2A Microfibres Flashcards
Manufactured polymers - synthetics
What are microfibres?
Extremely fine synthetic fibres: mainly polyester/polyamide(nylon)/acrylic
Properties (microfibres)
- 60 to 100 times finer than a human hair: invisible to the naked eye
- very lightweight
- soft
- drapes well
- durable/strong
- good absorbency/wicking characteristics
- washes well
- dries quickly
End-uses (microfibres)
- clothing products: activewear/all-weather wear (often blended with natural fibres to give high performance fabrics)
- industrial use
- towels/cloths
Fabrics (microfibres)
- can be knitted/woven/laminated/micro-encapsulated
- polyester microfibres: Microlux and Coolmax
- polyamide(nylon) microfibres: Tactel®
Types of Tactel®
Tactel®: a brand name of a modified PA microfibres, produced by Invista
- Tactel® Aquator: wicks moisture, often used in underwear/sportswear
- Tactel® Diablo: lustrous and drapes well, used for hosiery/lingerie
Why are microfibres used in medical textiles?
- very thin/lightweight/strong
- easy to engineer in a wide range of shapes/textures: to mimic body tissue as closely as possible
- excellent chemical resistance
- finishes can be added for added functionality
- shapes can be joined easily
- edges can be heat-sealed to prevent fraying
To achieve desired final product requirements and unique dimensions:
- yarn can be split/twisted/textured/heat set
- fabrics can be shape formed and customised
Features of knitted microfibres
- will not unravel (warp knitted fabrics)
- material stretches/conforms with the movement of the body: limits unwanted stress and discomfort
- uses digitally controlled equipment (CAD/CAM): to precisely define specific knit configurations to fit specific shapes (unique body)
- tubular fabric: the degree to which a fabric stretches radially/longitudinally can be precisely tuned
- other forms: circular knit/pile knit/ 3D shape formed fabrics
Woven microfibres for medical fabrics
- made up of interlacing yarns that cross one another at right angles
- weft yarns: run across the loom (left/right)
- warp yarns: run longitudinally (up/down)
- creates a dimensionally stable implantable fabric (flexible material) with high: tensile strength/suture(stitch) retention/burst strength
- low profile/porosity
Uses (woven microfibres)
The low profile/porosity that woven medical fabric can achieve has led to their use in:
- endovascular grafts (blood vessels)
- aortic valve skirts (heart)
- other structural heart implants
Features of woven microfibres
- can be manufactured to be comparatively thinner than knitted
- smaller pore size (for breathability)
- usually applied where the fabric is required to act as an impenetrable barrier
- state-of-the-art digitally controlled equipment can facilitate variable woven design configurations, with excellent tolerance and precision
- other configurations of implantable woven fabrics: leno weave(like lace)/twill weave/pile fabrics(like velvet)
Features of braided microfibres
- achieved by intertwining multiple strands(min. 3) of yarn in a diagonally overlapping pattern
- complex design options can be manufactured
- by varying the braid size and shape: mechanical properties can be tailored to suit design requirements, with the ability to transition between multiple configurations
- configurations: solid braids/hollow core braids/multi-layer braids/flat braids
Uses (braided microfibres)
Typically used for the manufacture of:
- suture (stitches)
- braided stents: tubes used to replace arteries
- catheters: thin tubes used to insert/remove liquid from the body
- other implantable devices
Examples of medical textile products
- blood pressure systems
- cystic fibrosis vests: loosens mucus in the chest by using high frequency vibrations
- conduct threads: to measure heart rates
- anti-bacterial masks/gowns
- dissolvable stitches
- plasters/bandages
- patches to administer drugs
- sanitary products
- hair nets
- bedding
