Synthesis and characterization of photocurable poly(caprolactone) networks with shape memory effect

This thesis focuses on the synthesis of photocurable copolymers networks with shape memory effect. Copolymers of epsilon-caprolactone and a new lactone monomer modified with a cinnamoyl moiety that can be cross-linked by UV light were synthesized. Various copolymer architectures (random and block) were synthesized and confirmed by 1H NMR, DSC and UV-VIS spectroscopic techniques. These copolymers were compression pressed into films and irradiated with a UV lamp for 1 hour on each side to form a network structure in the absence of photoinitiators. The thermal, mechanical and gel content characterization of the crosslinked networks was done by differential scanning calorimetry, tensile testing and solvent swelling respectively. The shape memory properties of the networks were quantified using thermo-mechanical cycling experiments. Of all the architectures, the triblock copolymer showed melting transition temperature at 53 °C. The triblock showed excellent shape fixation (∼99 %) and recovery (>99 %) after the second cyclic test. This work establishes a general methodology for inducing shape memory effect into any semicrystalline polyester networks. More specifically it can be applied to systems which have the highest transition temperature close to application temperature. An advantage of the novel copolymers is their biodegradability and biocompatibility enabling their use in biomedical devices for in-vivo applications.