Bulk Semicrystalline Polymers: A Status Report

1993 ◽  
Vol 321 ◽  
Author(s):  
H. D. Keith
Keyword(s):  
Crystallization Process ◽  
Polymeric Materials ◽  
Basic Research ◽  
Semicrystalline Polymers ◽  
Status Report ◽  
Structure Property ◽  
Chain Molecules ◽  
Property Relations ◽  
Technological Significance ◽  
Long Chain

ABSTRACTDiscovery several decades ago that long-chain molecules crystallize by folding prompted vigorous basic research on structure-property relations in bulk semicrystalline polymers with expectation of insights that, paralleling experience in metal physics, would lead to better materials for technology. However, complexity of the crystallization process and difficulty in exploring morphology in adequate detail were both underestimated. Important aspects of behavior were recognized but improved polymeric materials have resulted more from exploratory engineering with composites and blends than from basic research on homopolymers. A summary of this research is presented with emphasis upon developments key to present status; also upon the truly formidable challenges that remain, Most readily accessible questions for research being of limited technological significance.

An X-Ray Investigation of Crystallinity in Rubber

1939 ◽  
Vol 12 (4) ◽  
pp. 706-718
Author(s):  
S. D. Gehman ◽  
J. E. Field
Keyword(s):  
Crystalline Structure ◽  
Polymeric Materials ◽  
The Other ◽  
X Ray Diffraction ◽  
Random Orientation ◽  
Chain Molecules ◽  
Micellar Structure ◽  
X Ray ◽  
Recent Developments ◽  
Long Chain

Abstract The crystalline structure which rubber exhibits under certain circumstances has come to be regarded as associated with a secondary or micellar structure of long chain molecules. The exact mechanism by which the localized ordered regions appear is a speculative subject in recent developments of the micellar theory of long chain polymeric materials. The views of various workers on this subject have been summarized by other authors. The crystalline structure of rubber displays varying degrees and types of orientation of the crystal units, depending on the conditions under which crystallization occurs. The amorphous x-ray diffraction pattern of unstretched rubber is shown in Figure 1, the unoriented crystalline diagram for frozen rubber in Figure 2. When crystallization is induced by stretching, the crystallites are aligned along the axis of stretching, giving the fiber diagrams of Figures 3 and 4. In this case there is random orientation of the other two axes of the crystallites. “Higher orientation,” in which all three axes of the crystallites are aligned, gives the diagram of Figure 15 and can be secured with suitable dimensions of the stretched piece.

Synthesis of Cellulose Long-Chain Esters in 1-Butyl-3-methylimidazolium Acetate: Structure-Property Relations

2018 ◽  
Vol 60 (3) ◽  
pp. 349-353 ◽  
Author(s):  
Shuang Men ◽  
Xinyang Jiang ◽  
Xiaotong Xiang ◽  
Guoxin Sun ◽  
Yahong Yan ◽  
...  
Keyword(s):  
Structure Property ◽  
Property Relations ◽  
Long Chain

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.

Sign in / Sign up

Export Citation Format

Share Document