Search results for "plastic"

Synthesis and Characterization of Syndiotactic Polystyrene-Polyethylene Block Copolymer

2019

The direct synthesis of syndiotactic polystyrene-block-polyethylene copolymer (sPS-b-PE) with a diblock structure has been achieved. The synthetic strategy consists of the sequential stereocontrolled polymerization of styrene and ethylene in the presence of a single catalytic system: cyclopentadienyltitanium(IV) trichloride activated by modified methylaluminoxane (CpTiCl3/MMAO). The reaction conditions suitable for affording the partially living polymerization of these monomers were identified, and the resulting copolymer, purified from contaminant homopolymers, was fully characterized. Gel permeation chromatography coupled with two-dimensional NMR spectroscopy COSY, HSQC, and DOSY confirme…

LC‐Polymers and Smectic Phases with Special Substructures/Nanophase Segregation

2021

Monte Carlo simulation of polymer mixtures: recent progress

2000

On the reliability of the gradient column method for measuring densities of polymer single crystals

1966

From LC‐polymers to Nanomedicines: Different Aspects of Polymer Science from a Materials Viewpoint

2019

Special issue – Polymer foams

2015

Dielectric properties of a filled epoxy resin: Effect of thermal treatments

1982

Dielectric measurements have been performed at several frequencies on samples of a cycloaliphatic epoxy resin filled with aluminum hydroxide. The samples were thermally treated at three different temperatures for times up to 2,000 hours. At low aging temperatures and times an improvement of the characteristics is observed due perhaps to an assessment of the bulk of the polymer and more precisely to a change in the free volume. At high temperatures and times a thermo-oxidation involving layers deeper and deeper becomes the predominant mechanism responsible of the decrease in the properties with respect to the virgin material.

Functional Polymer-Opals from Core-Shell Colloids

2007

Colloidal photonic crystals were prepared from monodisperse core-shell particles. The shell is hereby formed from a functional monomer, such as glycidylmethacrylate or different reactive ester monomers, which can perform chemical reactions and the core from a standard monomer, which yields highly monodisperse colloids. It was possible to crystallize the core-shell particles into artificial opals with excellent optical properties. Reactions on the functional surface of the colloids were carried out, which lead to a dramatic rise in the mechanical stability or to a functionalization of His-tagged silicatein, which acts as nanoreactor to synthesize and immobilize gold nanoparticles from auric …

Synthesis of polyvinyl acetate-graft-poly-2-oxazolines

1994

Poly(vinyl acetate-co-vinyl chloroformate) (1) was synthesized via phosgenation of poly(vinyl acetate-co-vinyl alcohol). It was shown that (1) is capable of initiating the polymerization of 2-phenyl-2-oxazoline and 2-methyl-2-oxazoline, when the counter ion is exchanged using potassium iodide. Polyvinyl acetate-graft-poly-2-phenyl-2-oxazoline and polyvinyl acetate-graft-poly-2-methyl-2-oxazoline are obtained in the grafting reaction.

Synthesis, Characterization and Preliminary Biological Evaluation of P(HPMA)-b-P(LLA) Copolymers: A New Type of Functional Biocompatible Block Copoly…

2010

We describe a synthetic pathway to functional P(HPMA)-b-P(LLA) block copolymers. The synthesis relies on a combination of ring-opening polymerization of L-lactide, conversion into a chain transfer agent (CTA) for the RAFT polymerization of pentafluorophenyl methacrylate. A series of block copolymers was prepared that exhibited molecular weights $\overline M _{\rm n}$ ranging from 7 600 to 34 300 g · mol(-1) , with moderate PDI between 1.3 and 1.45. These reactive precursor polymers have been transformed into biocompatible P(HPMA)-b-P(LLA) copolymers and their fluorescently labeled derivatives by facile replacement of the pentafluorophenyl groups. The fluorescence label attached to this new …