1.1　BASIC CONCEPTS AND DEFINITIONS

1.1.1　Monomers and Polymers

A monomer is any substance that can be converted（转变）into a polymer.For example，ethylene CH₂CH₂ is a monomer that can be polymerized to polyethylene：

Overall reaction：

In addition：propylene+propylene+propylene+…→polypropylene（PP）

Poly（hexamethyleneadipamide）（聚己二酰己二胺，Nylon-66）is made from two monomers，hexanedioic acid or adipic acid and 1，6-diaminohexane（also known as hexane-1，6-diamine）.

Overall reaction：

n HOOC（CH₂）₄COOH+n H₂N（CH₂）₆NH₂􀰷NH（CH₂）₆NHOC（CH₂）₄CO􀰻+（2n-1）H₂O