BME 304 Lect 7-8

Polymers

Polymer

Large molecule made of repeating smaller units called monomers

Monomer

Small molecule that can chemically bond with other monomers to form a polymer

Oligomer

Short chain containing a relatively small number of repeating units

Vulcanization

Process that creates crosslinks between polymer chains, usually improving strength and elasticity

General polymer properties

Lightweight, flexible, corrosion-resistant, and easy to process; properties vary greatly with structure

Bonding in polymers

Strong covalent bonds hold atoms together within chains; weaker interactions can occur between chains.

Linear polymer

Long chains with little/no branching

Branched polymer

Main chain has side chains attached

Crosslinked polymer

Polymer chains connected together by crosslinks

Networked polymer

Highly interconnected, three-dimensional polymer structure

Molecular weight effect

Increasing molecular weight generally increases chain entanglement and can increase strength/toughness

Polymerization

Process of joining monomers to create polymers

Crystalline polymer

Polymer chains arranged in an ordered structure

Semicrystalline polymer

Contains both crystalline and amorphous regions

Amorphous polymer

Polymer chains lack long-range ordered structure

Polymer ductility

Ability of a polymer to undergo significant deformation before breaking

Biomedical polymers

Polymers used in medicine, such as PVA, PEG, acrylics, and other polymers used in implants, drug delivery, sutures, and devices