Thermally Stable and Mechanically Strong Mesoporous Films of Poly(ether imide)-Based Triblock Copolymers

2020 ◽  
Vol 2 (3) ◽  
pp. 1398-1405 ◽  
Author(s):  
Zhen Xu ◽  
Tianyu Liu ◽  
Ke Cao ◽  
Dong Guo ◽  
Joel Marcos Serrano ◽  
...  
Keyword(s):  
Triblock Copolymers ◽  
Thermally Stable ◽  
Mesoporous Films

Preparation of Mesoporous Titania Thin Films with Well-Crystallized Frameworks by Using Thermally Stable Triblock Copolymers

2013 ◽  
Vol 2013 (13) ◽  
pp. 2330-2335 ◽  
Author(s):  
Mohamed B. Zakaria ◽  
Norihiro Suzuki ◽  
Nagy L. Torad ◽  
Mikiya Matsuura ◽  
Kazuhiko Maekawa ◽  
...  
Keyword(s):  
Thin Films ◽  
Triblock Copolymers ◽  
Mesoporous Titania ◽  
Thermally Stable

Polyimide foams derived from poly(4,4'-oxydiphenylpyromellitimide) and poly(α-methylstyrene)

1995 ◽  
Vol 7 (2) ◽  
pp. 133-147 ◽  
Author(s):  
J L Hedrick ◽  
R DiPietro ◽  
Y Charlier ◽  
R Jerome
Keyword(s):  
Triblock Copolymers ◽  
Minor Component ◽  
Thermomechanical Analysis ◽  
Polymer Foams ◽  
Processing Conditions ◽  
Thermally Stable ◽  
Synthetic Route ◽  
Pore Sizes ◽  
Initial Block ◽  
Thermally Stable Polymer

An alternative route for the synthesis of high- Tg thermally stable polymer foams with pore sizes substantially smaller than those produced by other methods is described, using compositionally asymmetric microphase-separated block copolymers where the minor component, poly(α-methylstyrene), is thermally labile and the major component, a polyimide derived from poly(4,4'-oxydiphenylpyromellitimide), is thermally stable. Upon thermal treatment, the thermally unstable block can unzip to the monomer, leaving behind pores, the size and shape of which should, in principle, be identical to the initial block copolymer morphology. Triblock copolymers were prepared where the imide component was derived from poly(amic alfkyl ester) precursor using either the meta- or para-isomers with 4,4'-oxydianiline, and the α-methylstyrene component comprising the outside block of the ABA architecture. Dynamic mechanica] analysis confirmed microphase-separated morphologies for each of the copolymers. The decomposition of the α-methylstyrene block was studied by thermogravimetric, dynamic mechanical and thermomechanical analysis. Mild decomposition conditions were required to avoid rapid depolymerization of the α-methylstyrene and subsequent plasticization of the imide block. The resulting foams showed the expected reduction in density with pore sizes ranging from ∼200Å to ∼1 µm in size, depending on the synthetic route and processing conditions employed.

Investigation of the V4+-Centre in 6H- and 4H-SIC by the Method of Spectral-Hole Burning

1998 ◽  
Vol 512 ◽  
Author(s):  
C. Hecht ◽  
R. Kummer ◽  
A. Winnacker
Keyword(s):  
Electronic Properties ◽  
Room Temperature ◽  
Hole Burning ◽  
Band Offset ◽  
Spectral Hole Burning ◽  
Type Ii ◽  
Thermally Stable ◽  
Spectral Hole

ABSTRACTIn the context of spectral-hole burning experiments in 4H- and 6H-SiC doped with vanadium the energy positions of the V4+/5+ level in both polytypes were determined in order to resolve discrepancies in literature. From these numbers the band offset of 6H/4H-SiC is calculated by using the Langer-Heinrich rule, and found to be of staggered type II. Furthermore the experiments show that thermally stable electronic traps exist in both polytypes at room temperature and considerably above, which may result in longtime transient shifts of electronic properties.

