Chemical Technology March 2015

Perstorp to launch new high-performance products at ECS 2015

Hybrid nanowires eyed for computers, flexible displays

Leading global specialty chemicals group Perstorp will unveil new products and en- hanced support at the European Coatings Show 2015 as part of its on-going com- mitment to strengthen its offering for the global coatings and resins market. Perstorp’s raw materials enable custom- ers to create coatings systems with high perfor- mance and low environmental impact, for a wide range of decorative and industrial applications used in emerging growth markets such as coatings for electronic parts and materials, printing inks and pre-coating wood. Products making their European Coatings Show debut will include: a new addition to the Capa™ portfolio –Capa™ Lactide 8000 series, partially re- newable polyols for 2 K and 1 K industrial coatings. These new transparent liquid polyols are particularly suitable for production of high performance soft- touch coatings as well as coatings with enhanced adhesion to various substrates, and which require no solvents. The latest extension toPerstorp’sOxymer™range of polycarbonatediols for increasedweatherability of polyurethane dispersions (PUDs) aswell as castable and thermoplastic elastomers will be seen. New Oxymer™ HD types Oxymer™ HD56 and Oxymer™ HD112 are based on 1,6-hexane diol. Charmor™ PM40 Care, which provides the next development step in safe carbon sourceproducts for intumescent systems is another newcomer. It has an “unmatchable environmental profile”, being based on renewable feedstocks. Charmor is a leading car- bon source for intumescent coatings that preserve the integrity of steel structures when temperatures reach around 500 °C in a fire. Perstorp has also invested in new capacity for its Neopentyl Glycol essential building blocks for powder coatings and stoving enamels, demonstrat- ing its long-standing commitment to the Chinese coatings market.

FOCUS ON CORROSION & COATINGS

This graphic depicts a copper nanowire coated with graphene - an ultrathin layer of carbon (Purdue University)

amount of heating. “If the surface is covered with oxide then a lot of the electrical and ther- mal conductive properties of copper are lost,” Mehta said. “This is very important because you want as much current as possible going through these wires to increase speed, but they cannot take too much current because they will melt. But if the copper has good electrical and thermal conductivity you can push more current through it.” Thehybridwires arepromising for transpar- ent and flexible displays because they could be used in sparse numbers, maintaining transparency, and they arebendable. “Copper wires usually aren’t good for these displays because they eventually oxidize and stop working,” Mehta said. “If you can prevent the oxidation, they potentially become a good fit.” Until now it has been difficult to coat cop- per nanowires with graphene because the process requires chemical vapour deposition at temperatures of about 1 000 ºC, which degrades copper thin films and small-dimen- sionwires. The researchers have developed a new process that can be performed at about 650 ºC, preserving the small wires intact, using a procedure called plasma-enhanced chemical vapour deposition. Wires were tested in twowidth sizes: 180nanometres - or more than 500 times thinner than a human hair - and 280 nanometres.

A new process for coating copper nanowires with graphene - an ultrathin layer of carbon – lowers resistance and heating, suggesting potential applications in computer chips and flexible displays. “Highly conductive copper nanowires are essential for efficient data transfer and heat conduction in many applications like high-performance semiconductor chips and transparent displays,” said doctoral student Ruchit Mehta, working with Zhihong Chen, an associateprofessor of electrical and computer engineering at Purdue University. Now, researchers have developed a tech- nique for encapsulating the wires with gra- phene and have shown that the hybrid wires are capable of 15 % faster data transmission while lowering peak temperature by 27 % compared with uncoated copper nanowires. “This is compelling evidence for improved speed and thermal management by adapt- ing the copper-graphene hybrid technology in future silicon chips and flexible electronic applications,” he said. Researchers and industry are trying to create smaller wires to increase the ‘packing density’ of electronic components in chips. However, while smaller wires are needed to increase performance and capacity, scaling down the size of the wires reduces electrical and thermal conductivity, which can lead to overheating and damage. The graphene coat- ing prevents the copper wires from oxidising, preserving low resistance and reducing the

For more information tel +46 435 380 00 or email perstorp@perstorp.com z

Story by Emil Venere, 765-494-4709, venere@purdue.edu  z

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