Electrospinning of poly(MMA-co-MAA) copolymers and their layered silicate nanocomposites for improved thermal properties

Copolymers consisting of methyl methacrylate (MMA) and methacrylic acid (MAA) and their layered silicate nanocomposites were electrospun to form fibers with diameters in the sub-micron range. The presence of MAA increased the Tg and thermal stability of the copolymers through formation of anhydrides upon heating. Fibers of uniform diameters were obtained for the poly(MMA-co-MAA) copolymers and nanocomposites containing montmorillonite (MMT), while protrusions were observed on the electrospun fibers from nanocomposites containing fluorohectorite (FH). The electrospinnability of copolymer solutions and nanocomposite dispersions predicted based on both rheological analyses and conductivity measurements correlates well with the experimental electrospinning observations. Dispersion of clays within the nanocomposites improved the electrospinnability of the nanocomposite dispersions. MMT is predominantly exfoliated and well distributed within the fiber and oriented along the fiber axis. Char formation was observed when the MMT-containing fibers were heated above the decomposition temperature, indicating a potential for reduced flammability and increased self-extinguishing properties, whereas the FH-containing materials disintegrated into either film or powder form.