'There's a hole in my bucket ...'

Apr 25, 2005
Holger Wack inspects samples of his new plastics in dry and swollen condition

Cracks, splits and holes are by definition one of the biggest problems in sealing technology. A new addition has recently been made to the thermoplastic elastomer family: Swellable variants of these plastics react to leaking water and thus stop the leaks.
Everyone is familiar with thermoplastic elastomers (TPE) used in toothbrushes, cellphone keypads or screwdrivers. They benefit ordinary users, giving the hand a pleasantly soft and secure grip. They also benefit manufacturers, who can melt down the rubbery plastics and process them in the same way as the thermoplastics polyethylene, polypropylene and polystyrene. The TPE material can also be injection-molded, extruded or calandered (rolled into sheets and films) in large quantities at correspondingly low costs. It can even be welded, which is particularly desirable when using it in the building industry.

Image: Holger Wack inspects samples of his new plastics in dry and swollen condition.

Researchers from the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT have succeeded in extending this family of materials by adding a further component: polyacrylate which is known for its excellent absorptive properties. The resulting thermoplastic-elastomer composites are registered as Q-TE-C®. They swell up to several times their dry volume when in contact with water. But what is even more important: they can be processed like TPE. “We have moved into new territory,” Holger Wack firmly believes after extensive research in patent publications. “That encouraged us to apply for a patent on the basic formulation just under a year ago.”

The deputy head of the special materials department already has a laundry list of potential applications, mostly dealing with the broad topic of sealing technology. These plastics could reveal their talents whenever it is important to prevent water or aqueous solutions from leaking out or penetrating into adjacent spaces. Wack explains a self-sealing pond liner as an illustration of how they work. “It consists of a layer of the new material with normal waterproof sheeting on both sides. If water seeps out through a tiny hole, the Q-TE-C® layer swells up and seals the damaged spot.” In pipe connections, another significant factor comes into play: The damp material is now locked between solid parts, which restricts its volume expansion. The sealant increases the pressure on the solid parts and thus mends the leak.

The various types of plastic require different specific properties depending on their application. The researchers are therefore currently elaborating methods for demonstrating that a particular material is suitable for the sealing task it is designed to do. Details of this and other aspects will be shown in Hall B2 at IFAT, the leading international trade fair for waste disposal and the environment, held in Munich, Germany from April 25 to 29.

Source: Fraunhofer-Gesellschaft

Explore further: Greenland darkening to continue, predicts CCNY expert Marco Tedesco

Related Stories

Reducing energy usage with nano-coatings

Apr 08, 2015

Thermochromic nano-coatings employed appropriately can help reduce energy usage and generate savings. The coatings either absorb heat or permit its reflection, depending on their temperature. Researchers ...

Plastic parts for internal combustion engines

Apr 01, 2015

Efforts to produce lighter vehicles necessarily include engine parts, such as the cylinder casing, which could shed up to 20 percent of its weight if it were made of fiber-reinforced plastic rather than aluminum ...

Simple method of binding pollutants in water

Mar 26, 2015

New types of membrane adsorbers remove unwanted particles from water and also, at the same time, dissolved substances such as the hormonally active bis-phenol A or toxic lead. To do this, researchers at the ...

Recommended for you

DOJ, FBI acknowledge flawed testimony from unit

2 hours ago

The Justice Department and FBI have formally acknowledged that nearly every examiner in the FBI Laboratory's microscopic hair comparison unit gave flawed testimony in almost all trials in which they offered evidence against ...

Germany still has some way to go to 'smart factories'

2 hours ago

Collaborative robots and intelligent machinery may have wowed the crowds at this year's Hannover Messe, but experts see German industry as having some way to go towards incorporating them on factory floors ...

Quantum dot TVs are unveiled at China tech expo

14 hours ago

At this month's China Information Technology Expo (CITE) event, a headline-maker was the launch of quantum dot televisions, by QD Vision and Konka, the consumer electronics company. QD Vision's calling card ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.