD-PE films the water absorption and melting temperature evaluation tests were performed. Carried out tests show that the most aggressive medium for LD-PE film from used media is Coca-Cola. The most effective application of LD-PE film like wrapping on container transported is the Savo used as a Saponate for dish washing.

2

Enhancement of tribological properties and characteristic of polymer matrix composite (UHMWPE reinforced with short fibres of polyester) for Total Disc Replacement (TDR)

Obaid M. N., Radhi S. H.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 102, nr 2

55--65

EN

Purpose: The number of people suffering from Degenerative Disc Disease (DDD) is increasing. The disease causes heavy pain and restrict a number of day-to-day life activities. In extreme cases, the degraded disc is removed under total disc replacement which is usually made up of Ultra-High Molecular Weight Polyethylene (UHMWPE). The material has astounding biocompatible characteristics mechanical properties and wear resistance. However, these characteristics are insufficient in arthroplasty application. Therefore, research investigations are ongoing to improve tribological properties through reinforcement that may result in a composite material of UHMWPE. Thus the current study is aimed at reinforcing UHMWPE with short fibres of polyesters to enhance the tribological properties and surface characteristic so as to improve wear resistance and nourish the fibroblast cells on synthetic disc. Design/methodology/approach: The researcher prepared UHMWPE composite material, reinforced with different weight fractions of short polyester fibres (2, 4, 6, 8 and 10% following hot press method. Further pin-on-disc device was used to study the tribological properties (coefficient of friction and volume of wear). The study tested surface roughness and surface characteristics by atomic force microscopy (AFM) device, hardness by shore D device, contact angle to study the effect of polyester short fibres on wettability of UHMWPE surface and tested the thermal properties and crystalline degree using Differential Scanning Calorimetry measurement (DSC) device. Findings: The results infer that the wear resistance got improved when using 2% w.t polyester though it got decreased initially. However, the value was still more than neat UHMWPE. There was a decrease observed in coefficient of friction, but after 4 w.t% polyester, the coefficient of friction got increased due to increasing percentage of fibres which make it harder and stiff compared to UHMWPE. There was a decline observed in surface roughness due to alignment of the fibres with smooth surface. The contact angle got increased in a moderate range while the roughness enhanced the growth of fibroblast cell. The hardness of composite material got increased, because the fibres turned stiffer and harder than the matrix. DSC results infer the improvements in thermal stability due to high thermal properties of polyester fibres compared to UHMWPE. The degree of crystallinity got increased which in turn enhanced wear resistance, especially at 6 w.t % polyester fibres. There was a mild increase observed in density since the density of polyester is higher than polymer. Research limitations/implications: The major challenge was the dispersion of fibres. Uniform distribution of fibres within the matrix (UHMWPE) was achieved through two steps of mixing processes such as mechanical mixture and twin extruder. In future studies, fatigue tests must be conducted to study the behaviour of prepared composite materials under fatigue cycle. Practical implications: A significant objective is how to connect among different properties to obtain good improvement in tribological and surface properties so as to enhance wear resistance and growth of fibrolase cells. Originality/value: In this study, polymeric short fibres were used as reinforcement with polymeric matrix to enhance the wettability of fibres with matrix. In this way, the bonding among them got increased which supports the tribological, surface, and crystalline behaviour.

3

Improvements to the two-phase sandwich method for calculating the melting points of pure metals

Rybacki K., Winczewski S., Pleechystyy V., Rybicki J.

Computational Methods in Science and Technology

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2019

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Vol. 25, No. 2

105--116

EN

The thermophysical properties of metal alloys are often investigated via molecular dynamics (MD) simulations. An exact and reliable estimation of the thermophysical parameters from the MD data requires a properly and carefully elaborated methodology. In this paper, an improved two-phase sandwich method for the determination of the metal melting temperature is proposed, based on the solid-liquid equilibrium theory. The new method was successfully implemented using the LAMMPS software and the C++11 Standard Libraries and then applied to aluminum and copper systems. The results show that the proposed procedure allows more precise calculations of the melting temperature than the widely used onephase boundary methods.

