chapter  1
26 Pages

- Introduction to Medical Plastics

Biocompatibility ........................................................................................................5 Biomaterials Availability ............................................................................................5 Materials Performance ...............................................................................................6 Processability .............................................................................................................6 What Is a Polymer? ....................................................................................................7 Basics: Thermoplastic and Thermosets ......................................................................7 Cross-Linked Thermoplastics ....................................................................................7 What Is a Medical-Grade Plastic? ..............................................................................8 Finding Plastics ..........................................................................................................9 Plastics for Machining ...............................................................................................9 Plastics for Processing by Machining ...................................................................... 11

Acrylonitrile-Butadiene-Styrene ........................................................................ 11 Acrylic ................................................................................................................. 11 Polyvinylchloride ................................................................................................ 12 Polycarbonate ...................................................................................................... 12 Polypropylene ..................................................................................................... 13 Polyethelene ........................................................................................................ 13 Acetal .................................................................................................................. 14 Nylon (Polyamide) .............................................................................................. 14 Fluorinated Ethylene Propylene .......................................................................... 15

High-Performance Engineering Plastics for Machining .......................................... 15 Ultem® Polyetherimide ....................................................................................... 15 PEEK™ .............................................................................................................. 15 PTFE (Teon®) .................................................................................................... 16 Polysulfone and Polyphenylsulfone .................................................................... 16

Polyimide Rod and Sheet (Vespel®, Kapton®) ............................................... 17 Injection-Molded and Extruded Plastics ............................................................. 17

Considerations ................................................................................................ 17 Commodity Plastics ................................................................................................. 18

ABS ..................................................................................................................... 18 PC/ABS .......................................................................................................... 18 Acrylic ............................................................................................................ 19 Polycarbonate ................................................................................................. 19

When working with medical plastics, there are some basic considerations: relative biocompatibility, performance, processability, bondability, cost, and availability. Using these basic characteristics as a starting point will help you sift through the myriad of available plastics to arrive at a short list of candidates that best suit your design criteria.