Effects of chitosan fiber addition on the properties of polyurethane with thermo-responsive shape memory.

We investigated the effects of the addition of chitosan fiber (biomass nanofiber made by Sugino (BiNFi-s)) to polyether-based thermoplastic polyurethane (TPU) on material properties. BiNFi-s (2 and 5 wt %)/TPU composite materials were prepared via compression molding, and glass fiber (2 and 5 wt %)/TPU composite materials and plain TPU were also prepared for comparison. The glass transition temperature was analyzed using differential scanning calorimetry, and the crystal structure was investigated using X-ray diffraction.

Effects of temperature changes and stress loading on the mechanical and shape memory properties of thermoplastic materials with different glass transition behaviours and crystal structures.

Background/objective: To investigate the effects of temperature changes and stress loading on the mechanical and shape memory properties of thermoplastic materials with different glass transition behaviours and crystal structures.

Materials/methods: Five thermoplastic materials, polyethylene terephthalate glycol (Duran®, Scheu Dental), polypropylene (Hardcast®, Scheu Dental), and polyurethane (SMP MM®, SMP Technologies) with three different glass transition temperatures (T g) were selected. The T g and crystal structure were assessed using differential scanning calorimetry and X-ray diffraction.

Transformation behavior of nickel-titanium orthodontic wires under tensile load.

This study investigated transformations of nickel-titanium wires using differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) under tensile load (100 gf or 500 gf). Two nickel-titanium wires, 35°C Copper Ni-Ti and Nitinol SE, were selected. DSC analyses were performed between -90° and 100°C.