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Free radical polymerization of poly(ethylene glycol) diacrylate macromers: Impact of macromer hydrophobicity and initiator chemistry on polymerization efficiency

Paper ID Volume ID Publish Year Pages File Format Full-Text
1597 87 1972 8 PDF Available
Title
Free radical polymerization of poly(ethylene glycol) diacrylate macromers: Impact of macromer hydrophobicity and initiator chemistry on polymerization efficiency
Abstract

A series of poly(ethylene glycol)-co-poly(lactide) diacrylate macromers was synthesized with variable PEG molecular weights (10 or 20 kDa) and lactate contents (0 or 6 lactates per end group). These macromers were polymerized to form hydrogels by free radical polymerization using either redox or photochemical initiators. The extent of polymerization was determined by monitoring the compressive modulus of the resulting hydrogels and by quantitative determination of unreacted acrylate after exhaustive hydrolysis of the gel. Polymerization efficiency was found to depend on the lactate content of the macromer, with higher lactate macromers giving more efficient polymerization. For redox-initiated polymerization using ferrous gluconate/t-butyl hydroperoxide initiator, macromers containing approximately six lactate repeats per end group required lower concentrations of initiator to reach high conversion than lactate-free macromers. Photochemical polymerization with α,α-dimethoxy-α-phenylacetophenone (Irgacure 651®) was found to be less efficient than redox polymerization, requiring the addition of N  -vinyl-2- pyrrolidone (NVP) as a co-monomer to achieve conversions comparable with redox polymerization. When conditions were optimized to provide near complete conversion for all gels, the presence of lactate repeat units in the hydrogel was generally found to reduce swelling and increase the compressive modulus. Calculated values of molecular weight between cross-links (Mc¯) and mesh size using Flory–Rehner theory showed that macromer molecular weight had the greatest impact on the network structure of the gel.

Keywords
Poly(ethylene glycol); Hydrogel; Free radical; Redox initiator; Photo-initiator
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Free radical polymerization of poly(ethylene glycol) diacrylate macromers: Impact of macromer hydrophobicity and initiator chemistry on polymerization efficiency
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Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 7, Issue 5, May 2011, Pages 1965–1972
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us