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1
Content available Przegląd domieszek do żywicy fenolowej pod względem użycia ablacyjnego
Rybakiewicz Łukasz
Problemy Techniki Uzbrojenia
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2023
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R. 52, z. 166
67--97
PL
W artykule zebrano przebadane domieszki do żywicy fenolowej i kompozytów węglowo-fenolowych w celu zwiększenia ich stabilności termicznej, które były badane w kompozytach pod względem właściwości termicznych, z możliwością użycia materiału do celów ablacyjnych. Opisano zjawisko ablacji, procesy zachodzące w żywicy fenolowej podczas oddziaływania temperatury, produkcję włókien oraz ich wpływ zawartości na ablację. Przestawiono, jak domieszki wpływają na stabilność termiczną oraz proces utwardzania żywicy.
EN
The article collects tested additives for phenolic resin and carbon-phenolic composites in order to increase their thermal stability. The article presents additives that were tested in composites in terms of thermal properties, with the possibility of using the material for ablative purposes. The phenomenon of ablation, the processes occurring in the phenolic resin under the influence of temperature, the production of fibers and the effect of their content on ablation, how additives affect the thermal stability and the process of resin curing are described.
2
Content available Lightweight particleboards - manufacturing modification using a blowing agent from the group of bicarbonates
Bednarczyk Dominika, Boruszewski Piotr
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
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2022
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No. 117
55--62
EN
Lightweight particleboards - manufacturing modification using a blowing agent from the group of bicarbonates. Although the low-density particleboards have grown in popularity, due to their facilitated transportation and a lower mass in the assembled finished products, there is still certain constraints in their use caused by limited mechanical properties. These obstacles may be overcome by the mechanism of foaming the polymers that bind wood particles in the boards’ structure. The aim of this study was to determine the possibility of using sodium bicarbonate as a blowing agent of phenolic resin used for bonding wood particles in the technology of lightweight particleboards. It was found that the addition of sodium bicarbonate in the amount of 5% in relation to the dry weight of the phenolic resin significantly increase the internal bond strength of the manufactured particleboards.
PL
łyty wiórowe o obniżonej gęstości - modyfikacja wytwarzania przy użyciu poroforu z grupy wodorowęglanów. Pomimo tego, że płyty wiórowe o obniżonej gęstości zyskują na popularności, ze względu na ułatwiony transport i niższą masę gotowych produktów, nadal istnieją pewne utrudnienia w ich zastosowaniu, spowodowane niedostatecznymi właściwościami mechanicznymi. Ograniczenia te mogą zostać zminimalizowane dzięki zastosowaniu mechanizmu spieniania żywicy wiążącej cząstki drewna w płytach wiórowych. Celem pracy było określenie możliwości zastosowania wodorowęglanu sodu jako poroforu żywicy fenolowej stosowanej do zaklejenia cząstek drewna w technologii lekkich płyt wiórowych. Stwierdzono, że dodatek wodorowęglanu sodu w ilości 5% w stosunku do suchej masy żywicy fenolowej istotnie zwiększa wytrzymałość na rozciąganie prostopadle do płaszczyzny płyty w wytworzonym materiale.
3
Content available remote Fly ash/phenolic resin composite for brake pad application : fabrication, materials and thermal properties
Savetlana Shirley, Lubis Asnawi, Aditya Lingga, Irfan Muhammad, Siadari Dedi, Efendi Gunawan, Yusuf Muhammad, Jefri Hel
Composites Theory and Practice
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2020
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R. 20, nr 3-4
95--101
EN
Nowadays, many parts of automotive components are made of composites. One application of composites is brake lining material in braking systems. Fly ash is waste from burning coal in the power plant industry. Fly ash was added to a polimer matrix to enhance the wear properties of the composite. The appropriate temperature and pressure for composite fabrication were chosen from the composite which has the highest hardness. The addition of 30 wt.% fly ash to the phenolic resin matrix resulted in the lowest specific abrasion of the composite. Additions of graphite, iron powder and nitrile butadiene rubber increased the specific abrasion of the fly ash/phenolic resin composite. Scanning electron microscope micrographs showed the distribution and agglomeration of the particles in the phenolic resin matrix. The addition of fly ash to the phenolic resin matrix also increased the temperature resistance of the composite. Thermogravimetric analysis shows that the starting temperatures for decomposition of the composite constituents shifted to higher temperatures as the fly ash content increases.
4
Content available Effect of Silicate Modifier on the Emission of Harmful Compounds from Phenolic Resin used in Cold-Box Technology
Żymankowska-Kumon S., Bobrowski A., Drożyński D., Grabowska B., Kaczmarska K.
