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Selected Works

Polymer Science

Blends

Articles 1 - 30 of 32

Full-Text Articles in Engineering

Blending Of Immiscible Polymers In A Mixing Zone Of A Twin Screw Extruder- Effects Of Compatibilization, William Macknight, O. Franzheim, T. Rische, M. Stephan Dec 1999

Blending Of Immiscible Polymers In A Mixing Zone Of A Twin Screw Extruder- Effects Of Compatibilization, William Macknight, O. Franzheim, T. Rische, M. Stephan

William MacKnight

The dependence of the morphology development of physical as well as of reactive
compatibilized polypropylene/polyamide 6 (PP /PA6) blends in a mixing zone of a
co-rotating twin screw extruder on blend composition and screw rotational speed
was investigated. A special process analytical set-up based on a co-rotating twin
screw extruder was used, which allowed melt sampling from different positions
along the operating extruder in time periods less than 10 seconds. It has been
shown that the disperse particle sizes in physical blends depend crucially on the
blend composition because of the increasing influence of coalescence with an increasing
concentration of …

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Thermally Stable Silphenylene Vinyl Siloxane Elastomers And Their Blends, William Macknight, H. Dennis Zhu, Simon W. Kantor Dec 1997

Thermally Stable Silphenylene Vinyl Siloxane Elastomers And Their Blends, William Macknight, H. Dennis Zhu, Simon W. Kantor

William MacKnight

No abstract provided.

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Blends Of Amorphous-Crystalline Block Copolymers With Amorphous Homopolymers. Morphological Studies By Electron Microscopy And Small Angle Scattering, William Macknight, Kazuo Sakurai, David J. Lohse, Donald N. Schulz, J.A. Sissano, Jar-Shyoung Lin, Mikhail Agamalyan Dec 1995

Blends Of Amorphous-Crystalline Block Copolymers With Amorphous Homopolymers. Morphological Studies By Electron Microscopy And Small Angle Scattering, William Macknight, Kazuo Sakurai, David J. Lohse, Donald N. Schulz, J.A. Sissano, Jar-Shyoung Lin, Mikhail Agamalyan

William MacKnight

A morphological study was performed with symmetric diblock ethylene-propylene copolymer (DEP) and
the binary blends made from DEP and atactic polypropylene (APP) by use of small angle X-ray, light
and neutron scattering, and also scanning and transmission electron microscopy. DEP contains
a crystallizable polyethylene block and an amorphous atactic polypropylene block. Quenching the blends
in liquid nitrogen preserved the morphology in the melt state. This quenching technique revealed that DEP
forms a lamellar microdomain structure and blending DEP and APP includes morphological changes in the
microdomain structures as well as macrophase separation. When the APP chain was shorter than the …

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Compatibility Enhancement Of Blends Of Nylon 4 With Lithium-Neutralized Sulfonated Polystyrene, William Macknight, C. -W. Alice Ng, Michelle A. Bellinger Dec 1993

Compatibility Enhancement Of Blends Of Nylon 4 With Lithium-Neutralized Sulfonated Polystyrene, William Macknight, C. -W. Alice Ng, Michelle A. Bellinger

William MacKnight

No abstract provided.

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Blends Of Amorphous-Crystalline Block Copolymers With Amorphous Homopolymers. 2. Synthesis And Characterization Of Poly(Ethylene-Propylene) Diblock Copolymer And Crystallization Kinetics For The Blend With Atactic Polypropylene, William Macknight, Kazuo Sakurai, David J. Lohse, Donald N. Schulz, J.A. Sissano Dec 1993

Blends Of Amorphous-Crystalline Block Copolymers With Amorphous Homopolymers. 2. Synthesis And Characterization Of Poly(Ethylene-Propylene) Diblock Copolymer And Crystallization Kinetics For The Blend With Atactic Polypropylene, William Macknight, Kazuo Sakurai, David J. Lohse, Donald N. Schulz, J.A. Sissano

William MacKnight

No abstract provided.

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Intramolecular Interactions In Poly(Styrene-Co-Acrylonitrile)/Poly(Epsilon-Caprolactone) Blends.Pdf, William Macknight, V. Janarthanan, J. Kressler, F. E. Karasz Dec 1992

Intramolecular Interactions In Poly(Styrene-Co-Acrylonitrile)/Poly(Epsilon-Caprolactone) Blends.Pdf, William Macknight, V. Janarthanan, J. Kressler, F. E. Karasz

William MacKnight

No abstract provided.

