La fusion et la cristallisation de la poly(α,α-diéthyl-β-propiolactone): Comparaison avec d'autres polylactones

✍ Scribed by Normand, Yves ;Aubin, Madeleine ;Prud'homme, Robert E.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1979
• Weight: 880 KB
• Volume: 180
• Category: Article
• ISSN: 0025-116X
• DOI: 10.1002/macp.1979.021800320

✦ Synopsis

Abstract

Measurements of crystallization kinetics were made for a sample of poly(α,α‐diethyl‐β‐propiolactone) (DEPL) (syst. name: poly(oxy‐2,2‐diethyl‐1‐oxotrimethylene)). An Avrami exponent of 2 was found indicating a two‐dimensional growth rate of the crystal, following a pre‐determined and heterogeneous nucleation mode. Two melting peaks were found for most samples. The second melting peak (at high temperatures) is probably due to the re‐crystallization of part of the sample initially present under the first melting peak. A value of 21kJ.mol^−1^ was also determined for the heat of fusion of DEPL by the diluent method. This value leads to a degree of crystallinity of 17% which is about four times smaller than that found for poly(pivalolactone) (syst. name: poly(oxy‐2,2‐dimethyl‐1‐oxotrimethylene)). We have also determined an equilibrium melting temperature of 531 K for this polymer and an entropy of fusion of 40J.mol^−1^. K^−1^. Finally, the surface free energies σ and σ~e~ for the lamellar crystals were found to be 12.10^−7^J.cm^−2^ and 72.10^−7^J.cm^−2^, respectively.