Structure-property relations in non-linear, segmented copolyureas formed by reaction injection moulding, RIM

1987 ◽  
Vol 18 (6) ◽  
Author(s):  
A.J. Ryan ◽  
J.L. Stanford ◽  
A.N. Wilkinson
Keyword(s):  
Injection Moulding ◽  
Structure Property ◽  
Property Relations ◽  
Non Linear

scholarly journals Non-linear dielectric spectroscopy for detecting and evaluating structure-property relations in a P(VDF-TrFE-CFE) relaxor-ferroelectric terpolymer

2021 ◽  
Vol 127 (10) ◽  
Author(s):  
Thulasinath Raman Venkatesan ◽  
David Smykalla ◽  
Bernd Ploss ◽  
Michael Wübbenhorst ◽  
Reimund Gerhard
Keyword(s):  
Dielectric Spectroscopy ◽  
Vinylidene Fluoride ◽  
Paraelectric Phase ◽  
Space Charge Polarization ◽  
Relaxor Ferroelectric ◽  
Relaxation Processes ◽  
Structure Property ◽  
Property Relations ◽  
Non Linear ◽  
Thermally Stimulated Depolarization

AbstractNon-linear dielectric spectroscopy (NLDS) is employed as an effective tool to study relaxation processes and phase transitions of a poly(vinylidenefluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) relaxor-ferroelectric (R-F) terpolymer in detail. Measurements of the non-linear dielectric permittivity $${\varepsilon _{2}^{'}}$$ ε 2 ′ reveal peaks at 30 and 80$$\,^\circ$$ ∘ C that cannot be identified in conventional dielectric spectroscopy. By combining the results from NLDS experiments with those from other techniques such as thermally stimulated depolarization and dielectric-hysteresis studies, it is possible to explain the processes behind the additional peaks. The former peak, which is associated with the mid-temperature transition, is found in all other vinylidene fluoride-based polymers and may help to understand the non-zero $$\varepsilon _\mathrm {2}^{'}$$ ε 2 ′ values that are detected on the paraelectric phase of the terpolymer. The latter peak can also be observed during cooling of P(VDF-TrFE) copolymer samples at 100$$\,^\circ$$ ∘ C and is due to conduction and space-charge polarization as a result of the accumulation of real charges at the electrode–sample interface.

scholarly journals Jaws of Platynereis dumerilii: Miniature Biogenic Structures with Hardness Properties Similar to Those of Crystalline Metals

JOM ◽  
2021 ◽  
Author(s):  
Luis Zelaya-Lainez ◽  
Giuseppe Balduzzi ◽  
Olaf Lahayne ◽  
Kyojiro N. Ikeda ◽  
Florian Raible ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Indentation Depth ◽  
Organic Matrix ◽  
Structure Property ◽  
Structural Protein ◽  
Inductively Coupled ◽  
Property Relations ◽  
Biogenic Structures ◽  
Platynereis Dumerilii ◽  
Bristle Worms

AbstractNanoindentation, laser ablation inductively coupled plasma mass spectroscopy and weighing ion-spiked organic matrix standards revealed structure-property relations in the microscopic jaw structures of a cosmopolitan bristle worm, Platynereis dumerilii. Hardness and elasticity values in the jaws’ tip region, exceeding those in the center region, can be traced back to more metal and halogen ions built into the structural protein matrix. Still, structure size appears as an even more relevant factor governing the hardness values measured on bristle worm jaws across the genera Platynereis, Glycera and Nereis. The square of the hardness scales with the inverse of the indentation depth, indicating a Nix-Gao size effect as known for crystalline metals. The limit hardness for the indentation depth going to infinity, amounting to 0.53 GPa, appears to be an invariant material property of the ion-spiked structural proteins likely used by all types of bristle worms. Such a metal-like biogenic material is a major source of bio-inspiration.

scholarly journals Hydrogen adsorption on MoS2-surfaces: a DFT study on preferential sites and the effect of sulfur and hydrogen coverage

2017 ◽  
Vol 19 (24) ◽  
pp. 16231-16241 ◽  
Author(s):  
Rasmus Kronberg ◽  
Mikko Hakala ◽  
Nico Holmberg ◽  
Kari Laasonen
Keyword(s):  
Hydrogen Adsorption ◽  
Structural Parameters ◽  
Dft Study ◽  
Structure Property ◽  
Property Relations

H-Adsorption on MoS2-surfaces is studied as a function of structural parameters and an assessment of the intricate structure–property relations is conducted.

scholarly journals Structure–Property Relations in Oligomers of Linear Aliphatic Diisocyanates

2018 ◽  
Vol 6 (8) ◽  
pp. 9753-9759 ◽  
Author(s):  
Max Widemann ◽  
Piet J. Driest ◽  
Patrizio Orecchia ◽  
Frederik Naline ◽  
Florian E. Golling ◽  
...  
Keyword(s):  
Structure Property ◽  
Property Relations

scholarly journals Multiblock Copolymers of Norbornene and Cyclododecene: Chain Structure and Properties

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1756
Author(s):  
Yulia I. Denisova ◽  
Georgiy A. Shandryuk ◽  
Marianna P. Arinina ◽  
Ivan S. Levin ◽  
Vsevolod A. Zhigarev ◽  
...  
Keyword(s):  
First Generation ◽  
Average Length ◽  
Chain Structure ◽  
Random Copolymers ◽  
Multiblock Copolymers ◽  
Structure Property ◽  
Reaction Conditions ◽  
Property Relations ◽  
Cross Metathesis

We investigate the structure–property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting. We demonstrate that isolated dodecenylene units can be incorporated into crystalline lamellas so that even nearly random copolymers should retain crystallinity. Weak high-temperature endotherms observed in the multiblock copolymers of norbornene with cyclododecene and other cycloolefins could indicate that the corresponding systems are microphase-separated in the melt state.

Sign in / Sign up

Export Citation Format

Share Document