The new research into LEGO blocks took some of the plastic bricks that had weathered at sea and which were collected from English beaches, and then compared these with archived blocks which had been preserved in their original condition. Scientists from University of Plymouth then assessed the physical and chemical changes to the plastic, by undertaking a systematic assessment using different tests.
Traditional LEGO blocks are made from acrylonitrile butadiene styrene, a common thermoplastic polymer. The plastic is made by made by polymerizing styrene and acrylonitrile in the presence of polybutadiene.
The tests on the blocks used X-ray fluorescence analysis. X-ray fluorescence refers to the emission of characteristic “secondary” (or fluorescent) X-rays from a material that has been excited by being bombarded with high-energy X-rays or gamma rays. The technique is used for investigating metals, glass, ceramics and building materials.
The analysis looked at LEGO blocks had been subject to the sea and which had experienced ‘weathering’ in the form of fouling, cracking, pigment leaching and mass loss, and noted differences with the pristine archive set. The washed-up blocks were also found to be of lower mass, average stud height and mechanical strength. Through undertaking the comparison, the researchers concluded residence times of the plastic of between 100 to 1,300 years.
According to Wired, LEGO has moved to a more sustainable type of plastic in recent years. To date, some 25 different LEGO shapes, are made from sugarcane-based polyethylene rather than oil-based plastic. LEGO continues to move towards other products being formed from sustainable materials, with the aim of completing the transition by 2030.
The research has been published in the journal Environmental Pollution. The research paper is titled “Weathering and persistence of plastic in the marine environment: Lessons from LEGO.”