Viscoelastic properties of in situ composite based on ethylene acrylic elastomer (AEM) and liquid crystalline polymer (LCP) blend

• Published in: Composites science and technology Vol. 67; no. 6; pp. 1202 - 1209
• Main Authors: Shiva Kumar, E., Das, C.K., Banik, K., Mennig, G.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2007; Elsevier
• Subjects: Activation energy; Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Liquid crystalline polymer; Master curve; Polymer industry, paints, wood; Technology of polymers; Time–temperature superposition; Viscoelastic properties; Liquid crystalline polymer; Time–temperature superposition; Master curve; Viscoelastic properties; Activation energy; Viscoelasticity; Acrylic acid copolymer; Polymer blends; Olefin copolymer; Methyl acrylate copolymer; Acrylic elastomer; Thermotropic state; Benzoate(hydroxy) copolymer; Time-temperature superposition; Experimental study; Ester copolymer; Dynamic mechanical properties; Molecular mobility; Liquid crystal polymers; In situ composite; Ethylene copolymer; Temperature time superposition
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2006.05.004

Viscoelastic properties of in situ ethylene acrylic elastomer composites containing 10 and 20 wt.% of liquid crystalline polymer (LCP) were measured in dynamic mechanical experiments. The results show the significant improvement in the storage modulus of the composites with increasing LCP content. All the composites exhibits a single relaxation, which is glass to rubber transition, observed as a peak in the loss modulus at 1 Hz. The time–temperature superposition principle was applied for the pure ethylene acrylic elastomer (AEM) and its composites, in order to evaluate the changes in the viscoelastic properties of AEM by the addition of LCP. Temperature dependence of the shift factors were described using both the Arrhenius and William–Landel–Ferry (WLF) model at the glass transition region. The activation energies of the shift factors are increases with increasing temperature due to complexicity in the motions of the polymer chains, which is further confirmed by the large activation entropies. The principle of time–temperature superposition is used to study changes in the relaxation spectra of in situ AEM system. It is suggested that the change in the viscoelastic behavior, in the case of LCP reinforced AEM, is due to altered molecular mobility of the polymer chain segments in the vicinity of the LCP phase.