An Investigation of the Flammability, Morphology and Torque Rheology of Poly (vinyl chloride) with Silanes and Cu~(2+)Modified Montmorillonites

摘要

Silane-modified montmorillonites(MMTs) and Cu~(2+)-silane modified MMTs have been prepared by treating Na~+ montmorillonites (Na~+-MMTs) with silane coupling agents and copper (II) sulfate, and poly (vinyl chloride)(PVC)/ modified MMT composites were prepared by using a twin-screw extruder. The microstructures of the modified MMTs and the composites were characterised by XRD and SEM. The results indicated that the silanes and Cu~(2+)were intercalated into the interlayers, and that the silane-modified MMTs and Cu~(2+)-silane modified MMTs were exfoliated and dispersed in PVC by the melt-intercalation method. A small amount of Cu~(2+) was observed to shorten slightly the interlayer spacing of MMTs. The cone calorimetric data demonstrated that Na~+-MMTs and modified MMTs changed the flammability behaviour of the composites; they effectively reduced the peak heat release rate (pk-HRR), peak smoke production rate (pk-SPR), total smoke production (TSP) and ignition time (IT). Cu~(2+)-silane modified MMTs presented a better smoke suppressant effect than Na~+-MMTs and silane modified MMTs, and the smoke-reducing efficiency of Cu~(2+)-silane modified MMTs reached 44% although the Cu~(2+)-silane modified MMTs contained only a small amount of copper (II) ion, 0.6～0.8%. The torque experiments indicated that silane modified MMTs improved the processability of the composites, while Cu~(2+)-silane modified MMTs obviously increased the plasticising time of the composites. The tensile strength and flexural strength of the composites increased compared with PVC/ Na~+-MMTs composite.