Department of Chemical Engineering and Materials Science , University of Minnesota , Minneapolis , Minnesota 55455 , United States.
ACS Appl Mater Interfaces. 2019 Apr 3;11(13):12863-12870. doi: 10.1021/acsami.9b00209. Epub 2019 Mar 20.
Melt blowing combines extrusion of a polymer melt through orifices and attenuation of the extrudate with hot high-velocity air jets to produce nonwoven fibers in a single step. Due to its simplicity and high-throughput nature, melt blowing produces more than 10% of global nonwovens (∼$50 billion market). Semicrystalline thermoplastic feedstock, such as poly(butylene terephthalate), polyethylene, and polypropylene, have dominated the melt blowing industry because of their facile melt processability and thermal/chemical resistance; other amorphous commodity thermoplastics (e.g., styrenics, (meth)acrylates, etc.) are generally not employed because they lack one or both characteristics. Cross-linking commodity polymers could enable them to serve more demanding applications, but cross-linking is not compatible with melt processing, and it must be implemented after fiber formation. Here, cross-linked fibers were fabricated by melt blowing linear anthracene-functionalized acrylic polymers into fibers, which were subsequently cross-linked via anthracene-dimerization triggered by either UV light or sunlight. The resulting fibers possessed nearly 100% gel content because of highly efficient anthracene photodimerization in the solid state. Compared to the linear precursors, the anthracene-dimer cross-linked acrylic fibers exhibited enhanced thermomechanical properties suggesting higher upper service temperatures (∼180 °C), showing promise for replacing traditional thermoplastic-based melt blown nonwovens in certain applications. Additionally, given the dynamic nature of the anthracene-dimer cross-links at elevated temperatures (> ∼180 °C), the resulting cross-linked fibers could be effectively recycled after use, providing new avenues toward sustainable nonwoven products.
熔喷法将聚合物熔体通过喷丝孔挤出，并通过热高速气流将挤出物拉伸细化，从而一步法生产出非织造纤维。由于其简单性和高通量的特点，熔喷法生产的非织造布超过全球非织造布的 10%（约 500 亿美元市场）。半结晶热塑性原料，如聚对苯二甲酸丁二醇酯、聚乙烯和聚丙烯，由于其易于熔融加工和热/化学稳定性，主导了熔喷行业；其他无定形商品热塑性塑料（例如苯乙烯类、（甲基）丙烯酸酯等）通常不被采用，因为它们缺乏一个或两个特性。交联商品聚合物可以使它们能够用于更苛刻的应用，但交联与熔融加工不兼容，必须在纤维形成后进行。在这里，通过将线性蒽官能化丙烯酸聚合物熔喷成纤维，然后通过蒽二聚化来交联纤维，随后通过紫外线或阳光引发蒽二聚化来交联纤维。由于在固态下蒽的高效光二聚化，所得纤维具有近 100%的凝胶含量。与线性前体相比，蒽二聚交联的丙烯酸纤维表现出增强的热机械性能，表明更高的上限使用温度（约 180°C），有望在某些应用中替代传统基于热塑性塑料的熔喷非织造布。此外，鉴于高温（> ∼180°C）下蒽二聚交联的动态性质，所得交联纤维在使用后可以有效回收，为可持续的非织造产品提供了新途径。
