scholarly journals Effect of different factors on the yield of epoxy-terminated polydimethylsiloxane and evaluation of CO2 thickening

RSC Advances ◽  
2018 ◽  
Vol 8 (70) ◽  
pp. 39787-39796 ◽  
Author(s):  
Yanling Wang ◽  
Qiang Li ◽  
Weihong Dong ◽  
Qingchao Li ◽  
Fuling Wang ◽  
...  
Keyword(s):  
Taguchi Design ◽  
Polymer Yield

We focused on optimizing synthetic parameters based on a Taguchi design to maximize polymer yield and evaluate the polymer-thickening ability in CO2.

Metathesis Polymerization of Phenylacetylene by Tungsten Aryloxo Complexes

1995 ◽  
Vol 60 (3) ◽  
pp. 489-497 ◽  
Author(s):  
Hynek Balcar ◽  
Jan Sedláček ◽  
Marta Pacovská ◽  
Vratislav Blechta
Keyword(s):  
Molecular Weight ◽  
Catalytic Activity ◽  
Induction Period ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Polymer Yield ◽  
Positive Effect ◽  
Ligand Addition

Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOCl3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)2C6H3, 2,6-Cl2C6H3, 2,4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (20 °C, monomer to catalyst molar ratio = 1 000) was studied. The activity of WCl5(OAr) as unicomponent catalysts increases with increasing electron withdrawing character of the -OAr ligand. Addition of two equivalents of organotin cocatalysts (Me4Sn, Bu4Sn, Ph4Sn, Bu3SnH) to WCl5(O-C6H2Cl3-2,4 ,6) has only slight positive effect (slightly higher polymer yield and/or molecular weight of poly(phenylacetylene)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2, 6) catalyst, it enhances the activity considerably by eliminating the induction period. Poly(phenylacetylene)s prepared with the catalysts studied have weight-average molecular weight ranging from 100 000 to 200 000. They are trans-prevailing and have relatively low molar fraction of monomer units comprised in cyclohexadiene sequences (about 6%).

Taguchi design Analysis for optimization of probiotics cholesterol assimilation

2021 ◽  
Author(s):  
Amr A. El-Waseif ◽  
Tasneem Y. Roshdy ◽  
M.O. Abdel-Monem ◽  
Mervat G. Hassan
Keyword(s):  
Design Analysis ◽  
Taguchi Design

Development of Floating Multiple Unit Minitablets of Bosentan using QbD: Characterisation and Pharmacokinetic Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Santosh Kumar Panda ◽  
Manoranjan Sahu ◽  
Kahnu Charan Panigrahi ◽  
Chinam Niranjan Patra ◽  
Goutam Kumar Jena
Keyword(s):  
Quality By Design ◽  
Critical Factor ◽  
Taguchi Design ◽  
Multiple Dosing ◽  
Release Formulation ◽  
Effect Analysis ◽  
Box Behnken Design ◽  
Multiple Unit ◽  
Quality By Design Approach ◽  
State Concentration

Background: In order to achieve steady state concentration multiple dosing is required for bosentan. Hence formulating bosentan controlled release formulation could be an approach to solve this issue. Objective: The objective is to develop floating multiple unit minitablets of bosentan using Quality by design approach. Methods: : Failure mode effect analysis (FMEA) and taguchi design employed in order to screen highly critical factor. Box-Behnken design (BBD) was adopted for the process of optimization. Results: : Amount of gelucire 39/01, HPMC K15 M and sodium bicarbonate were screened as significant factor using Taguchi design. The Box-Behnken design results the optimised formulation showing floating lag time within 3 min, floating time of nearly 15 h, time to release 50% of drug of 3.6 h and time to release 90% of drug of 11h and better bioavailability compared to pure drug. Conclusion: : It can be concluded that floating multiple unit minitablet can be used as an encouraging approach for sustaining the drug release of bosentan.

Fabrication of Magnesium-Silicon Nanocomplexes by the Interaction of Polyphenylsiloxane with Magnesium Carbonate

2021 ◽  
Vol 1045 ◽  
pp. 32-39
Author(s):  
Nikolai Shapkin ◽  
Natalia Maslova ◽  
Evgeniy Papynov ◽  
Vladimir Kaminskii ◽  
Alevtina Kapustina ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Mechanochemical Activation ◽  
Magnesium Carbonate ◽  
Polymer Yield ◽  
Element Analysis ◽  
Exchange Method ◽  
Composition And Structure ◽  
Ion Exchange Method ◽  
Heating Up ◽  
Repeated Precipitation

The interaction of magnesium carbonate with polyphenylsiloxane under the conditions of mechanochemical activation with subsequent heating has been investigated. Based on the TGA and DTA data, it has been shown that, upon heating up to 420°C, the reaction proceeded completely with the release of carbon dioxide. The polymer was dissolved in DMFA and purified by repeated precipitation with water. The polymer yield was 64%. The residue insoluble in organic solvents has been obtained by evaporation of an aqueous solution. The composition and structure of the synthesis products have been analyzed by means of element analysis, IR spectroscopy, and diffractometry. It has been demonstrated that the fraction soluble in DMFA had a silicon-to-magnesium ratio equal to 4.2, while the fraction isolated from water had this ratio equal to 1.0. The IR and XRD data enabled one to conclude that, regardless of the different compositions, the structures of all fractions were similar and corresponded to mesomorphic layered polymers produced by the ion exchange method.

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