This contribution reported the radical copolymerization of vinyl acetate (VAc) with vinyl carboxylates bearing branched C₇–C₉ chains, including vinyl neononanoate (VV-9), vinyl neodecanoate (VV-10), and vinyl 2-ethylhexanoate (VV-EH), and the VAc units of the as-prepared copolymers were subsequently hydrolyzed to vinyl alcohol units in a base medium. With reactivity ratios of r₁ = 0.94 (VV-9) and r₂ = 0.96 (VAc), the copolymerization of VV-9 and VAc demonstrates an ideal azeotropic copolymerization. By simply adjusting the initial feed ratios, terpolymers of VV-9, VAc, and vinyl alcohol (PVVOH) with different compositions have been successfully prepared. As a proof-of-concept, their application as modifiers to improve the adhesive, hydrophilic, and oxygen barrier properties of low-density polyethylene (LDPE) was evaluated. When the PVVOH with 40 wt % VV-9 units was blended with LDPE, the dispersed PVVOH phase formed microdomains with a size of about 1 μm, and there was no observable two-phase structure. The water contact angles of the PVVOH/LDPE blends were reduced from 103.7 ± 0.9° to 51.1 ± 1.3° and retained after being soaked in water at ambient conditions for 30 days. PVVOH is also effective in improving the adhesion between LDPE and aluminum alloys. With the addition of 25 wt % PVVOH (20 wt % VV-9), the ultimate shear strength of the lap joint was effectively enhanced from 3.60 ± 0.17 MPa (pristine LDPE) to 4.87 ± 0.02 MPa. Furthermore, the addition of 20 wt % PVVOH reduced the oxygen transmission rates (OTR) of LDPE film from 145.3 to 52.2 cm³·mm·m^–2·day^–1·bar^–1.

中文翻译：

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带有支化 C7-C9 链的乙酸乙烯酯和羧酸乙烯酯的共聚物：合成、醇解和性能

_{该文章报道了乙酸乙烯酯 (VAc) 与带有支化 C 7} –C ₉链的羧酸乙烯酯的自由基共聚，包括新壬酸乙烯酯 (VV-9)、新癸酸乙烯酯 (VV-10) 和 2-乙基己酸乙烯酯 (VV-EH) ），所制备的共聚物的VAc单元随后在基础介质中水解为乙烯醇单元。当反应活性比为r ₁ = 0.94 (VV-9) 和r ₂ = 0.96 (VAc) 时，VV-9 和VAc 的共聚表现出理想的共沸共聚。通过简单调整初始投料比，成功制备了不同组成的VV-9、VAc和乙烯醇(PVVOH)三元共聚物。作为概念验证，评估了它们作为改性剂改善低密度聚乙烯 (LDPE) 的粘合性、亲水性和氧气阻隔性能的应用。当含有 40 wt% VV-9 单元的 PVVOH 与 LDPE 共混时，分散的 PVVOH 相形成尺寸约为 1 μm 的微区，并且没有观察到两相结构。 PVVOH/LDPE共混物的水接触角从103.7±0.9°降低到51.1±1.3°，并且在环境条件下在水中浸泡30天后保持不变。 PVVOH还可有效提高LDPE与铝合金之间的粘合力。添加25 wt% PVVOH（20 wt% VV-9）后，搭接接头的极限剪切强度从3.60±0.17 MPa（原始LDPE）有效提高到4.87±0.02 MPa。此外，添加20 wt%的PVVOH将LDPE薄膜的氧气透过率(OTR)从145.3降低至52.2 cm ³ ·mm·m ^–2 ·day ^–1 ·bar ^–1。