Question #ead66
1 Answer
There are chemical bonds between adjacent polymer chains, linking them together a bit like a net.
Explanation:
A regular polymer consists of large molecules that can be envisaged as long chains of molecular units (e.g. polyethylene is a long chain of
Cross linked polymers, however, also have chemical bonds that link across polymer chains, and can be imagined as a sort of "net" structure. These bonds prevent the individual chains from having the same mobility as non-crosslinked polymer chains when they are in the presence of solvents, or when heated.
As a result, cross linked polymers tend not to melt (although they will burn when the temperature is high enough). They also do not dissolve in solvents, but instead simply swell up.
For this reason sodium polyacrylate is used as a water absorbing medium in diapers. Another example of a cross linked polymer is vulcanised rubber (used in car tyres) - vulcanisation uses sulphur to form the cross links..
