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Fire‐retardant synergy of tris(1‐methoxy‐2,2,6,6‐tetramethyl‐4‐piperidinyl)phosphite and aluminum hypophosphite/melamine hydrobromide in polypropylene
Author(s) -
Liu Junhong,
Wu Hongzhi,
Sun Mingmei,
Su Shuqian,
Yan Bo,
Tang Linsheng
Publication year - 2021
Publication title -
journal of vinyl and additive technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 35
eISSN - 1548-0585
pISSN - 1083-5601
DOI - 10.1002/vnl.21788
Subject(s) - fire retardant , hypophosphite , limiting oxygen index , melamine , radical , materials science , combustion , polypropylene , polymer chemistry , nuclear chemistry , chemistry , organic chemistry , composite material , char
Fire‐retardant synergy of tris(1‐methoxy‐2,2,6,6‐tetramethyl‐4‐piperidinyl) phosphite (NORPM) and aluminum hypophosphite (ALHP)/melamine hydrobromide (MHB) in polypropylene (PP) was researched by limiting oxygen index (LOI) measurement, vertical burning test, and cone calorimetric test (CCT). The results reveal that NORPM, together with ALHP/MHB, has an exceptional fire‐retardant synergy in PP. For the FR‐PP containing 1.0 wt% of ALHP and 1.5 wt% of MHB, combining NORPM in 0.20 wt% concentration can make its LOI value increases from 19.0% to 26.1%, the fire‐retardant efficiency (EFF) increases from 0.48 to 3.07, synergistic efficiency (SE) is as high as 2.18, the vertical combustion rating can be improved from none to UL 94 V‐2, fire performance index (FPI) increases from 58.7 to 84.9, and various heat release parameter values are reduced markedly. NORPM induces the synergy with ALHP/MHB primarily by the mechanisms as follows: active free radicals formed through the decomposition of NORPM, such as CH 3 , CH 3 O, nitro radicals and amino radicals, together with PH 3 and HBr, trap active radicals (HO·) for combustion. Consequently, the reaction chain of combustion is terminated, which makes gaseous phase fire retardancy more efficient.