A step toward stronger polymers?
Researchers have, for the first time, found a way to measure how many loops are present in any given polymer network, an advance they believe could yield better, stronger materials with no weak spots.
The MIT team, led by postdoc Huaxing Zhou, began by measuring the percentage of loops in a gel. They did this by designing polymer chains with a chemical bond in a specific location that could be broken using hydrolysis.
Because they knew where the break points were, the team could predict the percentages of the four different degradation products expected to be found in an ideal, no-loop network.
By measuring the quantity of each degradation product and comparing it with the ideal, they were able to figure out what fraction of the polymer formed loops.
They found that the percentage of polymer loops ranged from about 9% to nearly 100%, depending on the concentration of polymers in the starting material and other factors.
"Even in the best material we can make, 9% of its junctions are wasted as loops, which tells us that if we can figure out a way to reduce loop formation, we'd have a 9% improvement in material properties," said Zhou.
The researchers are now looking for ways to reduce the number of loops by altering the mixture of polymers used to produce a material, as well as the reaction conditions.
