Search results for "copolymer"

Hydrophilic and hydrophobic copolymers of a polyasparthylhydrazide bearing positive charges as vector for gene therapy

2008

BACKGROUND: The design of polymeric vectors for gene delivery provided with specific properties is one of the most critical aspects for a successful gene therapy. These polymers should be biocompatible as well as able to carry efficiently DNA to target tissues and to transfect it into cells. RESULTS: The formation of complexes of poly[(α,β-asparthylhydrazide)–poly(ethylene glycol)] and poly[(α,β-asparthylhydrazide)–hexadecylamine] copolymers functionalised with glycidyltrimethylammonium chloride (PAHy–PEG-GTA and PAHy–C16-GTA, respectively) with DNA was studied. The effects of the introduction of hydrophilic (PEG) or hydrophobic (C16) moieties on the chains of PAHy–GTA copolymers, such as t…

Monofunctional metathesis polymers via sacrificial diblock copolymers.

2006

Die Darstellung von Gelen als stationäre Phase für die Gelchromatographie

1970

Bei vernetzten Copolymeren aus athylvinylbenzol/Divinylbenzol sowie Vinylacetat/Divinyladipat wird der Einflus der Herstellungsbedingungen auf die Eigenschaften der vernetzten Polymeren untersucht. Homogen-vernetzte Gele eignen sich vor allem zur Trennung von Oligomeren; mit heterogen-vernetzten Gelen konnen Polymere getrennt werden. Es wird gezeigt, das bei der heterogen-vernetzenden Polymerisation die Heterogenitat der Copolymeren mit sinkendem Solvatationsvermogen der Inertkomponente wachst; dies fuhrt gleichzeitig zu einer Erhohung des Aussechlusmolekulargewichtes. The influence of the mode of synthesis on the characteristics of crosslinked polymers is examined for crosslinked copolymer…

Die polymerisation und pfropf-mischpolymerisation des acroleins unter dem einfluß von Co - 60 - gamma - strahlen. Polymere acroleine. 14. Mitteilung

1959

Die Polymerisation des Acroleins im reinen Zustand und in Losung unter dem Einflus von γ-Strahlen wird beschrieden und mit anderen Polymerisations-Methoden verglichen. Bei der Block-Polymerisation entsteht ein stark vernetztes, glasartiges Polymerisat, das in wasriger schwefliger Saure unloslich ist. In Losung polymerisiert das Acrolein viel rascher; die relative Geschwindigkeit der Polymerisation ist am grosten in wasriger Losung. Das hier erhaltene Polymere enthalt reaktionsfahige Aldehyd-Gruppen und ist loslich in schwefliger Saure. Acrolein last sich auf Polymethacrylester aufpfropfen. Sowohl oberflachliche als auch durchgehende Pfropfung vorgeformter Proben des Polymethacrylesters ist …

Synthesis and properties of polymers with unusual structure

1985

This lecture summarize some recent results of our current research. The first part describes the homopolymerization and copolymerization of a monocyclic and two bicyclic unsaturated acetals. In this way polyacetals with 1,4-cis-butadiene units and cyclohexene units respectively are obtained. Secondly, the N-substitution of polyamides is described. By N-metalation and subsequent alkylation comb-like polyamides are available. Longer branches cause a side-chain crystallinity. The anionic “grafting-from” technique forms irregular branched polyamides. By termination reaction between living ends of poly(2-isopropenylnaphthalene) and suitable electrophiles new macromonomers are available. The last…

Copolymers with ordered chemical structure

1984

Copolymers with well defined sequences can be obtained for instance by ring-opening polymerization of selected acetals. In this way regular copolymers of formaldehyde and ethylenoxide of the following structure are available2. In the same way some other copolymers with formaldehyde units were obtained. Of special interest are unsaturated polyacetales; for instance3 They can be modified by chemical reactions, for instance by hydrogenation, addition of bromine, iodine isocyanate or epoxidation. Recently a bicyclic unsaturated cycloacetal was prepared and polymerized4 Branched copolymers with a definite number of uniform sidechains are prepared by N-alkylation of polyamides5 The dependence of …

ChemInform Abstract: Multifunctional Poly(ethylene glycol)s

2011

In the rapidly evolving multidisciplinary field of polymer therapeutics, tailored polymer structures represent the key constituent to explore and harvest the potential of bioactive macromolecular hybrid structures. In light of the recent developments for anticancer drug conjugates, multifunctional polymers are becoming ever more relevant as drug carriers. However, the potentially best suited polymer, poly(ethylene glycol) (PEG), is unfavorable owing to its limited functionality. Therefore, multifunctional linear copolymers (mf-PEGs) based on ethylene oxide (EO) and appropriate epoxide comonomers are attracting increased attention. Precisely engineered via living anionic polymerization and d…

1972

The determination of reactivity ratios is simplified by using an excess of one monomer (M1) at a time large enough that the copolymers will have a very small content of the other monomer (M2). In this case chain propagation takes place almost exclusively by addition to polymer radicals with a terminal M1-unit (P) and monomer consumption by propagation of P may be neglected. One reactivity ratio (r1) is obtained from monomer conversions by means of a simple integrated equation which is valid up to high conversions. A calculation is proposed in order to account for the neglected propagation via P. The other reactivity ratio (r2) is obtained from copolymerizations with excess M2. As the new me…

Fractionation

2012

The enormous diversity of polymers with respect to molecular weight, molecular architecture, and – in the case of copolymers – also the content and arrangement of dissimilar monomers requires well-targeted methods for the separation of the different species that are contained in a given sample. This chapter presents the most abundant fractionation procedures, which are either based on thermodynamic driving forces (like in the case of liquid–liquid phase separation) or on kinetic effects (as with field-flow fractionation).

1993

Several zwitterionic polymers were prepared by radical homopolymerization of surfactant monomers which bear diallyl, diene or vinylcyclopropane moieties. These polymer systems were complemented by alternating copolymers of appropriate zwitterionic vinyl compounds. Thus, polymers with reduced (as compared with simple vinylic homopolymers, or statistical copolymers) and well defined density of surfactant side groups are obtained. The solubilities found for these polymers are dominated by polymer geometry rather than by the balance of hydrophilic and hydrophobic fragments, thus corroborating a “main-chain spacer” model proposed recently. All water-soluble polymers exhibit characteristic featur…