نتایج جستجو برای: propylene polymerization
تعداد نتایج: 36246 فیلتر نتایج به سال:
Ziegler-Natta polymerization catalysts were characterized by a complex of surface- and bulk-sensitive methods (DRIFTS, XPS, ESR, and XAS = XANES + EXAFS). A diffuse-reflectance Fourier-transform IR spectroscopy (DRIFTS) study showed the presence of strong Lewis acid sites in different concentrations and absence of strong basic sites in the polymerization catalysts. X-ray photoelectron spectrosc...
To the Editor: We wish to substantiate the important observations of LeGatt and Tisdell (1) cautioning against the use of propylene glycol as an internal standard for quantifying ethylene glycol. A 32-yearold woman presented to our emergency department in an agitated state after the ingestion of multiple drugs in an attempted suicide. Gastric lavage and charcoal were administered as well as int...
We report the design, synthesis, morphology, phase behavior, and mechanical properties of semicrystalline, polyolefin-based block copolymers. By using living, stereoselective insertion polymerization catalysts, syndiotactic polypropylene-block-poly(ethylene-co-propylene)-block-syndiotactic polypropylene and isotactic polypropylene-block-regioirregular polypropylene-block-isotactic polypropylene...
We report an effective strategy for the synthesis of semi-crystalline block copolyethers with well-defined architecture and stereochemistry. As an exemplary system, triblock copolymers containing either atactic (racemic) or isotactic (R or S) poly(propylene oxide) end blocks with a central poly(ethylene oxide) mid-block were prepared by anionic ring-opening procedures. Stereochemical control wa...
In this research, a Ziegler–Natta catalyst intercalated MoS2 was synthesized through the intercalation of a Grignard reagent into MoS2 galleries, followed by the anchoring of TiCl4. During propylene polymerization, the intercalated MoS2 exfoliated in situ to form PP/exfoliated MoS2 (EMoS2) nanocomposites. The isotactic index values of the resultant PP/EMoS2 nanocomposites were as high as 99%, v...
Application of cellulose microfibers as a reinforcing agent for high-performance polyurethane composites is rarely mentioned because the inherent hydrophilicity combined with adverse aspect ratio fibers cause difficulties in dispersion within and compatibility polymer matrix. Here, we propose feasible approach to graft oligoethers synthesized by ring-opening polymerization heterogeneous reactio...
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