UTSA’s chemistry department has made discoveries that could potentially change manufactures’ production of plastics and petroleum.
Over 90 percent of the everyday products people use have a form of plastic in them. Plastic is made from oil deep underground that has been sitting for billions of years. The oil must be extracted, changed and formed to make petroleum-based products like plastic. Crude oil is transported by trucks or tankers to a refinery where the oil is then broken down into a variety of components like liquids and gas.
In addition to oil, plastic requires natural resources like water and energy. The water produces steam, which is needed to break apart the molecules used to form plastic. This way of separating is very expensive and requires a lot of energy.
UTSA’s chemistry department discovered a way to change the plastic production process. Lead researchers and post-doctoral students Libo Li and Ruibiao Lin expressed that they have always had a passion for chemistry.
“Ever since I was in middle school I always had a passion for chemistry and was fascinated seeing crystals under microscopes,” Li said. “During high school, my curiosity in seeing the structures of atoms got me interested in my current career,” Lin said.
Both of these students were under the guidance of professor Banglin Chen, dean’s distinguished chair professor of chemistry, had a hand in discovering a filtering material that may reduce the environmental cost of manufacturing plastic.
The researchers used a new framework to harvest the major form of ingredients that help form plastic. This new style of harvesting the chemical bonds cuts down on a lot of time and energy that is usually consumed in the process. The material used is a metal-organic framework (MOF), a class of substances used to separate individual hydrocarbons from organic molecules that are produced during the oil refining process. The chemistry team showed that a modification to a well-studied MOF enables it to separate purified ethylene out of a mixture with ethane.
Polyethylene – the most widely used form of plastic – is created from ethylene, one of the many hydrocarbon molecules found in crude oil. Ethylene must be highly purified. If it is not purified it will not work. The current available technology for purifying ethylene from all the other chemical bonds is a highly taxing process that requires cooling down the crude oil to less than 100 degrees below zero Celsius.
The team believed that to break the bonds in the molecule, the compound would have to first attract the molecule. The team used a MOF labeled under MOF-74 to test their studies on. When they modified MOF-74’s shell to contain a structure that resembled the compound, it turned out the molecule it attracted from their mixture was ethane.
“Once we got the organic compounds of the MOF we can use it as a starting point, mix it with certain metals to get the product of MOF,” Li said.
These products would form crystal-like structures which create new materials. One can now extract the structure information from these crystals that are produced.
The team would later use a technique called neutron diffraction. Neutron diffraction is a form of elastic scattering where the neutrons exiting the experiment have more or less the same energy as the incident neutrons. The sample to be examined is placed in a beam of thermal or cold neutrons and the intensity pattern around the sample gives information about the structure of the material. This technique showed that the modifications were a success.
Li, Lin and many researchers have been studying for years to find a more effective way to modify the bonds. These students were passionate about their work and encourage future “designers” like themselves.
“When choosing your path…follow your heart, focus on a field that you find interesting and that brings you joy. Find something you’re truly passionate about which will help you dive deep into your career,” Lin said. “If you want to have excellent work, go and do something different than the norm. Be unique. Think outside the box,” Li said. “The knowledge of one is limited but together is limitless.”