AbstractThin films of polyacrylic acid (PAA), 4,4‘-diphenylmethane diisocyanate (MDI) and borax were separately grown on a poly (ethylene terephthalate) (PET) film to afford a transparent film material with super gas barrier performance. Unlike electrostatic interactions or clay-loaded barrier thin films, which were easily peeled when subjected to exoteric force, excellent peel strength was obtained due to the formation of high density urethane chemical bonds. The gas vapor barrier value is dramatically decreased to the detection limit of commercial instrumentation (<0.005 cc/m2/day). These outstanding performances are attributed to the reaction between sodium metaborate and PAA, which is confirmed using online infrared radiation (IR) and X-ray photoelectron spectroscopy (XPS). The XPS of the multilayer film revealed that borax can permeate the PAA thin layer to completely crosslink the carboxyl group of PAA. The gas barrier properties are obviously improved by the permeating borax solution. In particular, compared to commercial PET film, the oxygen transmission rate (OTR) is reduced from 75 to <0.005 cc/m2/day. Moreover, the OTR value is almost same as that of poly(ethylene-co-vinyl alcohol) (EVOH) film, which is currently the best gas barrier plastic. Therefore, the PET/MDI/PAA/borax composite films show great potential for various packaging materials due to their excellent oxygen and moisture barrier characteristics, as well as other performance.By simply coating a thin layer of 4,4’-diphenylmethane diisocyanate, polyacrylic acid and borax on the surface of PET film, a transparent PET film with extremely low gas vapor barrier value can be obtained. The oxygen transmission rate can be dramatically decreased to the detection limit of commercial instrumentation (<0.005 cc/m2/day).

中文翻译：

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表面涂有聚电解质和硼砂的透明和超阻气性 PET 薄膜

摘要 在聚对苯二甲酸乙二醇酯 (PET) 薄膜上分别生长聚丙烯酸 (PAA)、4,4'-二苯基甲烷二异氰酸酯 (MDI) 和硼砂薄膜，以提供具有超气体阻隔性能的透明薄膜材料。与静电相互作用或负载粘土的阻挡薄膜不同，当受到外力时很容易剥离，由于形成高密度氨基甲酸酯化学键，因此获得了优异的剥离强度。气体蒸气阻隔值显着降低至商业仪器的检测极限（<0.005 cc/m2/天）。这些出色的性能归功于偏硼酸钠和 PAA 之间的反应，这一反应通过在线红外辐射 (IR) 和 X 射线光电子能谱 (XPS) 得到证实。多层膜的 XPS 表明硼砂可以渗透 PAA 薄层以完全交联 PAA 的羧基。渗透性硼砂溶液明显提高了阻气性。特别是，与商用 PET 薄膜相比，透氧率 (OTR) 从 75 降至 <0.005 cc/m2/天。此外，其OTR值与目前最好的阻气性塑料聚（乙烯-共-乙烯醇）（EVOH）薄膜的OTR值几乎相同。因此，PET/MDI/PAA/硼砂复合薄膜由于其优异的氧气和水分阻隔特性以及其他性能，在各种包装材料中显示出巨大的潜力。通过简单地涂覆一层薄薄的4,4'-二苯基甲烷二异氰酸酯， PET薄膜表面的聚丙烯酸和硼砂，可以获得具有极低气体蒸汽阻隔值的透明PET薄膜。氧气透过率可以显着降低到商业仪器的检测极限（<0.005 cc/m2/天）。