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Amorphous-Crystalline Block Copolymer And Amorphous Homopolymer Blends. 1. A Preliminary Report, William Macknight, Kazuo Sakurai, David J. Lohse, Donald N. Schulz, J.A. Sissano Dec 1992

Amorphous-Crystalline Block Copolymer And Amorphous Homopolymer Blends. 1. A Preliminary Report, William Macknight, Kazuo Sakurai, David J. Lohse, Donald N. Schulz, J.A. Sissano

William MacKnight

No abstract provided.

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Thermodynamic Aging Of Immiscible Polymer Blends, William Macknight, Ronald Koningsveld, Karel Sole Dec 1992

Thermodynamic Aging Of Immiscible Polymer Blends, William Macknight, Ronald Koningsveld, Karel Sole

William MacKnight

No abstract provided.

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Thermal And Rheological Properties Of Miscible Polyethersulfone/Polyimide Blends, William Macknight, K. Liang, J. Grebowicz, E. Valles, F. E. Karasz Dec 1991

Thermal And Rheological Properties Of Miscible Polyethersulfone/Polyimide Blends, William Macknight, K. Liang, J. Grebowicz, E. Valles, F. E. Karasz

William MacKnight

Blends of an aromatic polyethersulfone (commercial name Victrex) and a polyimide (com- mercial name Matrimid 5218), the condensation product of 3,3’,4,4’-benzophenone tetra- carboxylic dianhydride and 5 (6)-amino-1- (4’-aminophenyl) -1,3,3’-trimethylindane,
were studied by differential scanning calorimetry, dynamic mechanical analysis, and rheological techniques. The blends appeared to be miscible over the whole range of compositions when cast as films or precipitated from solution in a number of solvents. After annealing above the apparent phase boundary, located above Tg,the blends were irreversibly phase separated indicating that the observed phase boundary does not represent a true state of equilibrium. Only a narrow “processing window” …

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Thermal, Dielectric, And Mechanical Relaxation In Poly(Benzimidazole)/Poly(Etherimide) Blends, William Macknight, Kuiming Liang, Gyorgy Banhegyi, F. E. Karasz Dec 1990

Thermal, Dielectric, And Mechanical Relaxation In Poly(Benzimidazole)/Poly(Etherimide) Blends, William Macknight, Kuiming Liang, Gyorgy Banhegyi, F. E. Karasz

William MacKnight

Thermal, dielectric, and mechanical relaxation measurements on miscible blends of poly-
benzimidazole(PBI)and a polyetherimide (PEI, Ultem 1000)prepared by solution casting
from dimethylacetamide (DMAc) reveal a number of structurally related features. Annealing
below the glass transition temperature induces an enthalpy relaxation process typical of
single-phase glasses of nonequilibrium structure. Dielectric relaxation experiments on
samples annealed at ambient conditions reveal two relaxation processes below 400°C.At
lower temperatures (50-2OO0C), the desorption of water is observed. Above 200°C in the
first run, a composition-dependent relaxation is seen at the highest frequencies ( 100 kHz)
while a relaxation approximately independent of composition appears in the …

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Fourier Transform Infrared Spectroscopy Of Some Miscible Polybenzimidazole/Polyimide Blends, William Macknight, Gaetano Guerra, Soonja Choe, David J. Williams, F. E. Karasz Dec 1987

Fourier Transform Infrared Spectroscopy Of Some Miscible Polybenzimidazole/Polyimide Blends, William Macknight, Gaetano Guerra, Soonja Choe, David J. Williams, F. E. Karasz

William MacKnight

The IR spectra of representative miscible aromatic polybenzimidazole/aromatic polyimide (PBI/PI) blends have been studied. Composition-dependent frequency shifts of up to 55 cm-1 in the N-H stretching band of PBI and up to 6 cm-1 in the carbonyl stretching bands of Pl were observed. These shifts were removed by thermally induced phase separation. The results suggest that the miscibility of these blends derives from specific intermolecular interactions involving the > NH and carbonyl groups. 

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Miscible Polybenzimidazole Blends With A Benzophenone-Based Polyimide, William Macknight, Gaetano Guerra, David J. Williams, F. E. Karasz Dec 1987

Miscible Polybenzimidazole Blends With A Benzophenone-Based Polyimide, William Macknight, Gaetano Guerra, David J. Williams, F. E. Karasz

William MacKnight

No abstract provided.

