SHAPE MEMORY POLYMER COMPOSITE FOR 3D PRINTING OF MEDICAL ITEMS

This invention describes s medical purpose composite material based on a thermoplastic polymer with a bioactive shape memory ceramic, wherein the "hard" phase comprises the crystalline phase of the polymer matrix, chemical and physical crosslinking agents and a bioactive component, and the "soft" phase comprises the amorphous phase of the polymer matrix and a plasticizer. The composite material comprises the bioresorbable polyactide polymer matrix and hydroxyapatite bioactive filler with 100 to 1000 nm sized particles. The hydroxyapatite filling percentage is 15 to 35 wt.%. For reducing the shape memory effect activation temperature said composite material comprises a plasticizer, i.e., 4.6 to 15 wt.% polyethylene glycol. For stabilizing the mechanical properties said composite material has a crosslinked structure. The crosslinked structure of said polymer material and the presence of a hard phase, i.e. hydroxyapatite particles, provide for the development of recovery stresses of 3 MPa at a 98% shape recovery. Furthermore, the addition of the polyethylene glycol plasticizer reduces the materials glass transition temperature which is the shape memory effect activation point. Shape memory effect is activated in the 35 to 45ºC range. Youngs modulus and elastic modulus in compression of the composite material are 4 and 11 GPa, respectively. The melt of said composite material exhibits a high viscosity at above the melting point (170ºC) providing for a higher layerwise application accuracy in the 3D printing of medical items. The technical result of this invention is providing a polymer composite material suitable for the 3D printing of shape memory medical items. La présente invention concerne un matériau composite à usage médical à base d'un polymère thermoplastique avec une céramique à mémoire de forme bioactive, la phase "dure" comprenant la phase cristalline de la matrice polymère, des agents de réticulation chimiques et physiques et un composant bioactif, et la phase "molle" comprenant la phase amorphe de la matrice polymère et un plastifiant. Le matériau composite comprend la matrice polymère polyactide biorésorbable et une charge bioactive d'hydroxyapatite avec des particules de taille comprises entre 100 à 1000 nm. Le pourcentage de charge d'hydroxyapatite est compris entre 15 à 35 % en poids. Pour réduire la température d'activation de l'effet de mémoire de forme, ledit matériau composite comprend un plastifiant, à savoir, 4,6 à 15 % en poids de poly