Nematic Liquid Crystal Elastomers are lightly cross-linked polymeric networks that exhibit rubber elasticity and liquid crystalline orientational order. Two materials (side chain elastomers, SCE03 and SCE17) were investigated using differential scanning calorimetry and thermogravimetric analysis to correlate thermal behavior with structural and chemical differences between them. SCE03 and SCE17 differed in cross-link and mesogen composition. Fully reversible glass transitions, T_g, and nematic to isotropic transitions, T_(ni)~0, were observed in DSC upon heating and cooling. By varying the heating rate, we determine T_g~0 and T_(ni)~0, the values of these parameters at zero heat rate. We found T_g~0 = 8.6 °C (SCE03) and T_g~0 = -2.4 °C (SCE17). The nematic to isotropic transition temperatures were determined to be T_(ni)~0 = 78 °C (SCE03) and T_(ni)~0 = 90 °C (SCE17). We conclude that SCE03 material with more rigid cross-links has higher glass transition than SCE17 material with weaker cross-links, and the presence of larger mesogens in SCE17 increases its nematic to isotropic transition temperature.
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