Wyniki wyszukiwania - BazTech

1

Preparation and characterization of ZnO-PMMA resin nanocomposites for denture bases

Cierech M., Wojnarowicz J., Szmigiel D., Bączkowski B., Grudniak A. M., Wolska K. I., Łojkowski W., Mierzwińska-Nastalska E.

Acta of Bioengineering and Biomechanics

|

2016

|

Vol. 18, no. 2

31--41

EN

Purpose: The aim of the paper was to investigate the antifungal activity of zinc oxide nanoparticles (ZnONPs) against Candida albicans. Some attempts have been made to find out the best way to introduce ZnONPs into polymethyl methacrylate (PMMA) resin material and to determine some parameters of a newly formed composite. Material and methods: Zinc oxide nanoparticles were manufactured and their basic physical parameters were determined (average particle size, density, specific surface area). Minimal inhibitory concentration (MIC) of ZnONPs was determined for the Candida albicans standard strain. The average size of ZnO conglomerates in the monomer solution of PMMA resin was measured using a dynamic light scattering instrument. PMMA resin samples with incorporated ZnONPs were produced. The morphology of nanopowder and the newly formed composite was examined under a scanning electron microscope (SEM). In addition, the roughness parameter of PMMA resin material was investigated before and after ZnONPs modification. Results: Nanopowder with the average particle size of 30 nm, density of 5.24 g/cm3 and surface area of 39 m2 /g was obtained. MIC was determined at the level of 0.75 mg/mL. The average size of ZnO conglomerates in the monomer solution of acrylic resin dropped by 11 times after ultrasound activation. SEM examination of a newly formed composite showed a successful introduction of ZnONPs confirmed by the energy dispersive X-ray spectroscopy (EDS) analysis. There were no statistically significant differences in the biomaterial roughness before and after the modification of ZnONPs. Conclusion: Zinc oxide nanoparticles were successfully incorporated into acrylic resin used for the production of denture bases. The presence of nanoparticles with sizes below 100 nm was confirmed. Nevertheless a newly created composite needs to be further investigated to improve its homogeneity, and to check its microbiological properties, strength and biocompatibility prior to its possible clinical use.

2

Water glass modification and its impact on the mechanical properties of moulding sands

Kmita A., Hutera B.

Archives of Foundry Engineering

|

2013

|

Vol. 13, iss. 2

81--84

EN

The purpose of the presented experiment was to develop an effective water glass modifier. In the conducted research, an attempt was made to determine the effect of modifier addition on the wettability of quartz grains, viscosity and cohesion of binder and strength Rmu of the sand mixture. Water glass modification was carried out with, obtained in electrochemical process [1], colloidal suspension of ZnO nanoparticles in methanol (modifier I) or propanol (modifier II), characterised by a constant molar concentration of c = 0.3 M. It was demonstrated that the addition of a colloidal suspension of ZnO nanoparticles in propanol (modifier II) had a significant effect on wettability of quartz grains improvement without the accompanying increase in binder viscosity. Testing the mechanical properties Rmu of sand mixtures containing modified binder (modifier II) hardened at ambient conditions showed an approximately 28% increase in strength compared with the Rmu of the sand bonded with an unmodified binder.

PL

Celem badań zaprezentowanego eksperymentu było opracowanie skutecznego modyfikatora szkła wodnego. Przeprowadzone badania miały na celu określenie wpływu dodatku modyfikatora na: zwilżalność kwarcu przez szkło wodne, lepkość i kohezję spoiwa oraz wytrzymałość Rmu masy. Do modyfikacji szkła wodnego zastosowano koloidalne zawiesiny nanocząstek ZnO otrzymanych w procesie elektrochemicznym [1] w metanolu (modyfikator I) lub w propanolu (modyfikator II) o stałym stężeniu molowym c = 0,3 M. Wykazano, że dodatek w postaci koloidalnej zawiesiny nanocząstek ZnO w propanolu (modyfikator II) wpływał znacząco na poprawę zwilżalności ziaren kwarcu nie zwiększając równocześnie lepkości spoiwa. Weryfikacja właściwości wytrzymałościowych Rmu mas z dodatkiem spoiwa modyfikowanego (modyfikator II) utwardzanych w warunkach otoczenia wykazała ok. 28% wzrost wytrzymałości w porównaniu z Ruu masy ze spoiwem niemodyfikowanym.

