Page 43 - Plastics News May 2021

teChnoLogy

Nanoplastics and other harmful New technique that brings aging

pollutants found in disposable Polymers to light

face masks

ike people, polymers age, and when they do, the
Lmaterials become prone to cracking or breaking.
cientists from Swansea
SUniversity have uncovered Now, researchers reporting in ACS Central Science have
developed a method to visualize variations in polymers
potentially dangerous chemical that arise with age. Heat, sunlight, oxygen and humidity
pollutants that are released can all cause polymers to degrade over time. At early
from disposable face masks stages, polymer chains break, producing functional
when submerged in water. The groups, such as hydroxyl groups, and generating free
research reveals high levels radicals that speed up the aging process. Scientists
of pollutants, including lead, have developed methods to study more advanced signs
antimony, and copper, within of polymer aging, but these techniques don't provide
the silicon-based and plastic a microscopic 3D picture, and most aren't sensitive
fibres of common disposable enough to detect early aging. Rui Tian, Chao Lu and
face masks. The work is supported by the Institute colleagues wanted to find a way to visualize the aging
for Innovative Materials, Processing and Numerical process of polypropylene and polyethylene polymers
Technologies (IMPACT) and the SPECIFIC Innovation & in 3D. Such a technique could be used to detect aged
Knowledge Centre Project lead Dr Sarper Sarp of Swansea polymers so they can be repaired or replaced with new
University College of Engineering said: "All of us need to parts before they fail. The researchers based their
keep wearing masks as they are essential in ending the method on a commercially available fluorescent dye,
pandemic. But we also urgently need more research and called DBPA, that can specifically attach to hydroxyl
regulation on mask production, so we can reduce any groups in polymers as the chains break. The team
risks to the environment and human health."Outlined heated a thin sheet
in a recent paper, the tests carried out by the research of polypropylene
team used a variety of masks -- from standard plain face or polyethylene
masks to novelty and festive masks for children with many at 140 F and then
currently being sold in UK retail outlets.The findings reveal soaked the plastic
significant levels of pollutants in all the masks tested -- in a DPBA solution
with micro/nano particles and heavy metals released into to dye the aged
the water during all tests. Researchers conclude this will sites with hydroxyl
have a substantial environmental impact and, in addition, gr o ups . When
the researchers
raise the question of the potential damage to public health observed the sheets
-- warning that repeated exposure could be hazardous under a confocal
as the substances found have known links to cell death, microscope, they
genotoxicity and cancer formation.
found that the aged sites in the polymers -- as
To combat this, the team advise further research revealed by the fluorescently tagged hydroxyl groups
and subsequent regulations be put in place in the -- grew deeper, wider and more frequent with time.
manufacturing and testing process. The research team The method detected faster polymer aging when the
includes Professor Trystan Watson, Dr Javier Delgado sheets were exposed to higher temperatures. To the
Gallardo and Dr Geraint Sullivan. The IMPACT operation is researchers' knowledge, the fluorescent technique is
part-funded by the European Regional Development Fund the first that can sensitively monitor polymer aging
through the Welsh Government and Swansea University. in 3D, which will assist in identifying deteriorating
polymers at the earliest stages.

43 May 2021 Plastics News