SYNOPSISThe process of depolymerization of P E T resin by EG glycolysis under pressure is investigated. The kinetics of this pressurized depolymerization of PET resin is discussed. It was found that the rate of depolymerization is dependent of temperature, pressure, and concentration ratio of EG to PET. The rate of depolymerization is proportional to the square of EG concentration and faster than that under atmospheric pressure. Glycolyzed products under pressure consist of the PET monomer, BHET, and oligomers, mostly dimer and trimer. An equilibrium between BHET and oligomers is attained quickly soon after the depolymerization step is completed in the case of a higher ratio of E G / P E T used. In the case of lower ratio of EG/PET, the final product now consists of higher molecular weight of oligomers rather than monomer, dimer, and trimer.
Three series of epoxy/SiO 2 composites, containing 0.3-7 wt % nanosized SiO 2 with different specific surface area, were prepared by solution blending. The resulting composites exhibit the higher glass transition temperature (T g ) than that of pure epoxy. The T g of composite showed a maximum increment of 35.3C by the addition of 7 wt % A300. The trade name of A300 is Aerosil 300. It is one of the fumed silica nanoparticles products of Degussa. The decomposition temperatures (T d ) of composites were always higher than that of pure epoxy and showed a maximum increment of 20.8C by the addition of 5 wt % A300. The light transmittance of composites was as a function of the SiO 2 content and size. The water permeability of composites decreased with increasing SiO 2 content and the 7 wt % A300 composite exhibits a maximum decrement percentage of 35.6%. The T g , T d , storage modulus, and water-vapor barrier property are as a function of the SiO 2 content and size. These properties increased as the content of SiO 2 increased. The finer SiO 2 are more effective in increasing the T g , T d , and water-vapor barrier property.
Polymer substrates are widely used in the flat-panel-display industry because of their flexibility, light weight, and high power efficiency. However, the lower glass-transition temperatures and thermal stability and higher water/oxygen permeation of cycloolefin copolymers (COCs) constrain their applications in display substrates. In this research, COC/tetraethyloxysilane (TEOS) hybrids were synthesized via a sol-gel process. Differential scanning calorimetry indicated that the glasstransition temperature of the hybrids was higher than that of neat COC and rose significantly as the TEOS content was increased from 1 to 15 wt %. According to an analysis of IR spectra, the fraction of hydrogenbonded carbonyl groups in the hybrids increased as the TEOS content increased. This meant that the interfacial interaction contributed by hydrogen bonds for the COC/ TEOS hybrid system increased as the TEOS content increased from 1 to 15 wt %. On the basis of scanning electron microscopy, the number of dispersed droplets of silica increased as the content of TEOS increased. The decomposition temperatures of the hybrids, investigated with thermogravimetric analysis, were not affected significantly by the addition of TEOS.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.