Preparation Of Halogen-free Flame Retardants And Application In Leather

Leather,as a kind of natural macromolecular material with various excellent properties,is widely used in all aspects of life.At present,the requirements for flame retardancy of leather materials are increasingly strict,so it is of great significance to develop flame retardant materials suitable for leather utility and leather processing.Sulfomethylated pentaerythritol phosphate salt(modified PPM)was prepared from pentaerythritol,phosphoric acid,melamine and sodium bisulfite.Aluminum 2-carboxyethyl phenylphosphite(CEPPAAl)was prepared from 2-carboxyethyl phenylphosphite(CEPPA)and aluminum octadecanohydrate sulfate.Lanthanum 2-carboxyethyl phenylphosphite(CEPPALa)was prepared from CEPPA and lanthanum heptahydrate.CEPPAAl-OMMT was prepared from CEPPAAl and OMMT.The products were characterized by FTIR,XRD and TG.Four suspensions with a solid content of 15%were prepared by modified PPM,CEPPAAl,CEPPALa and CEPPAAl-OMMT and applied to leather processing,respectively.When the amount of modified PPM suspension was 12%,the oxygen index of flame retardant leather reached 31.7%.When the amount of CEPPAAl suspension was 12%,the oxygen index of leather reached 31%,the flame burning time decreased from 228 s of blank sample to 44 s,and the non-flame burning time decreased to 0 when the amount of CEPPAAl suspension was 16%.When CEPPALa suspension was 16%,LOI reached 29.8%,the flame burning time decreased obviously,and the non-flame burning time was almost close to zero.When the content of OMMT in CEPPAAl-OMMT was 20%,CEPPAAl-OMMT suspension was 8%,the oxygen index of flame retardant leather reached to 33.0%.The flame burning time and non-flame burning time are almost zero.The total and maximum heat release rates of leather were significantly reduced.The four kinds of flame retardants can improve the flame retardant effect of leather and maintain the mechanical properties of leather.The flame retardant mechanism of the modified PPM,CEPPAAl,CEPPALa and CEPPAAl-OMMT were studied by means of SEM,EDS,XPS and TG-IR analysis.The results showed that all the four flame retardants can both play the role in gas phase and condensed phase.Thermal degradation kinetics of leather was studied by Kissinger and flynn-wall-ozawa methods.The activation energy of thermal degradation of flame retardant leather was calculated.The results showed that the activation energy and thermal stability of leather were improved by adding flame retardant.