Search results for "Copolymer"

1982

The polyamides 3–5 were synthesized from α,ω-diamino-substituted oligo(oxyethylene)s (1) and bis-chlorides of dicarboxylic acids (2). As copolymers with defined sequences they contain up to five oxyethylene units per repeating unit. Hereby properties like solubility, thermal stability and complexing ability towards alkali metal cations are influenced.

Asymmetric Micellization of Oragnometallic Polyether Block Copolymers

2011

Inside Back Cover: Kinetically Controlled Sequential Growth of Surface-Grafted Chiral Supramolecular Copolymers (Angew. Chem. Int. Ed. 25/2016)

2016

1974

The formation and behaviour of radiation-induced free radicals in statistical copolymers of ethoxyvinylthiomethane (1a) with N-vinylpyrrolidone (2) (1:2,5) and of ethylthiovinylthiomethane (1b) with 2 (1:3,5) has been studied using electron spin resonance spectroscopy. After a γ-irradiation of the copolymers at 77K Cα-radicals in the vinylpyrrolidone moieties could be detected. Investigations on the behaviour of these radicals with an annealing procedure revealed that only in the copolymer (3b) with the dithioacetal group a transfer reaction of hydrogen atoms to the Cα-radicals in the vinylpyrrolidone moieties occurs. This process may be regarded as a repair mechanism. Es wurde die Bildung …

Dependence of solvent quality on the composition of copolymers: experiment and theory for solutions of P(MMA-ran-t-BMA) in toluene and in chloroform.

2014

The interaction of toluene with P(MMA-ran-t-BMA) and with the corresponding homopolymers was determined via vapor pressure measurements at 30, 50 and 70 °C. A unified thermodynamic approach served for the modeling of the results. It is capable of describing the behavior of the different solutions by means of two adjustable parameters, one representing the effective number of solvent segments and the other accounting for the interactions between the components. The solvent quality of toluene passes a maximum, a minimum and another maximum upon an increase of the t-BMA content of the copolymer at all temperatures. A similar behavior is discernable from vapor pressure data of chloroform publis…

Estimation of the Compatibility Between Poly(Methylmethacrylate) and Poly(Styrene Co Vinyl Phenol) Blends from Dilute Solution Measurements

2006

Abstract The compatibility of poly(methyl methacrylate) (PMMA) with poly(styrene‐co‐vinyl phenol) (PS‐VPh) with two different contents of vinyl phenol, 5.8 and 7.2%, in dilute tetrahydrofuran solutions has been investigated by size exclusion chromatography and fluorescence spectroscopy at 25°C. The chromatographic technique permits the evaluation of the preferential solvation at different PMMA/PS‐VPh ratios. Changes in the fluorescence properties of PS‐VPh, caused by its association with PMMA, were used to obtain the fraction of copolymer bound to PMMA at diverse PMMA compositions. Both techniques agree quantitatively in every system, indicating that the association increases when the PMMA …

Inducing mixing of water-in water BSA/dextran emulsion by a strong polyelectrolyte

2015

Abstract We examine whether a small amount of strong polyelectrolyte (dextran sulfate sodium salt/DSS/) can induce mixing in water-in-water bovine serum albumin/dextran (BSA/DEX) emulsion and how intermacromolecular interactions affect its the rheological properties. Addition of DSS to water-in-water emulsion at pH 5.4 leads to its mixing at the DSS/BSA weight ratio, ( q ( DSS / BSA ) ) ≥ 0.07 , a noticeable increase in viscosity and storage modulus (G′). Mixing is reversible: increasing the ionic strength leads to phase separation in the water/BSA/DEX/DSS system. The increase in viscoelasticity results from the interaction of DSS with both macromolecular compounds of the emulsion. We assum…

A facile way to build up branched high functional polyaminoacids with tunable physicochemical and biological properties

2016

Abstract Here, for the first time, branched polyaminoacids bearing α-amino acids as side functions, namely PAA-co-AA and PGA-co-AA, are prepared by heterophase ring opening of polysuccinimide (PSI) with l -arginine or glycine in aqueous environment and at controlled pH. The modulation of the pH of the reaction leads to high-molecular-weight copolymers with tunable functionalization and, as consequence, with tailor-made physicochemical properties. Furthermore, a branched polyaminoacid carrying a preformed bioactive peptide ( l -trileucine) and l -arginine as side pendants, named PATA-co-AA, was synthesized via a similar pathway thus leading to complex biomimetic materials potentially exploit…

Dynamic Light Scattering Investigation of the Kinetics and Fidelity of Supramolecular Copolymerizations in Water

2017

The self-assembly of supramolecular copolymers facilitates the preparation of multifunctional materials, with tunable mechanical, electronic, or bioactive properties. Compared to covalent copolymerization protocols, controlling the molecular weight, stability, and monomer sequence of a multicomponent supramolecular copolymer remains limited. Here, we report a light scattering investigation of the charge-regulated supramolecular copolymerization in neutral buffer of physiological ionic strength, supported with electron microscopy and circular dichroism spectroscopy experiments. Dendritic anionic and cationic peptide comonomers self-assemble into AB-type heterocopolymers with a nanorod-like m…

Bone-Targeted Cisplatin-Complexed Poly(γ-benzyl-L-glutamate)-Poly(glutamic acid) Block Polymer Nanoparticles: An Electrochemical Approach

2015

The voltammetric response of different osteotropic multifunctional nanoparticles based on cisplatin-complexed poly(γ-benzyl-L-glutamate)–poly(glutamic acid) block polymer (CDDP-PBLG-b-PGlu) copolymer, with or without poly(γ-benzyl-L-glutamate)–poly(ethylene glycol) block polymer (PBLG-b-PEG), and having bone-targeting properties is studied at biologically relevant pH. Significant differences in the cisplatin-centered voltammetric signals allow monitoring of the association of cisplatin to nanoparticles as well as release kinetics from them, in agreement with atomic absorption spectroscopy data. Electrochemical studies reveal that the cisplatin association is significant only if the proporti…