نتایج جستجو برای: ethylene polymerization

تعداد نتایج: 57827  

Journal: :Chemical communications 2015
He Li Bo Xu Jianghao He Xiaoming Liu Wei Gao Ying Mu

A series of zirconium-based porous coordination polymers (PCPs) containing FI catalysts in the frameworks have been developed and studied as catalysts for ethylene polymerization. These PCPs exhibit good catalytic activities and long life times, producing polyethylenes with high molecular weights and bimodal molecular weight distribution in the form of particles.

2013
Mihai Asandulesa George Rusu Ionut Topala Valentin Pohoata Marius Dobromir Nicoleta Dumitrascu

Atmospheric pressure plasma co-polymerization of ethylene glycol and styrene was applied to produce poly (ethylene glycol-co-styrene) using a dielectric barrier discharge. The chemical structure of polymerized films was studied by Fourier-transform infrared spectroscopy which confirms that we obtained copolymerized films with hydroxyl groups incorporated. Chemical composition of films was studi...

2001
Zhaomin Hou Shojiro Kaita Yasuo Wakatsuki

The replacement of one of the two C5Me5 ligands in the samarocene(II) complex (C5Me5)2Sm(thf)2 with a monodentate anionic ligand such as OAr, SAr, NR1R2, or CH(SiMe3)2 gave a unique catalytic system, which can not only polymerize styrene and ethylene, but also copolymerize them into block styrene–ethylene copolymers under the presence of both monomers. On the other hand, the addition of an appr...

Journal: :Journal of the American Chemical Society 2013
Shaofeng Liu Alessandro Motta Massimiliano Delferro Tobin J Marks

A heterobimetallic catalyst, {Ti--Cr}, consisting of a constrained-geometry titanium olefin polymerization center (CGC(Et)Ti) covalently linked to a chromium bis(thioether)amine ethylene trimerization center (SNSCr) was synthesized and fully characterized. In ethylene homopolymerizations it affords linear low-density polyethylene with molecular weights as high as 460 kg·mol(-1) and exclusively ...

2015
Wei Wang Changcheng Liu

A novel non-metallocene titanium complex was synthesized, and used as the catalyst for ethylene polymerization. It results in an acceptable activity, affording the polyethylene with ultra high molecular weights, and relative broad molecular weight distributions. Moreover, the molecular weight almost doesn’t change with the change of Al/Ti ratio.

Journal: :Chemical communications 2012
Zhichao Zhang Zhibin Ye

Upon the addition of an equimolar amount of 2,2'-bipyridine, a cationic Pd-diimine complex capable of facilitating "living" ethylene polymerization is switched to catalyze "living" alternating copolymerization of 4-tertbutylstyrene and CO. This unique chemistry is thus employed to synthesize a range of well-defined treelike (hyperbranched polyethylene)-b-(linear polyketone) block polymers.

Journal: :Macromolecular Rapid Communications 2021

A dithiocarbamate chain transfer agent (CTA) based on Z-group substituted with a diphenyl amine (–NPh2) moiety is selected for the synthesis of statistical and diblock copolymers ethylene vinyl acetate via reversible addition–fragmentation polymerization. Benefiting from good growth control polyethylene (PE), poly(vinyl acetate) (PVAc), poly(ethylene-co-vinyl (EVA) achieved this CTA, linear typ...

Journal: :Science 2006
Daniel J Arriola Edmund M Carnahan Phillip D Hustad Roger L Kuhlman Timothy T Wenzel

We report a catalytic system that produces olefin block copolymers with alternating semicrystalline and amorphous segments, achieved by varying the ratio of alpha-olefin to ethylene in the two types of blocks. The system uses a chain shuttling agent to transfer growing chains between two distinct catalysts with different monomer selectivities in a single polymerization reactor. The block copoly...

Journal: :Macromolecules 2012
Daniel J Siegwart Matthias Leiendecker Robert Langer Daniel G Anderson

Conventional synthesis of polymers by ATRP is relatively low throughput, involving iterative optimization of conditions in an inert atmosphere. Automated, high-throughput controlled radical polymerization was developed to accelerate catalyst optimization and production of disulfide-functionalized polymers without the need of an inert gas. Using ARGET ATRP, polymerization conditions were rapidly...

Journal: :Journal of the American Chemical Society 2010
Thomas Rünzi Damien Guironnet Inigo Göttker-Schnetmann Stefan Mecking

Polymerization of ethylene by complexes [{(P^O)PdMe(L)}] (P^O = κ(2)-(P,O)-2-(2-MeOC(6)H(4))(2)PC(6)H(4)SO(3))) affords homopolyethylene free of any methyl methacrylate (MMA)-derived units, even in the presence of substantial concentrations of MMA. In stoichiometric studies, reactive {(P^O)Pd(Me)L} fragments generated by halide abstraction from [({(P^O)Pd(Me)Cl}μ-Na)(2)] insert MMA in a 1,2- as...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید