Medical grade plastics: types of plastics used in medical devices

by Cathy Liao

12 January 2023

11:50

Medical grade plastics are applicable in making medical products such as MRI casings, plastic syringes, and prosthetics. These plastics are suitable for making medical devices due to biocompatibility, especially for medical components that come in contact with the human circulation system. They are also malleable, hard, precise, and compatible with injection moulding and 3D printing processes.

Every medical-grade plastic in the market has unique inherent properties similar to conventional plastic polymers. However, they are different in biocompatibility since conventional plastic polymers don't factor in biocompatibility. Choosing the right medical-grade plastic for your product can be challenging. But no worry, we will introduce the general types of medical plastics, and their advantages then we will bring you a list of medical grade plastics you can use for your project.

Yes, medical-grade plastics are safe for making medical components. Medical products have a single goal: "to prevent and treat diseases and disease-causing organisms’ growth.

Properties responsible for safety include non-permeability, chemical/heat resistance, hardness, and, most importantly, biocompatibility. By being non-permeable, these plastic polymers do not support the growth of disease-causing organisms. Also, they are sterilisable due to chemical and heat resistance. Consequently, medical graded polymers are suitable for making products used in transporting bio-hazardous materials that can spread dangerous infections.

Polyethylene is a top medical grade plastic due to its cost-effectiveness, impact resistance, corrosion resistance, and solid structural integrity when exposed to frequent sterilisation cycles. It is applicable in making prosthetics due to being biologically inert and non-degradable in the body.

The medical-grade polymer is resistant to stress, cracking, impact, and fatigue, and it has a high melting point (about 1710C). Due to its properties, it provides enough resistance to the heat produced in the autoclave. Therefore, it is applicable in making plastic components for medical devices such as disposable syringes, oxygenator membranes, prescription bottles, connectors, and finger-joint prostheses.

Polymethyl methacrylate has a high melting point (200-250°C) and is compatible with blow moulding or extrusion. The medical-grade product is applicable in making endoscopic medical parts.

Flexible PVC is dense, inexpensive, and readily available. It is applicable in areas where sterility is a priority. Rigid PVC is durable, strong, and hard. The two types of PVCs are suitable for manufacturing devices for hemodialysis, tubing, cardiac catheters, and artificial limb materials.

Polyamide or nylon is a natural and synthetic polymer made by linking the amino group of a molecule to the carboxylic group of another molecule. The material is known for its tensile strength, high abrasion resistance, chemical resistance, anti-corrosive properties, and flexibility.

Medical grade ABS plastic is made by polymerising styrene and acrylonitrile in the presence of polybutadiene. The polymer has tensile strength, high abrasion resistance, chemical resistance, and anti-corrosive properties. Compatible manufacturing processes include injection moulding, blow moulding, and extrusion.

The medical industry favours it for its high strength, good heat resistance, and biocompatibility. Hence, they are applicable in making medical components such as IV connectors used in renal dialysis, and cardiac surgery.

Medical graded plastics are applicable in making products such as plastic gloves, plastic syringes, and other surgical tools. They differ from conventional plastic polymers as they should be biocompatible. To select the right plastic material for your medical product, this article introduced a list of medical-grade plastics, their types, and their advantages.

by Cathy Liao

12 January 2023

11:50