Normandie Université, France.
Phys Chem Chem Phys. 2015 May 7;17(17):11313-23. doi: 10.1039/c4cp05524a.
Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB-co-4HB) films containing various contents of organo-modified montmorillonite C30B nanoclays were prepared by melt intercalation. Wide angle X-ray diffraction measurements and transmission electron microscopy observations evidenced aggregated and intercalated structures with individual nanoclay platelets in the nanocomposites and an orientation of nanoclays. Differential scanning calorimetry measurements showed that the nanoclay did not influence the crystalline structure of the matrix because it is mainly located in the polymer amorphous phase. The influence of the filler on the barrier properties of the film was evaluated by water diffusion, gas permeation (CO2, N2, O2) and liquid water sorption measurements. A decrease of the N2 permeability was measured due to the tortuosity effect of the filler associated with a decrease of the solubility within the matrix. The influence of the filler was more marked for O2 due to the larger decrease of O2 solubility. In contrast, the CO2 permeability increased whatever the filler content because of a facilitated transport mechanism due induced by the presence of quaternary ammonium cations on the C30B surface. The decrease of the water permeability with the filler was explained by a competition between the kinetic (diffusivity) and thermodynamic (solubility) contributions defining the permeability process.
聚（3-羟基丁酸-co-4-羟基丁酸）（P3HB-co-4HB）薄膜中含有不同含量的有机改性蒙脱土 C30B 纳米粘土，通过熔融插层制备而成。广角 X 射线衍射测量和透射电子显微镜观察表明，在纳米复合材料中存在着聚集和插层结构，纳米粘土片层呈各向异性排列。差示扫描量热法测量表明，纳米粘土不会影响基体的结晶结构，因为它主要位于聚合物非晶相中。通过水扩散、气体渗透（CO2、N2、O2）和液态水吸附测量评估了填料对薄膜阻隔性能的影响。由于填料的迂曲效应以及基体中溶解度的降低，测量到 N2 渗透率的降低。由于 O2 溶解度的大幅降低，填料对 O2 的影响更为显著。相比之下，由于 C30B 表面上存在季铵阳离子，促进了传输机制，无论填料含量如何，CO2 渗透率都会增加。由于动力学（扩散率）和热力学（溶解度）贡献对渗透率过程的限制，填料的存在导致水渗透率降低。
