An intumescent flame retardant - expandable graphite: Preparation, characteristics and flame retardance for polyethylene

Kuwait Journal of Science

DUAN MING-WEI¹  XIU-YAN PANG²  ZHAI ZHI-XIAO¹  TIAN YU¹ 

[1] College of Chemistry and Environmental Science, Hebei University, Baoding-071002, China

关键词: Borate;    expandable graphite;    intumescent flame retardant;    polyethylene;    synergistic efficiency;   

DOI  :  

学科分类：社会科学、人文和艺术（综合）

来源: Kuwait University * Academic Publication Council

【 摘 要 】

A combined intumescent flame retardant expandable graphite (EG), with an initial expansiontemperature of 155°C and expansion volume of 515 mL g-1, was successfully prepared based ona chemical intercalation method of material graphite under oxidation of KMnO4, intercalationof H2SO4 and Na4B2O7· 10H2O at the mass ratio C : KMnO4 : H2SO4 (98%) : Na 4B2O7· 10H2Oof 1.0 : 0.4 : 5.5 : 0.6 (H2SO4 diluted to a mass concentration of 80-wt. % before reaction),and characterized by expansion volume (EV), initial expansion temperature, X-ray diffraction(XRD). The flame retarding and thermal properties of LLDPE/EG and LLDPE/EG/APPcomposites (LLDPE-Linear low density polyethylene; APP-ammonium polyphosphate) wereinvestigated and characterized by limiting oxygen index (LOI), Fourier transform infraredspectroscopy (FTIR), thermal gravimetric (TG) and differential thermal analysis (DTA). Theresults showed that addition of EG (30-wt. %) increased the LOI of 70LLDPE/30EG compositeto 28.4 %. Even more, the synergistic effect of 20% EG together with 10% APP improvedthe LOI of 70LLDPE/20EG/10APP composite to 30.5%. At the same time, temperaturescorresponding to a 1% weight loss and a maximum weight loss rate increased at about 50°C and2°C, respectively. The 70LLDPE/10APP/20EG composite exhibited higher flame retardancyeven at a lower residual chars than 70LLDPE/30EG specimen. Cohesive and dense charlayer caused by swollen expanded graphite and decomposing products of APP played a moreimportant role in improving thermal stability and flame retardancy than weight of residualcarbon. The intercalated borate was more effectual in improving the flame retardancy than thedirect additive of Na4B2O7· 10H2O.

【 授权许可】

Unknown