Kinetics of mesophase transitions in thermotropic copolyesters. 4. Pendant side-group effect

1991 ◽  
Vol 24 (1) ◽  
pp. 150-157 ◽  
Author(s):  
Stephen Z. D. Cheng ◽  
Ronald L. Johnson ◽  
Zongquan Wu ◽  
Hak Hung Wu
Keyword(s):  
Group Effect ◽  
Side Group ◽  
Kinetics Of ◽  
Thermotropic Copolyesters

scholarly journals Fast-Scanning Chip-Calorimetry Measurement of Crystallization Kinetics of Poly(Glycolic Acid)

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 891
Author(s):  
Yongxuan Chen ◽  
Kefeng Xie ◽  
Yucheng He ◽  
Wenbing Hu
Keyword(s):  
Crystallization Kinetics ◽  
Temperature Region ◽  
Glycolic Acid ◽  
Crystal Nucleation ◽  
Side Group ◽  
Half Time ◽  
Temperature Range ◽  
Chip Calorimetry ◽  
Kinetics Of ◽  
Fast Scanning Chip Calorimetry

We report fast-scanning chip-calorimetry measurement of isothermal crystallization kinetics of poly(glycolic acid) (PGA) in a broad temperature range. We observed that PGA crystallization could be suppressed by cooling rates beyond -100 K s−1 and, after fast cooling, by heating rates beyond 50 K s-1. In addition, the parabolic curve of crystallization half-time versus crystallization temperature shows that PGA crystallizes the fastest at 130 °C with the minimum crystallization half-time of 4.28 s. We compared our results to those of poly(L-lactic acid) (PLLA) with nearby molecular weights previously reported by Androsch et al. We found that PGA crystallizes generally more quickly than PLLA. In comparison to PLLA, PGA has a much smaller hydrogen side group than the methyl side group in PLLA; therefore, crystal nucleation is favored by the higher molecular mobility of PGA in the low temperature region as well as by the denser molecular packing of PGA in the high temperature region, and the two factors together decide the higher crystallization rates of PGA in the whole temperature range.

Kinetics of mesophase transitions of thermotropic copolyesters. 2. Two transition processes

1989 ◽  
Vol 22 (11) ◽  
pp. 4240-4246 ◽  
Author(s):  
Stephen Z. D. Cheng ◽  
James J. Janimak ◽  
Anqiu Zhang ◽  
Zhenglong Zhou
Keyword(s):  
Transition Processes ◽  
Kinetics Of ◽  
Thermotropic Copolyesters

Kinetics of mesophase transitions in thermotropic copolyesters. 3. Poly[(phenyl-p-phenylene terephthalate)-co-[(1-phenylethyl)-p-phenylene terephthalate]] copolyester

1990 ◽  
Vol 23 (4) ◽  
pp. 1196-1202 ◽  
Author(s):  
Stephen Z. D. Cheng ◽  
Anqiu Zhang ◽  
Ronald L. Johnson ◽  
Zongquan Wu ◽  
Hak Hung Wu
Keyword(s):  
Kinetics Of ◽  
Thermotropic Copolyesters

X-ray Analysis of the Kinetics of Transesterification in Blends of Wholly Aromatic Thermotropic Copolyesters

1997 ◽  
Vol 30 (17) ◽  
pp. 4837-4844 ◽  
Author(s):  
C. M. McCullagh ◽  
J. Blackwell ◽  
A. M. Jamieson
Keyword(s):  
X Ray ◽  
Kinetics Of ◽  
Thermotropic Copolyesters
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