Abstract：
Poly (butylene adipate-co-terephthalate)/poly (L-lactic acid) (PBAT/PLLA) is one of the most important biodegradable polymer combinations; however, they are flammable with heavy melt dripping and incompatible. To achieve the objective of flame retardation and compatibility, a hybrid polyurethane (PU) with multiple flame retardation elements is synthesized via a new ring-opening polymerization (ROP) method and integrated into PBAT/PLLA film. The PU not only dissolves in different organic solvents at mild temperature but also improves the compatibility of PBAT/PLLA. As PU with respect to PBAT/PLLA is 20 wt%, the limiting oxygen index (LOI) and UL-94 reach 25.5 % and V-0 rating, respectively. In cone calorimeter test, the peak heat release rate (pHRR) of PU/PBAT/PLLA is ahead of PBAT/PLLA, and the total heat release (THR) decreases to 25.85 MJ/m2. The fire safety is achieved successfully. The initial pyrolysis of PU promotes the formation of a seed carbon layer; it continuously breaks down into a series of phosphorus‑oxygen radicals and generates different inert gases, while the pyrolytic solid products accelerate the carbonization to form the carbon/silicon composite layer. Then the polymeric combustion is braked completely. Besides, the PU can also tune the mechanical properties of PBAT/PLLA film and enhance its hydrophobicity. This work opens a new window for developing multifunctional flame retardant and paves the way for the richening engineering application of PBAT/PLLA.
摘要：
聚（己二酸丁二醇酯-共对苯二甲酸酯）/聚（L-乳酸）（PBAT/PLLA）是最重要的生物可降解聚合物组合之一；然而，它们易燃，有大量的熔体滴落和不相容。为了达到阻燃和相容性的目的，通过新的开环聚合（ROP）方法合成了具有多种阻燃元件的混合聚氨酯（PU），并将其集成到PBAT/PLLA薄膜中。PU不仅在温和的温度下溶解在不同的有机溶剂中，而且还提高了PBAT/PLLA的相容性。由于PU相对于PBAT/PLLA为20重量%，极限氧指数（LOI）和UL-94达到25.5%和V-0等级，分别。在锥形量热仪测试中，PU/PBAT/PLLA的峰值热释放速率（pHRR）领先于PBAT/PLLA，总放热(THR)降至25.85MJ/m2。成功实现了消防安全。PU的初始热解促进了籽晶碳层的形成；它不断分解成一系列磷-氧自由基，并产生不同的惰性气体，热解固体产物加速碳化形成碳/硅复合层。然后完全制动聚合物燃烧。此外,PU还可以调节PBAT/PLLA薄膜的机械性能并增强其疏水性。这项工作为开发多功能阻燃剂打开了一个新的窗口，并为PBAT/PLLA的富集工程应用铺平了道路。
