Mechanical strength - Page 9

The UK Technology Strategy Board launched a new collaborative R&D project called NanoSynth with a budget of almost a million GBP ($1.5 million USD) - to develop a synthesis platform for the industry-scale production of graphene-filled epoxy resins for advanced composite applications.

According to the NetComposites, the project coordinator, those graphene epoxy resins will improve current resins and will feature better strength, stiffness, toughness, electrical conductivity and thermal performance. The new resins may prove to have a significant impact on a wide range of markets, including the aerospace and automotive ones. The worldwide yearly market of epoxy resins is estimated at over $15 billion.

Researchers from Columbia demonstrated that a graphene sheet that is stitched together from many small crystalline grains is almost as strong as perfect graphene (this depends on the processing method, though). This solves the question whether graphene defects harm its mechanical strength (some theoretical simulations predict that grain boundaries are strong while other indicated they weaken the graphene sheet).

Commonly used methods for post-processing CVD-grown graphene may indeed weaken the grain boundaries and create a low-strength graphene. But the researchers developed a new transfer process (using a different etchant) that prevents any damage to the graphene.

Xolve signed an agreement with London's NTT Carbon Fiber Group to co-develop products for the aerospace industry. Xolve's graphene will be combined with NTT's epoxy resins and these new materials could be used to produce products such as airplane parts or even an airplane wing. This is just an early research work however, and Xolve says it could take anywhere from 18 months to give years till this is commercialized.

Back in 2010 Xolve raised $2 million, and the company is working to commercialize intellectual property that enables simple room temperature processing of graphene and other nanoparticle composites, solutions and coatings. You can read an interesting interview with the company's R&D VP here.

Researchers from Beijing's Tsinghua University managed to create a nacre-like material that's stronger than natural nacre (and most other composite). Nacre (mother of pearl) is made from calcium carbonate and biopolymers in a brickwork structure that's nearly a thousand times stronger than its component parts.

Natural nacre structure

To create the new material, the researchers started with a hyrdogel made from graphene and fibroin (a silk protein), and then solution coated it and dried it to create parallel graphene plates bound with fibroid, which self assembled to create a brickwork structure.

Researchers from Rice University and Tsinghua University discovered (using theoretical calculations) that defects in graphene can cause it to become weak - if they occur at the grain boundaries of graphene sheets. Those grain boundaries occur because graphene grown in labs (usually using CVD) are not perfect and this creates several "islands" of graphene that merge together. The researchers say that at these points, graphene is about half as strong as perfect graphene.

The atoms on the lines that connect those islands are called grain boundaries - and the atoms at those lines usually bond in five- and seven- atom rings. These are weaker than the normal hexagon rings of graphene. The weakest points are seven-atom rings. These are found at junctions of three islands, and that's where cracks in graphene are most likely to form.

Bluestone Global Tech released two short videos introducing Graphene. The first focuses on the different graphene properties (strength, flexibility, conductivity, etc):

The second video is all about the different graphene applications, such as displays, LEDs, touch screens, batteries, solar cells and conductive wires

A couple of weeks ago HEAD announced their new range of graphene tennis rackets (YouTek Graphene Speed series) - and these rackets are now shipping. HEAD offers five different rackets (the Speed Pro 18/20, Speed MP 16/19, Speed S, Speed REV and PWR Speed), ranging from $170 to $286 (with some cheaper racket for kids).

The graphene rackets apparently uses graphene coating on the shaft to make it stronger and lighter. HEAD says that by the graphene helps distribute the weight better and creates a stronger and better controlled racket.

HEAD unveiled their new YouTek Graphene Speed racket, which apparently uses graphene coating on the shaft to make it stronger and lighter. HEAD says that by the graphene helps distribute the weight better and creates a stronger and better controlled racket. Novak Djokovic, the world's top ranked tennis player will start using the graphene racket soon:

Sadly we don't have any technical details about the graphene used here and who's the supplier. HEAD didn't reveal when they'll release the new racket, and at what price.

Researchers from China's Zhejiang University in Hangzhou demonstrated meter long graphene fibers - made from nano-sized flakes of graphene oxide. These fibers are strong and flexible and can be tied in knots or woven into conductive "mats".

The researchers use web spinning to turn a graphene oxide solution into long (tens of meters!) fibers. They then treated those fibers with chemical reduction to turn them back in strings of graphene. The next stage for their research is to improve the fiber's strength - which currently cannot compete with carbon fibers.

Researchers from the Chinese Academy of Sciences' Institute of Metal Research developed a way to turn graphene into porous three-dimensional 'foam' using chemical vapor deposition (CVD). This 'foam' has extremely high conductivity and when permeated with a siloxane-based polymer it results in a composite that can be twisted, stretched and bent without harming its electrical or mechanical properties.

This foam has a unique network structure, large surface area, very low density and outstanding electrical and mechanical properties. This can find uses in many fields- flexible electronics, fuel cell electrodes, biomedical supports and more.