Title, for example teeth fillings or glass glue. How or why is it getting hard / solid just with UV light?
Thanks!
In: Physics
The resin contains things called “plasticizers”, which are basically any component that’s in there to keep something soft/liquid. These plasticizers sort of “accompany” the long chains of polymers, and help keep them separated so the long chains can move around each other and not get tangled or stuck together.
The plasticizers in some resins are formulated so that when hit with UV light, the light will cause them to get excited in such a way that they break apart. When the plasticizers break apart, they aren’t good at “accompanying” the long polymer chains, so the polymer chains become tangled with one another, and then they may even begin cross-linking (imagine joining 2 chains together… but in the middle, not end-to-end).
What you’re left with is a mess of tangled and cross-linked long chain molecules — or cured resin.
Latest Answers