Analysis of Poly(lactic acid) Amorphous Chain Structure Associated with Crystallization and Deformation Behavior

Shuhui Kang* and Shaw-Ling Hsu, University of Massachusetts-Amherst

 

 

Poly(lactic acid) (PLA) is a widely used biomaterial, as well as a new generation plastic. This is due to its biocompatibility, biodegradability and sustainability.  Investigation of amorphous chain structure characteristics such as conformation, configuration, monomer residue junction, and chain stiffness can provide a fundamental understanding on industrial processing and physical properties.  Raman spectroscopy, static light scattering, viscometry, in combination with normal coordinate analysis on disordered chain are used to characterize and analyze PLA in solid and solution states from segmental to molecular scales. This study has shown that the "trans-gauche-trans" (tgt) conformer is the dominant conformation (~80%) in the rotational isomeric state model of PLA, suggesting a stiff chain nature. The study has also shown that chain stiffness slowly decreases with defect content, reflecting a non-random nature in chain statistics and an elevated conformational energy at junction units.  In addition, it is found that the amorphous chain deformation is associated with a distorted conformational distribution in which the tgt population increases with stress.

 

 

*Presenting  author: Shuhui Kang

 

Category: MSEL

Mentor: Shaw-Ling Hsu

Division: Polymer (code: 854)

Lab: Material Science and Engineering

Room: A327

Building: 224

Mail Stop: 8541

Telephone: 301 975 4602

Fax: 301 975 3928

Email: skang@nist.gov

Sigma-Xi member: No