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103. posiedzenie Międzyresortowej Komisji ds. Najwyższych Dopuszczalnych Stężeń i Natężeń Czynników Szkodliwych dla Zdrowia w Środowisku Pracy

Skowroń Jolanta

Bezpieczeństwo Pracy : nauka i praktyka

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2023

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nr 1

24-28

PL

Podczas 103. posiedzenia Międzyresortowej Komisji ds. Najwyższych Dopuszczalnych Stężeń i Natężeń Czynników Szkodliwych dla Zdrowia w Środowisku Pracy, które odbyło się 20 października 2022 r., rozpatrywano propozycje wartości dopuszczalnych stężeń dla dwóch nowych substancji: metakrylanu 2,3-epoksypropanu i oksym butan-2-onu. Ponadto dyskutowano weryfikację wartości dopuszczalnych stężeń izoprenu i niklu [7440-02-0] oraz jego związków - w przeliczeniu na Ni - z wyłączeniem tetrakarbonylku niklu [13463-39-3].

2

Determination of mechanical properties of methyl methacrylate adhesive (MMA)

Kozłowski M., Bula A., Hulimka J.

Architecture Civil Engineering Environment

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2018

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Vol. 11, no. 3

87--96

EN

Experimental testing of epoxy adhesives, which are commonly used in civil engineering for the strengthening of existing structures with composite products have been a topic of limited studies. It was due to the damage which usually occurred not in the adhesive layer but in the strengthened material. Recent studies have shown that the choice of an adhesive significantly affects the load-bearing capacity of the entire joint. The paper presents the results of strength tests of a selected methyl methacrylate adhesive, carried out according to the standards EN ISO 527-1 and EN ISO 527-2. Comparing the results to the data provided by the manufacturer (tested in accordance with ASTM D638) discrepancies have been found in the normative assumptions and consequently differences in the results. Experiments on the adhesive showed clear dependency on the speed of testing which revealed through variable characteristics after the elastic limit. Numerical simulations were also carried out assuming the elastic-plastic material model. The analyses allowed to obtain the distribution of stresses and deformations along the length of the sample and allowed to verify the length of the extensometer used. Comparison of results obtained for different measuring lengths of chosen adhesive confirmed the need to use extensometers in the testing of mechanical properties.

3

Degree of conversion of dental composite materials in relation to different light-curing parameters

Malara P., Czech Z., Świderski W.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 70, nr 2

60--69

EN

Purpose: The aim of the work was determine conversion degree of composite dental materials with different resins in relation to different light-curing parameters. Design/methodology/approach: The article provides an insight on factors influencing conversion degree of composite materials. Standardized samples made of Herculite XRV based on a methacrylate resin and Filtek Silorane based on silorane resin and were cured using two types of Light Curing Units (LCUs) – halogen and LED. The samples were cured at different distances and for different times. Findings:Research has showed that the polymerization of Filtek Silorane composite is significantly slower than polymerization of Herculite XRV composite. Extending exposure time does not compensate for decrease of light intensity caused by increase of the distance of the light source from the surface of cured composite. Research limitations/implications: Further studies on degree of conversion of dental composite materials will allow to expand the knowledge on characteristics of materials used in dental clinical practice. Practical implications: Evaluation of curing methods, curing parameters and good knowledge on units used in light-curing of composite materials allow to acquire filling materials with best functional qualities. Originality/value: The paper presents degree of conversion of composite materials based on different matrixes and cured with different methods.

4

The influence of light curing parameters on wear resistance of selected resin-based dental composites

Malara P., Czech Z., Świderski W.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 64, nr 2

62--71

EN

Purpose: The aim of the work was to test influence of curing time and distance of the light source on wear resistance of composite dental materials. Design/methodology/approach: The following study provides an insight into factors influencing wear resistance of composite materials. Standardized samples were made of methacrylate-based material Herculite XRV and silorane-based material Filtek Silorane and were tested using two types of Light Curing Units (LCUs) – halogen and LED. The distance of light source and time of curing differed between samples. Findings: Filtek Silorane composite compared to Herculite XRV composite guarantees higher wear resistance, regardless of the used LCU type. Using LED LCU compared to halogen LCU allows to obtain higher wear resistance both for Herculite XRV and Filtek Silorane composite. The lower the distance of light source the higher the wear resistance of composite material. Research limitations/implications: Further studies will provide additional information on other properties such as compressive strength, and degree of conversion. Practical implications: This article shows important comparison between older and newer composite technology. It provides practical information on polymerization methods. Originality/value: Article shows broad spectrum of different curing methods, important to the composite material use in dentistry.

5

The effect of the curing time and the distance from the light source on hardness of Methacrylate and Silorane resin-based dental composite materials

Malara P., Czech Z., Świderski W.

