Thermal Analysis of the Conformational Disorder in SCLC Polymers with Rigid Backbone Glass transition studies |
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Authors: | Danch A Lohner K Ungerank M Stelzer F |
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Institution: | 1.Institute of Engineering Problems, Silesian University, ?nie?na 2, 41-200, Sosnowiec, Poland ;2.Institut für Biophysik und R?ntgenstrukturforschung, Austrian Academy of Sciences, Steyrergasse 17, A-8010, Graz ;3.Institut für Chemische Technologie organischer Stoffe, TU Graz, Stremayrgasse 16, A-8010, Graz, Austria ; |
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Abstract: | Bis (ω-(4′-cyanobiphenyl)-4-yl)oxy-n-alkyl]norborn-5-ene-2,3-dicarboxylate was polymerised via ring opening metathesis polymerisation
(ROMP). Two disubstituted polynorbornene derivatives both of cis configuration with different length of the side-chain were
studied. Differential scanning calorimetry (DSC) was used to study the effect of thermal history on the assignment of the
glass transition event associated with the biaxial orientation of a smectic phase. Glass transition temperatures, the change
of isobaric specific heats at Tg and the enthalpies of isotropisation were calculated. The DSC traces only show the classic step-wise change in Tg in some cases, giving the evidence that the amorphous domains are constrained and highly restricted in movement due to the
morphology developed as a result of the biaxial stretching. Based on the literature data of mono- and disubstituted polynorbornene
derivatives and our calorimetric experiments, the shape of Tg dependence on number of (CH2) units is interpreted. The origin of this shape is discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. |
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Keywords: | DSC glass transition side-chain liquid crystal polymer (SCLC) |
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