Polymorphic Behavior of Syndiotactic Poly(p-chlorostyrene) and Styrene/p-Chlorostyrene Cosyndiotactic Random Copolymers

2003 ◽  
Vol 36 (20) ◽  
pp. 7577-7584 ◽  
Author(s):  
Anna De Girolamo Del Mauro ◽  
Fausta Loffredo ◽  
Vincenzo Venditto ◽  
Pasquale Longo ◽  
Gaetano Guerra
Keyword(s):  
Random Copolymers ◽  
Polymorphic Behavior

Effects of Comonomer Structure on the Polymorphic Behavior of Syndiotactic Polystyrene-Based Random Copolymers

1998 ◽  
Vol 31 (25) ◽  
pp. 9081-9083 ◽  
Author(s):  
Bo Ki Hong ◽  
Keon Hyeong Kim ◽  
Jae Cheol Cho ◽  
Won Ho Jo ◽  
Jungahn Kim
Keyword(s):  
Random Copolymers ◽  
Syndiotactic Polystyrene ◽  
Polymorphic Behavior

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.

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

scholarly journals Crystallization of Random Metallocene-Catalyzed Propylene-Based Copolymers with Ethylene and 1-Hexene on Rapid Cooling

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2091
Author(s):  
Daniela Mileva ◽  
Jingbo Wang ◽  
René Androsch ◽  
Katalee Jariyavidyanont ◽  
Markus Gahleitner ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Metallocene Catalyst ◽  
Nucleating Agent ◽  
Random Copolymers ◽  
Rapid Cooling ◽  
Significant Difference ◽  
Chip Calorimetry ◽  
High Cooling Rates ◽  
Fast Scanning Chip Calorimetry

Propylene-based random copolymers with either ethylene or 1-hexene as comonomer, produced using a metallocene catalyst, were studied regarding their crystallization behaviors, with a focus on rapid cooling. To get an impression of processing effects, fast scanning chip calorimetry (FSC) was used in addition to the characterization of the mechanical performance. When comparing the comonomer type and the relation to commercial grades based on Ziegler–Natta-type catalysts, both an interaction with the catalyst-related regio-defects and a significant difference between ethylene and 1-hexene was observed. A soluble-type nucleating agent was found to modify the behavior, but to an increasingly lesser degree at high cooling rates.

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