Polymerisation: Kick started by initiator is described as which phase?

• A. Propagation
• B. Termination
• C. Initiation
• D. Cross-linking

Answer: (C)

Initiation is the phase where the initiator breaks down to form reactive species (usually free radicals) that start the polymer chain. In nail systems, the initiator is activated by heat or light and creates radicals that attack the monomer, forming the active center that kicks off polymerization. Once this center is formed, the growing chain enters the propagation stage, adding more monomer units. Termination stops the growth when two active chains meet or transfer their radicals to another molecule. Cross-linking creates bonds between chains to form a network, which strengthens the material, but it’s not the initial kick-start phase. So, the phase described as kicked off by the initiator is initiation.