Self-Assembly of Hydrogels From Elastin-Mimetic Block Copolymers

2002 ◽  
Vol 724 ◽  
Author(s):  
Elizabeth R. Wright ◽  
R. Andrew McMillan ◽  
Alan Cooper ◽  
Robert P. Apkarian ◽  
Vincent P. Conticello
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Triblock Copolymers ◽  
Variable Temperature ◽  
Inverse Temperature ◽  
Temperature Transition ◽  
Scanning Calorimetry ◽  
Design Synthesis ◽  
Inverse Temperature Transition ◽  
Functional Biomaterials

AbstractTriblock copolymers have traditionally been synthesized with conventional organic components. However, triblock copolymers could be synthesized by the incorporation of two incompatible protein-based polymers. The polypeptides would differ in their hydrophobicity and confer unique physiochemical properties to the resultant materials. One protein-based polymer, based on a sequence of native elastin, that has been utilized in the synthesis of biomaterials is poly (Valine-Proline-Glycine-ValineGlycine) or poly(VPGVG) [1]. This polypeptide has been shown to have an inverse temperature transition that can be adjusted by non-conservative amino acid substitutions in the fourth position [2]. By combining polypeptide blocks with different inverse temperature transition values due to hydrophobicity differences, we expect to produce amphiphilic polypeptides capable of self-assembly into hydrogels. Our research examines the design, synthesis and characterization of elastin-mimetic block copolymers as functional biomaterials. The methods that are used for the characterization include variable temperature 1D and 2D High-Resolution-NMR, cryo-High Resolutions Scanning Electron Microscopy and Differential Scanning Calorimetry.

Multiscale Simulations of Triblock Copolymers

2007 ◽  
Vol 5 (3-4) ◽  
pp. 167-179 ◽  
Author(s):  
Jan Andzelm ◽  
Frederick L. Beyer ◽  
James Snyder ◽  
Peter W. Chung
Keyword(s):  
Triblock Copolymers ◽  
Multiscale Simulations

Advanced Thermally Stable Jet Fuels Development Program Annual Report. Volume 1. Model and Experiment System Development

1990 ◽  
Author(s):  
Elmer Klavetter ◽  
Tim O'Hern ◽  
Bill Marshall ◽  
Merrill Jr. ◽  
Frye Ray ◽  
...  
Keyword(s):  
Annual Report ◽  
System Development ◽  
Development Program ◽  
Jet Fuels ◽  
Thermally Stable ◽  
Experiment System

Acetylene chemisorption at palladium: Effect of temperature and structure of the surface

1984 ◽  
Vol 49 (6) ◽  
pp. 1448-1458
Author(s):  
Josef Kopešťanský
Keyword(s):  
Work Function ◽  
Atomic Hydrogen ◽  
Effect Of Temperature ◽  
Thermally Stable ◽  
Template Effect ◽  
Temperature Range ◽  
Adsorbed Layers ◽  
Different Types ◽  
Adsorption Complexes ◽  
Low Coverage

The effect of temperature and structure of the palladium surfaces on acetylene chemisorption was studied along with the interaction of the adsorbed layers with molecular and atomic hydrogen. The work function changes were measured and combined with the volumetric measurements and analysis of the products. At temperature below 100 °C, acetylene is adsorbed almost without dissociation and forms at least two different types of thermally stable adsorption complexes. Acetylene adsorbed at 200 °C is partly decomposed, especially in the low coverage region. Besides the above mentioned effects, the template effect of adsorbed acetylene was studied in the temperature range from -80° to 25 °C. It has been shown that this effect is a typical phenomenon of the palladium-acetylene system which is not due to surface impurities.

Thermally Stable Half-Sandwich Benzhydryl Ln(II) (Ln = Sm, Yb) Complexes Supported by Sterically Demanding Carbazolyl and Fluorenyl Ligands

2019 ◽  
Vol 38 (24) ◽  
pp. 4615-4624 ◽  
Author(s):  
Alexander N. Selikhov ◽  
Andrey S. Shavyrin ◽  
Anton V. Cherkasov ◽  
Georgy K. Fukin ◽  
Alexander A. Trifonov
Keyword(s):  
Thermally Stable ◽  
Sterically Demanding ◽  
Half Sandwich
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