background and motivation viscosity modification ...€¦ · confinement. liquid crystalline...
TRANSCRIPT
Zhenpeng Li1, Zheng Zhou2, Shannon Armstrong2, Eric Baer2, D.R. Paul1, Christopher J. Ellison1
1McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 2Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106
Background and Motivation Viscosity Modification Characterization of Multilayer Films
Acknowledgements The Ellison Group
• Dr. Dustin Janes
The Paul Group
• Dr. Rajkiran Tiwari
The Freeman Group
Multilayer Film from Coextrusion
Challenges Conclusions
Liquid Crystalline Polymer Multilayer Film
The viscosity of LCP is dramatically increased by reacting with Heloxy without
affecting its unique liquid crystal structure.
The quality of multilayer films was significantly improved.
LCP chain aligns perpendicular to extrusion direction with ‘log-rolling’ effect.
The gas permeability of LCP thin film is dramatically decreased due to nano-
confinement.
Liquid Crystalline Polymer Multilayer Films for High Barrier Materials
Materials and Experiments
Rheological Properties Modification
Orientation of LCP in Multilayer Films
q*
q*
100 nm
A B
ABA
Feedblock
Layer
Multipliers
Surface layer
A
B
Surface layer
…
Crystal morphology under confinement
Enhanced barrier property by confinement
Tortuous Diffusion
PathwayPermeability decreased
by 2 orders of magnitude
Wang H, Freeman B et al. Science 2009, 323, 757.
High barrier properties
Good mechanical properties
High solvent resistanceLiquid Crystalline polymer (LCP)
nano scale
micro scale
LCP multilayer film Enhance barrier properties of LCP (Super high barrier film)
Decrease the price of the membrane products
The viscosities of the two components should match in order to make high quality multilayer films
Objective:
Enhance the viscosity of LCP to make high quality multilayer films
Preserve the intrinsic liquid crystal structures after the rheological modification
Microcompounder
Viscosity of V400p is increased by nearly 20x after reacting with Heloxy
The liquid crystal structure is not disturbed by the modification
The viscosity of Vectra V400p is dramatically increased, making it possible to
match the viscosity of other conventional polymers.
The processing window is chosen at the temperature where the viscosities of
V400p matches that of the PP-g-MA
d1
d2
The LCP chain is oriented perpendicular
to the extrusion direction due to a ‘log-
rolling’ effect.
Multilayer coextrusion
Z Li, et al. Polymer 2014
Improved Layer Quality by Viscosity Modification
Consecutive cross-section SEM images showing the layer integrity of the modified V400p/PP
multilayer films over large distances
Cross-section SEM images of the neat V400p and
modified V400p/PP multilayer filmsOverall quality of multilayer films
Permeability of LCP Thin Films
Optically transparent
Mechanically flexible
Deposition Spreading Thinning Drying
Spin coating process: powerful to make nano scale thin polymer films
Chemically and thermally inert
Cost effectiveNext generation see through
packaging materials