The Flame-retardant Properties Of Polyamide6/Modified Sepiolite Composite Materials

Polyamide is the most important engineering plastics, which has high mechanicalproperties, high melting point, good friction properties and performance grease. It isinsoluble in common organic solvents, comparison of thermal performance is alsogood. But it generally faces use of harsh environment, such as high humidity, hightemperature and high voltage and so on. Leakage, short circuit, arc, electric sparkcaused a great fire risk. Modification of polyamide’s flame retardant becomes thesubject of increasing concern to everyone, which most of it is by adding flameretardants currently. Polyamide/layer silicate composite materials is its excellentmechanical properties, dimension stability, gas barrier property, forming machiningand heat resistance and has caught people’s attention. Sepiolite is the magnesium-richsilicate clay minerals with chains in the transitional and2:1type layer molecularmicrostructure, it has high thermal stability and high temperature resistance up to1500~1700℃.In this paper, sepiolite and polyamide6was studied, the PA6/O-Sep series offire-retardant composite material were prepared by melt blending with acidificationand organic-modified sepiolite. In the meantime, other flame retardants were studiedin order to find flame retardant coordination effect in the multiple compound systems.The paper mainly includes the following aspects:1. PA6/O-Sep binary blend composites were obtained using aminopropyltriethoxysilane (KH550) modified sepiolite. The results show that composites’bending strength and tensile strength is increased and thermal stability is slightlyimproved with combining O-Sep into PA6, but the notched impact strength is reduced.The flame retardant effect of O-Sep is not obvious.2. In order to find the appropriate flame retardant formula, the PA6/O-Sep/conventional flame retardants composite materials were prepared and investigated.The results show that: O-Sep and melamine cyanurate (MCA) in flame retardant PA6exist against effect. O-Sep and magnesium hydroxide (MH) blends with PA6burnflame retardantly, but the thermal stability enhancing effect is not obvious. O-Sep andpolybrominated diphenyl ethers (DB), antimony trioxide (AO) can significantlyimprove PA6blends with the flame retardant ability and the thermal stability andflame retardant coordination effect exists among the three fire retardant, add PTFE can further improve the level of flame retardant materials.3. Further using KH550and cetyltrimethylam monium bromide (CTAB) tomodify sepiolite, the different proportion of PA6/O-Sep/DB/AO composite materialwere prepared. The results show that sepiolite modified with KH550is better thansepiolite modified with CTAB, the PA6/O-Sep-1/DB/AO/PTFE (73/5/15/5/2)composite materials have the best flame retardant properties.