Imagine a tire that could heal after being punctured or a rubber band that never snapped.
Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new type of rubber that is as tough as natural rubber but can also self-heal.
The research is published in Advanced Materials.
Self-healing materials aren’t new — researchers at SEAS have developed self-healing hydrogels, which rely on water to incorporate reversible bonds that can promote healing. However, engineering self-healing properties in dry materials — such as rubber — has proven more challenging. That is because rubber is made of polymers often connected by permanent, covalent bonds. While these bonds are incredibly strong, they will never reconnect once broken.
In order to make a rubber self-healable, the team needed to make the bonds connecting the polymers reversible, so that the bonds could break and reform.
“Previous research used reversible hydrogen bonds to connect polymers to form a rubber but reversible bonds are intrinsically weaker than covalent bonds,” said Li-Heng Cai, a postdoctoral fellow at SEAS and corresponding author of the paper. “This raised the question, can we make something tough but can still self-heal?”
Cai, along with Jinrong Wu, a visiting professor from Sichuan University, China, and senior author David A. Weitz, Mallinckrodt Professor of Physics and Applied Physics, developed a hybrid rubber with both covalent and reversible bonds.
The concept of mixing both covalent and reversible bonds to make a tough, self-healing rubber was proposed in theory by Cai but never shown experimentally because covalent and reversible bonds don’t like to mix.
“These two types of bonds are intrinsically immiscible, like oil and water,” said Cai.
So, the researchers developed a molecular rope to tie these two types of bonds together. This rope, called randomly branched polymers, allows two previously unmixable bonds to be mixed homogeneously on a molecular scale. In doing so, they were able to create a transparent, tough, self-healing rubber.
Typical rubber tends to crack at certain stress point when force is applied. When stretched, hybrid rubber develops so-called crazes throughout the material, a feature similar to cracks but connected by fibrous strands. These crazes redistribute the stress, so there is no localized point of stress that can cause catastrophic failure. When the stress is released, the material snaps back to its original form and the crazes heal.
Harvard’s Office of Technology Development has filed a patent application for the technology and is actively seeking commercialization opportunities.
The self-healing ability is appealing for a wide variety of rubber products.
“Imagine that we could use this material as one of the components to make a rubber tire,” said Wu. “If you have a cut through the tire, this tire wouldn’t have to be replaced right away. Instead, it would self-heal while driving enough to give you leeway to avoid dramatic damage.”
“There is still a lot more to do,” said Weitz. “For materials science, it is not fully understood why this hybrid rubber exhibits crazes when stretched. For engineering, the applications of the hybrid rubber that take advantage of its exceptional combination of optical transparency, toughness, and self-healing ability remain to be explored. Moreover, the concept of using molecular design to mix covalent and reversible bonds to create a homogenous hybrid elastomer is quite general and should enable development of tough, self-healing polymers of practical usage.”
The Latest on: Self-healing rubber
- The best iPhone 11 cases and coverson February 20, 2020 at 2:24 am
The ridged pattern enhances grip in a major way, but just in case it does slip from your grasp, the hard shell with shock-absorbent rubber inside ... it’s capable of self-healing small scratches ...
- Researchers developed soft, self-healing skin for robotson February 19, 2020 at 4:00 pm
Mashable is a global, multi-platform media and entertainment company. Powered by its own proprietary technology, Mashable is the go-to source for tech, digital culture and entertainment content ...
- Biological material could be 3D printed to create self-healing shoeson February 16, 2020 at 4:00 pm
Even the most advanced rubber-soled shoe can’t compare to the concept being proposed by London designer and researcher Shamees Aden. These shoes would be 3D printed from synthetic biological ...
- What’s faster, tubes or tubeless? The answer remains the same: it dependson February 11, 2020 at 4:59 pm
The latest crop of high-performance tubeless tires is often considered to be better yet (fitment hassles aside), since there’s no rubber inner tube migrating around inside the casing, and liquid latex ...
- Global Self-Healing Polymer Market Top Key players, Regions, Type and Application Outlook upto 2020 to 2025on February 9, 2020 at 4:00 pm
Eon Market Research in a report titled, "Self-Healing Polymer Market - Global Industry Analysis, Size, Share, Growth, Trends, and Forecast 2020 - 2025", offers a complete 360 degree overview of ...
- Dura-Bloc Ballistic Rubberon January 31, 2020 at 4:00 pm
The patented, cold-molded rubber composite is designed to encapsulate pistol and rifle ammunition up to 7.62 caliber. The self-healing properties of the rubber seal the bullet’s path after the ...
- Meggitt Training Systems to Demonstrate Export-Friendly FATS® 100MIL Virtual Simulator at SimTEX 2018on January 30, 2020 at 4:00 pm
Finally, the company debuted its Live-Fire Screen that brings all the benefits of virtual training to an indoor shooting range or shoot house, thanks to the use of a self-healing rubber screen ...
- Rubber Adhesives and Sealants Supplierson December 20, 2019 at 3:41 am
RG-2400® FAMILY A Family of Gel products which stop existing corrosion, or prevent corrosion on new piping systems, tanks, valves, vessels, any ferrous surface. Stops CUI. The ammonia systems friend.
- Self-Healing Cutting Matson April 4, 2019 at 4:41 am
Self-healing cutting mats work by using a type of rubber that undergoes a specific and very useful form of transformation when enough pressure is applied. Once the pressure crosses a certain point ...
- New product range and rural market to help achieve market leadership says Satish Sharma, Apollo Tyreson January 28, 2019 at 12:40 am
De-proteinized Natural Rubber, Silane Modified Clays, New Generation Silanised Silicas, Self Healing tyre etc., all focusing majorly on the three fundamental areas of tyre performance: lowering ...
via Google News and Bing News