Biomedical Engineering Reference
In-Depth Information
Fig. 8. Photopolymerization of Ulvan methacrylate under UV irradiation - 365 nm - in
presence of a photoinitiator.
Fig. 9. 1 HNMR spectra of Ulvan-methacrylate (UMA) before and after 10 min of UV
irradiation in the presence of IRGACURE ® 2959 as photoinitiator. Chemical structures of the
main disaccharide repeating units of the macromer is reported together with the relative
peak assignment as highlighted in the small boxe.
The exposure of Ulvan macromers to UV light Leads definitely to the formation of hydrogels
but the photopolymerization is not complete even after 10 minutes of irradiation as
demonstrated by the residual peak of the unreacted double bond protons c and b in the
1 HNMR spectrum. The degree of crosslinking has been monitored at fixed irradiation times and
showed that half (meth)acryloyl groups are polymerized after 5 minutes of UV curing (Table 1).
CD
(%)
1 22.5
2 31.5
3 38.0
5 51.0
10 68.5
Table 1. Crosslinking degree (CD) for UMA having SD = 1 under UV irradiation (365 nm,
8 mW · cm -2 ) as a function of exposure time.
UV exposure time
(min)
Search WWH ::




Custom Search