A New And Unusually Robust Form Of Plastic

As anybody who extrudes plastic noodles is aware of, the glass transition temperature of a cloth is a bit deceptive; polymers step by step transition between a glass and a liquid throughout a spread of temperatures, and calling any explicit level in that vary the glass transition temperature is a bit arbitrary. As a common rule, the shorter the glass transition vary is, the weaker it’s within the glassy state, and vice-versa. A stunning demonstration of that is supplied by compleximers, a category of polymers lately found by researchers from Wageningen College, and the primary natural polymers identified to kind robust ionic glasses (open-access article).

When a cloth transforms from a glass — a tough, non-ordered strong — to a liquid, it goes by way of varied rest processes. Alpha relaxations are molecular rearrangements, and are the principle rest course of concerned in melting. The progress of alpha rest may be described by the Kohlrausch-Williams-Watts equation, which may be exponential or non-exponential. The nearer the system for a given materials is to being exponential, the extra uniformly its molecules chill out, which ends up in a gradual glass transition and a powerful glass. On this case, nevertheless, the ionic compleximers had been extremely non-exponential, however however had lengthy transition ranges and fashioned robust glasses.

The compleximers themselves are primarily based on acrylate and methacrylate backbones modified with ionic teams. To forestall water from infiltrating the construction and altering its properties, it was additionally modified with hydrophobic teams. The ultimate glass was solvent-resistant and simple to course of, with a glass transition vary of greater than 60 °C, however was nonetheless robust at room temperature. Because the researchers demonstrated, it may be softened with a scorching air gun and reshaped, after which it cools into a tough, non-malleable strong.

The authors observe that these are the primary identified natural molecules to kind robust glasses stabilized by ionic interactions, and it’s nonetheless not clear what makes use of there could also be for such supplies, although they hope that compleximers might be used to make extra easily-repairable objects. The fascinating glass-transition means of compleximers makes us ponder whether their materials getting old could also be reversible.