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86 DESIGN007 MAGAZINE I APRIL 2022 tioning of a thermal paste over time. In other words, a poorly formulated paste can migrate over time and reduce the efficiency. ermally conductive resins can be used as an alternative solution to "keep things cool." Such resins also provide lots of other value- added benefits such as mechanical protection. If protecting components from mechanical shock and vibration are a concern, then a ther- mally conductive encapsulation resin is likely to be the best solution as it adds a level of sta- bility that helps to insulate the potted compo- nents against adverse mechanical movements. e arch enemy of electrical and electronic devices is the dreaded "moisture"; besides producing short-circuits moisture also causes corrosion, which leads to premature deterio- ration of components. You might also need to protect electrical or electronic components from encountering chemicals, including acids, alkalis, solvents, and other substances that pose a threat to delicate circuits and compo- nents. Encapsulating with a thermally con- ductive resin will help to ruggedize against all these harsh external factors. Lastly, it's worth citing that, aside from providing all the protec- tions listed above, opaque potting and encap- sulation resins also conceal what lies beneath. is could provide an effective foil against counterfeiters or those wishing to copy a cir- cuit layout, helping you to protect your intel- lectual property. 2. Which chemistry (if any) lends itself to thermal conductivity, i.e., epoxy, polyurethane, or silicone? Epoxy, polyurethane, and silicone chemis- tries are all capable of producing resins with high thermal conductivity values. e thermal conductivity is dictated by the type of filler used, particle size, particle size distribution, and morphology. When these four factors are carefully considered as part of the product design, you get encapsulation resins with high thermal conductivity values, irrespective of the reactive chemistry that hold the filler in place. One of our products provides the highest level of thermal conductivity combined with environmental protection afforded from the encapsulation process. is highly-filled epoxy resin possesses very high thermal conductiv- ity, 1.54 W/m.K. ermal conductivity, mea- sured in W/m.K, represents a material's abil- ity to conduct heat. Bulk thermal conductivity values give a good indication of the level of heat transfer expected, allowing for comparison between different materials. We utilise a mod- ified transient plane source (MTPS) method, amongst others, to provide accurate compari- sons of bulk thermal conductivity. Note there are different methods to determine thermal conductivity so remember that when compar- ing datasheets from different suppliers. 3. Apart from the obvious assumed benefit to the environment, what other benefits could be expected from bio-based resins and are there more to come? ere are many observed benefits to using bio-based resins aside from the obvious envi- ronmental credentials. Research has shown that quality of performance can be significantly improved. Resins where the reactive compo- nent is derived from biobased feedstocks can have improved performance in harsh envi- ronments, particularly their electrical insula- tion in hot, humid conditions, as compared to reactive components derived from crude oil. Comparing biogenic powders with mineral rock powders shows that bio-sources can be used to effectively dissipate heat away from high power density devices and they show improved protection in underwater environ- ments. ere can also be health and safety benefits. For example, the curing agent or hardener typ- ically used for polyurethanes is based on meth- ylene diphenyl diisocyanate (MDI); crude oil is a crucial raw material for the synthesis of MDI. It is a respiratory sensitiser and harm- ful if vapours are inhaled, from a H&S label perspective it contains the "exploding chest"