Archives of Materials Science and Engineering

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2014

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Vol. 70, nr 1

28--38

EN

Purpose: The aim of the work was to test hardness of composite dental materials with different resins in relation to different light-curing parameters. Design/methodology/approach: The following article provides and insight into factors influencing hardness of composite materials. Standardized samples made of Herculite XRV based on a methacrylate resin and Filtek Silorane based on silorane resin were tested using two types of Light Curing Units (LCUs) – halogen and LED. The distance of light source and time of curing differed between samples. Findings: Filtek Silorane composite compared to Herculite XRV composite guarantees higher hardness, regardless of the used LCU type. Using LED LCU compared to halogen LCU allows to obtain higher hardness both for Herculite XRV and Filtek Silorane composite. The lower the distance of light source the higher the hardness of composite material. Research limitations/implications: Further studies will provide additional information on other properties such as compressive strength, wear resistance and light transmission. Practical implications: This article presents important comparison between older and newer composite technology. It provides practical information on polymerization methods. Originality/value: Article shows broad spectrum of different curing methods, important to the composite use in dentistry.

6

Photocurable methacrylate/nanosilica composites

Andrzejewska E., Sądej M.

Polimery

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2008

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T. 53, nr 4

321-323

EN

Two types of photocurable systems containing triethylene glycol dimethacrylate (TEGDM) and 3-15 wt. % of nanosilica were prepared and investigated. The silicas used were structure modified fumed silicas aftertreated by methacrylsilane. The obtained dispersions were characterized by mean particle size (Z-average diameter), polydispersity index (PDI), Zeta potential and by the viscosity of the system (?). It was found that the maximum polymerization rate Rpmax and double bond conversion p increase with silica concentration up to 5 or 4 wt. %, depending on silica type; further increase in silica content reduces both Rpmax and p. This result correlates well with the stability of the dispersion as measured by its Zeta potential value. The lowest Zeta potentials were obtained for composites showing the highest Rpmax values.

PL

Otrzymano i zbadano dwa rodzaje kompozycji fotoutwardzalnych zawierających dimetakrylan glikolu trietylenowego oraz nanokrzemionkę w ilościach 3-15 % mas. Zastosowano nanokrzemionki pirolityczne modyfikowane strukturalnie oraz powierzchniowo. Otrzymane dyspersje scharakteryzowano poprzez średni rozmiar (Z-average diameter) i indeks polidyspersyjności (PDI) cząstek napełniacza, jak również przez potencjał Zeta oraz lepkość (...) kompozycji (tabela 1). Stwierdzono, że maksymalna szybkość polimeryzacji (Rpmax) i konwersja wiązań podwójnych (p) wzrastają po dodaniu krzemionki oraz rosną ze wzrostem jej zawartości osiągając maksymalną wartość przy stężeniu 5 lub 4 % mas., w zależności od rodzaju krzemionki. Dalszy wzrost zawartości napełniacza obniża zarówno Rpmax jak i p (rys. 1). Wynik ten dobrze koreluje ze stabilnością kompozycji określoną przez potencjał Zeta. Kompozycje o najwyższych wartościach Rpmax wykazywały najmniejsze wartości potencjału Zeta (rys. 2).

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Modyfikacje nienasyconych estrów skrobi aminami i tiolami

Stawski D.

Zeszyty Naukowe. Włókiennictwo / Politechnika Łódzka

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2005

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z. 61

45-56

PL

W pracy zsyntezowano estrowe pochodne skrobi (akrylan i metakrylan) metodą międzyfazowej estryfikacji skrobi odpowiednimi chlorkami kwasowymi. Zbadano nieopisaną dotąd w literaturze nukleofilową addycję amin pierwszo- i drugorządowych oraz tioli do grup winylowych akrylanu i metakrylanu skrobi. Określono wpływ temperatury, rodzaju aminy, stopnia podstawienia i rodzaju rozpuszczalnika na kinetykę addycji do akrylanu skrobi. Porównano odporność termiczną skrobi, jej pochodnej estrowej i aminowej. Wykazano działanie antyelektrostatyczne oraz sorpcyjne trzeciorzędowych i czwartorzędowych pochodnych skrobi.