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Miscibility And Phase Behaviour In Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And Poly(Fluorostyrene-Co-Bromostyrene) Blends, William Macknight, R. Vukovic, G. Bogdanic, Vjera Kuresevic, F. E. Karasz Dec 1987

Miscibility And Phase Behaviour In Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And Poly(Fluorostyrene-Co-Bromostyrene) Blends, William Macknight, R. Vukovic, G. Bogdanic, Vjera Kuresevic, F. E. Karasz

William MacKnight

Copolymers of or tho (para )fluorostyrene and ortho(para )bromostyrene with a range of copolymer compositions were prepared by free radical polymerization in toluene solution using azobis­(isobutyronitrile). The miscibility and phase behaviour of these copolymers in blends with poly(2,6-dimethyl-l,4-phenylene oxide) (PPO) have been studied by differential scanning calorimetry. Of the four possible copolymer systems, miscibility was observed only for PPO/poly(o-fluorostyrene­co-p-bromostyrene) blends in which the copolymer contains between 11 and 73 mo!% p-bromostyrene. High temperature phase separation in the miscible blends is a function of copolymer composition and of the thermal history. The results can be explained on the basis of the …

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Crystallization, Thermal Behavior, And Compatibility In Isotactic Polystyrene/Poly(O-Chlorostyrene-Co-P-Chlorostyrene) Blends, William Macknight, C. Silvestre, S. Cimmino, F. E. Karasz Dec 1986

Crystallization, Thermal Behavior, And Compatibility In Isotactic Polystyrene/Poly(O-Chlorostyrene-Co-P-Chlorostyrene) Blends, William Macknight, C. Silvestre, S. Cimmino, F. E. Karasz

William MacKnight

The dependence of the kinetics of crystallization and melting behavior in isotactic polystyrene/poly-o-chlorostyrene-co-p-chlorostyrene (iPS /P( o-CIS-co-p-ClS) blends on tempera­ture, thermal history, and blend composition has been investigated. The crystallization rate at a given temperature and copolymer composition decreases with increasing copolymer content in the blend when the samples are premelted. These effects can be ascribed to the reduction of mobility of the crystallizable chains due to the presence of the copolymer and to the decrease in the number of heterogenous iPS nuclei as a result of the premelting process. The Avrami exponent values and the analysis of the blend morphology …

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Poly(Ethylene Oxide)/ Poly(Methyl Methacrylate) Blends: Influence Of Tacticity Of Poly(Methyl Methacrylate) On Blend Structure And Miscibility, William Macknight, C. Silvestre, S. Cimmino, E. Martuscelli, F. E. Karasz Dec 1986

Poly(Ethylene Oxide)/ Poly(Methyl Methacrylate) Blends: Influence Of Tacticity Of Poly(Methyl Methacrylate) On Blend Structure And Miscibility, William Macknight, C. Silvestre, S. Cimmino, E. Martuscelli, F. E. Karasz

William MacKnight

No abstract provided.

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Miscibility In Polycarbonate/ Poly(Styrene-Co-Methacrylic Acid) Blends And The Ternary System Involving Styrene-Butyl Acrylate Block Copolymer, William Macknight, Saburo Akiyama, F. E. Karasz, Junji Nambu Dec 1986

Miscibility In Polycarbonate/ Poly(Styrene-Co-Methacrylic Acid) Blends And The Ternary System Involving Styrene-Butyl Acrylate Block Copolymer, William Macknight, Saburo Akiyama, F. E. Karasz, Junji Nambu

William MacKnight

The miscibility ofbisphenol-A polycarbonate (PC) and poly(styrene-co-methacrylic acid) [P(S-MAA)] was investigated by differential scanning calorimetry (d.s.c.) and dynamic mechanical thermal analysis (d.m.t.a.). They seem to be partially miscible in solution-cast film, but to be immiscible in melt blend. In solution cast blends, they are miscible in a limited range of composition; at fraction of P(S-MAA) > 70 %. Miscibility of the ternary system consisting of PC, P(S-MAA ), and poly(styrene-butyl acrylate) [P(S-BA)] was also examined. The compatibility was enhanced by adding small amounts of P(S-BA) block copolymer. 

