Coordinative chain transfer polymerization (CCTP) has opened a new path for the development of novel products like olefin block copolymers and chain-end functional polyolefins. However, conflicting results are frequently reported on the catalyst performance including activity and comonomer selectivity under CCTP conditions. Here we have selected two catalysts including rac-ethylenebis(1-η5-inde...

ethylene was polymerized in slurry phase over a ticl4/mg(oc2h5)2 catalyst activated by al(c2h5)3. it was shown experimentally that mass transfer resistance has no effect on polymerization kinetics. after estimation ofthe active site concentration by inhibition method with carbon monoxide, the effects of polymerization temperature, monomer and cocatalyst  oncentrations and hydrogen were investig...

Background and Aim: Minimizing the polymerization shrinkage of composite resins is a critical goals in composite restorations. Many factors affect polymerization shrinkage. This study aimed to evaluate the effect of composite resin shade on polymerization shrinkage. Materials and Methods: In this in vitro study, 14 composite discs measuring 1.5×8 mm were fabricated. The samples were prepared u...

Insertional mutations leading to expansion of the octarepeat domain of the prion protein (PrP) are directly linked to prion disease. While normal PrP has four PHGGGWGQ octapeptide segments in its flexible N-terminal domain, expanded forms may have up to nine additional octapeptide inserts. The type of prion disease segregates with the degree of expansion. With up to four extra octarepeats, the ...

Polyolefins are of vast economic importance, which is reflected by an annual production of more than 70 million tons of polyethylene and polypropylene. While the major portion of these materials is produced with Zieglerand chromium-based catalysts, the older free-radical process that affords low-density polyethylene (LDPE) has maintained its significance.[1] Despite the necessity of working at ...

The binding of molecular polymerization catalysts to solid supports, in the form of microporous particles or also flat substrates, has been extensively studied. 11 .] The primary aim is to gain control of the morphology of the polymer formed directly during polymerization. This approach can be convenient, for example, in saving additional processing steps if the polymer is formed directly in th...

Isospecific polymerization of polar styrenes is a challenge polymer science. Particularly challenging are monomers bearing electron-withdrawing substituents or bulky substituents. Here, we report the coordination halide- and amino-functionalized including para-fluorostyrene (pFS), para-chlorostyrene (pClS), para-bromostyrene (pBrS), para-(N,N-diethylamino)styrene (DMAS) using 2,2′-sulfur-bridge...