Spectroscopies I have known?Award address: Philips ACS Award in Applied Polymer Science

The network structure of UV-cured acrylates was analyzed by dynamic mechanical experiments, 1 H T2 NMR relaxation, and 13 C NMR spectroscopy. Photocured mixtures of difunctional (poly(ethylene glycol) diacrylate) and monofunctional (2-ethylhexyl acrylate) were studied. The mean crosslink density and fraction of dangling chains were varied in these networks by changing the content of monofunctional acrylate. Examining networks by 13 C NMR spectroscopy, we observed that the conversion is high, and the contribution or the effect of side reactions that generate extra cross-links is negligible. The spatial distribution of cross-links is very heterogeneous in the cured samples; i.e., polyacrylate ziplike network junctions are interconnected by polyether chains. An increase in the content of monofunctional monomer causes a significant decrease in the cross-link density because the monofunctional monomer acts as a chain extender. NMR T 2 relaxation method shows good correlation with mechanical tests with respect to molar mass between cross-links, Mc. Obtained values of Mc are significantly smaller compared to molar mass of diacrylate. As anticipated, it is apparent that classical rubber elasticity theories are not applicable for characterization of this type of networks containing ziplike network junctions.

show abstract

Characterization of the Cross-Linked Structure of Fumarate-Based Degradable Polymer Networks

Timmer

Wang

et al. 2002

Macromolecules

View full text Add to dashboard Cite

A new method was developed to examine networks formed with linear macromers of fumaric acid and diacrylate cross-linking agents in order to analyze their cross-linked structure. This method involved the accelerated degradation of the networks and the analysis of the degradation products. Two model networks of poly(propylene fumarate) (PPF) cross-linked with poly(propylene fumarate)-diacrylate (PPF-DA) and oligo(poly(ethylene glycol) fumarate) (OPF) cross-linked with poly(ethylene glycol)-diacrylate (PEG-DA) were evaluated with this method to determine the macromer and cross-linking agent conversions, the network cross-linking density, and an estimate of the molecular weight between crosslinks. The validity of the method was confirmed by the analysis of the composition of the un-cross-linked macromers and the correlation of the mechanical properties of the cross-linked polymers with the macromer/cross-linking agent double bond ratio. The results showed that acrylate species had participated more than fumarates in network formation. Furthermore, the structure of PPF/PPF-DA networks was influenced by the amount of cross-linking agent in the polymer formulation, and the OPF/PEG-DA network structure was controlled by the number of repeating fumarate units in the macromer. This method provides a new means to characterize the macromolecular structure of fumarate-based networks. Experimental SectionMaterials. Acrylic acid, acryloyl chloride, ammonium hydrogen phosphate, ascorbic acid, benzoyl peroxide, fumaric acid, N,N-dimethyl-p-toluidine, poly(ethylene glycol)-diacrylate (PEG-DA) (Mn 575), and triethylamine were purchased from Aldrich (Milwaukee, WI). Ammonium persulfate was purchased from EM Science (Gibbstown, NJ). Ammonium acetate,

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Spectroscopies I have known?Award address: Philips ACS Award in Applied Polymer Science

Cited by 3 publications

References 39 publications

Characterisation of UV-cured acrylate networks by means of hydrolysis followed by aqueous size-exclusion combined with reversed-phase chromatography

Characterisation of UV-cured acrylate networks by means of hydrolysis followed by aqueous size-exclusion combined with reversed-phase chromatography

Analysis of Network Structure of UV-Cured Acrylates by¹H NMR Relaxation,¹³C NMR Spectroscopy, and Dynamic Mechanical Experiments

Characterization of the Cross-Linked Structure of Fumarate-Based Degradable Polymer Networks

Contact Info

Product

Resources

About

Spectroscopies I have known?Award address: Philips ACS Award in Applied Polymer Science

Cited by 3 publications

References 39 publications

Characterisation of UV-cured acrylate networks by means of hydrolysis followed by aqueous size-exclusion combined with reversed-phase chromatography

Characterisation of UV-cured acrylate networks by means of hydrolysis followed by aqueous size-exclusion combined with reversed-phase chromatography

Analysis of Network Structure of UV-Cured Acrylates by1H NMR Relaxation,13C NMR Spectroscopy, and Dynamic Mechanical Experiments

Characterization of the Cross-Linked Structure of Fumarate-Based Degradable Polymer Networks

Contact Info

Product

Resources

About

Analysis of Network Structure of UV-Cured Acrylates by¹H NMR Relaxation,¹³C NMR Spectroscopy, and Dynamic Mechanical Experiments