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Miscible Blends Of Aromatic Polybenzimidazoles And Aromatic Polyimides, William Macknight, Louis Leung, David J. Williams, F. E. Karasz Dec 1985

Miscible Blends Of Aromatic Polybenzimidazoles And Aromatic Polyimides, William Macknight, Louis Leung, David J. Williams, F. E. Karasz

William MacKnight

A new family of high performance, miscible polymer blends based on aromatic polybenzimidazoles and aromatic polyimides has been discovered. Preliminary evidence, obtained with commercially available, soluble poly­mers suggests that polymers of these generic types may be miscible over a wide range of compositions and structural variations. Blend miscibility 
was evidenced in the form of single Tg's and well-defined single tan 6 relaxations intermediate to those of the component polymers, the formation 
of clear films and, in one case, enhanced solvent resistance. 

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Compatibility In Chlorinated Poly(Vinyl Chloride)/Poly(Ethylene-Co-Vinyl Acetate) Blends, William Macknight, Tomoo Shiomi, F. E. Karasz Dec 1985

Compatibility In Chlorinated Poly(Vinyl Chloride)/Poly(Ethylene-Co-Vinyl Acetate) Blends, William Macknight, Tomoo Shiomi, F. E. Karasz

William MacKnight

No abstract provided.

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Upper And Lower Critical Solution Temperature Behavior In Thermoplastic Polymer Blends, William Macknight, Guangmin Cong, Yuhui Huang, F. E. Karasz Dec 1985

Upper And Lower Critical Solution Temperature Behavior In Thermoplastic Polymer Blends, William Macknight, Guangmin Cong, Yuhui Huang, F. E. Karasz

William MacKnight

No abstract provided.

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On Blends Of Poly(Vinylidene Fluoride) And Poly(Vinyl Fluoride), William Macknight, Gaetano Guerra, F. E. Karasz Dec 1985

On Blends Of Poly(Vinylidene Fluoride) And Poly(Vinyl Fluoride), William Macknight, Gaetano Guerra, F. E. Karasz

William MacKnight

 Experimental evidence indicating immiscibility of the homopolymers poly(vinylidene fluoride) and poly(vinyl fluoride), both in the crystalline and amorphous phases, is presented. The X-ray analysis of the blended samples reveals patterns that are relatively insensitive to blend composition and that are similar to those found in previous studies. However, corresponding differential scanning calorimetry scans show well-defined and separate melting peaks of the component homopolymers, indicating immiscibility in the crystalline phase. In addition, the dynamic mechanical analysis indicates that the main relaxations of the two pure homopolymers are still present in the blend spectrum, implying also an immiscibility of the amorphous phase. 

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Compatibility In Blends Of Two Random Copolymers Having A Common Monomer Segment, William Macknight, Tomoo Shiomi, F. E. Karasz Dec 1985

Compatibility In Blends Of Two Random Copolymers Having A Common Monomer Segment, William Macknight, Tomoo Shiomi, F. E. Karasz

William MacKnight

Miscibility in blends of random copolymers (A.,B1-:r),.,_ and (CyB1-y)111 can conveniently be displayed as domains in a Cartesian coordinate system in which the abscissa and ordinate represent the compositions of the respective copolymers. For the case in which the two copolymers have a common monomer unit (e.g., B) the isothermal boundary between domains of miscibility and immiscibility in a mean field treatment is determined by three segmental interaction parameters, XAB, XAC, and XBC, and the degrees of polymerization r1 and r2 of the copolymers. We have termed such representations "miscibility maps". The shape and size of the miscibility domain are …

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Effect Of Sequence Distribution On The Miscibility Of Polymer/Copolymer Blends, William Macknight, Anna C. Balazs, Isaac C. Sanchez, Irving Epstein, F. E. Karasz Dec 1984

Effect Of Sequence Distribution On The Miscibility Of Polymer/Copolymer Blends, William Macknight, Anna C. Balazs, Isaac C. Sanchez, Irving Epstein, F. E. Karasz

William MacKnight

Previous theories describing the phase behavior of copolymer blends have ignored the sequence distribution of monomer unit.a in the copolymer. We introduce a parameter, 8, that describes the binary sequence distribution of the monomers in a copolymer chain. By varying 8, we can describe a block, random, or alternating copolymer. It is assumed that the interaction energy between a monomer of homopolymer C and the monomer A (or B) in the copolymer AB is mediated by the nearest neighbors chemically bonded to the A (or B) structural 
unit. It is found that the sequence distribution may significantly affect the degree …

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Stereoregular Poly(Alkyl Methacrylate)S: Polymer-Polymer And Copolymer-Polymer Blends, William Macknight, J. A. Schroeder, F. E. Karasz Dec 1984

Stereoregular Poly(Alkyl Methacrylate)S: Polymer-Polymer And Copolymer-Polymer Blends, William Macknight, J. A. Schroeder, F. E. Karasz

William MacKnight

No abstract provided.

