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Photopolymerization and shrinkage kinetics of in situ crosslinkable N ‐vinyl‐pyrrolidone/poly(ε‐caprolactone fumarate) networks
Author(s) -
Sharifi Shahriar,
Mirzadeh Hamid,
Imani Mohammad,
Atai Mohammad,
Ziaee Farshid
Publication year - 2008
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.31384
Subject(s) - photoinitiator , materials science , photopolymer , fourier transform infrared spectroscopy , polycaprolactone , shrinkage , caprolactone , monomer , reactivity (psychology) , polymer chemistry , polymerization , kinetics , self healing hydrogels , chemical engineering , composite material , polymer , medicine , alternative medicine , physics , pathology , quantum mechanics , engineering
Abstract Biodegradable, injectable and in situ photocrosslinkable macromers based on fumaric acid and polycaprolactone (PCLF) were prepared and characterized by FTIR, 1 HNMR, and 13 CNMR spectroscopy. The multifunctional macromers dissolved in N ‐vinyl pyrollidone (NVP) were photopolymerized by visible light irradiation in the presence of camphorquinone as photoinitiator. The photocrosslinking reaction was monitored by measuring shrinkage strain and shrinkage strain rate. The degree of photopolymerization reaction i.e. degree of conversion (DC%) was traced using FTIR spectroscopy. A three level factorial design was developed to study the effects of initiator concentration, NVP concentration, and molecular weight of PCLF upon photocrosslinking characteristics including degree of conversion and shrinkage strain. Results revealed that although neat PCLF was photopolymerized, but it was putty like after 220 seconds of irradiation and showed a very low degree of conversion (29%). Adding about 20% NVP caused a dramatic increase in its degree of conversion (63.33%). Increasing NVP up to 50% resulted in a decrease in DC% because of lower reactivity of NVP and leaving more unreacted NVP monomers. Sol fraction studies supported these results indicating that at higher NVP concentration, most of NVP and PCLF have not undergone the crosslinking reaction, leading to 55% decrease in DC%. Shrinkage strain measurement also confirmed the FTIR results. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008