Changing the chemical structure of 3D printing object with LED lamp in Massachusetts Institute of Technology

Recently, chemists at the Massachusetts Institute of Technology have developed a new 3D printing technology that allows changes in the chemical structure of the printed objects and the chemical connections of multiple 3D printing objects. It is reported that this technology can greatly expand the complexity of objects created using 3D printing.

3D printing is an incredible manufacturing technology that can create a lot of things from many kinds of materials. But technology has limitations: on the one hand, 3D printing objects are generally not changed. They can be processed, polished and even processed into smaller shapes, but the chemical structure of the 3D printing polymer objects is fixed. But now, a group of chemical experts at the Massachusetts Institute of Technology have developed a new technology to change the chemical structure of 3D printing objects, whose chemical components can be changed after printing, which allows multiple 3D printing objects to be merged together.

Now, the team at the Massachusetts Institute of Technology has published their research in the recent ACS Central Science Journal. Jeremiah Johnson, an associate professor of Firmenich career development in chemistry at the Massachusetts Institute of Technology and a senior author of the research paper, explains to MIT staff how to use this new technology to increase the complexity of 3D printing objects. "The idea is that you can print a material and take this material, use light to turn material into something, or further increase material," he said.

Stereolithography, 3D Systems first used liquid resin 3D printing technology, and Formlabs and other companies to promote the liquid resin 3D printing technology is one of the more accurate technology for ordinary users of 3D printing technology. The stereolithography 3D printer irradiates a series of bright projections onto a barrel of liquid resin, which is cured (hardened) in response to light and forms a solid object in a layer by layer. By combining stereolithography and combining it with the technology called "active polymerization", Johnson and its team have been able to create a 3D print material that can stop its growth and then restart at a later time point.

As early as 2013, researchers at the Massachusetts Institute of Technology found that by using ultraviolet light, they could break the polymer of the 3D printing structure and create a reactive molecule called "free radicals". The free radicals can then be bound to the surrounding new monomers and incorporate them into the raw material. Johnson said, "the advantage here is that you can turn on the lights, they grow, you turn off the lights, and they stop. In principle, you can repeat it indefinitely, and they can continue to grow. "

Unfortunately, the attempt to control the free radicals has proved to be very difficult, with excessive damage to the 3D printing material. But chemical experts at the Massachusetts Institute of Technology have come up with another way: blue light from LED. For example, the polymer used in 3D printing contains chemical group TTC, which can be activated by an organic catalyst that is opened by light. When the blue light comes from LED, the TTC extends along with the new monomer. As these monomers are added evenly, they provide new properties for the material. "We can take macro material and grow as we want it," Johnson said.

By using LED - ray technology, researchers at the Massachusetts Institute of Technology found that they could change the properties of the structure of 3D printing objects, including their stiffness and hydrophobicity (the extent of their rejection or absorption of water). By adding a single type of monomer, a chemist can also make the material respond to temperature expansion or contraction. In addition, they can melt two 3D printing objects by shooting light in the interconnected region. "This particular process can be used to create a huge, chemically stable 3D printing structure, with unprecedented complexity," the researchers said.

Now, one of the obstacles that researchers are facing is to keep the experimental environment oxygen free, because the organic catalyst used in the process does not work in the presence of oxygen. However, this group of tests can catalyze other catalysts similar to polymerization in an aerobic environment.

By merging the fields of polymer science and material science, researchers at the Massachusetts Institute of Technology have opened several exciting opportunities for advanced 3D printing.

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