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Equilibrium Melting Point Depression For Blends Of Isotactic Polystyrene With Poly(2,6-Dimethylphenylene Oxide), William Macknight, Joaquin Plans, F. E. Karasz Dec 1983

Equilibrium Melting Point Depression For Blends Of Isotactic Polystyrene With Poly(2,6-Dimethylphenylene Oxide), William Macknight, Joaquin Plans, F. E. Karasz

William MacKnight

The melting behavior of pure isotactic polystyrene (iPS) and blends with poly(2,6-di­methylphenylene oxide) (PPO) have been investigated by differential scanning calorimetry (DSC). Evidence for interaction between the blend components has been detected from melting point depression studies and by examining the composition dependence of the glass transition temperature. The interaction parameter has been evaluated via the Flory-Huggins approximation of the thermodynamic mixing of two polymers, which yielded an average value of x = -0.17 for the range of compositions analyzed. This result is in agreement with the interaction parameter values derived from the negative heat of mixing for a-PS/PPO liquid …

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Carboxylation Of Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And Thermal Properties Of Blends With Atactic Polystyrene, William Macknight, S. Xie, F. E. Karasz Dec 1983

Carboxylation Of Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And Thermal Properties Of Blends With Atactic Polystyrene, William Macknight, S. Xie, F. E. Karasz

William MacKnight

No abstract provided.

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Melting Point Depression In Multicrystalline Blends: Pvf(2)/Pmma, William Macknight, Joaquin Plans, F. E. Karasz Dec 1983

Melting Point Depression In Multicrystalline Blends: Pvf(2)/Pmma, William Macknight, Joaquin Plans, F. E. Karasz

William MacKnight

No abstract provided.

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Compatibility Of Some Fluorosubstituted Styrene Polymers And Copolymers In Blends With Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And With Polystyrene, William Macknight, Radivoje Vukovic, F. E. Karasz Dec 1982

Compatibility Of Some Fluorosubstituted Styrene Polymers And Copolymers In Blends With Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And With Polystyrene, William Macknight, Radivoje Vukovic, F. E. Karasz

William MacKnight

No abstract provided.

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Evidence For Critical Double Points In Blends Of Polystyrene And Poly(O-Chlorostyrene), William Macknight, Sherrie L. Zacharius, Gerrit Ten Brinke, F. E. Karasz Dec 1982

Evidence For Critical Double Points In Blends Of Polystyrene And Poly(O-Chlorostyrene), William Macknight, Sherrie L. Zacharius, Gerrit Ten Brinke, F. E. Karasz

William MacKnight

Theoretical and experimental evidence is put forward to prove that both UCST and LCST behavior can be found in blends of polystyrene and poly(o-chlorostyrene). Vapor sorption results combined with known results of heat of mixing experiments lead to the conclusion of the rather uncommon UCST behavior. 
Existing data of T, measurements show that the PS/PoClS system is extremely sensitive to a small change in molar mass. A decrease in molar mass of PS of less than 4000 transforms an only partially miscible system 
into a system that is miscible throughout the entire experimental temperature range from 150 to 400 °C. …

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Compatibility Of Poly(2.6-Dimethyl-1,4-Phenylene Oxide)/Poly(Fluorostyrene-Co-Chlorostyrene) Blends, William Macknight, Radivoje Vukovic, Vjera Kuresevic, F. E. Karasz, Nikola Segudovic Dec 1982

Compatibility Of Poly(2.6-Dimethyl-1,4-Phenylene Oxide)/Poly(Fluorostyrene-Co-Chlorostyrene) Blends, William Macknight, Radivoje Vukovic, Vjera Kuresevic, F. E. Karasz, Nikola Segudovic

William MacKnight

No abstract provided.

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Solid State Properties Of Polymer Blends, William Macknight, F. E. Karasz Dec 1979

Solid State Properties Of Polymer Blends, William Macknight, F. E. Karasz

William MacKnight

No abstract provided.

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