Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


JiangF.the (final comments 1).pdf (1.84 MB)

ETD Abstract Container

Abstract Header

Real-time Optical and Mechano-Optical Studies During Drying and Uniaxial Stretching of Polyetherimide Films from Solution

Jiang, Fanhui
http://rave.ohiolink.edu/etdc/view?acc_num=akron1398093793

Abstract Details

2014, Master of Science in Polymer Engineering, University of Akron, Polymer Engineering.
Polyetherimide (PEI) exhibits excellent thermal, chemical, and mechanical stabilities as well as good film forming behavior. These characteristics allow it to be used in harsh industrial applications including electronics, automotive and aerospace. In order to have a fundamental understanding of the temporal evolution of physical characteristics of PEI film and processing parameters, real time measurements are essential. Because drying process of solvent-cast polymer film is complex, off line measurements unable to reveal the temporally varying detailed information, especially for fast “transient events”. To solve this problem, two measurement systems, one for drying that tracks real time thickness, weight, surface temperature, in-plane and out-of-plane birefringence of solution casting film, and another for uniaxial stretching that tracks real time true stress, true strain and birefringence while subjecting film to heating and stretching were used. These allowed systematic investigation of development of optical anisotropy through in and out of plane birefringence monitoring drying of solution cast films and their mechano-optical behavior during stretching, and quantify the influence of solvent N-methyl-2-pyrrolidinone (NMP) on these relationships. In drying, the thickness and weight of PEI solution casting film reduce rapidly at the initial stage due to solvent evaporation, while both in and out of plane birefringence remain zero. Beyond a critical time, while the in-plane birefringence remains very close to zero, the out-of-plane birefringence shows an increase then leveling off. This indicates that the polymer chain axes rotate to preferentially lie in the film plane while exhibiting random in-plane orientation. The decrease of solid content in solution leads to increase in ultimate out-of-plane birefringence as a result of higher chain orientation in the plane. Mixing with low boiling-point solvent, casting at small thickness, drying at low temperature and fast surface air speed, all lead to increases in final value of out-of-plane birefringence due to this alignment. The presence of NMP solvent decreases the glass transition temperature of PEI that allows the PEI film to be stretched at relatively low temperatures. This offers an alternative to high temperature (Tg=216°C) stretching of pristine PEI. The PEI films with various NMP solvent contents all exhibit three regimes of non-linear stress and strain-optical behavior. The addition of solvent content brings a transition from plastic-like behavior to rubber-like behavior, and reduces the final birefringence due to relaxation. Rising stretching temperature and reducing stretching rate play a very similar role with increasing the solvent content that decrease the true stress value at given true strain and the birefringence because of relaxation.
Mukerrem Cakmak, Dr. (Advisor)
Mark Soucek , Dr. (Committee Member)
Kevin Cavicchi, Dr. (Committee Member)
92 p.
Polymers

Recommended Citations

Citations

  • Jiang, F. (2014). Real-time Optical and Mechano-Optical Studies During Drying and Uniaxial Stretching of Polyetherimide Films from Solution [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1398093793

    APA Style (7th edition)

  • Jiang, Fanhui. Real-time Optical and Mechano-Optical Studies During Drying and Uniaxial Stretching of Polyetherimide Films from Solution . 2014. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1398093793.

    MLA Style (8th edition)

  • Jiang, Fanhui. "Real-time Optical and Mechano-Optical Studies During Drying and Uniaxial Stretching of Polyetherimide Films from Solution ." Master's thesis, University of Akron, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1398093793

    Chicago Manual of Style (17th edition)

akron1398093793
997
© 2014, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.