Two antagonistic effects of flow/mixing on reactive polymer blending

Reactive polymer blending is basically a flow/mixing-driven process of interfacial generation, interfacial reaction for copolymer formation and morphology development. This work shows two antagonistic effects of mixing on this process: while mixing promotes copolymer formation by creating interfaces and enhancing collisions between reactive groups at the interfaces, excessive mixing may pull the in-situ formed copolymer out of the interfaces to one of the two polymer components of the blend, especially when the copolymer becomes highly asymmetrical. As such, the copolymer may loss its compatibilization efficiency. The mixing-driven copolymer pull-out from the interfaces is a catastrophic process (less than a minute), despite the high viscosity of the polymer blend. It depends on the molecular architecture of the reactive compatibilizer, polymer blend composition, mixing intensity and annealing. These findings are obtained using the concept of reactive tracer-compatibilizer and a model reactive polymer blend.

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In Situ Studies of Molecular Self-Assembling during the Formation of Ion-Conducting Membranes for Fuel Cells

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.792.623 ◽

2015 ◽

Vol 792 ◽

pp. 623-628 ◽

Cited By ~ 4

Author(s):

Kseniia N. Grafskaia ◽

Denis V. Anokhin ◽

Jaime J. Hernandez Rueda ◽

Dmitriy A. Ivanov

Keyword(s):

Fuel Cells ◽

High Temperature ◽

Molecular Architecture ◽

Self Assembling ◽

Ion Conducting ◽

Microscopy Data ◽

Conducting Membranes ◽

Green Fuel ◽

Synchrotron Beamlines

In present work a new setup for in situ studies of molecular self-assembling process for fabrication of ion-conducting membranes for “green” fuel cells was developed. Due to compactness, this unique setup can be used on the synchrotron beamlines. The GISAXS and optical microscopy data have shown the effectiveness of the control of molecular architecture by impact of high temperature, UV-irradiation and solvent vapors.

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Features of Mathematical Modeling of In-Situ Combustion for Production of High-Viscosity Crude Oil and Natural Bitumens

Chemistry and Technology of Fuels and Oils ◽

10.1007/s10553-015-0566-0 ◽

2015 ◽

Vol 50 (6) ◽

pp. 579-583 ◽

Cited By ~ 1

Author(s):

D. R. Isakov ◽

D. K. Nurgaliev ◽

D. A. Shaposhnikov ◽

O. S. Chernova

Keyword(s):

Mathematical Modeling ◽

Crude Oil ◽

High Viscosity ◽

In Situ Combustion

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Mixing and Comparative Properties of NR Compounds Filled with Different Types of Reinforcing Fillers

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.266.172 ◽

2017 ◽

Vol 266 ◽

pp. 172-176

Author(s):

Pattarawadee Maijan ◽

Nitinart Saetung ◽

Wisut Kaewsakul

Keyword(s):

Carbon Black ◽

Silica Surface ◽

High Viscosity ◽

Cure Rate ◽

Modified Silica ◽

Reinforcing Fillers ◽

Silane Coupling ◽

Different Types ◽

Cure Time

Mixing behaviors of the compounds filled with different reinforcing fillers were studied in correlation with compound and vulcanizate properties. Four filler systems were used including: 1) silica plus small amount of silane coupling agent; 2) carbon black; 3) pre-modified silica; and 4) silica+silane-carbon black mixed one. The results have shown that silica provides longer optimum cure time and shorter cure rate than carbon black due to accelerator adsorption on silica surface. In addition, owing to highly polar nature on silica surface the silica-based compounds show rather high viscosity, attributed to stronger filler-filler interaction as can be confirmed by Payne effect and reinforcement index. However, the commercial surface treatment or pre-modified form of silica shows superior properties than in-situ modification of silica by silane during mixing, while it gives comparable properties to carbon black-based compound. Tensile properties of vulcanizates show a good correlation with the basic properties of their compounds.

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A concept of reactive compatibilizer-tracer for studying reactive polymer blending processes

AIChE Journal ◽

10.1002/aic.15074 ◽

2015 ◽

Vol 62 (2) ◽

pp. 359-366 ◽

Cited By ~ 6

Author(s):

Wei-Yun Ji ◽

Lian-Fang Feng ◽

Cai-Liang Zhang ◽

Sandrine Hoppe ◽

Guo-Hua Hu ◽

...

