PVC
PVC (Polyvinyl Chloride) is produced by polymerisation of Vinyl Chloride Monomer. In order to produce commercial grades of the polymer - which meet various specification requirements - it is compounded with other additives using extrusion and mixing techniques. Depending on the additives used, properties such as flexibility, clarity, colour, heat stability, density and chemical resistance can be controlled and modified. This compound can be produced in granular or powder form. PVC has been used across all industries, including medical, for the last 50 years. It is one of the most widely researched and used thermoplastic materials today. Historically, PVC has been used as a replacement material for rubbers and glass components. Other uses have developed rapidly due to its ability to optimise performance and safety requirements at a low cost. PVC is characterised by a high degree of biocompatibility, transparency - where needed - and flexibility under changing temperatures and humidities. PVC is easily sterilised to meet a number of industry and medical standards. It also has excellent water and chemical resistance. Flexible PVC’s usually use a pthalate plasticiser. The most important pthalate in high volume use is DEHP, which is listed by the European Pharmacopoeia and recommended for softening disposable medical items, such as tubing and blood bags.

Silicone
Silicone is a synthetic polymer and is produced by a crosslinked polymer reinforced with silica. Further cross-linking takes place by heating with a particular catalyst (i.e. peroxide), to produce the required properties. Silicone has good environmental resistance to heat, cold, ozone, UV, humidity and abrasion. It has outstanding heat resistance, to over 230°C. Electrical resistance is also excellent, and Silicone is frequently used in high voltage/high current applications. However, Silicone can be modified with additives to make it electrically conductive. Silicone does not support microbiological growth, which makes it very useful in pharmaceutical and medical environments. Silicone is a high performance polymer and necessarily more expensive because of its properties. It is made in lower quantities and requires expensive equipment for the compound and the final product’s manufacture. Silicone is highly permeable to gas, which can be a useful property. Silicone is not classed as hazardous waste, and therefore can be disposed of according to local regulations.

Santoprene®
Santoprene® is a proprietary type of thermoplastic rubber elastomer, manufactured by Advanced Elastomer Systems L.P. Santoprene® is a polyolefinic material, produced by a proprietary dynamic vulcanisation which produces rubber particles dispersed throughout a continuous matrix of thermoplastic. The average rubber particle size is 1uM or less, which results in favourable properties allowing easy and consistent processing. This material combines the performance characteristics of vulcanised rubber and the processing ease of thermoplastics. Santoprene® has properties that make it very tolerant of temperatures, chemicals and environmental abrasion. Santoprene® is available in a range of hardnesses. The most popular hardness grade for small-bore peristaltic pump use is 64 Shore A. This gives the best combination of easy occlusion and good material recovery for effective long-life pumping. Other grades are available for alternative applications. Medical grades of Santoprene® have a DMF file lodged with the US FDA, and are approved to USP Class.

Viton®
Viton® is a proprietary type of fluoroelastomer rubber, manufactured by DuPont Industries. Viton® has one of the broadest ranges of chemical resistance in industry. We use Viton® B grade, which is regarded as an ideal type for peristaltic pump use. This combines excellent flexibility with high chemical resistance and anti-ageing properties over a wide range of environmental conditions. Viton® B is specified as a terpolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene and has a higher fluid resistance than Viton® A. Viton® B is not a medical class material, and the resultant extruded tubing is ideal for many industrial applications involving acids and oils.