ISSN:
1022-1352
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
[(Ph2PN)0,76(Ph(o-tolyl)PN)0,24] random copolymer (Ph: phenyl) was synthesized by the reaction of Ph2POCH2CF3 and Ph(o-tolyl)POCH2CF3 with trimethylsilyl azide. Differential scanning calorimetry (DSC) measurements showed that this copolymer has a single glass transition at ≈ 80°C and transforms into a mesophase at 162 ∼ 189°C depending upon the thermal history of the specimens. Lath shaped crystals with unit cell dimensions a = 1,30 nm, b = 1,13 nm and y = 87° (Form-I) were obtained from mixed dilute monochlorobenzene and p-xylene solution of the copolymer. Upon heating the specimens to 140°C, the “a” parameter of Form-I changes to a = 2,21 nm and the “b”, “y” remain unaltered (Form-II). When the specimens are cooled (10°C/min) from above T(1), the mesophase (δ-form) is “frozen in” and the δ-form specimens transform into Form-II by heating to 140°C. Another structure change (Form-III) occurs after the δ-form specimens were heated to 180°C followed by cooling below the glass transition temperature Tg. However, upon cooling the specimens slowly (0,2°C/min) from above T(1), Form-III results.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1995.021960528
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