Bazı halloysit-polimer nanokompozitlerin Hazırlanması ve karakterizasyonu

Abstract

Balikesir civarindan alinan dogal bir halloysit ornegi sulu suspansiyondan cokturme ile icerdigi illit ve kuars mineralleri buyuk olcude uzaklastirilarak saflastirilmistir. Metakrilamit (MAA) ve pirol (Py) monomerleri halloysit ile degisik oranlarda karistirilmistir. Karisimlar, yerinde (in-situ) yontemi ile polimerlestirilerek farkli oranlarda monomer iceren polimetakrilamit (PMAA)/halloysit ve polipirol (PPy)/halloysit kompozitleri hazirlanmistir. Dogal ve saflastirilmis halloysit yaninda farkli monomer/halloysit oranlarinda hazirlanan kompozitler X-isinlari difraksiyonu (XRD), taramali elektron mikroskopi (SEM), termal analiz (TGA/DTA), Fourier transform infrared (FTIR) spektroskopi, 77 K’deki azot adsorpsiyon/desorpsiyon ve konduktometri teknikleri ile incelenmistir. XRD verileri dogal ornegin sulu ve susuz halloysit minerallerinin karisimi oldugunu gostermistir. Polimerler icinde sulu halloysitin nanopartikuller, susuz halloysitin ise mikroparcaciklar halinde dagildigi belirlenmistir. Buna gore, hazirlanan kompozitlerin birer nanokompozit ve mikrokompozit karisimlari oldugu ortaya cikmistir. Metahalloysit de denilen susuz halloysitin polimer icinde tabakalarina ayrisarak nanokompozit olusumuna katilmamasi onemli bir sonuc olarak ortaya cikmistir. Degisik oranlarda karisim ile hazirlanan kompozitlerin termal bozunma sicakliklarinin polimerlere gore daha yuksek oldugu belirlenmistir. Halloysitin N2 adsorpsiyon kapasitesi, ozgul yuzey alani ve ozgul gozenek hacminin kompozitlerdeki polimer orani yukseldikce dustugu gorulmustur. Hazirlanan kompozitlerin iletkenliklerinin halloysit orani yukseldikce dustugu ortaya cikmistir.Abstract A natural sample of halloysite from Balikesir region was purified with precipitation from water suspension to remove illite and quartz minerals. Methacrylamide (MAA) and pyrrole (Py) monomers were mixed with halloysite in different ratio. The mixtures were polymerized with in-situ technique to prepare polymethacrylamide (PMAA)/halloysite and polypyrrole (PPy)/halloysite composites which had different ratio of monomers. Natural and purified halloysite, and also prepared composites with different ratio were examined with X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal analysis (TGA/DTA), Fourier transform infrared (FTIR) spectroscopy, N2 adsorption/desorption at 77 K, and conductometer methods. The sample examined with the XRD was appeared hydrated and dehydrated halloysite. It was determined that the hydrated halloysite was dispersed nanoparticles and dehydrated halloysite was dispersed microparticles in polymer matrix. For that reason, prepared composites were the mixture of nanocomposite and microcomposite. An important result was the dehydrated halloysite, which is well known metahalloysite, layers weren’t separated in polymer matrix for participating to be a nanocomposite. The thermal decomposition temperature of composites prepared with the mixture of different ratio were higher than the pure polymers. N2 adsorption capacity, specific surface area and specific pore volume in halloysite was decreased when the polymer ratio was increased. Prepared composites conductivities were decreased when the halloysite ratio was increased.