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Scientists from Nanyang Technological College, Singapore (NTU Singapore), have developed a brand new strategy to remedy adhesives utilizing a magnetic discipline.
Standard adhesives like epoxy that are used to bond plastic, ceramics and wooden are sometimes designed to remedy utilizing moisture, warmth or gentle. They usually require particular curing temperatures, starting from room temperature as much as 80 levels Celsius.
The curing course of is critical to cross-link and bond the glue with the 2 secured surfaces because the glue crystallises and hardens to realize its ultimate power.
NTU’s new “magnetocuring” glue can remedy by passing it via a magnetic discipline. That is very helpful in sure environmental situations the place present adhesives don’t work effectively. Additionally, when the adhesive is sandwiched between insulating materials like rubber or wooden, conventional activators like warmth, gentle and air can not simply attain the adhesive.
Merchandise comparable to composite bike frames, helmets and golf golf equipment, are at present made with two-part epoxy adhesives, the place a resin and a hardener are blended and the response begins instantly.
For producers of carbon fibre — skinny ribbons of carbon glued collectively layer by layer — and makers of sports activities gear involving carbon fibre, their factories use massive, excessive temperature ovens to remedy the epoxy glue over many hours. This energy-intensive curing course of is the principle cause for the excessive value of carbon fibre.
The brand new “magnetocuring” adhesive is made by combining a typical commercially out there epoxy adhesive with specifically tailor-made magnetic nanoparticles made by the NTU scientists. It doesn’t should be blended with any hardener or accelerator, in contrast to two-component adhesives (which has two liquids that have to be blended earlier than use), making it simple to fabricate and apply.
It bonds the supplies when it’s activated by passing via a magnetic discipline, which is well generated by a small electromagnetic machine. This makes use of much less power than a big standard oven.
For instance, one gram of magnetocuring adhesive may be simply cured by a 200-Watt electromagnetic machine in 5 minutes (consuming 16.6 Watt Hours). That is 120 occasions much less power wanted than a standard 2000-Watt oven which takes an hour (consuming 2000 Watt Hours) to remedy standard epoxy.
Developed by Professor Raju V. Ramanujan, Affiliate Professor Terry Steele and Dr Richa Chaudhary from the NTU Faculty of Supplies Science and Engineering, the findings had been revealed within the scientific journal Utilized Supplies In the present day and supply potential utility in a variety of fields.
This contains high-end sports activities gear, automotive merchandise, electronics, power, aerospace and medical manufacturing processes. Laboratory assessments have proven that the brand new adhesive has a power as much as 7 megapascals, on par with lots of the epoxy adhesives in the marketplace.
Assoc Prof Steele, an skilled in varied sorts of superior adhesives, defined: “Our key growth is a strategy to remedy adhesives inside minutes of publicity to a magnetic discipline, whereas stopping overheating of the surfaces to which they’re utilized. That is vital as some surfaces that we need to be part of are extraordinarily heat-sensitive, comparable to versatile electronics and biodegradable plastics.”
How “magnetocuring” glue works
The brand new adhesive is made from two foremost parts — a commercially out there epoxy that’s cured via warmth, and oxide nanoparticles made out of a chemical mixture together with manganese, zinc and iron (MnxZn1-xFe2O4).
These nanoparticles are designed to warmth up when electromagnetic power is handed via them, activating the curing course of. The utmost temperature and fee of heating may be managed by these particular nanoparticles, eliminating overheating and hotspot formation.
With out the necessity for big industrial ovens, the activation of the glue has a smaller footprint in area and power consumption phrases. The power effectivity within the curing course of is essential for inexperienced manufacturing, the place merchandise are made at decrease temperatures, and use much less power for heating and cooling.
For example, producers of sports activities footwear usually have problem heating up the adhesives in between the rubber soles and the higher half of the shoe, as rubber is a warmth insulator and resists warmth transmission to the traditional epoxy glue. An oven is required to warmth up the shoe over a very long time earlier than the warmth can attain the glue.
Utilizing magnetic-field activated glue bypasses this problem, by immediately activating the curing course of solely within the glue.
The alternating magnetic discipline can be embedded on the backside of conveyor belt techniques, so merchandise with pre-applied glue may be cured once they go via the magnetic discipline.
Bettering manufacturing effectivity
Prof Raju Ramanujan, who’s internationally recognised for his advances in magnetic supplies, collectively led the venture and predicts that the expertise might improve the effectivity of producing the place adhesive joints are wanted.
“Our temperature-controlled magnetic nanoparticles are designed to be blended with current one-pot adhesive formulations, so lots of the epoxy-based adhesives in the marketplace could possibly be transformed into magnetic field-activated glue,” Prof Ramanujan mentioned.
“The pace and temperature of curing may be adjusted, so producers of current merchandise might redesign or enhance their current manufacturing strategies. For instance, as an alternative of making use of glue and curing it half by half in a standard meeting line, the brand new course of could possibly be to pre-apply glue on all of the components after which remedy them as they transfer alongside the conveyor chain. With out ovens, it could result in a lot much less downtime and extra environment friendly manufacturing.”
First writer of the research, Dr Richa Chaudhary mentioned, “The curing of our newly-developed magnetocuring adhesive takes solely a number of minutes as an alternative of hours, and but is ready to safe surfaces with excessive power bonds, which is of appreciable curiosity within the sports activities, medical, automotive and aerospace industries. This environment friendly course of may also result in value financial savings because the area and power wanted for standard warmth curing are diminished considerably.”
This three-year venture was supported by the Company for Science, Expertise and Analysis (A?STAR).
Earlier work on heat-activated glue used an electrical present flowing via a coil, generally known as induction-curing, the place the glue is heated and cured from outdoors. Nevertheless, its drawbacks embody overheating of the surfaces and uneven bonding as a result of hotspot formation inside the adhesive.
Shifting ahead, the crew hopes to have interaction adhesive producers to collaborate on commercialising their expertise. They’ve filed a patent via NTUitive, the college’s innovation and enterprise firm. They’ve already obtained curiosity of their analysis from sporting items producers.
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