I noticed that almost all glues nowadays have polymer substances in their composition. Why is that? What properties of polymers give such good adhesion?
There are adhesives that have monomers in their composition, polymerization proceeds as they already set.
I know a polyvinyl alcohol glue, PVA is a water-soluble polymer, which is characterized by high crystallinity and strong adhesion. Here is a detailed introduction to it: http://www.china-pva.net/category/PVA-2488-PVA-2499.html