3

Wpływ modyfikacji szkła wodnego na jego lepkość i zwilżalność osnowy kwarcowej

Kmita A., Hutera B.

Archives of Foundry Engineering

|

2012

|

Vol. 12, iss. 1s

103--106

PL

Przedmiotem pracy jest opracowanie modyfikatora szkła wodnego. Do badań zaadaptowano termiczną metodę wytwarzania nanocząstek tlenku metalu. Wykorzystano nanocząstki ZnO pochodzące z rozpadu termicznego. Opracowany został sposób wprowadzenia modyfikatora oraz wpływ jego ilości, rodzaju organicznego rozpuszczalnika na właściwości fizykochemiczne spoiwa tj. lepkości i zwilżalność kwarcu. Lepkość spoiw określono wyznaczając krzywe płynięcia za pomocą reometru rotacyjnego RHEOTEST 2 z oprogramowaniem. Zwilżalność kwarcu określano badając zmiany wartości kąta zwilżania w czasie dla układu: kwarc-spoiwo, aż do stabilizacji wartości kąta. Modyfikację spoiwa przeprowadzono na szkle wodnym sodowym: R „145”. Modyfikatorami szkła wodnego były: zawiesiny nanocząstek ZnO w propanolu i metanolu ostałym stężeniu c=0,3 M i wielkości nanocząstek w przedziale <61–981 nm>. Modyfikacja szkła wodnego zawiesinami nanocząstek ZnO w metanolu i propanolu wykazała wpływ modyfikatora na oddziaływanie lepkie i międzyfazowe kwarc – spoiwo. Wpływ ten zależy od rodzaju alkoholu. Zawiesina ZnO w alkoholu o dłuższym łańcuchu węglowodorowym (propanol) silniej oddziaływuje na lepkość i zwilżalność w porównaniu z zawiesiną w metanolu.

EN

The paper is to develop a water glass modifier. The study adapted the method of thermal producing of metal oxide nanoparticles. Were used ZnO nanoparticles from thermal decomposition of basic zinc carbonate. It was developed as the introduction of the modifier and the impact of the amount, type of organic solvent on physicochemical properties such as viscosity of the binder and wettability of quartz. Determining the viscosity binders flow curves identified using a rotational rheometer RHEOTEST 2 with software. Wetting of quartz was determined examining change the value of contact angle in time for the system quartz-binder, to stabilize the value of the angle. The modification of the binder was carried out sodium water glass: R "145". Water glass modifiers were suspensions of ZnO nanoparticles in propanol and methanol, concentration of suspension 0.3 M and the size of nanoparticles in the range of <61-981 nm>. Modification of water-glass suspensions of ZnO nanoparticles in methanol and propanol showed the impact modifier to the effects of viscous and interfacial quartz - a binder. This effect depends on the type of alcohol. ZnO suspension in alcohol with a longer hydrocarbon chain (propanol) strongly influences the viscosity and wettability compared with the suspension in methanol.

4

Effect of water glass modification on its viscosity and wettability of quartz grains

Kmita A., Hutera B.

Archives of Foundry Engineering

|

2012

|

Vol. 12, iss. 3

59-62

EN

The aim of the present study was to develop a modifier for water glass. The method of thermal generation of metal oxide nanoparticles was adapted and used in the research. Nanoparticles of ZnO from the thermal decomposition of basic zinc carbonate were used. A method for the modifier introduction was developed, and the effect of modifier content and organic solvent type on the physico-chemical properties of binder (viscosity) and quartz wettability was determined. Binder viscosity was examined from the flow curves plotted with the help of a RHEOTEST 2 rotational rheometer equipped with proper software. Quartz wettability was determined examining time-related changes in the value of the contact angle in a quartz-binder system, until full stabilisation of the angle value has been achieved. Binder modification was carried out on sodium water glass designated as R"145". The water glass modifiers were suspensions of ZnO nanoparticles in propanol and methanol at a fixed concentration of c = 0.3 M and with the size of nanoparticles comprised in a range of <61 - 981 nm>. Water glass modification with the suspensions of ZnO nanoparticles in methanol and propanol showed the effect of modifier on the water glass viscosity and quartz wettability. This effect depends on the type of alcohol used. The ZnO suspension in propanol (alcohol with a longer hydrocarbon chain) affects more strongly the viscosity of binder and quartz wettability than the methanol suspension.