Follain N, Crétois R, Lebrun L, Marais S
Normandie University, UNIROUEN, INSA Rouen, CNRS, PBS, 76000 ROUEN, France.
Phys Chem Chem Phys. 2016 Jul 27;18(30):20345-56. doi: 10.1039/c6cp04147g.
Biodegradable polyester-based films constituted of poly(hydroxyalkanoates) (PHA) were successfully extruded with various Cloisite 30B contents. The morphology was highly dependent on the matrix, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate), the polymer crystalline phase fraction, the matrix/nanoclay interfacial regions as well as the nanoclay content. Water vapour resistance was investigated through sorption kinetics, isotherms, modelling aspect, and diffusivity. A typical sigmoid-shaped isotherm was obtained in every case. It emerges that the nanoclay highly contributed to the increase of water solubility of matrices. The dependence of polymer crystallinity on the affinity of the nanocomposite films for water was highlighted. Thermodynamic and kinetic contributions of the sorption process were also correlated with the film morphology. According to the matrix used, water diffusivity in films was differently impacted by the sorbed water amount. The access of sorbed water molecules within films was examined through a mathematical modelling approach and the deduced mean cluster size of water vs. its activity was corroborated by sorption kinetics.
由聚羟基脂肪酸酯（PHA）构成的可生物降解聚酯基薄膜成功地与不同含量的Cloisite 30B进行了共挤出。其形态高度依赖于基体，聚（3-羟基丁酸酯-co-3-羟基戊酸酯）和聚（3-羟基丁酸酯-co-4-羟基丁酸酯）、聚合物结晶相分数、基体/纳米粘土界面区域以及纳米粘土含量。通过吸附动力学、等温线、建模方面和扩散率研究了耐水蒸气性。在每种情况下均获得了典型的S形等温线。结果表明，纳米粘土对基体水溶性的增加有很大贡献。强调了聚合物结晶度对纳米复合薄膜与水亲和力的依赖性。吸附过程的热力学和动力学贡献也与薄膜形态相关。根据所使用的基体，薄膜中的水扩散率受到吸附水量的不同影响。通过数学建模方法研究了吸附水分子在薄膜内的进入情况，吸附动力学证实了推导得出的水的平均簇尺寸与其活度之间的关系。
