Syringes, particularly disposable ones used in medical applications, are primarily made from plastic materials that are chosen for their safety, durability, and cost-effectiveness. The most commonly used plastics for
manufacturing syringes include:
1. Polypropylene (PP)
Properties: Polypropylene is a thermoplastic polymer that is highly resistant to chemicals, has a high melting point, and does not react with water or most pharmaceutical products. It is also relatively flexible.
Usage: It is widely used for the barrel and plunger of syringes because it provides clarity (which helps in seeing the contents), can withstand sterilization processes like autoclaving, and does not interact with medications.
2. Polyethylene (PE)
Properties: Polyethylene is known for its strength, lightweight nature, and flexibility. It also has good resistance to impact and moisture barrier properties.
Usage: Often used for making the plunger of disposable syringes due to its low friction characteristics which ensure smooth movement within the polypropylene barrel.
3. Polycarbonate (PC)
Properties: Polycarbonate is noted for its transparency, stiffness, and excellent impact resistance. It can also withstand high temperatures.
Usage: Sometimes used in more durable components of syringes or in specialized syringes where clear visibility and high strength are required.
4. Cyclic Olefin Copolymer (COC) or Cyclic Olefin Polymer (COP)
Properties: These materials offer high transparency similar to glass, excellent moisture barrier properties, and resistance to acids and alkalis.
Usage: Used in some specialized
medical syringes where glass-like clarity is needed along with resistance to breakage.
Additional Components:
Rubber or Silicone: For parts like the gasket or seal within the plunger that ensures airtight movement and prevents leakage of medication from the syringe barrel.
These materials are selected not only for their physical and chemical properties but also based on their safety profiles ensuring they do not leach harmful substances into medications or cause adverse reactions upon contact with patients' bodies. The choice of material may vary depending on specific requirements such as the type of medication being administered (some drugs may interact with certain plastics), the required sterility levels, and whether the syringe needs to be resistant to breakage during use.