Search results for "Copolymer"

Langmuir-Blodgett films of biocompatible poly(HPMA)-block-poly(lauryl methacrylate) and poly(HPMA)-random-poly(lauryl methacrylate): influence of pol…

2010

Membranes based on functional biocompatible polymers can be regarded as a useful model system to study biological interactions, e.g. antibody-antigen interactions or protein polymer interactions. These model systems may give a better insight into these processes and may help to find suitable polymeric structures offering biocompatibility as well as reduced polymer protein interaction. In this respect, Langmuir-Blodgett (LB) layer formation at the air/water (A/W) interface is studied in respect to polymer architecture in this article. For this purpose, narrowly distributed N-(2-hydroxypropyl)-methacrylamide (HPMA) random and block copolymers have been prepared by the RAFT polymerization meth…

Cyclodextrins in polymer synthesis: photocrosslinkable films via free radical copolymerization of methylated β-cyclodextrin-complexed styrene with so…

2001

The copolymerization of a methylated-β-cyclodextrin (m-β-CD) 1:1 host-guest compound of styrene (1a) with various molar ratios of sodium 4-(acrylamido)-phenyldiazosulfonate (2) is described. The copolymerization of complex 1a with 2 was carried out in water with 2,2′-azobis(N,N′-dimethyleneisobutyramidine)-dihydrochloride as the free radical initiator at 40°C. Depending on the amount of 2 incorporated in the copolymer, water- or DMF-soluble copolymers of high molar mass were obtained. Irradiation of the copolymers with UV light in solution resulted in rapid decomposition of the azo chromophore, and irradiation of the polymers as films led to crosslinking and thus to insolubility.

Polyaspartamide-graft- Polymethacrylate Nanoparticles for Doxorubicin Delivery

2011

A new PHEA-IB-PMANa + copolymer has been synthesized and its pH-induced self-assembly has been investigated in an aqueous medium. PHEA-IB-PMANa + formed nanoparticles with diameters from 25 to 50 nm upon protonation of the carboxylic acid moieties dislocated along the grafted polymethacrylate sodium salt side chains. The physico-chemical characterization of the nanoparticles was performed using light scattering, zeta-potential measurements, SEM, and AFM. Doxorubicin-loaded nanoparticles were prepared and drug release profiles were evaluated under conditions mimicking physiological media. A biological characterization was carried out by testing the cytotoxicity on Caco-2 cells, and cellular …

Well-Defined Multi-Amino-Functional and Stimuli-Responsive Poly(propylene oxide) by Crown Ether Assisted Anionic Ring-Opening Polymerization

2017

Multi-amino-functional poly(propylene oxide) (PPO) copolymers were synthesized by the anionic ring-opening copolymerization (AROP) of N,N-diethyl glycidyl amine (DEGA) and propylene oxide (PO). A solvent free synthesis route using potassium counterions and crown ether for the AROP enabled controlled (co)polymerization with full conversion. The strategy provided access to PPO-b-PDEGA block copolymers, statistical PPO-co-PDEGA copolymers, and, for the first time, PDEGA homopolymer. Molecular weights in the range of 1400 to 4200 g/mol (Mn) and dispersities (Mw/Mn) below 1.1 were obtained. Both the kinetics and resulting microstructure of the statistical copolymerization were investigated by in…

Cyclodextrins in polymer chemistry: Influence of methylated β-cyclodextrin as host on the free radical copolymerization reactivity ratios of isoborny…

1999

Methylated β-cyclodextrin (me-β-CD) was used to complex the hydrophobic monomers isobornyl acrylate (1) and butyl acrylate (2) yielding the water-soluble host/guest complexes isobornyl acrylate/me-β-CD (1a) and butyl acrylate/me-β-CD (2a). The included monomers were copolymerized in water by free-radical mechanism and the kinetics were studied. In order to evaluate these results, the corresponding uncomplexed monomers 1 and 2 were also copolymerized in organic solution. The reactivity ratios of 1a and 2a (r1a = 0.3, r2a = 1.7) differ significantly from the reactivity ratios of the corresponding uncomplexed acrylates 1 and 2 in organic solution (r1 = 1.3, r2 = 1.0). In addition, we found tha…

Consequences of linking charged and uncharged monomers to binary copolymers studied in dilute solution. Part II: Non-additivity effects in the viscom…

2017

Abstract Copolymers of ethylene oxide (EO) and N,N-dimethyl aminoethyl methacrylate (R) or [2-(methacryloyloxy)ethyl] trimethylammonium iodide (R+) were studied in dilute solution: P ( EO p – b – R n ) ( I ) , P(Rn(1−f) – ran – R+n f) ( II ) , and P ( EO p – b – R n + ) ( III ) ; n and p give the numbers of monomers and f is the degree of charging. For II (variable f) and III (variable n) the effects of charging on the intrinsic viscosities [η] are well described by Boltzmann sigmoids. The deviation of [ η ] from [ η ] add (calculated from the corresponding homopolymer data, assuming additivity of the individual contributions) are quantified by σ = [ η ] / [ η ] add - 1 measuring the segreg…

Temperature and light sensitive copolymers containing azobenzene moieties prepared via a polymer analogous reaction

2009

Abstract Four different series of polyacrylamides containing different amounts of azobenzene moieties have been synthesized via a polymer analogous reaction of poly(pentafluorophenylacrylate) (PPFPA). All copolymers were designed to exhibit a lower critical solution temperature (LCST) in aqueous solution, which was dependent on (i) the amount of incorporated chromophoric azobenzene groups and (ii) the isomerization state of the respective azobenzene group. Higher LCST values were measured for UV-irradiated solutions of the copolymers in comparison to the non-irradiated copolymer solutions. A maximum difference in the LCST of up to 7 °C was found for the copolymer poly(N,N-dimethylacrylamide…

Phase Transitions of Polymer Blends and Block Copolymer Melts in Thin Films

1999

Treatment of poly(styrene-co-methacrylic acid)/poly(4-vinylpyridine) blends in solution under liquid–liquid phase-separation conditions. A new method…

2006

Phase diagrams are contributed for polymer mixture systems in solution. One polymer has proton-acceptor character and the other has growing proton-donor nature, which is reflected in the phase diagrams. Usually, these diagrams are obtained from size-exclusion chromatographic (SEC) measurements. A totally novel application, which is exposed in this report, is the construction of the phase diagram from the viscometric experiments of polymer mixtures. The evaluated binodal or cloud-point isotherms so built agree well with those from SEC. The results indicate an augmentation in the dimensions of donor polymer B, in the presence of acceptor polymer C, intensifying with the concentration of C, wh…

Aminofunctional polyethers: smart materials for applications in solution and on surfaces

2013

In recent years, biocompatible polyethers with multi-aminofunctionality have been used for a variety of applications in different fields. Both established and recently developed synthesis strategies for such polymers and applications as stimuli-responsive materials, non-viral vectors, shell crosslinked micelles and for surface functionalization are reviewed. The intriguing potential of such materials is due to both polyether and polyamine components and can thus be readily tuned by the copolymer microstructure and composition. © 2013 Society of Chemical Industry