Blacksburg, Virginia - Virginia Polytechnic Institute (Virginia Tech) researchers have developed a process to 3D print styrene butadiene (SBR) latex rubber, unlocking the ability to print a variety of elastic materials with complex geometric shapes.
For the new process, researchers chemically modified liquid latexes to make them printable through a ‘vat photopolymerisation’ (VP) technology, which uses UV light to cure or harden a viscous resin into specific shapes or form, said Virginia Tech in a 13 July statement.
Polymeric colloids (latexes) have high molecular weight and are not amenable to VP due to concomitant high solution and melt viscosities,
To maintain the stability of “extremely fragile” liquid rubber, macromolecular science and engineering student Phil Scott decided to build a “scaffold, similar to those used in building construction, around the latex particles to hold them in place.”
This way, the latex can maintain its structure, while photoinitiators and other compounds could be added to the latex to enable 3D printing with ultraviolet (UV) light.
To correctly print the resin, the researchers chose to use vat photopolymerisation, and custom built a printer that specifically scans UV light across a large area. To avoid scattering latex particles, a camera was embedded onto the printer to capture an image of each vat of latex resin.
With custom algorithm, the machine is able to "see" the UV light's interaction on the resin surface and then automatically adjusts the printing parameters to avoid the resin scattering and to cure just the intended shape.
The new development is claimed to help increase the use of latex rubber for a variety of applications, including soft robotics, medical devices, or shock absorbers.
According to Virginia Tech, this project is a joint collaboration between institute and Michelin North America via a National Science Foundation award, which supports teamed research between academia and industry.
Details of the initial results of the project has been published in ACS Applied Materials & Interfaces.