scholarly journals Effect of the Monomer Ratio on the Strengthening of Polymer Phase Boundaries by Random Copolymers

1997 ◽  
Vol 30 (22) ◽  
pp. 6727-6736 ◽  
Author(s):  
Chi-An Dai ◽  
Chinedum O. Osuji ◽  
Klaus D. Jandt ◽  
Benita J. Dair ◽  
Christopher K. Ober ◽  
...  
Keyword(s):  
Random Copolymers ◽  
Polymer Phase ◽  
Phase Boundaries ◽  
Monomer Ratio

Strengthening Polymer Phase Boundaries with Hydrogen-Bonding Random Copolymers†

1997 ◽  
Vol 30 (25) ◽  
pp. 7958-7963 ◽  
Author(s):  
Zhihua Xu ◽  
Edward J. Kramer ◽  
Brian D. Edgecombe ◽  
Jean M. J. Fréchet
Keyword(s):  
Hydrogen Bonding ◽  
Random Copolymers ◽  
Polymer Phase ◽  
Phase Boundaries

scholarly journals Strength of polymer phase boundaries with large interfacial width: Effects of interfacial profile and phase separation morphology

2010 ◽  
Vol 48 (16) ◽  
pp. 1834-1846 ◽  
Author(s):  
Chun-Jie Chang ◽  
Yi-Huan Lee ◽  
Chi-Ju Chiang ◽  
Yu-Ping Lee ◽  
Hao-Ching Chien ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polymer Phase ◽  
Phase Boundaries

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

Growth of spinel into alumina

1987 ◽  
Vol 45 ◽  
pp. 294-295
Author(s):  
Y. Kouh Simpson ◽  
C. B. Carter
Keyword(s):  
Misfit Dislocations ◽  
Phase Boundaries ◽  
Large Rotation ◽  
Alumina Phase ◽  
Metallic Interfaces ◽  
Small Rotation

The structure of spinel/alumina phase boundaries has recently been studied using the selected- area diffraction technique. It has been found that there exist several dominant topotactic relationships; of these, the two most common situations are when the {111} plane of spinel is parallel to either the (0001) plane or the {1120} plane of alumina. In both of these cases, it has been found that there is often a small rotation from exact topotaxy (typically 0° to 2° but with larger rotations possible) which partially eliminates the need for misfit dislocations. This rotation is a special phenomenon that may be unique to non-metallic interfaces such as phase boundaries in ceramics. In this report, a special spinel/alumina interface in which a large rotation from the exact topotaxy exists between the (111) plane of spinel and the (OOOl) plane of alumina is discussed.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

Fluctuation Theory of Random Copolymers

1995 ◽  
Vol 5 (3) ◽  
pp. 365-377 ◽  
Author(s):  
Andrey V. Dobrynin ◽  
Igor Ya. Erukhimovich
Keyword(s):  
Fluctuation Theory ◽  
Random Copolymers

Fluctuation Theory of Charged AB-Random Copolymers

1995 ◽  
Vol 5 (8) ◽  
pp. 1241-1253 ◽  
Author(s):  
Andrey V. Dobrynin
Keyword(s):  
Fluctuation Theory ◽  
Random Copolymers
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