What are some medical plastics and their common applications?

 

 

Medical plastics are a class of plastic materials used in the medical field. They possess various properties and have a wide range of applications. Below is some important information about medical plastics:

 

I. Commonly Used Medical Plastics and Their Characteristics:

 

**Polyvinyl Chloride (PVC):**

 

Characteristics: Low cost, wide range of applications, easy to process, good chemical resistance, but poor thermal stability.

 

Uses: Commonly used in the manufacture of blood bags, various cannulas, catheters, tubing, artificial peritoneum, etc. Due to its flexibility and processability, it is suitable for medical devices that require bending and deformation.

 

**Polycarbonate (PC):**

 

Characteristics: Possesses good toughness, strength, rigidity, and heat steam sterilization resistance; high transparency. However, this material is prone to stress cracking.

 

Uses: Can be used to manufacture blood dialysis filters, various housings, connectors, surgical tool handles, oxygen cylinders, needle-free injection systems, perfusion instruments, blood centrifuge bowls and pistons, etc. Its high transparency makes it widely used in some medical devices requiring observation of internal conditions.

 

Polyethylene (PE):

 

Characteristics: High chemical stability, good biocompatibility, but not easy to bond.

 

Classification and Uses:

 

1. Low-density polyethylene (LDPE): Commonly used in medical packaging and intravenous injection containers, with good flexibility and transparency.

 

2. High-density polyethylene (HDPE): Can be used in artificial urethras, artificial lungs, artificial tracheas, artificial larynxes, artificial kidneys, artificial bones, orthopedic repair materials, etc., with high hardness and strength.

 

3. Ultra-high molecular weight polyethylene (UHMWPE): Used in artificial lungs, artificial joints, etc., with high impact strength, low friction, stress crack resistance, and good energy absorption characteristics.

 

Polystyrene (PS):

 

Characteristics: Low cost, low density, transparent, dimensionally stable, radiation resistant (sterilization). Hard and brittle, with a high coefficient of thermal expansion.

 

Applications: Crystalline polystyrene can be used to make laboratory glassware, Petri dishes and tissue culture plates, respiratory equipment, and suction cups, etc.; high-impact polystyrene can be used for catheter trays, heart pumps, dura mater trays, respiratory equipment, and suction cups, etc.

 

Polypropylene (PP):

 

Characteristics: Non-toxic, odorless, with good mechanical properties, chemical stability, and heat resistance; good insulation, low water absorption; good resistance to solvents, oils, weak acids, and weak alkalis; good molding properties; no environmental stress cracking issues. However, it has a large molding shrinkage rate, high surface inertness, and is difficult to print and bond.

 

Applications: Commonly used in disposable syringes, connectors, transparent plastic covers, pipettes, parenteral nutrition packaging, dialysis membranes, etc.

 

Polyurethane (PU):

 

Characteristics: Excellent physical properties, good chemical stability, good biocompatibility, strong abrasion resistance, and smooth surface.

 

Applications: Used in the medical field for artificial heart assist devices, urinary catheters, artificial joint pads, etc.

 

Thermoplastic Polyurethane (TPU):

 

Features: Good transparency, high strength and tear resistance, good chemical and abrasion resistance, wide hardness range, smooth surface, antifungal and antimicrobial properties, and high water resistance.

 

Applications: Used in medical catheters, oxygen masks, artificial hearts, drug delivery devices, IV connectors, blood pressure monitor cuffs, and topical wound dressings.

 

Polytetrafluoroethylene (PTFE):

 

Features: High crystallinity, very low coefficient of friction, good heat resistance, high chemical stability, does not react with strong acids, alkalis, or various organic solvents, good biocompatibility and hemocompatibility, no harm to human physiology, no adverse reactions after implantation, and can be sterilized at high temperatures.

 

Applications: Used in the manufacture of venous vessels, cardiac membranes, endoscopes, forceps catheters, endotracheal tubes, other tubes, bottles, filter cloths, and other medical devices.

 

Polyamide (PA):

 

Characteristics: Flexible, flexural, highly tough and not easily broken; good chemical resistance and abrasion resistance; does not release any substances harmful to the human body, therefore does not cause inflammation of the skin or tissues.

 

Applications: Commonly used in the manufacture of hoses, connectors, adapters, pistons, etc.

 

Polyetheretherketone (PEEK):

 

Characteristics: Heat resistant, abrasion resistant, fatigue resistant, radiation resistant, corrosion resistant, hydrolysis resistant, lightweight, good self-lubricating properties, good processability, and can withstand repeated autoclaving.

