Prediction and design of first super-strong liquid-crystalline polymers

Journal Article · Sat Jul 15 00:00:00 EDT 1989 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.457155· OSTI ID:6062056

Dowell, F

This paper presents the details of the theoretical prediction and design (atom by atom, bond by bond) of the molecule chemical structures of the first candidate super-strong liquid-crystalline polymers (SS LCPs). These LCPs are the /ital first/ LCPs designed to have good compressive strengths, as well as to have tensile strengths and tensile moduli significantly larger than those of existing strong LCPs (such as Kevlar). The key feature of this new class of LCPs is that the exceptional strength is three dimensional on a microscopic, /ital molecular/ level (thus, on a macroscopic level), in contrast to present LCPs (such as Kevlar) with their one-dimensional exceptional strength. These SS LCPs also have some solubility and processing advantages over existing strong LCPs. These SS LCPs are specially-designed combined LCPs such that the side chains of a molecule interdigitate with the side chains of other molecules. This paper also presents other essential general and specific features required for SS LCPs. Considerations in the design of SS LCPs include the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and side chains, the degree of polymerization, the length of the side chains, the regularity of spacing of the side chains along the backbone, the interdigitation of side chains in submolecular strips, the packing of the side chains on one or two sides of the backbone, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and side chains for easy alignment.

• Research Organization: Theoretical Division, Los Alamos National Laboratory, University of California, Los Alamos, New Mexico 87545(US)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6062056
• Journal Information: J. Chem. Phys.; (United States), Vol. 91:2
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
36 MATERIALS SCIENCE
LIQUID CRYSTALS
SOLIDIFICATION
POLYMERS
SYNTHESIS
TENSILE PROPERTIES
COMPRESSION STRENGTH
DESIGN
CRYSTALS
FLUIDS
LIQUIDS
MECHANICAL PROPERTIES
PHASE TRANSFORMATIONS
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory
360603 - Materials- Properties
360601 - Other Materials- Preparation & Manufacture