4

Research on the properties of Co-TiC and Ni-TiC HiP-sintered alloys

Cherepova Tetiana, Dmitrieva Galyna, Tisov Oleksandr, Dukhota Oleksandr, Kindrachuk Myroslav

Acta Mechanica et Automatica

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2019

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Vol. 13, no. 1

57--67

EN

Three types of sintered alloys were fabricated based on cobalt, nickel and high-temperature alloy ZhS32-VI matrix with titanium carbide strengthening phase. TiC content was in a range of 30–50 vol. %. The melting temperatures of alloys are higher than 1320°C, and they may undergo undamaged through all technological procedures together with turbine blades, including soldering and outgassing. DSC analyses indicates no additional thermal effects until melting, which confirms their structural stability. The examinations of microstructure revealed three types of constituents – TiC particles, matrix solid solution and blow outs – structural defects having negative effects on all the studied properties. It was found that heat resistance of nickel based sintered alloys at the temperature of 1100°C is superior as compared with the alloys based on cobalt and alloy ZhS32-VI. It has been established that wear resistance in conditions of fretting wear at temperatures of 20, 850, 950 and 1050°C of sintered alloy with ZhS32-VI matrix is mostly superior as compared with the other alloys. The properties of produced alloys allow to use them for manufacturing of components of friction couples operating in conditions of high temperature fretting wear, including protective pads of turbine blades top shrouds contact faces.

5

Comparison of Cupola Furnace and Blast Furnace Slags with Respect to Possibilities of Their Utilization

Pribulová A., Futáš P., Petrík J., Pokusová M., Brzeziński M., Jakubski J.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1865--1873

EN

Blast furnace and cupola furnace are furnace aggregates used for pig iron and cast iron production. Both furnace aggregates work on very similar principles: they use coke as the fuel, charge goes from the top to down, the gases flow against it, etc. Their construction is very similar (cupola furnace is usually much smaller) and the structures of pig iron and cast iron are very similar too. Small differences between cast iron and pig iron are only in carbon and silicon content. The slags from blast furnace and cupola furnace are very similar in chemical composition, but blast furnace slag has a very widespread use in civil engineering, primarily in road construction, concrete and cement production, and in other industries, but the cupola furnace slag utilization is minimal. The contribution analyzes identical and different properties of both kinds of slags, and attempts to explain the differences in their uses. They are compared by the contribution of the blast furnace slag cooled in water and on air, and cupola furnace slag cooled on air and granulated in water. Their chemical composition, basicity, hydraulicity, melting temperature and surface were compared to explain the differences in their utilization.

6

Charakterystyka i zastosowania kompozytów jednopolimerowych

Żenkiewicz M., Moraczewski K., Rytlewski P., Stepczyńska M., Żuk T.

Polimery

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2015

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T. 60, nr 1

3--11

PL

Artykuł stanowi przegląd literatury dotyczącej właściwości i zastosowań kompozytów jednopolimerowych (SPC), stosunkowo nowej i obiecującej grupy materiałów polimerowych o dużych możliwościach aplikacyjnych. Omówiono rodzaje i wybrane właściwości SPC i porównano ich najważniejsze cechy: adhezję na granicy wzmocnienia i osnowy kompozytu, różnicę wartości temperatury topnienia fazy krystalicznej wzmocnienia i osnowy, wytrzymałość na rozciąganie i moduł Younga. Scharakteryzowano SPC wytwarzane obecnie w skali przemysłowej.

EN

This paper constitutes a review of the literature concerning properties and applications of the single polymer composites (SPC). These materials are a relatively new and promising group of polymer composites which have good mechanical properties and high potential of application. The types and selected properties of single polymer composites were discussed. The most significant of these properties include adhesion at the interface of reinforcement and matrix, different melting points of crystalline phase of reinforcement and matrix, tensile strength and Young's modulus. Additionally, SPC currently produced in an industrial scale were characterized.

7

Development of Flux Structure for Processing of Aluminium Casting Production Wastes

Turakhodjaev N. D., Tursunov T. K., Yakubov L. E., Abdurakhmanov K. Z., Turakhodjaeva S. N.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 3 spec.

