Divinylsiloxane‐bisbenzocyclobutene‐based polymer modified with polystyrene–polybutadiene–polystyrene triblock copolymers

Divinylsiloxane‐bisbenzocyclobutene (DVS‐bisBCB) polymer has very low dielectric constant and dissipation factor, good thermal stability, and high chemical resistance. The fracture toughness of the thermoset polymer is moderate due to its high crosslink density. A thermoplastic elastomer, polystyrene–polybutadiene–polystyrene triblock copolymer, was incorporated into the matrix to enhance its toughness. The cured thermoset matrix showed different morphology when the elastomer was added to the B‐staged prepolymer or when the elastomer was B‐staged with the DVS‐bisBCB monomer. Small and uniformly distributed elastomer domains were detected by transmission electron micrographs (TEM) in the former case, but TEM did not detect a separate domain in the latter case. A high percentage of the polystyrene–polybutadiene–polystyrene triblock copolymer could be incorporated into the DVS‐bisBCB thermoset matrix by B‐staging the triblock copolymer with the BCB monomer. The elastomer increased the fracture toughness of DVS‐bisBCB polymer as indicated by enhanced elongation at break and increased K1c values obtained by the modified edge‐lift‐off test. Elastomer modified DVS‐bisBCB maintained excellent electrical properties, high T_g and good thermal stability, but showed higher coefficient of linear thermal expansion values. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1591–1599, 2006     

High-throughput analysis in catalysis research using novel approaches to transmission infrared spectroscopy

This study has demonstrated that high-throughput FTIR transmission measurements using a newly designed array-based support formed using silicon wells and a silicon wafer is a very useful and robust tool for the characterization of polymer composition for combinatorial materials research. The comonomer content in copolymers can be measured accurately with a fully automated throughput of >300 samples/day (8 h). The transmission measurement is more robust, reliable, and easier to automate than other spectroscopic methods. The support itself provides excellent resistance to aggressive organic solvents at elevated temperatures and allows the unattended deposition and preparation of polymer films for infrared analysis. Because of the excellent durability of the support with respect to the solvent, the support can be rinsed and reused many times. This high-throughput approach to infrared transmission spectroscopy can be used for measuring a wide array of polymer characteristics: vinyl content, geometrical isomers, crystallinity, and tacticity. As well, this IR approach can be used to predict the oxidative stability of the antioxidant packages. Because the support provides a means of containing hot polymer solutions while the solvent evaporates, the support is also suitable for high-throughput nanoindentation methods for the determination of modulus and other physical properties of the polymer.