Molecular Weight Distribution as a Means to Control Polymer Properties
Loading...
No Access Until
Permanent Link(s)
Collections
Other Titles
Authors
Abstract
A process for the precise control of polymer molecular weight distribution (MWD) shape is developed. Temporal control of polymer chain initiation was achieved through the metered addition of discrete initiating species to controlled radical polymerizations and anionic polymerizations. Series of polymers can be prepared with the same molar mass and breadth but with vastly different MWD shapes. Using anionic polymerization, living polymers with skewed distribution functions can be chain extended to afford well-defined block copolymers with systematically deviating compositions of molecular weights. Rheological measurements reveal that the MWD shape has an important influence on the viscoelastic behavior of homopolymer melts such as viscosity and storage modulus. Dynamic mechanical analysis showed that the Young’s modulus of block copolymers can be tuned over a broad range by modifying the shape of the MWD in one block. Investigation of the phase behavior of block copolymers by transmission small-angle X-ray scattering and grazing-incidence small-angle X-ray scattering demonstrates that the distribution symmetry enables tuning of the thin film domain spacing and the boundaries of the bulk morphological phase diagram. Additionally, the development of a kinetic model for the predictive design of MWDs is explored.
Journal / Series
Volume & Issue
Description
Sponsorship
Date Issued
2019-08-30
Publisher
Keywords
molecular weight distributions; skew; Mechanical properties; Chemistry; synthesis; Polymer chemistry; Self-assembly; Organic chemistry
Location
Effective Date
Expiration Date
Sector
Employer
Union
Union Local
NAICS
Number of Workers
Committee Chair
Fors, Brett P.
Committee Co-Chair
Committee Member
Collum, David B.
Coates, Geoffrey
Coates, Geoffrey
Degree Discipline
Chemistry and Chemical Biology
Degree Name
Ph.D., Chemistry and Chemical Biology
Degree Level
Doctor of Philosophy
Related Version
Related DOI
Related To
Related Part
Based on Related Item
Has Other Format(s)
Part of Related Item
Related To
Related Publication(s)
Link(s) to Related Publication(s)
References
Link(s) to Reference(s)
Previously Published As
Government Document
ISBN
ISMN
ISSN
Other Identifiers
Rights
Attribution 4.0 International
Rights URI
Types
dissertation or thesis