Bioplastics are plastic materials made from biomass instead of crude oil and natural gas. They are more environmentally friendly but tend to be less durable and flexible than traditional plastics. They are also less stable when exposed to heat.
Fortunately, scientists at the University of Akron (UA) have found a solution to this last shortcoming by going beyond the capabilities of bioplastics. Their development could make a significant contribution to the sustainability of plastics in the future.
Shi-Qing Wang, PhD lab at UA, is developing efficient strategies for converting brittle polymers into rigid and flexible materials. The team’s latest development is a polylactic acid (PLA) cup prototype that is ultra-strong, transparent, and won’t shrink or deform when filled with boiling water.
Plastic has become an integral part of our daily lives, but most of it is not recyclable and therefore accumulates in landfills. Some promising biodegradable/compostable alternatives like PLA are often not strong enough to replace traditional fossil fuel based polymers like polyethylene terephthalate (PET) because these sustainable materials are very crunchy.
PLA is a popular form of bioplastic used in packaging and utensils because it is cheap to produce. Before Wang’s lab did this, the use of PLA was limited because it couldn’t withstand high temperatures. That’s why this research could be a breakthrough for the PLA market.
Dr. Ramani Narayan, renowned bioplastics scientist and professor emeritus at Michigan State University, said:
PLA is the world’s leading 100% biodegradable and fully compostable polymer. But it has low impact strength and low heat distortion temperature. It softens and breaks down structurally at about 140 degrees F, making it unsuitable for many types of hot food packaging and disposable containers. Dr. Wang’s research could be breakthrough technology because his prototype PLA cup is strong, transparent, and can hold boiling water.
The team rethought the complex structure of PLA plastic at the molecular level to achieve heat resistance and ductility. This material is made up of chain molecules bound together like spaghetti, intertwined with each other. To be a strong thermoplastic, the researchers had to ensure that crystallization did not disrupt the weave structure. He interprets this as an opportunity to pick up all the noodles at once with a pair of chopsticks, rather than a few noodles that slide off the rest.
Their PLA plastic cup prototype can hold water without decomposing, shrinking or becoming opaque. These cups can be used as a more environmentally friendly alternative to coffee or tea.
Post time: Feb-08-2023