摘要:
A high-bending-strength and high-density osteosynthetic material and a high-strength implant material, comprising either a biodegradable and bioabsorbable crystalline thermoplastic polymer material or a composite material comprising the above polymer material and a bioceramic powder having a particle diameter of 0.2 to 50 νm dispersed therein, wherein crystals of the polymer material are pressure-oriented essentially parallel to a plurality of reference axes rather than uniaxially; and a process for preparing the above materials by pressure orientation, comprising preparing either a biodegradable and bioabsorbable crystalline thermoplastic polymer material or a mixture comprising a dispersion of a biodegradable and bioabsorbable crystalline thermoplastic polymer material and a dispersion of a bioceramic powder, melt-forming the mxiture into a preform, and pressure filling the preform into a cavity of a closed mold to prepare an oriented form. This process enables the preparation of ideal biomaterials, i.e., an osteosynthetic material and an implant material comprising an oriented form with crystals oriented parallel to a plurality of reference axes and possessing low anisotropy, high denseness, and high strength, which have suitable hydrolyzability, can retain satisfactory strength for a period of time necessary for bone coaptation and, after the recovery of the fractured portion, is degraded and adsorbed at such a rate as will not cuase any inflammation, thus eliminating the need to conduct reoperation.
摘要:
A high bending strength and high density material for osteosynthesis, which comprises a biodegradable and bioabsorbable crystalline thermoplastic polymer material, and a high strength implant material, comprising a composite material in which a bioceramics powder of from 0.2 to 50 µm in particle size is dispersed in the polymer material, wherein crystals of the polymer material are pressure-oriented not in a uni-axial direction but basically in parallel with a plurality of reference axes; and a production method by pressure orientation, which comprises preparing in advance a biodegradable and bioabsorbable crystalline thermoplastic polymer material or a dispersed mixture of the polymer material and a bioceramics powder and melt-molding it into a pre-molded material which is then press-charged at a cold temperature into a cavity of a closed type forming mold, thereby obtaining an oriented molding. Since the osteosynthesis and implant materials are dense and high strength oriented moldings having less anisotropy in which crystals are oriented in parallel with a plurality of reference axes, excellent ideal biomaterials can be provided which have appropriate hydrolysis property, can maintain sufficient strength during a period required for bone union and are degraded and absorbed at such a rate that they do not induce inflammatory reactions after healing of the fractured bones so that re-operation is not required.