Posted by jerry wigutow on May 11th, 2018
The following article is found in Specialty Fabrics Review.
“Insulating fabric, or polar bear pelt?”
Polar bears have a thick pelt that keeps them warm in the arctic environment even when temperatures average -40F during the winter months.
The polar bear must be well fed for the “pelt” to retain their body heat. Polar bears that die from starvation still have their “pelt” covering them. The “pelt” is their last level of defense against the cold, but without nourishment to feed their muscles which is where their heat comes from just like humans they do freeze to death.
Scientists at China’s Zheijiang University College of Chemical and Biological Engineering studied the microstructure and thermal insulation qualities of the polar bear’s coat and have developed a fiber that mimics it. The hair of these arctic animals consists of a sponge-like network of hollows (I think they are referring to the hairs being hollow) at the core that seals in the air. When air is static, heat convection cannot take place, reducing the loss of heat and making it a super insulator.
I believe the Chinese are a day late and a dollar short here. In the late 1960’s one company selling fiberfill insulation to skiwear firms started advertising they had a hollow fiberfill product that mimicked the hollow hair that caribou grow. Actually all hair grown on any animal is hollow even the hair grown on humans. So what is so revolutionary to find out that the polar bear hair, coat, pelt; call it what you want is also hollow.
Yes still air (static air) will not move (convection) away from the source; however it will move via conduction which takes place at a slower rate, so long as the heat is continually produced. Yes it is a super insulator for the polar bear so long as the polar bear is alive.
The research team developed a freeze-spinning technique to continuously fabricate a silk fibroin solution into a fiber with an aligned porous microstructure. The biomimetric fibers can be woven into a textile that has remarkable thermal insulation, is breathable and wearable, and offers a promising material for personal thermal management.
Remarkable that they have a “porous microstructure” which I believe is another way of saying they have a hollow fiber. This accomplishment is in 2018 and DuPont had hollow fibers in the late 1960’s. Today almost all fiberfill used for insulation is hollow, even the fiber used to make Lamilite. Every garment you wear has some insulating value, so the same would be true of any garment made with fabric made from these fibers. How about personal thermal management, get to warm just take it off, in that way you are managing your person.
In addition to passively insulating heat loss (I believe they may mean reducing heat loss), the textile could be a wearable heater when “doped” with electro-heating materials such as carbon nanotubes. (Interesting use of the word doped, I guess they mean combined with). The treatment would promote a fast thermal response and uniform heating while maintaining a soft and porous quality for comfort.
This whole paragraph is conjecture. They have no idea if what they are working on will ever work in reality.
Research and development work whether it is done in China or any place else in the world when it is funded by government rarely yields the results that do occur when the work is done by private industry. When people have an incentive to create something that they believe will earn the greater financial rewards.
When it comes to insulations the structure of insulation made from continuous filament fiberfill is as simple as it gets and is so superior to EVERY other form of insulation on the planet those others are not even in the same discussion.
Continuous filament fiber is hollow, continuous filament fiber eliminates radiant heat loss, reduces convective heat loss to almost nothing, reduces conductive heat loss by at minimum 90 percent, and allow evaporation to take place while not experiencing evaporative heat loss. My proof is the performance of all of the Lamilite/Climashield insulated products I make. Literally, virtually, absolutely all of these researchers are looking for a magic bullet when in reality what works best has existed for I just figured out 60 years now; silicone treated continuous filament fiber. Regardless of the success of this product there are people who are trying to make something that they conjure up in their minds that will somehow work. Unfortunately these people and there are lots of them have who have no foundation of knowledge about insulations and how the body works that they can draw from in order to start the process of making an insulating material. If they did they would be using or trying to duplicate continuous filament fiber!
The Chinese University is a day late and a dollar short. Polar bears should be left alone, that way they do fine.
PS Yesterdays article was reprinted from sportstextiles online