91--94

EN

The objective of research is to define aluminium and its production wastes melting modes in electric unit while applying protective fluxes layer. This article cites the results of researches on development of flux structure for melting of aluminium production wastes. Melting unit diagram and results of research defining aluminium production wastes melting temperature regime are exemplified. Modes of metal charging, heating-up and melting of aluminium and its production wastes are exemplified for the electric unit with movable upper and immovable lower electrodes. The article describes the results of researches and recommendations that smelting chamber temperature to be maintained in the range of 1000-1100 °С, with melting zone temperature at 1400-1500 °С. It is recommended that charging of production wastes slag was carried after flux melt and reached 700-750 °С. Tables cite fluxes compositions that allow conducting aluminium melting process in various units. In the conclusion it is stated that application of a corresponding design of melting unit in aggregate with graphite electrodes and protective fluxes provides: - reduction of irretrievable metal burn-off losses; - savings on energy expenditures; - quality upgrade of liquid smelt due to decrease of oxide inclusions and occluded gas concentration.

8

Pomiary temperatury topnienia zamienników lutów cynowo-ołowiowych

Ambroziak A., Lange A., Mosińska S.

Przegląd Spawalnictwa

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2010

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R. 82, nr 9

78-81

PL

Zgodnie z trendami panującymi na całym świecie, które wypierają luty ołowiowe, celowe staje się zastąpienie ich lutami bezołowiowymi. Istnieje więc potrzeba określenia właściwości lutownicznych nowo opracowanych stopów (lutów bezołowiowych). Przedstawiono wyniki pomiarów derywatograficznych DTA przeprowadzonych na próbkach stopów na osnowie cynku z aluminium, srebrem, miedzią i cyną z dodatkami krzemu i magnezu w celu ustalenia zakresu temperatury pracy nowo opracowywanych spoiw lutowniczych.

EN

In accordance with the prevailing trends around the world, which are displacing lead solders, there is a need for replacement with lead-free solders. Therefore a need to define properties of the newly developed solder alloys (lead-free solders). This article presents the results of the DTA measurements carried out on samples in the matrix alloy of zinc and aluminum, silver, copper and tin with additions of silicon and magnesium in order to determine the temperature range of newly developed solder adhesives.

9

The examination of the structure of PP composites with the glass fibre

Kwiatkowski D., Nabiałek J., Gnatowski A.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 7

405-408

EN

Purpose: of the examination is determination of selected physical properties: melting and crystallization temperature for polypropylene PP and its composites with glass fiber during observation the melting and congealing process by means of optical microscope in white light. Design/methodology/approach: Examination of melting and crystallization temperature of polypropylene composites with glass fibre became carried out by means of the set for the microscopic observation of phase transformations. The set consist of polarized microscope and computer system recording. By means of the set the crystal objects were tested during melting and crystallization process of polymer plastic going through the sample in normal light. The melting and crystallization temperatures were determined visuallily. Examination were carried out registering by means of the microphotography at the definite temperature occurring transformations during heating polymer samples and composites with speed of 200 °C /min, and also during cooling with speed of 50 °C/min in white light. Findings: Fibrous filler in the form of the glass fibre nucleation and modifies the process of the crystallization of the polypropylene composites. Research limitations/implications: The influence of other fillers on crystallization process of polypropylene composites will be defined in future. Practical implications: The carried out tests of structure are useful especially for determination how the used filler nucleates and modifies the crystallization process of polypropylene and its composites. Originality/value: The computer system of recording of the picture enables the carrying out of proceeding processes on-screen of the computer monitor and the recording of single frames and sequences the video, what enables more precise analysis of processes occurring at the high speed.

10

Wpływ zawartości modyfikowanego glinokrzemianu na procesy topnienia, krystalizacji i rozkładu cieplnego kompozytu na osnowie polipropylenu

Dzjubienko L. S., Łukasik K., Nikitin J. A., Sapjanenko A. A.

