Influence of Early-Stage Hydrolysis on Tensile Fracture Behavior of HAp/PLA Composites Interface-Controlled by Reaction Control Utilizing Photodissociable Protecting Groups
Mototsugu Tanaka*,†, Tomoyuki Takahashi**, and Isao Kimpara***
*Department of Mechanical Engineering, Kanazawa Institute of Technology
Ohgigaoka 7-1, Nonoichi, Japan
**Kanazawa Institute of Technology, Nonoichi, Japan
***Research Laboratory for Integrated Technological Systems, Kanazawa Institute of Technology, Hakusan, Japan
In this study, the change in the tensile fracture behavior of HAp/PLA composites, interface-controlled using pectin and chitosan, was evaluated for the case of the early-stage hydrolysis. Here, the reaction between the HAp particles and modification polymers was controlled using o-nitrobenzyl alcohol. Tensile tests after immersion in a pseudo biological environment indicated that the interface-control method employed in this study improved the fracture properties of HAp/PLA composites significantly, inducing the large plastic deformation. In addition, the effects of early-stage hydrolysis on fracture behavior and mechanism are discussed from the viewpoint of interfacial structures for the interface-controlled HAp/PLA composites. Observations of fracture morphologies and surfaces suggest that the interface-control employed in this study successfully improved interfacial bonding, enabling the effective usage of the deformability of the PLA matrix. The interface-control method employed in this study also maximized the fracture strain through the combination of improved interfacial bonding and an increase in the ductility of the PLA matrix after a 2-week immersion. Test results also suggest that the cancelation induced by the degradation of chitosan accelerated the degradation of the PLA matrix after a longer immersion.
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