Question

If a small amount of p-divinylbenzene is added to styrene, a cross-linked polymer can be formed. Show why this would be the case with structures and brief mechanism. Predict how cross-linking of the polymer chains might change the polymer's physical properties.

Answer 1

First, we discussed what is cross-linked polymer-

Atom bonded to polymer chain are called cross-linked.They form during formation of polymerization of a monomer or in separate reaction after the formation of a polymer. If we talk about p-divinylbenzene has two alkene function groups, each of which can form a part of a different polymer by an additional polymerization reaction . One alkene of p-divinylbenzene is incorporated in a chain whose major components are styrene.

For mechanism-

1) Decomposition of initiator -

R₂ 2R

2) Initiation-

  

3) cross-linking-

Now come to how cross-linking chain change property as below-

DVB is an extreamely versatile cross-linking agent that improve polymer properties.As a result, It has been used to manufacture adhesive, plastic, elastomer and ion exchange resins. A very small amount of DVB is needed to improve physical and chemical properties.