Today's KNOWLEDGE Share:AEROGEL

Today's KNOWLEDGE Share:

AEROGEL

Aerogel is an emergng technology used to prevent thermal runaway in batteries.

Guinness World Record Achievements of Aerogel:

Lowest density solid: "Solid smoke", more than 90% of the volume of aerogel is air, and the density is as low as 0.12 mg/cm3, which is about 1/10 of the density of air.

Widest density range: Due to different components and different processes, the density variation range is very wide, adjustable within the range of 0.0012-0.500 g/m3 enabling wide commercial applications.

Smallest aperture: The pore size is generally around 50nm and the smallest pore size can even be less than 1nm. The main reason is for its strong isolation ability.

Highest porosity: The porosity is as high as 99.9%, so the specific surface area is particularly large.

Lowest dielectric constant: Dielectric constant is less than 1.003, which is a good dielectric material, which can reduce the leakage current of integrated circuits, reduce the capacitance effect between the wires, and reduce the heating of the integrated circuit.

Lowest loss tangent: It has a low loss tangent of 10-4, so its wave transmittance is good, making it a good wave-transmitting material.

Lowest Young's Modulus: The Young's modulus (the ability to resist deformation) is less than 106 N/m2, which is 4 orders of magnitude lower than the corresponding non-porous glassy materials.

Lowest thermal conductivity: Thermal conductivity can be lower than 0.016 W/(m·k). The radiation heat conduction of silica aerogel can be further reduced by doping. Thermal conductivity of carbon-doped aerogel at room temperature and pressure can be as low as 0.013 W/(m·k), which is the solid material with the lowest thermal conductivity at present.

Widest compressive modulus: Compressive modulus, which can be varied within 6 orders of magnitude, determines the density tunability of the aerogel material, thereby enabling functional applications with different density requirements.

Lowest speed of sound: The variable range of acoustic impedance is large (103-107 kg/m2·s), and it is an ideal acoustic impedance coupling material for super detectors.

Highest acoustic impedance: Acoustic impedance can be as high as 106 kg/m2 s, while the acoustic resistance of air is 400 kg/m2 s. Aerogels have extremely low longitudinal acoustic propagation rates and a wide range of acoustic resistance with density, so it is an ideal acoustic impedance coupling material.

Lowest refractive index: Due to the extremely high proportion of air in the aerogel, the refractive index can be as low as 1.007, which is very close to the refractive index of air of 1.0.

Source:Brendan Jephcott

Visit MY BLOG http://polymerguru.blogspot.com

#aerogel #technology #batteries #wave #transmitters

Today's KNOWLEDGE Share:FOUNTAIN FLOW AND FREEZING

Today's KNOWLEDGE Share:

FOUNTAIN FLOW AND FREEZING:

I often get questions in my seminars about molecular orientation in molded specimens.

People often get a bit confused about the layers that could possibly show some degree of molecular orientation, potentially observed as birefringence for transparent grades.

- The very skin is coming directly from the fountain flow and freezing, so it is not very oriented at all since it never experienced much flow in the main direction.

- The "frozen skin" below it is extremely oriented since, by definition, it freezes UNDER FLOW. As a result it is very oriented, almost regardless of the polymer relaxation time / molecular weight.

- Other layers below, approaching the center line can show orientation induced during the second stage of the molding process, the packing phase. This flow stress is active at later times, thus acting on deeper layers.

- Although thick parts should show little orientation below the frozen skin, high molecular weight materials could still show significant orientation if their relaxation time exceeds the overall cooling time of the specimen. Try molding a blow-molding grade and see for yourself !

- Strictly speaking, the very center line should not show orientation since the shear-rate and shear-stresses are zero at all times during the process.

A quick test to assess the degree of average orientation (which really works perfectly for opaque crystalline polymers) is to examine the degree of (post-)shrinkage in the flow direction when annealing the specimen at the appropriate temperature (just below Tg for amorphous, just below Tm essentially for semi-crystalline).

Orientation is not strictly speaking a "residual stress" given the weakness of the entropic force at play. Upon reheating or softening with a solvent (PVC and acetone for instance reveal flow induced orientation), such tiny force can produce this significant post-shrinkage.

Source:VITO LEO

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#plastics #injectionmolding #amorphous #semicrystalline #relaxationtime #molecularorientation #freezing #orientation #flow

Today's KNOWLEDGE Share:Bioluminescent:

Today's KNOWLEDGE Share:

Bioluminescent:
My passion for innovation and the sportswear industry has led me to envision a near future where bioluminescence is applied to sportswear fabrics.

Inspired by this idea, I have created with the help of AI a night-time running jacket that ensures visibility and protection when darkness falls.

BioGlow™
Redefining night-time running with our new revolutionary bioluminescent running jacket
Introducing the ultimate companion for night-time runners. Our revolutionary running jacket is designed to elevate your safety and style.

Embrace the power of bioluminescence with our innovative application that illuminates the jacket, ensuring visibility and protection when darkness falls.
This cutting-edge technology uses natural light-emitting organisms to create a captivating glow, making you instantly recognizable to drivers even in the darkest of nights. Crafted with precision and performance in mind, our running jacket combines waterproof materials and breathable fabrics, allowing you to conquer any weather conditions without compromising on comfort.
With its sleek and sporty design, this jacket embodies both functionality and fashion, empowering you to shine bright as you pursue your running goals. Stay safe, stay visible, and enjoy running!

