Investigation of the crystallinity and orientation of polypropylene with respect to temperature changes using FT-IR, WRD, and Raman techniques
Author(s)
Advisor
Date
2004Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
Having good mechanical and barrier properties, polypropylene films are widely used
in food-packing industry. The relation of crystallinity and orientation of
polypropylene with these properties are well known. Temperature increase has an
important effect on the crystallinity and orientation of polypropylene. The purpose of
this study is to understand better crystallinity and orientation changes of the cast and
bi-axially oriented polypropylene films with respect to temperature effect. These
changes were investigated using especially in-situ FT-IR and dichroism as well as
XRD and Raman spectroscopy.
For this purpose, an in-situ variable temperature set-up is developed and adapted for
FT-IR studies. Accordingly, the changes in the peaks related to the amorphous and
crystalline contents of the films as well as the peaks reflecting the orientation of the
films were investigated over the temperature range from 120-170o
C. Temperature
cycle was also applied. Moreover, the films were investigated after application of
additional stress at 120o
C for various durations.
The crystallinity and orientation of the films are affected significantly when the films
were analyzed at higher temperature (>150o
C). The crystallinity content of the film recovers after returning back to room temperature whereas orientational loss are
permenant.
Keywords
PolypropylenePhase Transition and Temperature Effect
Raman Spectroscopy
XRD
Dichroism
FT-IR