Novel phosphorus/nitrogen-rich oligomer with numerous reactive groups for durable flame-retardant cotton fabric

A phosphorus/nitrogen-rich oligomer with numerous reactive groups (PEI-P) was synthesized and used as highly efficient durable flame retardant for cotton fabric. The O=P-ONH4 and O=P-OH groups in PEI-P reacted with O-H group in cellulose during finishing process. PEI-P triggered the decomposition of cotton fabric in advance, while markedly increased the char yield at high temperature. Treated fabrics showed superior flame resistance and durability. With the add-on of 19.3%, treated fabric achieved an LOI value of 38.7%. It self-extinguished even after 50 laundering cycles during vertical burning test. The PHRR and THR decreased by 86.10% and 65.11% in contrast to control fabric, respectively. PEI-P exerted gaseous and condensed flame-retardant effects by restraining the release of flammable volatiles, producing nonflammable gases and catalyzing the formation of stable phosphorus/nitrogen-rich char layers. Compared to control fabric, treated fabrics obtained well-maintained crystal structure and physical properties.

Automated summary

The phosphorus/nitrogen-rich oligomer PEI-P acts as an efficient durable flame retardant for cotton fabric through advanced decomposition and increased char yield. Treated fabrics exhibit superior flame resistance and durability with high LOI value and resistance to laundering, showing reduced PHRR and THR.