The gas barrier properties of polymers can be improved by reducing gas diffusivity and solubility by using graphene oxide (GO) of various lateral sizes (~3, ~25, ~45 µm). By using GO, the gas diffusion path of the polymer was effectively increased. To reduce the solubility, alkylated GO (AGO) was synthesized by an S_N2 reaction between octyl amine and GO. The hydrophobicity of AGO was confirmed through contact angle measurements, and octylamine on the AGO surface was identified by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis. When GO and AGO with comparatively large lateral size (~45 µm) were homogeneously dispersed in polyvinyl alcohol (PVA) and polyvinylidene chloride (PVDC), respectively, the oxygen transmission rates (OTR) of resulting PVA/GO and PVDC/AGO composite films were significantly reduced. The OTR of PVA/GO composite film reduced from 1.9 × 100 to 5.0 × 10⁻² cm³/m²·day as compared to neat PVA; whereas, the OTR of PVDC/AGO composite film reduced from 1.2 × 100 to 6.8 × 10⁻¹ cm³/m²·day. In addition, the water vapor transmission rate (WVTR) of the PVDC/AGO composite film remarkably decreased from 1.4 g/m²·day (neat PVDC) to ∼5.5·10⁻¹ g/m²·day, where the lateral size of AGO was insignificant. The WVTR results of PVDC/AGO composite films are in contrast to those for PVA/GO composite films, which did not demonstrate any improvement in WVTR with the addition of GO. Based on the experimental results, it was determined that oxygen permeability and water vapor permeability are more affected by diffusivity and solubility, respectively.

中文翻译：

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使用大尺寸的片状氧化石墨烯改善阻隔性能

通过使用各种横向尺寸（〜3，〜25，〜45 µm）的氧化石墨烯（GO），可以通过降低气体扩散率和溶解度来提高聚合物的阻气性。通过使用GO，有效地增加了聚合物的气体扩散路径。为了降低溶解度，通过S _N合成了烷基化的GO（AGO）2辛胺与GO之间的反应。通过接触角测量确认了AGO的疏水性，并通过傅立叶变换红外光谱和X射线光电子能谱分析鉴定了AGO表面上的辛胺。当具有较大横向尺寸（〜45 µm）的GO和AGO分别均匀分散在聚乙烯醇（PVA）和聚偏二氯乙烯（PVDC）中时，所得PVA / GO和PVDC / AGO复合膜的透氧率（OTR）被大大减少。与纯PVA相比，PVA / GO复合膜的OTR从1.9×100降低至5.0×10 ^-2 cm ³ / m ² ·天。PVDC / AGO复合膜的OTR从1.2×100降低至6.8×10 ^-1 cm ³/ m ² ·天。此外，PVDC / AGO复合膜的水蒸气透过率（WVTR）从1.4 g / m ² ·天（纯PVDC）显着降低至〜5.5·10 ^-1 g / m ² ·天，其中横向尺寸AGO的影响微不足道。PVDC / AGO复合膜的WVTR结果与PVA / GO复合膜的WVTR结果相反，在添加GO的情况下WVTR没有任何改善。根据实验结果，确定氧渗透性和水蒸气渗透性分别受扩散率和溶解度的影响更大。