LESSON 5: POLYMERS Flashcards
These are large molecular compounds made up of many repeating units called monomers.
Polymers
It is a chemical reaction by which the monomers are linked together to form polymers.
Polymerization
TYPES OF POLYMERIZATION
The entire monomer becomes part of the polymer. They involve molecules with double bonds or triple bonds.
Addition Polymerization
TYPES OF POLYMERIZATION
Monomers join together at the same time losing a small molecule like water as a by-product.
Condensation Polymerization
POLYMER ARRANGEMENTS AND STRUCTURES
The arrangement of atoms is like that of a long chain. This long chain is often referred to as the backbone. Atoms or small groups of atoms attached to the long chain are called pendant atoms.
Linear Polymers
POLYMER ARRANGEMENTS AND STRUCTURES
Resemble linear polymers with the addition of shorter chains hanging from the spaghetti backbone.
Branched Polymers
POLYMER ARRANGEMENTS AND STRUCTURES
Resemble ladders. The chains link from one backbone to another.
Cross-Linked Polymers
POLYMER ARRANGEMENTS AND STRUCTURES
They are complex polymers that are heavily linked to form a complex network of three-dimensional linkages.
Networked Polymers
IMPORTANT PROPERTIES OF POLYMERS
The extent to which the plastic or polymer acts as an effective insulator against the flow of heat.
Heat Capacity
IMPORTANT PROPERTIES OF POLYMERS
The extent to which the polymer expands or contracts when heated or cooled.
Thermal Expansion
IMPORTANT PROPERTIES OF POLYMERS
The extent to which the polymer chains are arranged in a regular structure instead of a random fashion.
Crystallinity
IMPORTANT PROPERTIES OF POLYMERS
The extent to which the polymer chains are arranged in a regular structure instead of a random fashion.
Crystallinity
IMPORTANT PROPERTIES OF POLYMERS
The tendency of a polymer to pass extraneous materials.
Permeability
IMPORTANT PROPERTIES OF POLYMERS
The quantity that measures an object or substance’s resistance to being deformed elastically (i.e., non-permanently) when stress is applied to it.
Elastic Modulus
IMPORTANT PROPERTIES OF POLYMERS
The strength of plastic. (The force that must be applied in one direction to stretch the plastic until it breaks.)
Tensile Strength
IMPORTANT PROPERTIES OF POLYMERS
The ability of the plastic to resist abrasion and wear.
Resilience
IMPORTANT PROPERTIES OF POLYMERS
The extent to which the plastic affects light as it passes through the polymer.
Refractive Index
IMPORTANT PROPERTIES OF POLYMERS
Insulator: Most polymers do not conduct electricity
Resistance to Electric Current
IMPORTANT PROPERTIES OF POLYMERS
Most polymers are not affected by air or water, and many are not affected by chemicals that make plastic durable and safely contain and protect many substances.
Unreactivity
They are used to increase the ability of a plastic to resist oxidation, to make it less sensitive to either heat light, or as flame retardants.
Stabilizers
They increase the flexibility of plastic by acting as a lubricant, decreasing the friction between molecules as one polymer chain moves past another.
Plasticizers
It is manufactured using a very high pressure (2000 atm) and a temperature of 2000°C with trace oxygen. This results in the formation of branched polymer and prevents polymer chains from packing closely hence low density.
Low-density Polyethene or Polythene (LDPE)
It is manufactured using a catalyst at a temperature of 500°C and a slightly raised pressure (80 atm). This results in the formation of straight polymer chains that facilitates polymer chains packing close together hence, high density.
High-Density Polyethene or Polythene (HDPE)
It consist of tangled web chains and are attracted by weak intermolecular forces
Thermosoftening Polymers
When heated they form crosslinks between molecules that are covalently bonded.
Thermosetting Polymers
