Background and Motivation Viscosity Modification ...€¦ · confinement. Liquid Crystalline...

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