 

Applications: Can replace metals in surgical and dental instruments, replace titanium alloys in the manufacture of artificial bones, has advantages in minimally invasive surgery, and does not produce artifacts.

 

II. Performance Requirements:

 

1. Chemical Stability: Medical plastics need to have good chemical stability, and will not react chemically with drugs or in the internal environment of the human body, nor release harmful substances, to ensure patient safety.

 

2. Biosafety: Non-toxic and harmless to the human body, does not cause toxicity or damage to tissues and organs, and does not cause adverse biological reactions such as immune rejection. 3. Physical and Mechanical Properties: Depending on the application scenario, appropriate physical and mechanical properties such as strength, elasticity, toughness, and hardness are required to meet the usage requirements of medical devices. For example, artificial joint materials need high strength and wear resistance, while catheter materials need a certain degree of flexibility and bendability.

 

4. Processing Performance: Easily processed into products of various shapes and sizes, adaptable to different production processes such as injection molding, extrusion, and blow molding.

 

5. Sterilization Adaptability: Able to withstand various sterilization methods, such as high-temperature autoclave sterilization, radiation sterilization, and ethylene oxide sterilization, without significant impact on performance after sterilization.

 

III. Application Areas:

 

1. Medical Devices: Medical plastics are an important material in the manufacture of medical devices, such as disposable infusion sets, syringes, catheters, and cannulas. Using medical plastics in these devices reduces costs, facilitates use, and ensures hygiene and safety, reducing the risk of cross-infection. In addition, there are various medical plastic products, such as endotracheal tubes, endotracheal tubes, vascular cannulas, puncture cannulas, etc., as well as instruments used for repair, nursing, physiotherapy, and diagnosis.

 

2. Medical Packaging: Used for pharmaceutical packaging, medical consumable packaging, etc. For example, medical packaging materials such as eye drop bottles, oral liquid bottles, PVC Plastic Bottles, and low-density polyethylene ointment tubes need to have good barrier properties, sealing properties, and chemical stability to ensure the quality and safety of medicines.

 

3. Implant Materials: Some medical plastics can be used as implant materials to repair or replace human tissues and organs, such as artificial joints, artificial bones, and artificial blood vessels. These implant materials need to have good biocompatibility and long-term stability, be able to integrate well with human tissues, and not cause rejection or other complications.

 

IV. Development Trends:

 

1. High Performance: With the continuous development of medical technology, the performance requirements for medical plastics are becoming increasingly stringent. In the future, medical plastics will continue to develop towards higher performance, such as improved strength, wear resistance, fatigue resistance, and biocompatibility, to meet the needs of more complex medical applications.

 

2. Green and Environmentally Friendly: Increased environmental awareness is driving the development of medical plastics towards green and environmentally friendly directions. Developing biodegradable medical plastics to reduce environmental pollution and improving the recycling rate of medical plastics will be future development trends.

 

3. Intelligent: The research and development of intelligent medical plastics is also an important direction. For example, medical plastics with sensing functions can monitor patients' physiological parameters in real time, such as blood pressure and heart rate; medical plastics with drug sustained-release functions can automatically control the release rate and dosage of drugs according to the patient's condition, improving treatment effectiveness.

 

V. Commonly Used Medical Plastic Products Include:

 

1. Medical Syringes

 

Medical syringes are one of the most commonly used medical devices in medical institutions and individual consumers. Most medical syringes are made of plastic. Medical syringes can be divided into disposable syringes and reusable syringes. Disposable syringes are widely used in hospitals and home healthcare. 1. **Medical Syringes:** Materials primarily include polyolefins, PVC, PC, and PP.

 

2. **Infusion Sets:** Infusion sets are also commonly used medical devices in medical institutions and by individual consumers. They consist of plastic tubing and fittings, primarily made of PVC and PP. Common capacities include 50ml, 100ml, and 250ml.

 

3. **Blood Collection Devices:** Blood collection devices are used by medical institutions and individual consumers to collect blood samples. Most blood collection devices are now disposable, primarily made of polypropylene and ABS.

 

4. **Disposable Masks:** Disposable masks are commonly used personal protective equipment in recent years, mainly used to block bacteria, microparticles, and other small particles from entering. The main materials for disposable masks are polypropylene fiber and meltblown fabric.

 

5. **Medical Gloves:** Medical gloves are commonly used by healthcare workers, primarily protecting their hands from infectious diseases. Common materials for medical gloves include latex and nitrile.

 

In summary, many of the various instruments and supplies needed in modern medicine are made of plastic. The widespread use of plastic products makes the quality of medical supplies more stable and safe, and also provides reliable support for medical security.