Lignin-Based Flame Retardants Containing Phosphorus,Nitrogen and Silicon Elements for Flame Retardant Polylactic Acid
Lignin-based flame retardant(FR-Lig)containing phosphorus,nitrogen and silicon elements was successfully prepared through alkali lignin(Lig)with 3-aminopropyl trimethoxysilane,4-(diethylamino)salicylal-dehyde and 9,10-dihydro-9-oxa-10-phosphorophenanthrene-10-oxide as modifiers by a three-step process.TGA re-sults of FR-Lig show that compared with Lig,FR-Lig presents good thermal stability and charring ability in air,with T5%increased by 45℃,and the residual at 550℃enhanced from 1.8%to 31.6%.FR-Lig was used to prepare fully bio-based flame retardant polylactic acid composites(FR-Lig/PLA),and the properties of FR-Lig/PLA were investigated in detail.It suggest that with the addditon of FR-Lig,the flame retardancy of PLA is improved.And with 20%FR-Lig loading amoun,the LOI value of PLA is increased to 27.5%,and the vertical combustion UL-94 passes V-0 level.Even if 10%FR-Lig can increase LOI of PLA by 2 values accompanied with UL-94 improving from no grade to V-2 grade;and the tensile strength of PLA reaches 41.8 MPa,and impact strength is increased by about 60%compared with pure PLA.Moreover,the thermal stability,fire resistance,and smoke suppression capa-bilities of PLA with 10%FR-LIg are enhanced.The analysis results of residual char and TG-IR for PLA show that both gas-phase flame retardancy and condensed phase flame retardancy work in PLA,in which the laterr plays a dominant role,and a possible flame retardant mechanism was proposed.
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万方数据
维普
