Influence of Cu2+-Organic Montmorillonites on Thermal Decomposition and Smoke Emission of Poly(vinyl chloride)by Cone Calorimetric Study

摘要

Cu-Organic montmorillonites were prepared by modifying Na+ montmorillonite(Na+-MMT)with silane coupling agents and cupric sulfate.PVC/organic montmorillonite composites were prepared by the melt intercalation method.Morphological structure of modified MMT and PVC/MMT was obtained by using XRD and SEM.The XRD results showed that silanes and Cu2+ were intercalated among interlayers and that modified MMT may have exfoliated dispersion in PVC.Effects of Cu2+-organic montmorillonites on decomposition and smoke emission of polyvinyl chloride)(PVC)in the flaming mode were investigated by using a cone calorimeter at an incident heat flux of 25 kW m~(-2).Cone experimental data demonstrated that the Cu2+-organic montmorillonites prepared were new effective smoke suppressants.They clearly promoted an early HCI elimination,cross-linking reactions,and char residue formation,based upon the decomposition parameters of mass loss,mass loss rate,and time of initial decomposition(t_(initial))-Cu2+-Organic montmorillonites decreased peak heat release rate,total heat release,peak smoke production rate,total smoke production,and smoke extinction area during the flaming process.The smoke-reducing efficiency of Cu2+-organic montmorillonites(Cu2+-OMMTs)was the best.However,the content of cupric ion was only 0.6-0.8% in Cu2+-OMMTs and 0.03-0.04% in PVC composites.They may make the smoke-reducing efficiency reach 45-50%.This result further demonstrates that Cu2+ ion is a very effective smoke suppressant for PVC.