Fabrication and characterization of melamine formaldehyde fibers with enhanced mechanical properties and high fire resistance by dry spinning

摘要

High-performance melamine formaldehyde (MF) fibers are successfully produced by innovatively utilizing dry spinning with high efficiency and low emission. Three ways are adopted to enhance the mechanical performance of MF fiber. First, MF resin is modified by introducing flexible chain segments into MF three-dimensional network and reducing the network crosslink density. Second, the energy dissipation capacity of the MF fibers is improved through constructing of hydrogen bond networks among modified MF resin, nano-SiO2, and/or polyvinyl alcohol and forming interpenetrating network structures of modified MF resin and nano-SiO2. Third, homogeneous and stable spinning solutions without phase separation are prepared, which can reduce interior defects of MF fibers. The chemical changes in the spinning solutions with increasing temperature and the rheology behavior of the solutions are investigated. In addition, the effects of fiber compositions on microstructure, morphology, and the properties of the MF fibers are also systematically studied. The prepared MF fibers possess high fire retardancy (i.e., limiting oxygen index >40%), thermal stability (i.e., T-max >360 degrees C), and mechanical properties (i.e., tensile strength >2.5 cN/dtex).