Mechanical strength - Page 5

Scientists at the University of Vienna in Austria have managed to synthesize carbyne for the first time. Carbyne has been theorized in the past, and said to be stronger than graphene and posses other intriguing properties. However, this is the first time that a stable form was actually made.

Creating a stable form was technically difficult because carbyne is composed of a long one-dimensional chain of carbon atoms linked one to the other. To do this, the scientists took two sheets of graphene and rolled them together and then used this stable superstructure to fashion the carbyne. The new structure is 6,400 atoms long and the material's potential applications will need to be explored.

Researchers at the US Department of Energy's Lawrence Berkeley National Laboratory have found that polycrystalline graphene has quite low toughness, or resistance to fracture, despite having very high strength. 

The researchers say that while the extremely high strength is impressive, it can't necessarily be utilized unless it has resistance to fracture. The senior scientist in the Materials Sciences Division of Berkeley Lab developed a statistical model for the toughness of polycrystalline graphene to better understand and predict failure in the material. This mathematical model found that the strength varies with the grain size up to a certain extent, but most importantly it defined graphene's fracture resistance. 

Sunvault Energy and Edison Power Company announced that it recently conducted a number of tests on its graphene reinforced plastic technology. Sunvault has created a Graphene Reinforced Plastic that is cost effective and with potential uses that could change the landscape of plastics utilization. This revolutionary material can give products increased endurance but with the weight and simplicity of plastic. In addition to the material's many consumer advantages, it also has some protective attributes that are truly impressive.

Two video presentations were made, the first demonstrated the ability of the graphene reinforced plastic to stop a collection of 22 caliber and 45 caliber bullets, before demonstrating in the second video presentation the ability to stop the most commonly faced weapon of aggression in the military: the AK47.

A collaboration between researchers from Cardiff University and Haydale conducted a study focused on component-scale hierarchical composites using nanocarbons, mainly graphene and CNTs. The team's main aim was to explore techniques for component-scale manufacture of hierarchical composites by liquid infusion.

A plasma process, developed by Haydale, was adopted for controllable functionalization of large batches of nanocarbons (100s of grams) prior to mixing with epoxy resin. A rheological study indicated that filler morphology, functionalization and fill weight all have an effect on epoxy resin viscosity. Using these developed nanocomposite resins, a resin infusion under flexible tooling (RIFT) technique was developed. Resin flow studies informed an optimum setup that facilitated full wet-out of large area UD carbon fibre laminates and the resulting materials showed significant improvements in mechanical properties, demonstrating up to ~50% increase in compression after impact (CAI) properties.

Scientists at Northwestern University have found how graphene oxide's inherent defects may present an interesting mechanical property. It seems that graphene oxide exhibits remarkable plastic deformation before breaking; While graphene is very strong, it can still break suddenly. It was found that graphene oxide, however, will deform first before eventually breaking.

The researchers used an experimentation and modeling approach to examine the mechanics of GO at the atomic level. Their discovery could potentially unlock the secret to successfully scaling up graphene oxide, an area that has been limited because its building blocks have not been well understood.

Vittoria Industries recently declared plans to launch a full range of graphene-enhanced road race and MTB tires around next September. The company also won the IDTechEx printed electronics europe 2015 award for "best commercialization", for using graphene in their bicycle wheels and tires. The company used pure and high grade graphene of 3 to 7 layers from Directa Plus.

The Vittoria Group president and founder stated that the company was successful with both existing products, as the carbon wheels show a dramatic improvement of heat dissipation and significant increased material strength and the tires have a much lower rolling resistance whilst improving grip and traction. He says sales are increasing around the world and some are even used as service wheels in the big professional bike races.

Researchers at Trinity College Dublin invented a rubber-stamp printing method (GraFold) to introduce waves into graphene, in a simple and large-scale way. The printing process is done using computer modelling to show the behavior of the graphene films on the stamp and substrate, and the wavy graphene can be printed onto any type of surface allowing for more sophisticated investigations of its properties.

In this transfer printing process called GraFold, the excess graphene required for forming the folds is induced by using PDMS stamps with a relief pattern such that the graphene tension and adhesion is modulated across the stamp. The graphene is kept on a planar structure at first, then the supporting polymer is dissolved and the graphene layer can ease into the recessed patterns. The graphene inked stamp is then placed gently onto the destination substrate, and then the stamp is peeled away leaving the mechanically patterned graphene film attached to the substrate.

It is well within the realm of gossip, but too interesting to pass on: rumor has it that a Chinese based international company called DJI is planning to come out with a drone called DJI Inspire Graphene around March-April 2015.

The multi-rotor aircraft is said to have graphene used in components like frame, arms and props to achieve light-weight and stiffness, but also in the drone's battery, for more capacity, faster loading and longevity. The battery part seems especially hard to believe as graphene batteries have not yet been commercially used.

Researchers from the Indian Institute of Science (IISc) developed a new shock absorbor made from graphene foam. The foam's load bearing capacity is very high, and when combined with PDMS it is very flexible and has an even higher load-bearing capacity - in fact six times higher than the bare graphene foam. The researchers say this can be used for mobile devices.

The GF-PDMS composite is reusable - it can withstand several cycles of operation without deformation. The material also features excellent thermal and electrical conductivity. The GF-PDMS is very light - its density is only 0.54 grams per cubic cm (iron has a density of 7.87 g/cm³, for example).

International wheel producer Vittoria released a new range of bicycle race wheels that are built from graphene-enhanced composite materials. The new wheels (called Qurano) are the best wheels offered by Vittoria, and they say these are the fastest wheels in the world - all thanks to graphene.

The company explains that adding graphene to their carbon-fiber matrix built wheel rim improved the material properties by 10-30%. The graphene reduces temperature build-up, it increases spoke-hole strength and improves the lateral stiffness. Vittoria tells us that even though the Qurano wheels outperform their previous carbon-fiber wheels, they are priced the same.