Przetwórstwo Tworzyw

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2006

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[R.] 12, nr 6

176-181

PL

W pracy wykazano, że modyfikowanie warstwy wierzchniej napełniaczy (porowatego glinokrzemianu) stosowanych przy wytwarzaniu kompozytów na osnowie polipropylenu jest celowe. Wpływa korzystnie na temperaturę ich topnienia, krystalizacji i utleniającego rozkładu cieplnego. Pokazano także, że modyfikowanie cząstek glinokrzemianu za pomocą oligomeryzacji jego powierzchni n-butylwinylowym eterem przy małej zawartości napełniacza w polimerowym kompozycie podwyższa temperaturę początku topnienia o 4 ÷ 6°C, temperaturę topnienia o 2 ÷ 5°C praktycznie nie zmieniając tego zakresu i prowadzi do podwyższenia stopnia krystaliczności polimeru. Modyfikowanie glinokrzemianu sprzyja obniżeniu temperatury początku krystalizacji i zawężeniu zakresu temperatury krystalizacji. Przy małej zawartości napełniacza w badanych kompozytach zaobserwowano podwyższenie temperatury początku rozkładu cieplnego. Wpływ modyfikowanego glinokrzemianu na w/w efekt przypisano plastyfikującemu oddziaływaniu cząsteczek modyfikatora na granicy rozdziału glinokrzemian - polipropylen.

EN

This paper presents that modification of the top layer of fillers (foamed aluminosilicates) during production of composites on polypropylene matrix is purposeful. It profitably influences their melting temperature, crystallization and oxidative pyrolyzis. The article also shows that by modifying particles of aluminosilicates by surface oligomerization using n-buthylvinyl ether in not very high amount of filler in polymer composite raises the beginning of melting temperature by 4 ÷ 6°C and melting point by 2 ÷ 5°C. Practically not altering this range it increases the crystallity of polymer. Aluminosilicates modification favors decrease of beginning of crystallization temperature and narrows the range of crystallization temperature. The increase of pyrolyzis temperature was observed at small content of filler in studied composites. The influence of modified aluminosilicates. On described effect was attributed to plastifying interaction of modified filler particles on the aluminosilicates - polymer matrix boundary.

11

Struktura nadcząsteczkowa i własności termiczne kompozytów na osnowie polipropylenu wzmacnianych włóknem szklanym

Sobczak R., Nitkiewicz Z., Koszkul J.

Kompozyty

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2003

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R. 3, nr 8

343-348

PL

Przeanalizowano wpływ zawartości włókna szklanego na stopień krystaliczności i własności termiczne kompozytów na osnowie polipropylenu. Badaniom poddano polipropylen oraz kompozyty o zawartości 30 i 50% włókna szklanego. Przeprowadzono badania metodą różnicowej kalorymetrii skaningowej (DSC) oraz badania mikroskopowe z wykorzystaniem przystawki temperaturowej. Badania DSC przeprowadzono na urządzeniu DSC 200 PC Phox firmy Netzsch. Próbki (ok. 10 mg) ogrzano do temperatury 200°C, wytrzymano je w tej temperaturze przez 4 min w celu wyeliminowania termicznej historii materiału. Następnie próbki schłodzono do temperatury krystalizacji Tc osnowy. Badania prowadzono w atmosferze azotu z szybkością skanowania 10°C/min. Po krystalizacji próbki byty ogrzewane do temperatury topnienia osnowy kompozytów. Temperatury topnienia Tm i krystaliczność kompozytów wyznaczono dla maksymalnej powierzchni endotermicznego piku. Tcrmogramy DSC przedstawiono na rysunkach 1 i 2. Parametry termiczne, takie jak: temperatura topnienia Tm, temperatura krystalizacji Tc, entalpia topnienia [delta]H oraz stopień krystaliczności badanych próbek zestawiono w tabeli 1. Badania morfologii osnowy polimerowej przeprowadzono za pomocą zestawu do mikroskopowej obserwacji przemian fazowych (Mettler Toledo FP82HT) z wykorzystaniem optycznego mikroskopu polaryzacyjnego. Wzrost sferolitów polipropylenu zarejestrowano na mikrofotografiach. Na rysunkach 3 i 4 przedstawiono morfologię polipropylenu oraz kompozytów na osnowie polipropylenu z włóknem szklanym. Stopień krystaliczności kompozytów obniża się wraz ze wzrostem zawartości włókien szklanych w badanych kompozytach, co wskazuje, że włókna szklane nie działają jako czynnik zarodkujący proces krystalizacji polipropylenu. W kompozytach sferolity polipropylenu nie są dobrze określone, a ich rozmiary są mniejsze niż w czystym polipropylenie. Powodem tego są włókna szklane, które ograniczają rozwój sferolitycznej struktury.

