Effect of nano-aluminum hydroxide on mechanical properties, flame retardancy and combustion behavior of intumescent flame retarded polypropylene. (5th January 2016)

• Record Type: Journal Article
• Authors: Qin, Zhaolu; Li, Dinghua; Li, Qian; Yang, Rongjie
• Is Part Of: Materials & design. Volume 89(2016)
• Page Start: 988
• Page End: 995
• Publication Date: 2016-01-05
• Subjects: Ammonium polyphosphate -- Dipentaerythritol -- Intumescent flame retardant -- Polypropylene -- Nano aluminum hydroxide -- Thermal degradation; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2015.10.007
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: In view of the relatively low efficiency of intumescent flame retardants compared to that of traditional flame retardants, nano-aluminum hydroxide (nano-ATH) was added to polypropylene (PP), along with ammonium polyphosphate (APP) and dipentaerythritol (DPER), to prepare intumescent flame retarded polypropylene (IFR-PP). The effect of nano-ATH on the mechanical properties, flame retardancy and combustion behavior of the IFR-PP was investigated. The mechanical properties of the IFR-PP were enhanced by the partial replacement of APP with nano-ATH. The results of the limiting oxygen index (LOI) test, the UL-94 vertical burning test and cone calorimetry tests demonstrated that the flame retardancy of the IFR-PP was optimized when 2 wt.% APP was replaced by the nano-ATH. In this case, the LOI value of the IFR-PP increased from 26.6% to 31.2% and the sample passed V-0 rating in the UL-94 test. The peak heat release rate (PHRR) decreased by 56%. Investigation of the char residues from the cone calorimetry tests indicated that the incorporation of the nano-ATH contributed to the formation of a more intact and homogeneous char during combustion. Based on these results, the flame retardant mechanism was proposed. Graphical abstract: Highlights: The flame retardancy and mechanical properties of polypropylene/ammonium polyphosphate/dipentaerythritol (PP/APP/DPER) composites were enhanced by the replacement of APP with nano-ATH. The char forming behavior for flame retarded PP was improved by the formation of the ceramic char. The flame retardation mechanism relies on the balance of two reactions: APP with nano-ATH and APP with DPER.