Page 60 - Plastics News June 2019

TECHNOLOGY

A clean and convenient method to oxidize plastic surfaces for industry

esear cher s at Os aka controlled or highly polluting. The new process is thus
RUniv er s ity hav e no w the first clean and convenient solution to this problem,
developed a convenient light- and may prove to be a valuable industrial tool in the
driven process for oxidizing customization of synthetic plastics. A research team has
PP without harmful waste. As used chlorine dioxide to oxidize polypropylene. Under LED
reported in ChemComm, the irradiation, ClO2* radicals attacked the methyl groups of
process uses radicals to make polypropylene, converting them to carboxylic acid. The
the plastic react. The surface of C-H bond-breaking was selective to the side chain. The
PP bristles with methyl groups oxidized surface could be stained with cationic dyes.
(-CH3), which constitute the side chains of the polymer. Surface oxidation of plastics is industrially important, but
The strong C-H bonds in methyl groups make PP an existing methods are polluting or poorly controlled. This
unreactive material, which for many purposes is exactly clean, convenient process could produce functionalized
what is needed. However, these bonds can be cleaved plastics for medical or printing uses.
by the highly reactive chlorine dioxide radical, ClO2* "In
applications like printing and medical materials, plastics Chem-trend new technology
must be surface-modified," explains study co-author
Tsuyoshi Inoue. "Oxidizing C-H bonds is a textbook case develops products meeting food
in organic chemistry. With polymers, however, the risk safety compliance
is that anything strong enough to do this may also break
the C-C bonds of the main chain, ripping the polymer hem-Trend, a world market leader in the development
apart. Luckily, the ClO2* radical is selective to react the Cand manufacturing of high-performance release
side chain." The highly reactive radical is easily made by agents, purging compounds, and other process chemical
mixing sodium chlorite and hydrochloric acid. It then just specialties, today announced the arrival of Lusin®
needs to be photochemically activated -- for this, the LU1201F, a lubricant specifically created for the
Osaka team chose an LED lamp as the light source. The thermoplastics packaging industry. Lusin® LU1201F
activated ClO2* now splits into Cl* , which whips off an H completes a larger portfolio of chemical specialty
atom from the side chain of PP; and O2, which marches in products developed in support of customers trying to
afterward to oxidize the exposed -CH2* group. As a result, achieve SQF Certification, making Chem-Trend a single
while the bulk polymer remains intact, the surface now source for thermoplastic packaging products when food
bears a multitude of carboxylic acid groups (-CO2H), with compliance is needed.
major effects on the chemical reactivity. For example, “Chem-Trend understands the complexity of food The High-Tech Show
the colorless plastic can now be stained with cationic packaging manufacturing. Our vast research and
dyes, such as Rhodamine B or Brilliant Green, which react development team set out to create an innovative Oct.06-10,2020
with the anionic carboxylate ions. The originally water- product line that supports food safety management
repellent surface also becomes more hydrophilic. "The systems. We’re pleased to offer this full suite of www.ipfjapan.jp
reaction actually proved to be doubly selective for our products, providing food-packaging customers with
purposes," says lead author Kei Ohkubo. "Not only did it customizable options that will fit their unique needs Gateway to the high-tech Japanese market & meeting place with
cleave the C-H instead of C-C bonds, it specifically oxidized and, in many cases, achieve a competitive edge,” the decision-makers of Japanese enterprises.
those on the side chain, even though they are stronger said Antje Scholl, Business Development Director –
Thermoplastics, Chem-Trend. Chem-Trend’s complete
than those on the main chain. This is because the oxidation portfolio of targeted products for those working to
step, involving O2, is most favorable when the target for achieve food safety compliance includes: ●Lusin®
oxidation is CH2* " Previous methods for oxidizing olefinic Release Agents,●Ultra Purge™ and Lusin® Purging
polymers such as PP and polyethylene were either poorly Compounds,●Lusin® Cleaners, ●Lusin® Lubricants.

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