نتایج جستجو برای: polystyrenes

تعداد نتایج: 5181  

2009
Tsuneomi Kawasaki Christiane Hohberger Yuko Araki Kunihiko Hatase Klaus Beckerle Jun Okuda Kenso Soai

Chiral isotactic polystyrenes induce the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, affording the enantiomerically enriched pyrimidyl alkanol with the corresponding absolute configuration to that of cryptochiral polystyrenes in conjunction with asymmetric autocatalysis.

Journal: :Chemical communications 2011
Toshiki Nokami Takashi Watanabe Naoki Musya Tatsuya Morofuji Kazukuni Tahara Yoshito Tobe Jun-ichi Yoshida

Dendritic diarylcarbenium ions exhibited sufficient electrophilicity to react with unfunctionalized polystyrenes. The polymers obtained by the reaction of the first and the second generation dendritic diarylcarbenium ions with polystyrenes were well characterized by MALDI-TOF MS and SEC-MALLS analyses and observed by AFM.

2013
Carmen Jarne Vicente L. Cebolla Luis Membrado Eva M. Gálvez Jesús Vela Rosa Garriga

A repeatable separation of polystyrenes according to MW, from 1920 to 520000 u.m.a, has been obtained under adsorption conditions using a method that comprises the use of Lichrospher HPTLC plates, and a controlled, isocratic elution with a 78:22 (v/v) mixture of cyclohexane (Cy)-tetrahydrofuran (THF). Likewise, UV-densitometric quantification of polystyrenes in mixtures can be achieved, by an i...

Journal: :Polymer Chemistry 2021

Aqueous emulsion polymerization via reversible complexation mediated living radical yielded low-dispersity poly(methyl methacrylate)s and polystyrenes.

Journal: :Chemical communications 2005
Femke de Loos Irene C Reynhout Jeroen J L M Cornelissen Alan E Rowan Roeland J M Nolte

A series of mono-functionalized metallo-porphyrin polystyrenes have been synthesized using atom transfer radical polymerization and their self-assembling behavior was studied by electron microscopy showing that the polystyrene tail-length influences the aggregate architecture.

Journal: :Chemical communications 2005
Toshiyuki Oyama Hiroki Yoshioka Masao Tomoi

In the asymmetric addition of allyltrichlorosilane to benzaldehyde, polystyrenes with chiral phosphoramide substituents as Lewis base catalysts showed up to 2.4 times better catalytic activity and 1.4 times higher enantioselectivity than the corresponding low-molecular-weight analogues.

2002
R. A. WEISS P. K. AGARWAL R. D. LUNDBERG

Polystyrenes containing up to about 20 mol % sulfonic acid are reproducibly and readily prepared by the sulfonation of polystyrene at 50°C with acetyl sulfate in 1,2-dichloroethane solution. The metal salts of sulfonated polystyrene possess extremely high melt viscosities and are soluble in single solvents such as toluene and THF only at very low sulfonate levels. Such properties are the result...

2017
Ken Terao Brandon S. Farmer Yo Nakamura Hermis Iatrou Kunlun Hong Jimmy W. Mays

The molecular weight dependence of the radii of gyration Rg in a Θ solvent (trans-decalin) of one regular branched comb and three regular centipede polystyrenes was studied using a gel permeation chromatography system equipped with a two-angle light scattering detector and a refractive index detector. Rg in trans-decalin for each sample of particular molecular weight was about 25% smaller than ...

Journal: :Journal of Applied Polymer Science 1974

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