The impressive growth of the medical
device, biomedical and healthcare industries over the past 15 years continues
unabated even as materials such as fluoropolymers are meeting the increasingly
challenging demand for new products and procedures. In general, fluoropolymers
are progressively replacing other plastics in medical applications owing to
their ability to meet the physical and biocompatibility requirements of the
next generation drugs and devices.
Fluoropolymers meet a unique set of performance criteria in such
applications. These include biocompatibility, lubricity, sterilization,
chemical inertness, a wide temperature use range, low binding to process
equipment, high-purity with low extractables, dielectric properties, and USP
Class VI certification.
The family of available fluoropolymers that
meet the above needs include grades of PTFE, FEP, PFA and PVDF resin from
various resin producers. PTFE(teflon) has a well-established implant history of soft
tissue replacement due to its biocompatibility and inertness. Resin and
downstream product manufacturers continue to respond to new performance
requirements by making appropriate modifications to the chemistry of the resin
and surface configuration of the products, respectively.
The biocompatibility of any polymer is a
principal requirement in any medical device such as catheters, bio-containment
vessels, syringes and sutures. PTFE, FEP and PVDF are well established
biocompatible materials, and their lubricity and chemical resistance make them
the material of choice for products such as multi lumen tubing and others that
are used in minimally invasive procedures. Multi lumen fluoropolymer catheter
tubing for example allows surgeons to perform multiple procedures using the
same catheter.
Fluoropolymers, especially PTFE(teflon)and PVDF
are widely used in microporous membranes. Membranes, containing billions of
pores ranging in size from 0.01 to 10 microns act as filters for particles and
bacteria in critical fluids. PTFE and PVDF are among the few polymers used for
filter membranes. The surfaces of the polymers membranes can be modified to
deliver specific filtration properties and can be hydrophobic (water repelling)
and oleophobic (oil, solvent, low surface tension fluid repelling). PVDF
membranes can be also be surface modified to be hydrophilic (water loving) for
removal of viral particles in the manufacture of therapeutic proteins and
monoclonal antibodies. PVDF blotting membranes are particularly well suited for
low background immunoblotting (western blot analysis), as well as for amino
acid analysis and protein sequencing.
Accessory equipment, such as pumps, tubing,
fittings used in conjunction with medical devices must meet similar performance
and specification parameters. Accessories in direct contact with fluids are
constructed of fluoropolymers such as PTFE and PVDF. For example, metering
pumps such as diaphragm pumps are required for precise and repeatable flow,
sometimes for chemically aggressive fluids.
Both PTFE and PVDF tubing are used in the construction of these pumps
for this reason.
PVDF, although having a lower use
temperature limit than PTFE(teflon), has a relatively high tensile strength and
excellent permeation resistance to many fluids. It has a lower density (1.78
g/cc) than other fluoropolymers (approximately 2.18 g/cc). Due to a lower
melting temperature than other fluoropolymers, it is more easily processible
into products such as pipes, tubes, injection molded parts and films. It offers
excellent dimensional and UV stability and is therefore finding new uses in
aerospace, sensors, biotechnology and robotics markets.
Tags:teflon, Fluoropolymers,medical device
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