Enhancing Healthcare using Polyurethane

Just as we can find polyurethane in our everyday lives, so too can we find it throughout many of the medical procedures we probably don’t care to think too much about. Many of these applications in the medical realm are a result of the attractive properties of polyurethane, which can be attributed to the chemical structure of this polymer.

In the synthesis of polyurethane, a flexible polyol that makes up the polyurethane backbone, reacts with an isocyanate to generate the cross-linked polymer and the ‘soft’ segment of the material, as well as a low molecular weight hydroxyl- or amine-based chain extender that also reacts with the isocyanate to form, due to the additional presence of intramolecular hydrogen-bonding interactions, the ‘hard’ segment of the resultant polyurethane. The generation of this block co-polymer, whereby the soft and hard segments alternate, leads to a unique material that is elastomeric, as well as tough and tear resistant in nature.

These properties of polyurethane lead to its advantages in medical devices over other types of polymers, such as polyvinyl chloride or polyethylene, as the material is able to withstand continual bending and rubbing during its use, without becoming weakened or breaking.

Read on to learn more about some of the medical applications and recent advancements that rely on the benefits of polyurethane.


Biomedical Polyurethane

If we consider the use of polyurethane in medical applications, one of the first things that surely comes to mind is its compatibility with the body. Luckily, much work has been carried out in the fields of chemistry, engineering, and medicine to ensure that the materials used today have sufficient structural, chemical, and mechanical integrities, so we can rest assured that implants will maintain their shapes and desired functions, and will not be degraded by biological attack while in the body.

Historically, polyurethane can be commonly found in a range of medical tubings, for example in catheters and feeding tubes, as well as in surgical gloves and other medical garments, and in bedding. More recently, however, a more diverse range of applications are being realised.

One such application is a polyurethane-based heart valve reported by South African scientists, which offers the advantage, through 3D printing of a titanium frame and dip moulding to introduce the polyurethane valve, of being constructed specifically for each patient. This particular valve offers an exciting alternative treatment to the traditionally utilised biological valve, which degenerates fairly quickly in younger patients, or mechanical valve, which requires life-long anti-coagulation therapy – this development is thus ideal for younger patients in developing countries, such as those in sub-Saharan Africa, where rheumatic heart disease is unfortunately prevalent. Animal and further mechanical testing of the valve is currently underway, so keep an eye out for future progress in this field!

Image courtesy of Central University of Technology, Free State

Thermoplastic Polyurethane

Patient comfort is an integral part of healthcare and treatment, and one particular polyurethane, thermoplastic polyurethane, offers a significant advantage over other plastics due to its ability to respond to heat due to the presence of transient cross-links between hard segments in the copolymer. The subsequent flexibility of the polyurethane imparted by this property allows for the material to act more as a rubber than a plastic, and adapt to movement in the patient’s body, which makes it much less cumbersome and annoying for the patient.

As such, these thermoplastic polyurethanes have a range of applications in a variety of tubings, oxygen masks, and wound dressings, as well as in a range of intravenous and intra-aortic balloon catheters, all of which are subject to much motion, and which patients appreciate for their flexibility.


Polyurethane Foam

When we think of polyurethane foams, their incorporation into medical devices may not be the first thing that comes to mind. Their rigid structure as a result of extensive cross-linking between the hard and soft segments of the co-polymer, is a bonus when support and inflexibility are required, however.

One such example of a rigid support comes in the form of a suture alternative, known as the Zip, which uses an adjustable ladder-type structure to close evenly an incision in places of stitches or staples. The polyurethane the Zip is made of facilitates the dynamic nature and conformability of the device, so the precision is also protected from the forces of patient movement, which aids in healing and recovery, and, perhaps most importantly for patients, also minimises scarring and track marks left by more traditional methods, so also offers cosmetic benefits.

Video courtesy of ZipLine Medical

For those who have suffered the ill-fate of broken bones and wearing a cast, the hassles of showering, the perpetual and unreachable itch, and the general discomfort can be appreciated. Luckily for any of our future breaks, a new company, Cast21, hailing from the University of Illinois at Urbana-Champaign has developed a means of addressing these issues. The cast, while still maintaining the rigidity required to repair a broken bone, is also hollow (so no itching!) and waterproof (showerproof!). To achieve this remarkable feat, the cast is based around a flexible network of silicon tubes into which the two components of polyurethane are injected, react, harden, and form a rigid foam exoskeleton that distributes force evenly across the limb in need of repair. Simple!

Image courtesy of Cast21

Imagine if all of this was possible, whilst also enabling the capture and storage of pesky waste CO2… check out how Econic can make this possible, or contact us for more information.

