The three general categories of IFSs are metal, polyetheretherketone (PEEK), and bioabsorbable. Currently, titanium is the most common material used in metallic IFSs, and it offers high initial fixation strength, low tissue reactivity, and good clinical results in soft tissue fixation.
PEEK (polyetheretherketone) is a high-performance engineering plastic with outstanding resistance to harsh chemicals, and excellent mechanical strength and dimensional stability. It offers hydrolysis resistance to steam, water, and sea water.
Moisture absorption (also known as water absorption) is the capacity of a material to absorb moisture from its environment. The only polymer with zero water absorption is PTFE. Plastics with very low water absorption are polymers such as PEEK,PPS, PSU, PPSU, PEI, PVDF, PET, PPE, PP and PE.
What is PEEK? Polyether ether ketone (PEEK) is a colourless organic thermoplastic polymer in the polyaryletherketone (PAEK) family, used in engineering applications. PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures.
050 mm) and larger extrusions with diameters up to 1 inch (25.4 mm) with 0.010 inches (0.254 mm) wall thicknesses. Thin wall PEEK tubing can be manufactured semi-transparent or in custom colors.
Popular Application of Polyetheretherketone (PEEK)
It is extensively used in demanding applications such as aerospace, automotive, electrical, medical etc. Because of its robustness, PEEK is used to fabricate items, including bearings, piston parts, pumps, HPLC columns, compressor plate valves, and cable insulation.The fraction of the ordered molecules in polymer is characterized by the degree of crystallinity, which typically ranges between 10% and 80%. Higher values are only achieved in materials having small molecules, which are usually brittle, or in samples stored for long time at temperatures just under the melting point.
Crystallinity makes a material strong, but it also makes it brittle. A completely crystalline polymer would be too brittle to be used as plastic. The amorphous regions give a polymer toughness, that is, the ability to bend without breaking and the ability to absorb impact energy. These are both good properties to have.
Factors affecting crystallinity:
- Length of the chain:Long chain ( high degree of polymerisation) are less likely to crystalize.
- Branching:Branched chains are less likely to crystalize .
- Copolymer : Copolymer are different types :
- Tacticity or storeoisomerism. Atactic does not show crystallinity.
- plastizers :
Crystallinity refers to the degree of structural order in a solid. In a crystal, the atoms or molecules are arranged in a regular, periodic manner. The degree of crystallinity has a big influence on hardness, density, transparency and diffusion.
Heat of crystallization or enthalpy of crystallization is the heat evolved or absorbed when one mole of given substance crystallises from a saturated solution of the same substance.
For semi-crystalline polymers, the degree of crystallinity is one of its most important physical parameters since it reflects the sample's morphology and determines various mechanical properties, such as the Young modulus, yield stress as well as the impact strength.
Crystallinity. Crystallinity refers to the degree of structural order in a solid. In a crystal, the atoms or molecules are arranged in a regular, periodic manner. The degree of crystallinity has a big influence on hardness, density, transparency and diffusion.
Cristallinity from XRD scans is in principal determined simply by drawing an amouphous halo in order to separate the crystalline peaks from the amorphous scattering, and by calculating the ratio of the areas of the crystalline peaks to the total area [4-5]. This basic idea has been refined over the years.
