posted on 2019-03-07, 00:00authored byKailong Jin, Aditya Banerji, David Kitto, Frank S. Bates, Christopher J. Ellison
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.