Scientists from UNAM develop sustainable PET degradation method

Scientists from the National Autonomous University of Mexico (UNAM) developed a new simple and efficient chemical process that seeks to regenerate the monomers (molecules) of PET products , which can take up to 500 years to degrade .

PET is one of the most popular thermoplastics in the industrial sector: It is light, hygienic, transparent, hermetic, resistant, non-toxic , and does not alter the chemical properties of its contents. It is not considered to be a toxic pollutant, but it is not biodegradable .

According to the Ministry of Environment and Natural Resources (SEMARNAT) , 80% of overall domestic waste is reusable or recyclable .

PET containers can be reused for the manufacture of new bottles, which would generate an important ecological impact by saving energy, raw materials, and natural resources.

With a philosophy focused on Green Chemistry, through which chemical processes are applied to reduce or eliminate harmful products, researchers from the School of Higher Studies (FES) Cuautitlán created a project that seeks the depolymerization and recycling of polyethylene terephthalate (PET) through heterogeneous catalysis , an economic process which is less aggressive to the environment.

The scientific team is integrated by José Guillermo Penieres Carrillo, José Guadalupe García Estrada and Luis Antonio Martínez Arellano .

According to information from UNAM Global , the process to achieve degradation began when a PET flake was added to a flask before the catalyst was added. The mixture was subject to thermal heating, resulting in an amorphous solid called terephthalic acid (TFA).

By using a natural Mexican clay as a catalyst and reaction medium to chemically degrade the waste PET, the specialists obtained good yields of one of its monomers: the TFA .

The above can be carried out with or without solvents and under milder atmospheric pressure reaction conditions, high yield percentages, and short reaction times from the use of microwave, thermal, and infrared energy.

The methodology applied in the research was repeated by the specialists on several occasions; in each case they achieved similar results.

The TFA obtained in the degradation process turned out to be an advantage, since this monomer can be used to generate new containers and create a polymer called " Kevlar ", which is able to withstand high temperatures and is five times stronger than steel .

The research team, coordinated by Guillermo Penieres , will seek to create a pilot plant for PET degradation that may eventually offer its services to different industries

The academics stressed that the accumulation of PET and its ecological impact will depend "on each of us and on the culture that we generate for future generations."

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