반응성 난연제 3-HPP의 함량이 에폭시 수지의 난연성에 미치는 영향

Flame retardant epoxy resins with various phosphorus contents (0, 1, 2, and 3wt%) were prepared by reacting reactive-type flame retardant (hydroxyphenylphos-phinyl- propanoic acid) with epoxy prepolymer (diglycidyl ether of bisphenol A, YD-128) and curing with 4,4''-diaminodiphenylmethane (DDM). This study focused on the effect of phosphorus content on the thermal decomposition, flame retardancy, and impact strength of cured epoxy resins (samples: P0, P1, P2, and P3; the number represents the wt% of phosphorus). As the phosphorus content increased, the thermal decomposition temperatures (T10% and Tmax) of the samples decreased, whereas the char content in the range 410-800 oC increased. The limiting oxygen index (LOI) value of the cured epoxy samples increased from 23.0 to 30.0% with increasing the phosphorus content from 0 to 3 wt%. As the phosphorus content increased, the peak heat release rate (PHRR) and fire growth rate (FIGRA) decreased, whereas the time to reach the PHRR increased significantly. That is, the analysis result of the cone calorimeter demonstrated that the flame retardancy of the sample greatly improved with an increase in the phosphorus content. As a result of the UL-94 V test, sample P3 showed V-0 exhibiting complete flame retardancy. The impact strength of the cured sample increased considerably with increasing phosphorous content. These results indicated that sample P3 had perfect flame retardancy and excellent impact strength; therefore, it will have high applicability as a flame retardant material.