Keyword(s):

Polymer Blending ◽

Reactive Polymer ◽

Reactive Compatibilizer

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Mechanical Properties of Thermoplastic Composites via In Situ Polymerization from Cyclic Oligomers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.7 ◽

2013 ◽

Vol 750-752 ◽

pp. 7-10

Author(s):

Kou An Hao ◽

Zhen Qing Wang ◽

Li Min Zhou

Keyword(s):

Mechanical Properties ◽

In Situ Polymerization ◽

High Viscosity ◽

Thermoplastic Composites ◽

Thermoplastic Matrix ◽

Polymerization Catalyst ◽

Short Beam ◽

Beam Shear ◽

Cyclic Oligomers

Fiber impregnation has been the main obstacle for thermoplastic matrix with high viscosity. This problem could be surmounted by adapting low viscous polymeric precursors Woven basalt fabric reinforced poly (butylenes terephthalate) composites were produced via in-situ polymerization at T=210°C. Before polymerization, catalyst was introduced to the reinforcement surface with different concentration. DSC is used to determine the polymerization and crystallization. SEM is used to detect whether the catalyst existed on surface. Both flexural and short-beam shear test are employed to study the corresponding mechanical properties.

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IN SITU GEL AS PLATFORM FOR KETOCONAZOLE SLOW RELEASE DOSAGE FORM

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2018v10i5.27849 ◽

2018 ◽

Vol 10 (5) ◽

pp. 76

Author(s):

Methaq Hamad Sabar ◽

Iman Sabah Jaafar ◽

Masar Basim Mohsin Mohamed

Keyword(s):

Drug Release ◽

Guar Gum ◽

Polymer Concentration ◽

Hydroxypropyl Methylcellulose ◽

In Vitro Release ◽

High Viscosity ◽

In Situ Gel ◽

Alginate Concentration

Objective: The aim of this study was to formulate ketoconazole (keto) as oral floating in situ gel to slow the release of keto in the stomach.Methods: Sodium alginate (Na alginate) was used as a primary polymer in the preparation of the in situ gel and was supported by the following polymers: guar gum (GG), hydroxypropyl methylcellulose (HPMC) K4M, K15M and carbapol 940 as viscosity enhancing agents. As a consequence, and to complete the gelation process of above formulations was by adding the calcium carbonate (CaCO3). The in situ gels were investigated by the following tests: floating lag time, floating duration, viscosity, drug content, in vitro gelling studies and in vitro release study.Results: The study showed that the faster release was obtained with F1 which contained Na alginate alone. Additionally, reduction in Na alginate concentration resulted in significant increase in drug release. It was also noted that the increase in GG (viscosity enhancing polymer) concentration resulted in non-significant decrease in percent drug release and the reduction in CaCO3 concentration led to significant increase in drug release. Moreover, the release of drug was also affected by grade of viscosity enhancing polymer, the faster release was observed with the formula which contained a polymer of low viscosity (HPMC K4M) and an opposite result was with the high viscosity polymer (HPMCK15M).Conclusion: This study showed the formulation of Na alginate with GG and CaCO3, led to gain floating in situ gel and a sustained release of keto.

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Bond of Steel Bars to Masonry Mortar Joints: Test Results and Analytical Modelling

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.747.319 ◽

2017 ◽

Vol 747 ◽

pp. 319-325 ◽

Cited By ~ 3

Author(s):

Matteo Maragna ◽

Cristina Gentilini ◽

Giovanni Castellazzi ◽

Christian Carloni

Keyword(s):

High Strength ◽

Experimental Tests ◽

Analytical Investigation ◽

Masonry Walls ◽

Test Results ◽

Bond Slip ◽

Pull Out ◽

Steel Bars ◽

Masonry Mortar

In this paper, the preliminary results of a series of pull-out tests conducted on mortar cylinders with embedded bars are presented. The bars are made of high strength stainless steel and are of helical shape to increase mechanical interlocking with the surrounding mortar. Usually, such bars are employed in situ to realize structural repointing in the case of fair-faced masonry walls. To this aim, they are inserted in the mortar bed joints of masonry for providing tensile strength to the walls and with the function of crack stitching. The aim of the present experimental tests is to determine the bond-slip relationship for bars embedded in masonry. Firstly, pull-out tests are conducted on mortar cylinders considering different embedded lengths of the bars. Further tests are on-going on masonry specimens with bars embedded in the mortar joints. An analytical investigation is also carried out for the interpretation of the pull-out test results.

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