Author, econicuser

The Night Before (a Polyurethane) Christmas

Twas the night before Christmas, when all through the house, not a creature was stirring, not even a mouse. The stockings were hung by the chimney with care, in hope that St Nicholas soon would be there.

christmas-chocolate-santa-sleigh-mould

Many of us will be halfway through our advent calendars by now. Don’t worry though, this isn’t where we tell you the chocolate is made from polyurethane. Rather, the moulds used to shape and store the chocolates are made from polycarbonate. Typically, low molecular weight polycarbonate is used which is durable and flexible enough to pass its shape onto the chocolate, but also allow you to free the chocolate from its casing to enjoy each day.

With a little old driver, so lively and quick, I knew in a moment it must be St Nick. More rapid than eagles his coursers they came, and he whistled, and shouted, and called them by name!
“Now, Dasher! now, Dancer! now, Prancer and Vixen! On, Comet! On, Cupid! on, Donner and Blitzen! To the top of the porch! to the top of the wall! Now dash away! Dash away! Dash away all!”

Santa+reindeerThe impending end of our advent calendars can then mean only one thing – Santa’s visit. With all of the families that Santa visits on Christmas Eve, he surely relies heavily on polyurethane to aid him in the vast distances and climes he will travel through. To reduce friction and make the journey a little easier on his reindeer, his sleigh will most likely be coated in polyurethane. To keep him warm, both at the North Pole and while he’s flying through the night skies, he probably wears boots made from polyurethane incorporated into the shoe’s upper. The hard thermoplastic polyurethane in the soles of his boots are also probably really useful when he needs to clamber over snowy and slippery roofs. And just to be safe, we suggest that he takes an umbrella coated in waterproofing polyurethane in case it’s raining out!

Not all of us, especially those in the Southern Hemisphere, are lucky enough to celebrate a white Christmas. With the help of chemistry though, we can guarantee snow for all this Christmas, not necessarily falling from the sky however. As a more permanent solution, porous polyurethane foam is often coated on artificial Christmas trees to mimic a snow-clad forest tree. Alternatively, a more hands-on snow can be made at home using sodium polyacrylate, a very absorbent polymer, which, when mixed with water, expands in size by many orders of magnitude, and, due to the endothermic nature of water uptake, becomes cold.

He spoke not a word, but went straight to his work, and filled all the stockings, then turned with a jerk. And laying his finger aside of his nose, and giving a nod, up the chimney he rose!

christmas-tree-presents

There is nothing more magical than waking up to a Christmas tree twinkling with lights, sparkling with baubles, and festively surrounded by gifts, a sight that would be lacking, if not for various forms of polyurethane and polycarbonate. Artificial Christmas trees, in combination with polyvinyl chloride or polyethylene fir leaves, comprise a polyurethane foam-based trunk. The decorations and baubles that adorn our trees are typically coated with polyurethane for longevity and shininess, while the lights that trim the tree are encased in a polycarbonate shell. Polyurethane is also prevalent in the gifts under the tree – from the flexible polyurethane foam that protects our packaged gifts, to the rigid polyurethane plastic that makes up our gifts.

At the end of the festivities, rest assured that you can relax in the comfort of your polyurethane foam couch cushions and memory foam mattress, while listening to Christmas songs or watching films on polycarbonate CDs and DVDs. (Polymeric) perfection.

He sprang to his sleigh, to his team gave a whistle, and away they all flew like the down of a thistle. But I heard him exclaim, ‘ere he drove out of sight, “Happy Christmas to all, and to all a good-night!
– Clement Clarke Moore

Happy holidays from the Econic team!

Author, econicuser

Polymers & Plastics in the Paralympics

The 2016 Rio Paralympic Games are now in full swing, with medals being won, records being broken, and a viewers from around the world being inspired. Plastics and polymers have had a huge influence upon these games, which may come as a surprise to you (even the medal ribbons are 50% recycled plastic bottles this year!). Technological and scientific advances are imperative to the continued growth and expansion of the paralympics, and all athletic endeavours. Carry on reading to find out some more about the technology on show at this year’s Games.


Wheelchairs 

Let’s kick off, or more aptly, tip off, with wheelchair basketball. Although the majority of chairs used currently are made from welded titanium, there has been a significant increase in the belief that carbon fibre-reinforced polymers, typically polyepoxide-based, in fact offer the attributes desirable for a more successful wheelchair, typically leading to the chair being lightweight and manoeuvrable, but also able to withstand impact. Carbon fibre-reinforced polymers are more commonly used in running blades, a mainstay of the modern paralympic games, as they offer the best combination of strength and weight. Although this technology is not the norm within more chair-based sports, there are athletes who will be using these chairs, so it’s down to the action on the court for a preview of what may be more widespread in the future for wheelchair basketball.

