Enhanced Fire Safety of Rigid Polyurethane Foam via Synergistic Effect of Phosphorus/Nitrogen Compounds and Expandable Graphite
Chuan Liu,
Ping Zhang,
Yongqian Shi,
Xiaohui Rao,
Suncheng Cai,
Libi Fu,
Yuezhan Feng,
Liancong Wang,
Xueqin Zheng,
Wei Yang
Affiliations
Chuan Liu
College of Environment and Resources, Fuzhou University, 2 Xueyuan Road, Fuzhou 350116, China
Ping Zhang
State key Laboratory of Enviromental Friendly Energy Materials & Department of Materials, Southwest University of Science and Technology, Mianyang 621010, China
Yongqian Shi
College of Environment and Resources, Fuzhou University, 2 Xueyuan Road, Fuzhou 350116, China
Xiaohui Rao
College of Environment and Resources, Fuzhou University, 2 Xueyuan Road, Fuzhou 350116, China
Suncheng Cai
College of Environment and Resources, Fuzhou University, 2 Xueyuan Road, Fuzhou 350116, China
Libi Fu
College of Civil Engineering, Fuzhou University, 2 Xueyuan Road, Fuzhou 350116, China
Yuezhan Feng
Key Laboratory of Materials Processing and Mold Ministry of Education, National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China
Liancong Wang
State Key Laboratory of Coal Mine Safety Technology, CCTEG Shenyang Research Institute, Fushun 113122, China
Xueqin Zheng
College of Safety and Environment, Fujian Chuanzheng Communications College, 80 Shoushan Road, Fuzhou 350007, China
Wei Yang
School of Energy, Materials and Chemical Engineering, Hefei University, Hefei 230601, China
In order to explore highly efficient flame-retardant rigid polyurethane foam (RPUF), phosphorus/nitrogen compounds and expandable graphite (EG) were successfully incorporated into RPUF by a free one-spot method. The combustion results showed that the fire safety of the RPUF samples was remarkably improved by the addition of phosphoric/nitrogen compounds and EG. With the incorporation of 22.4 wt.% phosphorus/nitrogen compounds and 3.2 wt.% EG, the RPUF composites achieved UL-94 V-0 rating. Besides, the total heat release and total smoke release of RPUF composites were reduced by 29.6% and 32.4% respectively, compared to those of the pure RPUF sample. PO• and PO2• together with nonflammable gaseous products were evolved from phosphoric/nitrogen compounds in the gas phase, which quenched the flammable free radicals in the matrix and diluted the concentration of combustible gaseous products generated from PRUF during combustion. The compact char residues which acted as excellent physical barriers were formed by catalysis of EG and phosphoric/nitrogen compounds in the condense phase. The fire hazard of RPUF was significantly reduced by the synergistic effect of phosphorus-nitrogen compounds and EG. This work provides a promising strategy to enhance the fire safety of RPUF.