Currently, bioluminescent clothing is not widely available on the market.
However, scientists are conducting research to harness bioluminescence for technological applications, including clothing. There have been some demonstrations of prototype garments that utilize bioluminescent materials, such as fabrics impregnated with fluorescent proteins derived from jellyfish or genetically modified bacteria. These materials can be activated by a source of energy, such as pressure or movement, to produce a faint light.

Despite promising discoveries in research, bioluminescent clothing is not yet a practical or widespread option for the average consumer. There are several technical challenges to overcome, such as the long-term stability of bioluminescent materials, their durability, and safety for human use. Additionally, there are ethical considerations regarding the use of living or engineered organisms for the production of bioluminescent materials.

However, with further developments in research and technology, it may be possible to see the emergence of bioluminescent clothing in the future. It could lead to unique and fascinating creations that naturally light up, offering new creative possibilities in the fashion industry.

Source:Ignacio Valentini
Visit MY BLOG https://lnkd.in/fcSeK9e

#innovation #creative #textileindustry #fashiontrends  #fashion #bioluminiscence #sportswear #fashionindustry #research #conceptdesign #clothing 

Today's KNOWLEDGE Share:SODIUM-ION BATTERY INDUSTRY

Today's KNOWLEDGE Share:

SODIUM-ION BATTERY INDUSTRY

The working principle of a sodium-ion battery is similar to that of the lithium-ion battery following an intercalation-based “rocking chair” mechanism, whereby the embedding (intercalation) and stripping (deintercalation) process of sodium-ion between positive (cathode) and negative (anode) electrodes, which are parted by the separator soaked in electrolyte, realises charge and discharge.

In terms of product performance, sodium-ion batteries advantages include good safety, rate performance, and low temperature performance, but have the disadvantages of poor cycle life and its energy density is comparable to only that of conventional lithium iron phosphate batteries.

Due to the comparable energy density, excellent rate performance and significant cost advantage of sodium-ion batteries, they are considered cost-effective and will be applied to large-scale energy storage systems, two-wheeler electric vehicles and low-speed electric vehicles and are expected to complement and eventually replace lithium-ion batteries in the future. Large-scale energy storage systems mainly include wind power plants, solar power plants and household energy storage systems while low-speed electric vehicles mainly include logistics vehicles, agricultural vehicles, electric vehicles, electric buses and electric boats.

Source"Brendan Jephcott

Visit MY BLOG http://polymerguru.blogspot.com

#evbatteries #sodiumionbattery #ev

Today's KNOWLEDGE share:Wind turbine blade damage:

Today's KNOWLEDGE share:

Wind turbine blade damage:

As we all know, erosion can be a huge problem when dealing with wind turbine blades... The thing is, generally, wind turbines are so far from us that we almost never see how erosion can affect them! Unless... You get quite close to it! 

To combat leading edge erosion, wind turbine operators employ maintenance and repair techniques that ensure the blades maintain optimal performance. When signs of erosion become apparent, proactive measures are taken to restore the blades to their original condition and preserve their efficiency. 

However, in this case, it seems that no precautions were taken... I mean, just look at how bad it got! 

In this case, we can say that shit is slowly, but constantly hitting the ''fan''.

Guess a more durable leading-edge protection material would be handy! 

Source: Alexsandro Pedro da Silva - GWO/ #managingcomposites

Visit MY BLOG http://polymerguru.blogspot.com

#composites #windblade #windenergy #windturbine #erosion #maintenance

Today's KNOWLEDGE Share:Mold Coatings:

Today's KNOWLEDGE Share:

Mold Coatings:

If you browse through the documentation of mold coating suppliers (PVD, WS2, others) they all claim better flow (i.e. lower pressure to fill) after coating the mold with just a few microns of their coating (typically a metal oxide, salt, or some other complex).

These layers do impart lubricity indeed, which is great to help ejection of the molded part.

But in Injection Molding there is no slip against the wall. Actually if/when you get some, you invariably end up with a surface defect !

So improved lubricity, as claimed by suppliers, DOES NOT explain better flow.

What is most probably happening is that the added layer, which is not "metallic" has always a lower Thermal Effusivity.

Effusivity is the material property that controls interfacial temperature.

So what we really have here is a slightly thinner frozen skin resulting from a somewhat higher interfacial temperature between plastic and coated steel. In a flat flow, effective available thickness for flow has a quadratic effect on pressure drop. For a runner/gate (cylinder) it is even a cubic dependence.

So the smallest reduction in the frozen layer, especially for thin cavities, can immediately explain the observed 5-10 % decrease in pressure drop (or, conversely, increase in flow length).

Source:VITO LEO

Visit MY BLOG http://polymerguru.blogspot.com

#plastics #injectionmolding #runner #gate #moldflow #coatings #lubrication #polymerscience #moldfilling #frozen #lowcoeffient

CAI Performance Additives Unveils Epoxy Chain Extender for Virgin & Recycled Materials

CAI Performance Additives announces the launch of the latest product, ST-CE37, a polymeric epoxy functional chain extender for both virgin and recycled materials needing help to meet performance and process requirements.

Improving Viscosity Characteristics of Polymers:

This innovative additive significantly improves viscosity characteristics, mechanical properties, and inhibits the hydrolysis of polymers such as PA, PET and other polycondensation resins.

ST-CE37 chemistry beats competitors given its innovative reactive side chain, so the chain extension is much easier for the host polymers to ‘find’ during compounding.

The commitment to provide innovative solutions for the plastics industry, and the introduction of ST-CE37 is just one example of their dedication to deliver superior products that meet the evolving needs of the customers.

Source: CAI Performance Additives/Polymer-additives.specialchem.com

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#polymers #plasticsindustry #specialtychemicals #epoxychainextender #recycledplastic