Non-Isothermal Crystallization Kinetics of Poly(4-Hydroxybutyrate) Biopolymer

Molecules

Pau Turon¹  Lutz Funk¹  Jordi Puiggalí²  LuisJ. del Valle²  Lourdes Franco²  Ina Keridou² 

[1] B. Braun Surgical, S.A. Carretera de Terrassa 121, 08191 Rubí (Barcelona), Spain;Departament d’Enginyeria Química, Universitat Politècnica de Catalunya, Escola d’Enginyeria de Barcelona Est-EEBE, c/Eduard Maristany 10-14, 08019 Barcelona, Spain;

关键词: poly(4-hydroxybutyric acid);    bioabsorbable sutures;    crystallization kinetics;    non-isothermal crystallization;    isoconversional methods;    spherulites;    synchrotron radiation;   

DOI  :  10.3390/molecules24152840

来源: DOAJ

【 摘 要 】

The non-isothermal crystallization of the biodegradable poly(4-hydroxybutyrate) (P4HB) has been studied by means of differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). In the first case, Avrami, Ozawa, Mo, Cazé, and Friedman methodologies were applied. The isoconversional approach developed by Vyazovkin allowed also the determination of a secondary nucleation parameter of 2.10 × 10⁵ K² and estimating a temperature close to 10 °C for the maximum crystal growth rate. Similar values (i.e., 2.22 × 10⁵ K² and 9 °C) were evaluated from non-isothermal Avrami parameters. All experimental data corresponded to a limited region where the polymer crystallized according to a single regime. Negative and ringed spherulites were always obtained from the non-isothermal crystallization of P4HB from the melt. The texture of spherulites was dependent on the crystallization temperature, and specifically, the interring spacing decreased with the decrease of the crystallization temperature (T_c). Synchrotron data indicated that the thickness of the constitutive lamellae varied with the cooling rate, being deduced as a lamellar insertion mechanism that became more relevant when the cooling rate increased. POM non-isothermal measurements were also consistent with a single crystallization regime and provided direct measurements of the crystallization growth rate (G). Analysis of the POM data gave a secondary nucleation constant and a bell-shaped G-T_c dependence that was in relative agreement with DSC analysis. All non-isothermal data were finally compared with information derived from previous isothermal analyses.

【 授权许可】

Unknown