Derivatization of a new poly(ether urethane amide) containing chemically active sites

Stern, Theodor; Penhasi, Adel; Cohn, Daniel

doi:10.1016/0142-9612(95)91091-c

Cited by 11 publications

(13 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Polyurethanes are among the most applied and researched polymers worldwide. Polymers representing the polyurethane family exhibit an endless variety of mechanical and physical properties, resulting in a vast variety of applications in fields ranging from the most simple consumer products such as shoe‐soles, foams, and textile fibers to state‐of‐the‐art artificial organs and parts of the total artificial heart …”

Section: Introductionmentioning

confidence: 99%

“…Polyurethane synthesis is typically achieved through the reaction between difunctional isocyanates and difunctional primary alcohols, leading to the formation of urethane‐containing repeating polymer units. The synthesis of polyurethane block copolymers requires in most cases the preliminary synthesis of a macrodiisocyanate prepolymer, which is subsequently reacted with additional difunctional reagents such as diamines, diols, or dicarboxylic acids, commonly termed as chain extenders . These general synthesis methods lead to the formation of linear thermoplastic polyurethanes, suitable for many industrial melt or solution processing methods and applications.…”

Section: Introductionmentioning

confidence: 99%

“…Allophanate formation is most abundant in bulk polyurethane syntheses (ie, without the use of a solvent). To minimize the probability of allophanate formation, some polyurethane syntheses are performed in solution, as in the case of many types of polyurethane elastomers …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hierarchical fractal‐structured allophanate‐derived network formation in bulk polyurethane synthesis

Stern

2017

Polymers for Advanced Techs

View full text Add to dashboard Cite

Polyurethanes are among the most applied and researched polymers worldwide. Nevertheless, polyurethane synthesis is accompanied by a side-reaction occurring between isocyanate groups and the secondary nitrogen of already formed urethane groups, leading to the formation of crosslinking allophanates. This inevitably requires the development of highly diagnostic direct analytical methods that can be performed in the solid state of the polymer. The present research focused on the direct investigation and diagnostic determination of the chemical structure formation in bulk polyurethane synthesis, using a combination of Fourier transform infrared and solidstate 13 C nuclear magnetic resonance analysis. Polyurethane syntheses were performed in bulk and designed as to obtain significantly strong diagnostic analytical measurements signals for the accurate identification of each of the investigated chemical structures. The present research results led to the conclusive analytical identification of allophanate formation during polyurethane synthesis. In addition, the occurrence of a new reaction mechanism was discovered in the present research. It was demonstrated in the present research that this newly described reaction occurs via the further reaction of the allophanate secondary nitrogen with an isocyanate group, the reaction creating a tertiary nitrogen and an additional reactive secondary nitrogen, and so on, in a consecutive step progression, leading to the formation of a 3-dimensional hierarchical fractal-like crosslinked polymeric structure. Solid-state 13 C nuclear magnetic resonance analysis results were highly consistent with the Fourier transform infrared results. The discovery of this newly described reaction can facilitate the optimization of industrial processes and potentially opens a new door to the development of a vast variety of biomedical and nanotechnology applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hierarchical fractal‐structured allophanate‐derived network formation in bulk polyurethane synthesis

Stern

2017

Polymers for Advanced Techs

View full text Add to dashboard Cite

show abstract

“…In two previous articles, the chemical derivatization of polyurethanes through chemically active sites situated along the polymer chain was described. 1,2 In those studies, along with the desired properties, a significant undesired change in the mechanical properties was observed, caused by the interference of the grafted molecules with the microphase separation of the polymers.…”

Section: Introductionmentioning

confidence: 97%

Surface tailoring of biomedical polymers: An FTIR study

Stern

Cohn

2001

J of Applied Polymer Sci

View full text Add to dashboard Cite

A multistep, surface-tailoring process of polymeric materials was developed with two consecutive plasma treatments and followed by derivatization reactions. In the first step, tetrafluoroethylene was plasma-polymerized, generating a highly crosslinked perfluoric surface layer. The next step introduced amine groups into the plasma polymer through exposure of the surface to plasma of ammonia. The reactive amine moieties were then used as anchoring sites for further derivatization. Finally, poly(ethylene glycol) chains were grafted onto the surface via a hexamethylene diisocyanate spacer. This method, aimed at the chemical modification of polymers for biomedical applications, was first demonstrated with poly(ethylene terephthalate) (PET) as a substrate in a previously published study (Cohn, D.; Stern, T. Macromolecules 2000, 33, 137). The aim of this study was to demonstrate the applicability of the method described previously to different polymers: poly(lactic acid), poly(ethylene) (PE), polystyrene (PST), poly(methyl methacrylate), a polybutadiene-based polyurethane (PEUOXAB-20), and Lycra. Fourier transform infrared (FTIR) spectroscopy was used to characterize the surface-modified substrates and the various control treatments. The results obtained were consistent with the derivatization scheme and in full agreement with the FTIR and ESCA results previously obtained for PET.

show abstract

“…Previous methods of incorporating PEG grafts onto a poly-(urethane) include preparation of surface physical interpenetrating networks (SPIN), 28 covalent grafting onto the urethane group through an allophanate linkage, 29 or onto main chain fumaramide double bonds of a poly(ether urethane amide) via Michael addition of an amine terminated PEG. 30 Kohn et al 31 prepared polyurethanes from bis-hydroxysuccinimidyl PEG carbonates and lysine esters, which, after hydrolysis, had pendant carboxylic acids. These have been functionalized to form hydrogels and drug carriers.…”

Section: Introductionmentioning

confidence: 99%

Easily grafted polyurethanes with reactive main chain functional groups. Synthesis, characterization, and antithrombogenicity of poly(ethylene glycol)-grafted poly(urethanes)

Orban

Chapman

Wagner

et al. 1999

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

Derivatization of a new poly(ether urethane amide) containing chemically active sites

Cited by 11 publications

References 15 publications

Hierarchical fractal‐structured allophanate‐derived network formation in bulk polyurethane synthesis

Hierarchical fractal‐structured allophanate‐derived network formation in bulk polyurethane synthesis

Surface tailoring of biomedical polymers: An FTIR study

Easily grafted polyurethanes with reactive main chain functional groups. Synthesis, characterization, and antithrombogenicity of poly(ethylene glycol)-grafted poly(urethanes)

Contact Info

Product

Resources

About