Preparation And Characterization Of Vermiculite Modified By Synthesized Quaternary Phosphonium Salt/PMMA Composites

Clay/polymer nanocomposites have been become a hotspot of researchers incomposites field because of their excellent mechanical propertie, a number of light、electricity、magnetic and other properties. Now, montmorillonite modify with alkyquaternary ammonium is researched the most frequency，but its application in thefield of polymer materials is limited by its low thermal sability. So, we havesynthesized two kinds of quaternary phosphonium salts, and have modifiedvermiculite (VME) for preparing OVME. At last, we prepared OVME/PMMAcomposites by ultrasonic in-situ polymerization method. The structure and propertiesof composites were studied.Firstly, benzyl triphenyl phosphorus chloride (BTP) and dodecyltriphenyl-phosphonium bromide (C12P) were synthesized through bimolecular nucleophilicsubstitution (SN2) reaction. The two quaternary phosphonium salts were characterizedby FTIR, NMR and TG. BTP and C12P have been successfully synthesized.The BTPand C12P’s initial temperature of decomposition are310℃and281℃, respectively.Secondly, we modified VME by synthesized quaternary phosphonium salt (BTPand C12P), then it were characterized by XRD、SEM、TEM and TG. The results showthat BTP and C12P were successfully intercalated into the interlayer of VME, and wehave got OVME of BTP-VME and C12P-VME; The heat resistant temperature haveimprovement of quaternary phosphonium salt insert VME. The BTP and C12P in theOVME’s initial temperature of decomposition reach320℃and290℃.Finally, We prepared PMMA/BTP-VME、PMMA/C12P-VME composites byultrasonic in-situ polymerization. The structure and property were analyzed by XRD,TEM, Tensile testing machine and TG. We found ultrasonic treatment could improvethe dispersion of PMMA/BTP-VME, PMMA/C12P-VME which were prepared bysitu polymerization method; When1wt%BTP-VME and C12P-VME contained, themost of VME in PMMA/BTP-VME reached exfoliation, PMMA/C12P-VME evenreached totally exfoliation; The thermal stability of composites also had obviousincreased comparing with the pure PMMA, when3wt%BTP-VME and C12P-VME contained, the initial degradation temperature of PMMA/BTP-VME andPMMA/C12P-VME are273℃and277℃, the glass transition temperature are104℃and105℃, and the tensile strength are65Mpa and64Mpa respectively. Theirbest comprehensive properties have been developed.