Wyniki wyszukiwania - BazTech

1

State of water in chitosan /tripolyphosphate polyelektrolyte complex membranes for pervaportation

Gierszewska-Drużyńska M., Ostrowska-Czubenko J.

Polish Journal of Applied Chemistry

|

2009

|

Vol. 53, nr 1

15-21

EN

Polyelectrolyte complexes (PECs) are known as new interesting membrane materials applicable in industry, medicine and pharmacy. In this work PEC membranes from chitosan (Ch) and pentasodium tripolyphosphate (TPP) designed for pervaporation w'ere prepared by dipping Ch membranes in TPP solution. The PEC formation between Ch and TPP was confirmed by FTIR spectroscopy. Various amounts of w'ater were added into the dry ChATPP hydrogels to cause them to swell, and the amounts of water in various states were determined by the DSC ice-melting technique. Three types of water in hydrogel membranes w'ere identified: non-freezing bound water, freezing bound water, and freezing free w'ater. States of water in Ch/TPP and Ch membranes were compared and the effect of ionic crosslinking on the non-freezing water content was discussed.

2

Medical polyurethanes with different hard segments content obtained from polycaprolactone diol , aliphatic diisocyanates and butanediol

Gibas I., Janik H.

Polish Journal of Applied Chemistry

|

2009

|

Vol. 53, nr 1

9-14

EN

Three series of segmented polyurethanes (PUs) with biomedical destination were synthesized using two-step catalyzed polymerization method. PUs with a broad range of hard segments content were obtained from the following components: 1,6-diisocyanatohexane or dicyclohexylmethane diisocyanate, poly(s-caprolactone)diol (olygodiol) and 1,4-butanedioI (chain extender). Chemical and physical structures were examined with the use of IR and DSC methods. Swelling behavior in water, oil and saline, contact angle and roughness were also investigated. The samples are crystalline, slightly hydrophilic with different surface properties, which can be controlled in a wide range by molar ratio of the components used for the synthesis. The results of hexane/water extracts tests do not exclude them to be applied for medical applications. The further studies to use the obtained PUs as medical non-solvent coatings are being continued.

3

Effect of chemical additives on flow characteristics of coal slurries

Mosa E. S., Saleh A.-H. M., Taha T., El-Molla A. M.

Physicochemical Problems of Mineral Processing

|

2008

|

Vol. 42

107-118

EN

In the present paper, the effect of chemical additives or reagents on rheological characteristics of coalwater slurry (CWS) was investigated. The power-law model was applied to determine the non- Newtonian properties of coal slurries. Three types of dispersants namely, sulphonic acid, sodium tripolyphosphate and sodium carbonate were studied and tested at different concentrations ranging from 0.5 to 1.5% by weight from total solids. Sodium salt of carboxymethyl cellulose (Na-CMC) and xanthan gum were tested as stabilizers at concentrations in the range of 0.05 to 0.25 % by weight from total solids. It was found that apparent viscosity and flow properties of CWS are sensitive to the use of chemical additives (dispersants and stabilizers). Among studied dispersing agents, sulphonic acid recorded the best performance in modification and reducing CWS viscosity. The best dosage of all tested dispersants was found to be as 0.75 % by wt of solids. With regard to studied stabilizers, Na-CMC recorded better performance than xanthan gum. The best dosage of investigated stabilizers was found to be as 0.1 % by wt. from total solids.

PL

W pracy badano wpływ odczynników na charakterystykę reologiczną zawiesin wodno-węglowych (CWS). Zastosowano model potęgowy do wyznaczenia nieniutonowkich właściwości zawiesin węglowych. Badano trzy typy dyspersantów: kwas sulfonowy, tripolifosforan sodu oraz węglan sodu przy różnych ich stężeniach od 0.5 to 1.5% wagowego. Zastosowano sól sodową carboksymetylocelulozy (Na- CMC) oraz gumę guarową jako stabilizatory zawiesin używając ich w ilości od 0.05 to 0.25 % wagowego. Stwierdzono, że pozorna lepkość i charakterystyka przepływu CWS są podatne na użyte dyspersanty i substancje stabilizujące. Wśród badanych dyspersantów, kwas sulfonowy odznaczał się najlepszym działaniem i wysoka redukcją lepkości CWS. Ilość użytych dyspersantów wyniosła 0.75 % wagowego. Wśród substancji stabilizujących lepszą okazała się Na-CMC niż guma guarowa. Najodpowiedniejsza ilość stabilizatora to 0.1 % wagowego.