Title

Effect of Uniaxial Drawing of Soy Protein Isolate Biopolymer Film On Structure and Mechanical Properties

Document Type

Article

Publication Date

4-1-2007

Department

Polymers and High Performance Materials

Abstract

The effect of uniaxial drawing of biodegradable soy protein isolate (SPI) polymer film on mechanical properties was investigated to accelerate the efforts to develop SPI films with improved properties. The films containing 0-30 wt% glycerol were drawn uniaxially up to a draw ratio of 2.5. The mechanical properties of the SPI film increased significantly after uniaxial drawing. The tensile strength of the undrawn film (49.7 MPa) was approximately doubled by subjecting the film to uniaxial drawing to a D.R. of 2.5. Wide-angle X-ray diffraction and differential scanning calorimetry measurements did not show evidence of generation of a crystal phase in the drawn SPI films. ATR-FTIR revealed that the protein film contained mainly alpha-helix and beta-sheets secondary structures. Microwave molecular orientation analysis showed that birefringence increased with increasing draw ratios. Mechanical anisotropy of the SPI film via orientation of alpha-helix and beta-sheets structure is thought to be responsible for the enhancement of mechanical properties with uniaxial drawing of the SPI films.

Publication Title

Polymer Engineering and Science

Volume

47

Issue

4

First Page

374

Last Page

380