Abstract
The stability of a polymeric nematogen's chemical sequence was studied by differential scanning calorimetry, optical microscopy, and 13C-NMR; the nematogen studied was a thermotropic polyester and had a periodic chemical structure. Model compounds were used to investigate transesterification in the melt at different temperatures with the addition of phenol or benzoic acid as analogues of polymer end groups. Ester interchange reactions at high temperature were found to be partly suppressed when acidic end groups of the periodic nematogen were capped. However, sequence reorganization was completely suppressed in capped nematogen when temperatures remained below the isotropization transition of the nematogen investigated. Rapid disordering of the periodic nematogen was observed above the nematic-isotropic transition, suggesting that both chemical and physical factors play a role in sequence redistribution of periodic nematogens.
| Original language | English |
|---|---|
| Pages (from-to) | 285-293 |
| Number of pages | 9 |
| Journal | Journal of Polymer Science, Part A: Polymer Chemistry |
| Volume | 32 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1994 |
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ASJC Scopus subject areas
- Materials Chemistry
- Polymers and Plastics
Cite this
Stability of chemical sequence in a periodic polymeric nematogen. / Wu, J. L.; Stupp, Samuel I.
In: Journal of Polymer Science, Part A: Polymer Chemistry, Vol. 32, No. 2, 1994, p. 285-293.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Stability of chemical sequence in a periodic polymeric nematogen
AU - Wu, J. L.
AU - Stupp, Samuel I
PY - 1994
Y1 - 1994
N2 - The stability of a polymeric nematogen's chemical sequence was studied by differential scanning calorimetry, optical microscopy, and 13C-NMR; the nematogen studied was a thermotropic polyester and had a periodic chemical structure. Model compounds were used to investigate transesterification in the melt at different temperatures with the addition of phenol or benzoic acid as analogues of polymer end groups. Ester interchange reactions at high temperature were found to be partly suppressed when acidic end groups of the periodic nematogen were capped. However, sequence reorganization was completely suppressed in capped nematogen when temperatures remained below the isotropization transition of the nematogen investigated. Rapid disordering of the periodic nematogen was observed above the nematic-isotropic transition, suggesting that both chemical and physical factors play a role in sequence redistribution of periodic nematogens.
AB - The stability of a polymeric nematogen's chemical sequence was studied by differential scanning calorimetry, optical microscopy, and 13C-NMR; the nematogen studied was a thermotropic polyester and had a periodic chemical structure. Model compounds were used to investigate transesterification in the melt at different temperatures with the addition of phenol or benzoic acid as analogues of polymer end groups. Ester interchange reactions at high temperature were found to be partly suppressed when acidic end groups of the periodic nematogen were capped. However, sequence reorganization was completely suppressed in capped nematogen when temperatures remained below the isotropization transition of the nematogen investigated. Rapid disordering of the periodic nematogen was observed above the nematic-isotropic transition, suggesting that both chemical and physical factors play a role in sequence redistribution of periodic nematogens.
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UR - http://www.scopus.com/inward/citedby.url?scp=0028294772&partnerID=8YFLogxK
U2 - 10.1002/pola.1994.080320209
DO - 10.1002/pola.1994.080320209
M3 - Article
VL - 32
SP - 285
EP - 293
JO - Journal of Polymer Science, Part A: Polymer Chemistry
JF - Journal of Polymer Science, Part A: Polymer Chemistry
SN - 0887-624X
IS - 2
ER -