Archives of Foundry Engineering
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2018
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Vol. 18, iss. 1
151--156
EN
In many foundries, the requirements placed on castings production have risen mainly over the few years. Further trends in recent years have been the ever increasing level of automation and introduction of new alloys, especially composites. On the other hand, the foundry environment has become increasingly difficult because is used many organic binders. Environmental regulations will be further tightened up. These processes are pursued at national, European and global level. Conformity with emission limits is becoming increasingly difficult. The problem is emission of aromatic hydrocarbons, phenol, odours and other harmful compounds to environment. The main purpose of many companies is reduction of this toxins. The new cold-box systems (based on phenolic resins) try to reduce the emission by introducing into the resin structure silicate modifiers. Research presented of this article evaluate the effectiveness of these methods. The results show comparison of two resins ("without" and "with" silicate modifier) for assessment of emission of harmful aromatic hydrocarbons and phenol.
5
Content available Technology of manufacturing foundry cores using additive methods
Matysik P., Drożyński D., Olszowska-Sobieraj B., Grzegorek J., Bubrowski P.
Metallurgy and Foundry Engineering
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2017
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Vol. 43, no. 3
189--198
EN
The use of additive manufacturing methods for the production of sand cores with organic binders is currently the latest trend in small and unit production, as it allows for a quick and simple way to get a final cast part; this is known as Rapid Prototyping. In this article, manufactured additive method cores were analyzed that were made of quartz sand with furfuryl resin and cores made of synthetic sand. Derivatographic measurements were compared, and examples of the high complexity cores are shown. Furthermore, the aspect ratio of the grains was determined by microscopic observation. Each type of core was characterized by a different flexural strength and differentiated results of abrasion. The results were collected and compared.
PL
Wykorzystanie przyrostowych technik zwanych „szybkim prototypowaniem” do produkcji rdzeni z mas ze spoiwami organicznymi jest obecnie najnowszym trendem w produkcji małoseryjnej i jednostkowej. Techniki te umożliwiają otrzymanie gotowego wyrobu w bardzo szybki i prosty sposób. W niniejszym artykule przeanalizowano wytworzone metodą addytywną rdzenie z piasku kwarcowego ze spoiwem furfurylowym oraz rdzenie z piasku syntetycznego ze spoiwem syntetycznym, porównano wyniki pomiarów derywatograficznych oraz pokazano przykładowe rdzenie o dużym stopniu skomplikowania. Ponadto na podstawie obserwacji mikroskopowych wyznaczono współczynnik kształtu ziaren. Każdy typ rdzenia charakteryzował się inną wytrzymałością na zginanie oraz zróżnicowanymi wynikami ścieralności. Wyniki zostały zebrane i porównane.
6
Content available The Influence of Thermal Expansion of Unbonded Foundry Sands on the Deformation of Resin Bonded Cores
Svidró J., Diószegi A., Tóth L., Svidró J. T.
Archives of Metallurgy and Materials
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2017
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Vol. 62, iss. 2A
795--798
EN
Depending on the preparation and the applied materials, moulds and cores can be of high rigidity or can be flexible. Although, chemically bonded moulding materials have relatively good flexibility, their high temperature behaviour determines the dimensional accuracy, the stresses in the castings and can induce several casting defects, such as rattail, veining, etc. The phenomenon is based on two major effects: the thermal expansion of the unbonded foundry sands and the deformation of the sand mixtures. The main objective of the present work was to study the relationship between these two effects, and to improve the knowledge related to the thermo-mechanical interactions between the casting and the mould. Dilatometric analysis of unbonded sand samples were performed and compared to the results of hot distortion tests of moulding mixture specimens. The results showed, that the thermal expansion of foundry sand largely influences the hot distortion behaviour, but depending on the type of binder used.
7
Content available FTIR method in studies of the resol-type phenol resin structure in the air atmosphere over certain time intervals
Bobrowski A., Grabowska B.
Metallurgy and Foundry Engineering
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2015
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Vol. 41, no. 3
107--113
EN
This paper presents the results of structural-type studies of resol phenolic resin used for the preparation of molding and core sands exposed to air. The FTIR study was carried out using a transmittance technique. Recorded changes in the IR spectra of resin can indicate a progressive polycondensation process, the consequences of which being changes in the aromatic rings of methylene bridges (among others).
PL
W artykule przedstawiono wyniki badań strukturalnych żywicy fenolowej typu rezolowego stosowanej do sporządzania mas formierskich i rdzeniowych, poddanej działaniu powietrza atmosferycznego. Badania prowadzono metodą FTIR z zastosowaniem techniki transmisyjnej. Zarejestrowane zmiany w widmach IR żywicy mogą świadczyć o postępującym procesie polikondensacji, którego konsekwencją są m.in. zmiany w obrębie mostków metylenowych pierścienia aromatycznego.
