An exciting new material called Sugru is capturing the imagination of consumers all over the UK. This breakthrough material is a self-setting rubber that can be molded by hand just like play-dough. Hence it has aptly been named Sugru, which is a derivation from an Irish word for play- ‘súgradh’. It was chosen by Time magazine as one of the 50 best inventions of 2010 and is now set to become an importnant household item.
Sugru was envisioned by Jane Ní Dhulchaointigh from Kilkenny, Ireland, during her post-graduate research period at the Royal College of Art in 2003 while she was working on a mixture of standard silicone sealants and sawdust. She wanted to create a material that would enable people to easily repair or customize items owned by them in an inexpensive manner.
With the help of business grants, Ní Dhulchaointigh along with some retired scientists from Dow Corning and a silicone expert, worked to develop Sugru at the Materials Department at Queen Mary, University of London.
Sugru is marketed by FormFormForm Ltd, a UK-based company with over 100,000 customers as of 2012 and annual sales reaching up to $2 million.
Material Properties of Sugru
Sugru is officially a patented formable silicone technology. It is known as Formerol F.10.Both Sugru and Formerol are listed in several well known materials-related organizations such as Material Connexion (a global materials consultancy with the world's library of advanced, innovative and sustainable materials and processes), MateriO (information center for designers of materials and innovate products), Materia.nl (a knowledge centre for developments and innovations in materials, and their applications), and globally-recognized universities such as Delft University of Technology, Central Saint Martins College of Art & Design, and Harvard University Design School.
The basic material used is RTV moisture curing silicone. The ideal working temperature is between 50 to 180°C. The uncured FORMEROL F.10 is white, however this can be altered to any shade. It is also preserved in a moisture-proof packaging and ready for use. The surface on which the silicone elastomer is to be bonded, must be clean and degreased. The cured FORMEROL F.10 has good moisture resistance and flame resistance, and an even better ozone/UV-resistance and oxidation resistance.
Processing of the FORMEROL F.10 can be done at room temperature in dry atmosphere. The normally used processing methods are compression molding, extrusion, or manual shaping. The Formerol team is currently looking into injection molding.
Sugru contains methyltris(methylethylketoxime)silane, γ-aminopropyltriethoxysilane, and dioctyltin dilaurate. The composition can be varied depending on the need to provide multiple levels of plasticity, softness, consistency, density, surface adhesion, curing time, resiliency, modulus and abrasion resistance, and floatability. It is available in a number of colors. According to the EU Health & Safety regulations, Sugru is listed as ‘not dangerous’. However, users are advised to be cautious as it may cause skin allergy for some.
When Sugru is taken out of its airtight, moisture-proof container, it is in malleable form and can retain this form for 30 minutes. At room temperature, Sugru is self-curing for about 24 hours. Sugru is designed in such a manner that it can stick to as many materials as possible just like Super Glue. Despite its soft nature, this patented material is strong and durable and provides a good grip. Apart from being user-friendly, Sugru is waterproof, weather-proof, saltwater resistant, fade resistant and dishwasher-safe. It has a thermal insulating quality with a service temperature ranging from -60 to 180°C (-140 to 356°F). However, Sugru is not resistant to certain solvents, and has a shelf life of only six months.
In case you want to remove Sugru from a non-porous material after curing, you can do so by simply cutting it off with a knife and removing any residue with just your fingernails and tissue paper.
Sugru’s properties are varied based on specific applications.
- Cold molding: when Sugru is molded at low temperatures, the silicone parts can be directly molded onto unusual substrates such as aluminium and ceramics, opening doors to a wider range of new designs.
- Fixing, fitting and forming: The high plasticity of Sugru allows it to be molded into any shape and its elasticity and adhesion features multiples its advantages.
The physical and mechanical properties of Sugru are listed below:
- Shore A hardness of 70 (standard used BS EN ISO 868)
- Density of 1.3g/cm3
- Tensile strength of 1.89 Mpa
- Youngs modulus of 5.59MPa
- Strain to failure of 211%
- DIN abrasion resistance of 24% ARI index (standard used ISO4649 Method A)
- Thermal conductivity- 0.189 W/m^2.K
- Electrical resistivity - surface 1.40 x 10^14 Ohms (standard used BS903)
- Electrical resistivity - volume 2.55 x 10^14 Ohms (standard used BS903)
- Dielectic strength- 398V/mil
- Williams plasticity of 160mm.
Brief Introduction to Silicone
Silicones are defined as inert, synthetic compounds with myriad forms and applications. Their heat-resistant and rubber-like characteristics allow them to be used in sealants, lubricants, medical applications, adhesives, insulation, and cookware. Silicones are available in the form of silicone rubber, silicone resin, silicone oil, silicone grease, and silicone caulk.
Silicones are polymers that are a combination of silicon with hydrogen, oxygen, carbon, and in some cases other elements.
Applications of Sugru
Sugru was created primarily to reduce the amount of things that are thrown away every year due to small defects or inconveniences in repairing and extending their service life.
This smart material has so many uses and the innovation seems to have no limits.
Some of its applications are listed below:
- To close holes that occur with long time usage
- To mend broken handles and cracks
- To customize an item to suit the specific need of user
- To provide a waterproof lining
- To provide a better grip or softer touch on a pen or handle
- To smoothen out corners, and soles of old shoes
- To decorate glasses
- To fix leaks in sinks and repair dishwashers as it can withstand harsh detergents
- For use in skiing, paragliding and deep sea diving equipment as it can withstand saltwater and extreme temperatures
- To provide an extra lining in sports shoes such as wakeboarding boots, for better fit, smoothness, and ease in stepping in and out of
- To modify water sprinkler to alter its shooting distance
- To make a camera ‘drop-proof’, so children can use it freely
- To seal water diffuser so as to withstand up to 80 psi.
- To mend a broken link
Surgru definitely stands a chance of becoming a handy tool in every home in the coming years.
Sources and Further Reading