Everwide newsletter No.449

Experiment § Graphene thermal conductive potting adhesive

As the power of electronic products continues to increase, the demand for thermal management also keeps growing. This product uses epoxy resin as the base material (thermal conductivity coefficient of 0.2-0.3 W/mK). By adjusting the particle size distribution to achieve the densest packing state, the thermal conductivity coefficient is enhanced. Graphene, a two-dimensional planar material with high thermal conductivity, tends to aggregate due to π-πelectron interactions, resulting in poor dispersion. Adding a small amount of graphene to the resin causes a significant increase in viscosity. To solve this problem, the raw material supplier employs coating technology, where graphene is coated onto spherical alumina, effectively improving graphene dispersion and enhancing the resin's fluidity (Figures 1, 2). The filling ratio of the powder for this material reaches 89%, with a distribution ratio of 86 wt% alumina and 3 wt% alumina@graphene thermal conductive potting adhesive (Figure 3). At 25°C, the viscosity is measured to be around 150,000 to 200,000 cps, making it easy to handle and apply. After curing at 100°C for 50 minutes, the thermal decomposition temperature reaches 398°C, ensuring high-temperature stability. According to ASTM D5470, its thermal conductivity coefficient is greater than 5 W/mK, and its volume resistivity is 2-6 × 10^15 Ω·cm. This product has the characteristics of high thermal conductivity and insulation. ─Author: Mr. Shih Yao-Wei

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Activity § The First Quarter of Everwide News

In the first quarter, we accomplished many fulfilling activities. The Taiwanese farmers' products remain a great choice for gifts to our colleagues, such as the original mushroom box gift and the Asian pear. Supply chain management has also been continuously strengthened, ensuring quality and safety through vendor audits. This year's interns have been very proactive, gaining in-depth knowledge of the factory and showing initiative in their work. We also participated in the scientific event at Jinlun Station’s Science Train, helping students discover more connections between science and daily life. Encouraging colleagues to participate in beach cleanup to support environmental protection and make the beaches cleaner. (Figure 1–5).

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Knowledge § Why do thermoplastic plastics need a certain molecular weight to possess strength?

Thermoplastic plastics have a linear structure and can flow at high temperatures, solidifying and fixing when cooled. The strength of this type of plastic mainly relies on the entanglement of molecular chains, which can be seen as "physical crosslinking." When the molecular weight is low, the molecular chains cannot entangle with each other, and the relationship between melt viscosity and molecular weight is linear. In this case, the plastic has no strength. When the molecular weight is large enough for the molecular chains to entangle, the melt viscosity changes with the molecular weight raised to the power of 3.4. At this point, the plastic has strength.

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Living § Go to Antarctica to see penguins

The day we arrived at "Cuverville Island," it was snowing. We saw quite a few penguins, and even witnessed them walking on the snow. An explorer said, "Wait a moment, let the penguins pass first." Our team members stood on the path, taking pictures of the penguins to our right. Red flags were planted in the snow, and we were to follow the flags. Climbing in the snow was exhausting, so the expedition team designed a Z-shaped route for us. We walked in a straight line between red flags, and when we reached a flag, we turned but couldn’t get too close to the penguins. What would happen if we got too close? There are videos online of penguins charging at humans because they are territorial and will drive away intruding creatures. I said to my 85-year-old father, "It’s steep up ahead. I’ll climb up to look, and you go watch the penguins over there, okay?" He replied, "You go ahead! I’ll walk around by myself." So, I continued to follow the Z-shaped path and climb. The penguins moved one after another, swaying back and forth, and the one at the back suddenly tripped, sliding forward in a dog-paddle style before getting up again. These photos are hard to capture the "Penguin Highway": they, like humans, walk on fixed paths in the snow because the snow is compacted by the penguins' back-and-forth travel, making walking easier. On the way down, "When should we follow in the footsteps of those who came before us, and when should we discard the past and try something new?" From a learning perspective, it's important not to blindly try and error, nor to repeat known mistakes. We must quickly absorb knowledge, for the end of the path paved by those who came before us is the foundation for innovation. Innovation isn’t about abandoning the past, but rather understanding it deeply—both its achievements and its limitations—and starting from there to innovate. ─Author: Dr. Li Mingxu