TA Instruments TGA 2950 - Plastic Laboratory Tubing

TA I NSTRUMENTS TGA 2950 B–71
Hi-Res
TM
Option
Plastic
Laboratory Tubing
In Figures B.21 through B.25 we analyzed a
sample of Tygon
®
R-3603 plastic tubing, a poly-
vinyl chloride (PVC) based clear flexible tubing
commonly used in laboratories and industry. A
number of overlapped transitions are evident
between 100
°
C and 350
°
C, followed by two well
resolved transitions at approximately 400
°
C and
500
°
C. Of interest are the changes in resolution
of the various transitions as maximum heating
rate changes in both the conventional and Hi-
Res
TM
scans.
Observing the two conventional scans (Figures
B.21 and B.22) we see that the resolution of the
initial overlapped transitions is good in the 1
°
C/
minute scan, but poor in the 20
°
C/minute scan.
In contrast, the resolution of the two transitions
at 400
°
C and 500
°
C are best in the 20
°
C/minute
scan and reduced in the 1
°
C/minute scan. In
both cases, however, the small backside transi-
tion at 25% to 35% weight loss is barely
discernable. Comparing the conventional TGA
results in figures B.21 and B.22 to the 50
°
C/
minute Hi-Res
TM
scan in Figure B.23, we see
that all of these transitions are better resolved in
the Hi-Res
TM
TGA scan in a timely fashion.
Using Figures B.23, B.24, and B.25 we can
compare the result of changing the maximum
heating rate of a dynamic rate Hi-Res
TM
scan.
Maximum heating rates of 50
°
C/minute (Figure
B.23), 20
°
C/minute (Figure B.24) and 10
°
C/
minute (Figure B.25) were used with a method
consisting of a single Hi-Res
TM
ramp segment.