Abstract

Dichroic value of poly (ethylene terephthalate) (PET) and polypropylene (PP) films dyed with C. I. Disperse Yellow 7 was measured at high temperatures in order to investigate the influences of draw ratio and temperature of stretching on the thermal change of the dichroism.When the break appearing in the plot of D versus temperature was plotted against the D measured at room temperature, a linear relation was observed. This leads us to conclude that the glass transition temperature of PET rises linearly with increase in the degree of amorphous orientation.As for the PP film the following results were obtained:(1) Three transition points were observed above Tg at T0 (38_??_50°C), T1 (74_??_85°C) and T3 (108_??_120°C).(2) T1 and T3 are nearly constant independently of the value of D, while T0 drops at first and then rises with increase in D through a minimum value at D=0.7_??_0.8.(3) T1 and T3 decrease systematically with increase in the content of atactic fraction, hence, tacticity has a great influence on the mobility of PP segment.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.