Classification and main uses of medical TPU Thermoplastic polyurethane elastomer (TPU) The polyurethane elastomer used in medical treatment is mainly thermoplastic polyurethane (TPU) elastomer. Processing methods can be injection molding, extrusion molding or solution casting. Thermoplastic polyurethanes are linear block polymers consisting of soft segments (long-chain oligomeric diols) and hard segments (diisocyanates and chain extenders). Due to the strong polarity of the hard segment, the microphase region of the hard segment is formed by hydrogen bonds, and is distributed in the matrix of the soft segment to form a physical cross-linking point, so that the elastomer has the elastic recovery performance of vulcanized rubber. . Due to the difference in polarity between the soft and hard segments in the polyurethane molecular structure, this structure makes it biocompatible. Due to its convenient handling and excellent properties, TPU has been widely used in various medical and healthcare products, such as medical materials that can be used for long-term and short-term implantation in the human body.

The performance of TPU depends on the type and proportion of raw material diisocyanate, oligomeric diol and short-chain diol chain extender. In the preparation of medical polyurethane elastomers, two commonly used diisocyanates are aromatic 4,4′-diphenylmethane diisocyanate (MDI) and aliphatic methylene dicyclohexyl diisocyanate (HMDI). Commonly used oligomeric polyols include polytetramethylene ether glycol (PTMEG), polyester diol, and polycarbonate diol. Due to the excellent mechanical strength, water resistance and biocompatibility of polyurethane elastomers made of PTMEG and MDI or HMDI, PTMEG is an important oligomer diol and polyester diol for medical polyurethane materials and can also be used in medical grades Polyurethane material. Currently, attention is focused on ester diols on polycarbonate. The most commonly used chain extender is 1,4-butanediol (BD).