EN

The effect of glass fibre content on degree of crystallinity and thermal properties of polypropylene composites nas been examined. The polypropylene and its composites filled with 30 and 50% of the glass fibre have been tested. The study has been carried out by means of the differential scanning calorymetry (DSC) and the thermal microscopy. The thermal analysis measurements were performed using a DSC 200 PC Phox by Netzsch. The samples of about 10 mg were heated to 200°C at then held for 4 min in order to eliminate any thermal history in the material. Then the samples were cooled to the crystallization temperature Tc. The experiments were carried out in nitrogen atmosphere and the seans were obtained at 10°C/min. After crystallization, the samples were heated to the melting point of the matrix composites. The melting temperatures Tm and the degree of crystallinity of the composites were obtained from the maximum and the area of the endothermic peaks. The DSC thermograms are shown in Figures 1-2. Thermal parameters such as: melting temperature Tm, crystallization temperture Tc, heat of fusion [delta]H and the degree of crystallinity of the studied samples are reported in Table 1. The morphology of the polymer matrix was studied by using an optical polaryzing microscopy with Mettler Toledo FP82HT automatic stage thermal control. The PP spherulitic growth was observed by taking photomicrographs. Figures 3 and 4 show the morphology of polypropylene and polypropylene with the glass fibre composites. The degree of crystallinity of the composites decrease as fibre content increases which is indicating that the glass fibres doesn't as act as nucleant agents. In the composites, the PP spherulites are not well defined and their size decreases which could be attributed to restrictions created by the glass fibres on the development of a spherulitic structure.

12

Thermal behaviour of rapidly quenched Cu-Ni based alloys with phosphorus

Ziewiec K., Gajerski R., Dutkiewicz J., Król J.

Metallurgy and Foundry Engineering

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2002

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Vol. 28, no. 2

149-156

EN

Thermal behaviour of Cu-Ni-P alloys at or near eutectic during heating has been investigated. The microstructure of the alloys has been studied by means of optical microscope. Melt spinning of alloys has been carried out to obtain amorphous structure, then X-ray diffraction analysis was used to study the structure after rapid solidification. Thermal properties of the alloys using DTA and DSC have been investigated.

PL

Badano charakterystykę termiczną szybko chłodzonych stopów Cu-Ni-P o składach bliskich eutektyki podczas nagrzewania. Mikrostrukturę stopów zbadano za pomocą mikroskopu optycznego. W celu uzyskania struktury amorficznej przeprowadzono odlewanie taśm metodą melt spinning. Następnie, aby określić strukturę po szybkim krzepnięciu, przeprowadzono analizę rentgenowską. Własności termiczne stopów zbadano za pomocą urządzeń DTA i DSC.

13

Teoria zarodkowania krystalizacji polimerów. Cz. I. Modyfikacje klasycznej teorii zarodkowania

Ziabicki A.

Polimery

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2000

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T. 45, nr 7-8

520-527

PL

Omówiono podstawy klasycznej (jednowymiarowej) teorii zarodkowania kryształów Yolmera-Webera [1] i Beckera-Dóringa [3], wraz z modyfikacjami wprowadzonymi w celu dostosowania teorii do opisu krystalizacji polimerów. W szczególności, omówiono wpływ kształtu agregatów krystalicznych oraz wpływ symetrii i orientacji krystalizujących cząsteczek. Przedyskutowano też proces zarodkowania uwarunkowany translacyjną i rotacyjną dyfuzją krystalizujących cząsteczek.

EN

The Volmer-Weber [1] and Decker-Doring [3] nucleation theories are described and modified to adjust the classical theories to polymer crystallization with particular reference to cluster shape and orientation and concentration of the crystallizing molecules. Nucleation is also discussed in relation to translational and/or rotational diffusion of the crystallizing molecules.