Plastic, rubber, and a number of other useful materials are composed of polymers — long chains set in a cross-linked network. At the molecular level, these polymer networks have structural defects that weaken them.
Many years ago, MIT researchers were the first to measure specific types of these flaws, known as “loops,” which are caused when a chain in the polymer network binds to itself rather than to another chain. At present, the same researchers have discovered a simple way to decrease the number of loops in a polymer network and thus reinforce materials produced from polymers.