Hybrid poly(ethylene terephthalate)/silica nanocomposites prepared by in‐situ polymerization

Abstract

AbstractThe nanocomposites, based on hybrid poly(ethylene terephthalate) (PET)/silica nanoparticles, were prepared via in‐situ condensation polymerization of terephthalic acid and ethylene glycol in the presence of silica nanoparticles pretreated with a silane coupling agent. Such a polymerization process ensured that the silica nanoparticles were well dispersed in PET matrix with the size ranging from 40 to 60 nm, which was confirmed by transmission electron microscope (TEM) observation. Attributed to the unique bonding between SiO2 nanoparticle and PET, the crystallization behavior of PET was improved significantly, at a low temperature in particular. To further explore the effects of silica nanoparticles on crystallization, extensive differential scanning calorimeter (DSC) measurements were performed in an attempt to reveal the impact of the morphology of the dispersed silica nanoparticle (i.e., sphere or gel‐like) on the peak temperature during melting as well as the amount of heat involved in crystallization. The influences of the structure of polyether glycol (PEG) used for PET preparation as well as the addition of glass fibres (GF) were also investigated using DSC. It was concluded that the synergy among silica nanoparticles, modified PEG, and GFs lowers both Tg and Tm of PET, thus facilitating the injection processes in application. POLYM. COMPOS. 28:42–46, 2007. © 2007 Society of Plastics Engineers