Polymer flame retardancy: A new approach

Melamine cyanurate (MCA) was utilized as an environmental friendly additive to prepare the nonhalogen flame retardant MCA/Nylon 66 composites by melt blending technique. Because of the strong hydrogen bond interactions and fine interfacial compatibility between MCA and Nylon 66, the resultant even dispersion of MCA filler in polymer matrix leads to the better toughness and strength of MCA/Nylon 66 composites than those of neat Nylon 66. Both Nylon 66 and MCA/Nylon 66 composites exhibit similar a-crystalline structure, but the presence of MCA influences the distribution of a1 and a2 crystalline phases in Nylon 66 by inducing its hydrogen-bonded sheet separation. Moreover, the blending of MCA and Nylon 66 increases the crystallization temperature and exothermicity but decreases the thermal stability of Nylon 66 and accelerates the degradation of MCA. The MCA/Nylon 66 composites show better flame retardancy at intermediate MCA contents of 10 and 15 wt %.

Section: Introductionmentioning

confidence: 99%

Preparation and properties of environmental friendly nonhalogen flame retardant melamine cyanurate/nylon 66 composites

Qiao

Yang³

et al. 2011

“…Core‐shell structured MSiS is not only an impact modifiers but also a flame retardant for the recycled PC because of its silicone‐based rubbery core. It has been reported that silicone‐containing chemicals have a characteristic of high heat resistance and nontoxicity, which are considered to be “environment friendly” flame‐retardant additives 38‐41. They release less amounts of toxic gasses in case of fire.…”

Section: Resultsmentioning

confidence: 99%

Modification of recycled polycarbonate with core‐shell structured latexes for enhancement of impact resistance and flame retardancy

Sun

Wang

et al. 2010

Two types of core-shell structured latexes, poly(methyl methacrylate-co-butadiene-co-styrene) (MBS) and poly(methyl methacrylate-co-methylphenyl siloxaneco-styrene) (MSiS) were used to modify recycled polycarbonate (PC) for the enhancement of toughness and flame retardancy. The impact strength of the modified PC blends was not improved after melt-blending recycled PC with these two kinds of latexes, probably because the latex particles were not evenly dispersed in the PC matrix because of the incompatibility between PC and PMMA shell of the latexes. Addition of a compatibilizer, e.g. diglycidyl ether of bisphenol-A or poly(styrene-co-maleic anhydride), can effectively enhance the toughening effect of recycled PC with core-shell structured modifiers. The presence of compatibilizer in the blends reduces the interfacial tension and introduces a steric hindrance to coalescence, and thus enhances the interfacial adhesion between PC domain and PMMA shell, and improves the dispersion of core-shell structured particles in the PC matrix. The ternary blends achieve a high impact resistance by cavitation of the particles, which relieves the triaxial stress and promotes massive shear yielding of the matrix, and then enables the matrix to fracture by the plane stress ductile tearing mode. Additionally, MSiS has a silicone-based core and can effectively retard the combustion of recycled PC. The blends containing 7 wt % MSiS and 3 wt % compatibilizer can achieve a UL94 V-0 rating in vertical burning test. We proposed that, during combustion, a fine dispersion of MSiS particles in the PC matrix facilitates the rapid migration of MSiS and formation of a uniform and highly flame resistant char barrier on the surface of the modified PC.

“…Because of the environmental problems, some halogen‐containing flame‐retardants that have high flame‐resistant efficiency have been forbidden gradually 5,6. Consequently, it is essential that new flame‐retardant systems should be developed to meet the constantly changing demand of new regulations, standards, and test methods.…”

Section: Introductionmentioning

confidence: 99%

Synergistic effect of organic silicon on the flame retardancy and thermal properties of polycarbonate/potassium‐4‐(phenylsulfonyl) benzenesulfonate systems

Yuan

Deng

Yin

et al. 2012

Melt blending was used to prepare a series of flame-retardant hybrids based on bisphenol A, polycarbonate (PC), potassium-4-(phenylsulfonyl)benzenesulfonate (KSS), and the organic silicon compounds N-(b-aminoethyl)-c-aminopropylmethyldimethoxysilane (KH-602) and diphenylsilanediol. The flame retardancy and thermal stability of the hybrids were investigated by the limiting oxygen index (LOI) test, the UL-94 vertical burning test, and thermogravimetric analysis. The results show that the flame retardancy of the PC/KSS system and the weight of the residues improved with the addition of the organic silicon. When the content of diphenylsilanediol was 4 wt % and KH-602 was 1 wt %, the LOI value of the PC/KSS system was found to be 47, and Class V-0 of the UL-94 test was achieved. The microstructures observed by scanning electron microscopy indicated that the surface of the char for PC/KSS systems with KH-602 and diphenylsilanediol hold a more cohesive and denser char structure when compared with the pure PC/KSS system.