How is polypropylene synthesized, and what are its main applications?

Describe the synthesis and applications of polyvinyl chloride $($PVC$).$

What are the main monomers used in the synthesis of polystyrene, and what are its applications?

Discuss the synthesis and applications of polyethylene terephthalate $($PET$).$

Explain the synthesis and applications of polytetrafluoroethylene $($PTFE$).$