Polylactide-Polycaprolactone Reinforced with Boron Nitride Nanotubes

In addition to chitin being reinforced with boron nitride nanotubes, another matrix material used is polylactide-polycaprolactone (PLA-PCL). PLA and PCL are both promising biodegradable polymers, which have significant differences in mechanical strength and biodegradability, and therefore their blends allow to tune their properties to those desired for tissue engineering applications. PLA has a crystalline structure, and is brittle, with a high strength and low elongation and fracture. It degrades at fast rates by enzymatic or alkali hydrolysis [29]. PCL has a semicrystalline structure and its mechanical properties have characteristics of elastomers. It has a low degradation rate as it is hydrophobic [30].

In order to increase the strength of PLA-PCL copolymers BNNTs are proposed as reinforcements, but at low contents as they do not biodegrade. Particularly, 2 wt% and 5 wt% BNNTs were considered in the study to be summarized below [26]. The length of these nanotubes ranged between 0.43 and 5.8 ^m, and their diameter between 32 and 145 ^m, while their aspect ratio was 15-84.

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