Synthesis of nano-sized TiO2/poly(AA-co-MMA) composites by heterocoagulation and blending with PET

Nano-sized TiO2 or SiO2/TiO2 particles were prepared by hydrolysis and condensation reactions in aqueous media, followed by mixing with poly(AA-co-MMA) latex to form different composites, then blending with poly(ethylene terephthalate), PET. The TGA results of composites indicated that negative charged latexes had greater interaction with TiO2/ or SiO2/TiO2 particles through strong electrostatic forces, while cationic latexes incorporated with TiO2 or SiO2/TiO2 particles by pH induced coagulation, carbonyl group chelation and hydrogen bonding. The soapless latex polymer particles showed lower ability of adsorption to TiO2 particles due to the decrease of total surface area of these larger particles. If SiO2/TiO2 particles were used instead of TiO2 particles, unexpected high adsorption result was observed. Morphology results observed by SEM showed that PET blended with positive charged composites was more homogeneous than PET blended with negative charged composites. DSC results also indicated that the TgTg of PET was increased, melting temperatures (TmTm or Tm′) were increased, and the temperature range of crystallization was narrowed after blending with the composites. The presence of composites affected the mobility and packing of PET molecular chains therefore changing the thermal properties of PET.

SEM of TiO2/cationic latex composite (c) showed homogeneous distribution of TiO2, while large aggregations of TiO2 particles were apparent in the SEM of TiO2/soapless latex composite (a). The morphology of TiO2/anionic latex complex (b) showed less aggregation than TiO2/soapless latex composite.Figure optionsDownload as PowerPoint slide