Sustainable Synthesis and Characterization of Bisphenol A-Free Polycarbonate from Six-Membered Dicyclic Carbonate.

Bisphenol A, (2,2-bis(4-hydroxyphenyl)propane, BPA)-free polycarbonate (PC) from six-membered di-cyclic carbonate, di-trimethylolpropane di-cyclic carbonate (DTMPC) was developed as a new type of PC by ring opening homo-polymerization. The polymerization was controlled by using metal-free organic-based catalyst systems. The results indicated that the conversion rate depends on the basicity of the catalyst in the order of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 4-dimethylaminopyridine (DMAP), triethylamine (TEA) from high to low. Over 99% conversion of DTMPC was obtained at 130°C within 15 min by TBD, DBU and DMAP. The resulting PC as a homo-polymer showed high optical transparency and hardness, low swelling property in organic solvents, and thermally stable at temperatures as high as 200 °C. High cell viability as the cyto-compatibility of C3H 10T1/2 cells seeded directly on the surface of PC films was obtained. This implied that PC is a viable material for biomedical and consumer products applications where safety is an important consideration.

One-step synthesis of structurally controlled silicate particles from sodium silicates using a simple precipitation process.

Silicate particles with various types of internal structures were prepared via one-pot synthesis. Spherical particles with sizes of 50-100 nm could be obtained by a simple precipitation process with the addition of alcohol to an aqueous sodium silicate solution. By controlling the reaction conditions such as the precipitating solvent (different types of alcohols), reaction time, temperature, and addition rate, spherical silicate particles with hollow, porous, dense internal structures were synthesized without using an external template. In addition, the amount of Na in the silicate particles was effectively reduced by washing with hot water, acid, or ion-exchange resins. Spherical particles maintained their morphologies after heat treatment at 500 degrees C. Electron microscopy, N(2) adsorption/desorption measurements, ICP-OES, XRD analysis, and IR and (29)Si NMR spectrometry were performed to elucidate the chemical and physical properties of the obtained silicate particles. This method of synthesis could provide a commercial route to the simple, economical mass production of silica particles.