نتایج جستجو برای: Copolymerization

تعداد نتایج: 2777  

Journal: :علوم و تکنولوژی پلیمر 0
سعید احمدجو حسن عربی مهدی نکومنش حقیقی غلامحسین ظهوری مهدی مرتضوی

bis(indenyl)zirconium dichloride as a catalyst was synthesized using a modified method at the room temperature. polymerization of ethylene and copolymerization of ethylene and propylene were carried out by this metallocene catalyst. ethylene propylene (p/e) feed ratios of 0.25, 0.5, 1, and 2 were employed into the copolymerization systems. copolymerization conditions like cocatalyst/catalyst ra...

2016
Judita Britner Helmut Ritter

The first detailed study on free-radical polymerization, copolymerization and controlled radical polymerization of the cyclic push-pull-type monomer methylenelactide in comparison to the non-cyclic monomer α-acetoxyacrylate is described. The experimental results revealed that methylenelactide undergoes a self-initiated polymerization. The copolymerization parameters of methylenelactide and styr...

2003
TURNER ALFREY

Synopsis. From data in the literature on relatine rates of copolymerization it has been possible to evaluute two constants, Q and e , cheracteristic of a n individual monomer, which appear to account satisfactorily .for its behavior in copolymerization. The constant Q describes the “general monomer reactivity” and is apparently related to possibilities for stabilization in a radical adduct. The...

Journal: :Chemical communications 2015
Shyeni Paul Yunqing Zhu Charles Romain Rachel Brooks Prabhjot K Saini Charlotte K Williams

Controlled routes to prepare polyesters and polycarbonates are of interest due to the widespread application of these materials and the opportunities provided to prepare new copolymers. Furthermore, ring-opening copolymerization may enable new poly(ester-carbonate) materials to be prepared which are inaccessible using alternative polymerizations. This review highlights recent advances in the ri...

2006
Shiro KOBAYASHI

Enzymatic ring-opening copolymerization of lactones was carried out by using Pseudomonas f luorescens lipase in bulk. In the copolymerizaton of r-caprolactone (E-CL) and b-valerolactone at 60°C for 10 days a copolymer with molecular weight of 3.7 x 103 was obtained and its structure was found to be of random structure having both units from 13C NMR anlaysis. Effects of the feed ratio, the react...

2016
Martin S. Engler Kerstin Scheubert Ulrich S. Schubert Sebastian Böcker

For many years, copolymerization has been studied using mathematical and statistical models. Here, we present new Markov chain models for copolymerization kinetics: the Bernoulli and Geometric models. They model copolymer synthesis as a random process and are based on a basic reaction scheme. In contrast to previous Markov chain approaches to copolymerization, both models take variable chain le...

Journal: Polyolefins Journal 2019

The new highly active supported vanadium-magnesium catalyst (VMC) has been studied in α-olefin (1-butene, 1-hexene)/ ethylene copolymerization in the presence of hydrogen. Data on the effect of α-olefin/ethylene ratio in copolymerization on the content of branchings in copolymers, kinetic profile, copolymer yield, molecular weight and molecular weight distribution of copolymers have been obtain...

Journal: :Chemical communications 2012
Mustafa Ciftci Muhammet U Kahveci Yusuf Yagci Xavier Allonas Christian Ley Haja Tar

Lightly branched, hyperbranched and cross-linked polymers with clickable sites were synthesized via a modified version of self-condensing photoinitiated copolymerization of methyl acrylate (MA) with propargyl acrylate (PA). The method is based on the use of a PA monomer containing two polymerizable groups, namely acrylate and propargyl groups with different reactivities in photoinitiated free r...

Journal: :Chemical communications 2012
Celia Blanco David Hochberg

A chemical equilibrium model of template-controlled copolymerization is presented for describing the outcome of the experimental induced desymmetrization scenarios recently proposed by Lahav and co-workers.

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