EN

Ester derivatives of starch, which contain reactive vinyl bonds, such as starch acrylate and methacrylate, were synthesized. The synthesis of these compounds, which had not been sufficiently described as yet, was carried out at a low temperature (about -7°C) by the interfacial esterification of starch with appropriate acid chlorides. Under these conditions no degradation of the polysaccharides chain and no side reactions of vinyl bonds take place. Based on the results of elementary analysis and FTIR, H-NMR and C-NMR spectra, the chemical composition of the esterification products has been confirmed. The second stage of this study was intended for detailed investigation of the so far unreported reactions of nucleophilic addition of primary and secondary amines and dodecanitiole to vinyl groups of starch acrylate and methacrylate under the conditions of pseudo-first order reaction. Based on the obtained results it has been found that the effect of temperature on the reaction rate is consistent with the general assumption of chemical kinetics. The calculated activation energies for the secondary amine addition ranged from 13.2 to 24.2 kJ/mol and those for primary amines from 11.7 to 13.0 kJ/mol. A slight effect of THF and dioxane on the addition kinetics was also observed, while the reaction course was slower in DMSO, which is characterized by a considerably higher dielectric constant. On the other hand, a clear decrease in the constants of pseudo-first order reaction rates was observed in the case of primary and secondary amines with different lengths of aliphatic chain. The presence of amine and thiol groups in the products of addition was confirmed by the methods of FTIR, H-NMR and C-NMR. On the basis of the results of thermogravimetric analysis of starch and products of its modification it has been found that the thermal resistance of starch acrylate is slightly higher than that of initial starch and the degree of substitution with ester groups exerts no significant influence on their thermal stability. The starch derivatives containing tertiary amine groups and anionic groups were successfully used as an antistatic finish for polyester fabrics. The use of N,N-dipropylaminepropionate of starch as a sorbent of copper ions has been also investigated. The results obtained show that the amine derivatives of starch can combine about 1.5 mmole of Cu2+/g sorbent after 10 h.

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Fotoprzewodnictwo w polimerach z grupowaniem karbazolowym

Diduch K., Wubbenhorst M., Kucharski S.

Prace Naukowe Instytutu Technologii Organicznej i Tworzyw Sztucznych Politechniki Wrocławskiej. Konferencje

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2003

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Vol. 52, nr 25

338-341

PL

Przeprowadzono syntezę nowych polimerów metakrylanowych z dwufunkcyjnymi monomerami zawierającymi fragment karbazolowy i azofenylosulfonową grupę chromoforową. Określono właściwości fizykochemiczne otrzymanych homo i kopolimerów. Przeprowadzone badania wykazały dobre właściwości fotoelektrycznych badanych układów polimerowych. Stwierdzono znaczący wpływ dodatku 2,4,7-trinitro-9-fluorenonu (TNF) na wielkość fotoprzewodnictwa w badanych próbkach.

EN

A novel bi-functional photorefractive methacrylate polymer with carbazolyl fragments and chromophoric azophenyl sulfonyl group were synthesized and characterized. Photoelectrical properties were revealed by the generation of photocurrents on illumination. The addition of TNF resulted in a considerable increase of the photoconductivity of polymers.

9

Preparation and modification of microspheres by dispersion copolymerization of 3-chloro-2-hydroxypropyl methacrylate and methyl methacrylate

Łukaszczyk J., Cebulska A.

Zeszyty Naukowe. Chemia / Politechnika Śląska

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2001

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z. 146

27-30

EN

Epoxy-functional polymeric microspheres were obtained by the modification of the surface of microspheres based on copolymers of 3-chloro-2-hydroksypropyl methacrylate. Microspheres were prepared by dispersion polymerization. The effect of the type of stabilizer (PVAc or PEO) on the particle size, size distribution and yield was investigated.

10

Polymerization of methyl methacrylate in the presence of carbon - nanotubes (CNTs)

Szafko J., Onderko K., Pabin-Szafko B.

Zeszyty Naukowe. Chemia / Politechnika Śląska

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2001

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z. 146

45-49

EN

The verified values of the densities of methyl methacrylate (MMA) and poly(methyl methacrylate) (PMMA) were determined in the temperature range of 20-60 degrees C, which were used to establish the dependence between the contraction of monomer and its conversion (by dilatometric method). Polymerization of MMA initiated by 2,2'-azobis (2-methyl-4-hydroxybutyl propionate) (AIB-BD) in N,N'-dimethylformamide (DMF) was also observed in the presence of three kinds of carbon-nanotubes (CNTs). The interpretation of kinetics of this process was performed according to equation of the first order.

11

Calorimetric study of polymerisation of dimethacrylate monomers

Barszczewska-Rybarek I., Gibas M.

Zeszyty Naukowe. Chemia / Politechnika Śląska

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2001

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z. 146

55-58

EN

The new urethane-dimethacrylates were examined by Differential Scanning Calorimetry (DSC) in order to evaluate conversion of double bonds and then the network parameter values of the polymer networks formed. The latter were calculated for: ideal Flory network, non-ideal network with tetrafunctional junction points and non-ideal network with trifunctional junction points to compare with DMTA results.

12

Współczynnik transportu w drewnie nasycanym metakrylanem metylu

Kyzioł L.

Zeszyty Naukowe Akademii Marynarki Wojennej

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1999

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R. 40 nr 3 (140)

63-70

PL

Przedstawiono rozkład koncentracji metakrylanu metylu w bielastym i twardzielowym drewnie sosnowym. Określono charakterystyki współczynnika transportu metakrylanu metylu w drewnie sosnowym dla kierunku nasycania promieniowego i stycznego dla przedziału czasowego t=4-800h

EN

The paper presents distribution of concentration of methacrylate methyl in pine alburnous wood and heart-wood. It shows transport coefficients of mathacrylane methyl in pine wood for the direction of radial and contact treatment for the time interval t=4-800h.