8
Content available Influence of a liquid metal temperature on a thermal decomposition of a phenolic resin
Holtzer M., Bobrowski A., Dańko R., Żymankowska-Kumon S., Kolczyk J.
Archives of Foundry Engineering
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2013
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Vol. 13, iss. 2
35--38
EN
Due to the presence of harmful substances in resins those mould sands may be hazardous to the natural environment and workers. The general assessment of harmfulness of sands used for molds and cores encompasses 2 basic points: emission of hazardous substances during processes of preparing sands, pouring mold with liquid metals (high temperatures), cooling and shaking-out; possibility of washing out hazardous substances from used sands to the environment, during storage or economic use outside foundries. We present the results of research on the emission of BTEX compounds from mould sands with phenolic resins during pouring liquid metal of different temperature (cast iron and Al alloy). The research was conducted according to the original method prepared by the authors, which has been used for years in cooperation with various foundries (Poland, abroad).
9
Content available Elution of mixed moulding sands with the GEOPOL binder and core sands with the phenolic resin
Holtzer M., Żymankowska-Kumon S., Dańko R., Kmita A.
Archives of Foundry Engineering
|
2013
|
Vol. 13, iss. 4
53--56
EN
Out of moulding and core sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. Depending on the kind of the applied resin under an influence of a temperature such compounds as for example BTEX group and polycyclic aromatic hydrocarbons (PAHs) can be formed and released. During storing or economic utilization of used sand is possibility of eluting harmful substances into the environment. Therefore at assessing an influence of the used sand on the environment two above elements should be taken into consideration. Only such investigations provide the complete assessment of the given sand harmfulness.
10
Content available Assessment of Harmfulness of Phenolic Resins Hardened by CO2 in an Aspect of Emission of Substances from BTEX and PAH Groups
Holtzer M., Żymankowska-Kumon S., Bobrowski A., Dańko R., Kmita A.
Archives of Foundry Engineering
|
2013
|
Vol. 13, iss. 1 spec.
39--43
EN
Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. If in the initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylobenzene, xylenes), and also polycyclic aromatic hydrocarbons (PAHs) can be formed and released.
11
Content available Synteza i właściwości mezoporowatych węgli otrzymanych z żywic fenolowych w obecności polimerów blokowych
Choma J., Kloske M., Zawiślak A., Jaroniec M.
Ochrona Środowiska
|
2007
|
R. 29, nr 1
3-9
PL
Zaproponowano syntezę mezoporowatego węgla poprzez polimeryzację floroglucyny i formaldehydu w obecności trójblokowego kopolimeru Lutrol F127 użytego jako składnik strukturotwórczy. Otrzymany w ten sposób węgiel MC-ST scharakteryzowano na podstawie izoterm adsorpcji i desorpcji azotu w temperaturze 77 K, które użyto do wyznaczenia powierzchni właściwej, objętości porów i funkcji rozkładu objętości porów. Stwierdzono, że otrzymany węgiel MC-ST zawiera jednorodne mezopory o średnim wymiarze ok. 9 nm, ma powierzchnię właściwą ok. 450 m2/g i całkowitą objętość porów 0,70 cm3/g. Wykazano, że otrzymany materiał jest mezoporowatym węglem z niewielkim, mało znaczącym, udziałem mikroporów.
EN
Mesoporous carbon was synthesized by polymerization of phloroglucinol and formaldehyde in the presence of the triblock copolymer Lutrol F127 used as the structure directing agent. The resulting MC-ST carbon was characterized on the basis of the nitrogen adsorption-desorption isotherm measured at 77 K, which was used to evaluate the specific surface area, pore volume and pore size distribution. It has been shown that the MC-ST carbon contains uniform mesopores with a diameter of about 9 nm, and has a specific surface area and a total pore volume of about 450 m2/g and about 0.70 cm3/g, respectively. The material is a mesoporous carbon with a very small fraction of micropores.
12
Content available remote Application of phenolic resin-based spherical carbons for adsorption of carbon dioxide
Przepiórski J., Szałek M., Morawski A. W.
Polish Journal of Chemical Technology
|
2001
|
Vol. 3, nr 3
20-21
EN
Two sorts of spherical carbons were prepared by a carbonisation of phenolic resin-based spheres in both, N2 and CO2 atmospheres. CO, adsorption tests were performed for the obtained carbons. Surface coverage calculated for the carbon spheres prepared in CO2 atmosphere was found as bigger than that one for the carbon obtained with use of N,. The coverage was bigger than total surface area of the carbon. In spite of different gases used for the preparations, the tested samples did not show significant differences in their surface chemistry. Keywords: phenolic resin, carbon, adsorption, carbon dioxide
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