High‐Temperature Viscoelastic Relaxation in All‐Cellulose Composites. Issue 1 (June 2014)

• Record Type: Journal Article
• Authors: Duchemin, Benoît J.C.; Staiger, Mark P.; Newman, Roger H.; Saiter, Jean‐Marc
• Is Part Of: Macromolecular symposia. Volume 340:Issue 1(2014)
• Page Start: 52
• Page End: 58
• Publication Date: 2014-06
• Subjects: Macromolecules -- Congresses; Polymers -- Congresses; Polymerization -- Congresses; Macromolecules -- Periodicals; Polymers -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1002/masy.201300123
• Languages: English
• ISSNs: 1022-1360

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Summary</title> <sec id="masy201300123-sec-0001" sec-type="section"> <p>All‐cellulose composites were prepared across a range of different crystallinities in order to examine relationships between phase composition and viscoelastic behaviour in the temperature range of 270 °C to 340 °C corresponding to the α₁ mechanical relaxation. Composite films were prepared by partial dissolution of microcrystalline cellulose in a LiCl/<italic>N, N</italic>‐dimethylacetamide (LiCl/DMAc) solvent system using the film casting technique. Dynamic mechanical analysis showed two contributions to α₁ relaxation, with tan δ maxima at 303 ± 2 °C and at approximately 325 °C. The height of the maximum or shoulder at 303 ± 2 °C decreased with increasing crystallinity, and was therefore assigned to molecular motion associated with chemical decomposition in non‐crystalline domains. The maximum at 325 °C was assigned to chemical decomposition in chains associated with the surfaces of crystalline domains. Composites with high crystallinity showed best retention of the dynamic storage modulus when tested at 300 °C.</p> </sec> </abstract>