Page 171 - Biodegradable Polyesters

References 149

Their work aimed at enhancing the recovery stress and accelerating the shape
∘
recovery process. Stents with fast recovery at T = 37 Cwerealsoproducedform
poly(ε-caprolactone-co-D,L-lactide) which not only has the appropriate T trans but
also degrades better than the reference PLA [84].

6.4
Outlook and Future Trends

Biodegradable SM polyesters can not only biodegrade in the body but also
have further beneficial properties such as easy shaping, tuning of the shaping
temperature, and adjustable degradation rate. Their disadvantages are mostly
related to the relatively high shaping temperature (T ), slow recovery rate, and
trans
low recovery stress. These aspects will remain in the forefront of future R&D
works. T manipulation by copolymerization and conetworking, T adjustment
g
m
by copolymerization seem to be the right tools in this respect. Moreover,
these methods may contribute also to achieve controllable degradation of the
corresponding SMPs. Creation of conetwork and IPN structures may markedly
enhance the recovery rate and stress. Semi-IPN-structured systems may exhibit a
further function, namely self-healing, which would widen the application field of
SMPs. To enhance the recovery stress, biodegradable polyester-based composites
will be developed. Exploring various thermo- and photoreversible reactions
to ensure easy thermoplastic-type recycling of the SMPs is a challenging task.
Biodegradable SM polyesters are predestinated for medical use. The related
development will be fueled by the needs of scaffolding materials and stents in
particular.

Acknowledgments

The work reported here was supported by the Hungarian Research Fund (OTKA
NK 83421), by the Széchenyi plan project “Intelligent functional materials”
(TÁMOP-4.2.2.A-11/1/KONV-2012-0036), and by the Office of the Higher Edu-
cation Commission under the grant agreement from King Mongkut’s University
of Technology North Bangkok, Thailand.

References
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2. Hu, J., Zhu, Y., Huang, H., and memory polymers. Adv. Mater., 22
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