There have also been developments on the chairs used throughout the games off the basketball court, whereby  British athletes have been able to achieve a 20% increase in acceleration thanks to work between UK Sport and BAE Systems (more commonly associated with the aerospace industry). This increase in speed has been made possible for Team GB’s racing chairs through the development of a new, lighter composite-based wheel, that is also three times more rigid than previous wheels. This rigidity allows for a reduction in a force known as ‘toe-in’, and prevents the wheel from bending inwards as the athletes propel themselves forwards, thereby reducing the amount of friction between the athlete and the track. As we know, a margin of 20% is a big deal in athletic competition, so this development will have a huge impact on athletes’ hunt for gold.

It isn’t only Team GB who have put time into developing their wheelchairs, the US team have teamed up with BMW to create ‘the world’s fastest wheelchair’. The chair does not resemble a traditional chair, with its low, long, and triangular body produced from carbon fibre by BMW’s California-based design firm Designworks. Each chair is also personalised to fit each individual athlete to allow their performance to be optimised even further.These developments will lead to some intense competition this year, which may not only be between the athletes, but also between the companies behind the chairs too.

bmw-wheelchair-hed-2016
Image courtesy of BMW

Canoeing & Kayaking 

Taking a dip in the waters of Brazil may conjure up images of golden beaches and lapping shore lines, and although that may be true, the athletes at the Paralympics will be competing in somewhat less relaxing circumstances. Events such as the paracanoe and rowing are in full effect, and the technology involved is proving to hold an influence on the speed, agility and success of the athletes. The shape, style and flexibility of canoes and kayaks is heavily influenced by innovations in plastics technology, with these materials able to offer the development of more lightweight apparatus without sacrifice of their rigidity.

Canoe events were introduced into the Paralympics for the first time this year, with six medal events added. It is no surprise that racing canoes are no longer made of wood or bark, but instead most are now constructed from the polymer Kevlar, which allows for an increase in speed and agility due to the lightweight nature of the material.

As well as the canoes and kayaks themselves, plastics are incorporated into the events at the Lagoa Stadium in Rio, with high-density polyurethane blocks used to form obstacles. These objects take the form of artificial rocks and are bolted together to the bottom of the water channel in order to constrict the water flow with the aim of replicating a natural whitewater feature.

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Image courtesy of Rio 2016 Paralympic Games

Swimming

The use of polyurethane swimsuits has caused much controversy over the years at the Olympic and Paralympic Games, with the use of whole-body suits being banned since 2010 and the the 2012 London Games. Of course, athletes have long sourced any advantages in competition, such as removing every follicle of hair from their bodies, but the banned suits are an example of technology advancement gone too far (in the eyes of the Olympic governing bodies, that is). The suits allowed for swimmers to become far more buoyant as a result of the extremely thin material trapping small pockets of air. Maybe there is room for technological development in this event, but even without these suits, paralympians have already been posting some impressive times in the pool this year.


3D-Printed Prostheses

The world’s first 3D-printed prosthesis will be on show at this year’s Games, a milestone in prosthetic technology. German cyclist Denise Schindler, with the help of software company Autodesk,  will be using the fully 3D-printed polycarbonate-based prosthesis as she competes for gold in Rio. A significant advantage of using such technology is the pace at which the limb can be produced using a 3D printer, rather than by hand as standard athletic prosthetic limbs are generally produced. This increased speed of production allows for any necessary changes to be made to the design with little disruption, meaning the prosthesis can evolve at a greater pace during the production process. Additionally, as the prosthesis is prepared from an electronic blueprint obtained from 3D scanning of the athlete, the joint prepared can provide a much better fit than can be achieved through the useful method of plaster casting.  The team have been printing and testing a range of printed prostheses based on polycarbonate split into two parts, and the development will continue right until the start of the Games, with the aim to have the most aerodynamic version possible.

The hope is that this technology will open the door for these new types of prosthetic limbs to become available not only to elite athletes, but also to be more readily accessible to a much larger range of people who have suffered the loss of a limb. Schindler herself has said that a huge goal of hers is to ‘open up the sports world for the average amputated person’. Developments such as this could not only help to make the dreams of those inspired to compete at the Paralympics a closer reality, but also to assist those using prostheses in their everyday lives.

Video courtesy of Dezeen

 

 

Author, econicuser