Events

Description:

Wed April 12

Joint meeting with the Northern California SAS (Society for Applied Spectroscopy)

Dr. Bruce Chase

DuPont Central Research, Wilmington, DE

"Raman Spectroscopy as a Probe of Structure/Orientation in Polymeric Fibers"

Abstract

Polymeric macroscopic properties such as tenacity, modulus, elasticity, etc. are determined by molecular level effects such as conformational state populations, orientation, and intermolecular interactions. Significant changes occur at the molecular level as a molten or solution phase polymer is spun into fiber form. The polymer goes from an unoriented, amorphous state to an oriented, semi-crystalline material via the deformations imposed by spinning and drawing. Raman spectroscopy can potentially provide information on both structure and orientation. Changes in band intensities can be related to conformational populations and to formation of crystalline regions. Changes in relative intensities as a function of incident and scattered polarization yields information on chain orientation. The use of polarized Raman scattering done in both 90 and 180 degree scattering geometries has been used to determine the second and fourth order orientation functions for both polyethylene and PET fibers. Raman measurements have been made in both the laboratory frame and on-line for 66 nylon and PET fibers. For both PET and 66 nylon, crystallinity levels and a qualitative measure of orientation can be obtained.

Location: Michaels at Shoreline, Mountain View

Dinner Choices: (Indicate Choice when RSVP?ing)

Breast of Chicken, Piccata

Chilean Sea Bass, Ginger Shallot Sauce

Grilled Vegetable Brochette with Wild Rice