Wyniki wyszukiwania - BazTech

1

Waterlogged archaeological wood silanization with MTMOS

Siuda Joanna, Mazela Bartłomiej, Perdoch Waldemar

Drewno : prace naukowe, doniesienia, komunikaty

|

2019

|

vol. 62, nr 203

169--179

EN

A wooden object that has survived in a wet environment is characterised by water saturation and is called waterlogged wood. The subject of the study was elm piles, dating back to the 10th and11th century, excavated from Lednica lake archaeological site. Wooden piles showed a high degree of degradation. This was evidenced by their spongy and fragile structure. As a result of the biotic and abiotic degradation of the wood cell wall, a significant change in its chemical composition was observed. The weakening of the wood structure and its increase in porosity were as a result of cellulose degradation. The archaeological wood conservation method used until now is polyethylene glycol (PEG). However, this method has some drawbacks such as highdensity wood after treatment, the colour of the wood and it is a long-term process. It has already been found that alkoxysilanes are potential alternatives to the commonly used PEG. The purpose of the study was to determine the optimum concentration of methyltrimethoxysilane (MTMOS) for the medieval elm wood conservation. The general aim of the study was to develop an effective waterlogged wood dimensional stabilization through its silanization with MTMOS. After long-term dehydration (replacement of water for ethanol, during an ethanol bath) wood samples were saturated with MTMOS solutions of various concentrations. Wood samples were treated through the oscillating vacuum-pressure method. Dimensional stabilization of the sililated wood was estimated through the anti-shrink efficiency (ASE) calculation. The ASE value for PEG and MTMOS treated wood samples was 88.6% and 96.8% respectively. It was found that an ethanol solution of 20% MTMOS is the optimum concentration for waterlogged elm wood dimensional stabilization treatment (ASE = 94.1 %). The other advantage of this method includes a short impregnation time and low density of the preserved wood.

2

Wpływ dodatku modyfikowanej nanokrzemionki na poprawę własności mechanicznych kompozytu ceramika-polimer

Przybyła M., Michta A.

Materiały Ceramiczne

|

2013

|

T. 65, nr 2

220--226

PL

W artykule przedstawiono ocenę wpływu modyfikowanej nanokrzemionki na polepszenie na etapie preparowania własności wytrzymałościowych kompozytu typu ceramika-polimer na bazie węglika krzemu. Dodatek modyfikatora częściowo zredukował napięcie powierzchniowe na granicy faz ceramika–polimer. Jako aktywator powierzchni nanokrzemionki wykorzystano związek o nazwie trietoksywinylosilan, TEVSi. Badania spektrofotometryczne IR potwierdziły przyłączenie winylosilanu do powierzchni krzemionki. Kompozyty ceramiczne zawierające węglik krzemu otrzymano metodą odlewania żelowego. Proszek ceramiczny był w nich fazą rozproszoną, a polimer ciągłą. Próbki zawierające proszki krzemionki modyfikowane powierzchniowo grupami winylowymi miały wyższe zagęszczenia niż próbki bez dodatku krzemionki i z nie modyfikowaną krzemionką. Wykazano, że już niewielki dodatek hydrofobizowanej krzemionki skraca czas wiązania zdyspergowanego proszku ceramicznego, w efekcie poprawia własności wytrzymałościowe materiału. Zaobserwowano blisko trzykrotny wzrost wytrzymałości na ściskanie próbek po spieczeniu.

EN

The paper presents effects of application of silica nanoparticles containing vinyl groups on some mechanical properties of ceramics–polymer composites. Silica nanoparticles with vinyl groups were obtained during silanization of surfaces with vinyltriethoxysilane. The degree of modification of the silica powders with vinylsilane was investigated by IR spectroscopy. Ceramic composites containing silicon carbide were obtained by gel-casting methods. In these composites ceramic powder is the dispersed phase, and polymer is the continuous phase. It was shown that samples containing silica powders with vinyl groups had higher bulk densities than the samples with and without native silica powders. The threefold increase in compressive strength of the sintered samples has been found.

3

Functionalization of polyurethane surfaces for further attachment of bioactive molecules

Marczak B., Butruk B., Ciach T.

Challenges of Modern Technology

|

2012

|

Vol. 3, no. 4

9--13

EN

The challenge for cardiovascular tissue engineers is to design hemocompatible biomaterials that promote neo-tissue formation. Cardiovascular implants are prone to occlusion caused by surface thrombogenicity. In native tissue non-thrombogenic surface is provided by the endothelium. Endothelialization of implantable cardiovascular devices is thereby among the techniques of functionalizing biomaterials. Surfaces covered with peptides have been shown to enhance endothelial cells adhesion and proliferation. For the purpose of further cell-specifi c peptides immobilization, a three-step method for incorporating carboxyl groups onto a polyurethane surface was developed. In the fi rst step silanol groups were incorporated into the polyurethane surface. Successful reaction was proven by FTIR analysis. Subsequently, incorporation of surface amine groups was proceeded. In the last step amine groups were acylated using glutaric anhydride to create carboxylates. To determine the presence of surface functional groups, colorimetric method was applied. Measurement of water contact angle revealed signifi cant increase in surface hydrophilicity.

4

Silanizacja jako metoda poprawy adhezji powłok PLLA do gwoździ śródszpikowych – badania wstępne

Choińska E., Sobiecki J. R., Święszkowski W., Kurzydłowski K.J.

Engineering of Biomaterials

|

2010

|

Vol. 13, no. 96-98

88--92

5

Polypropylene surface modified hollow fibers for immunoisolation of cells

Granicka L. H., Chwojnowski A., Kawiak J.

Biocybernetics and Biomedical Engineering

|

2004

|

Vol. 24, no. 2

59-67

EN

Membranes preventing the tissue overgrowth as well as toxic influence of the environment on cells encapsulated within them were elaborated. The permiselective polypropylene hollow fibers were modified using different methods of silanization, and the effect of silanization on the membrane transport properties as well as on the tissue overgrowth was assessed, in the light of their perspective application in encapsulation of the cells. The membrane's pressure silanization has been found to result in obtaining membranes allowing to decrease and/ or delimit the diffusive transport through the membrane of large solutes without a simultaneous transport change for small solutes. The applied different types of membrane's silanization allowed to avoid a massive tissue overgrowth during the implantation. The membranes have been found to comply with the requirements for membranes applied in immunoisolation.