Chapter 14 Polymer Structures Flashcards
what is a polymer
polymer is a substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits.
ancient polymers
- wood
- cotton
- leather
- rubber
hydrocarbons
a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon.
molecular structures example
Unsaturated hydrocarbons
Unsaturated hydrocarbons are hydrocarbons that have double or triple covalent bonds between adjacent carbon atoms. The term “unsaturated” means more hydrogen atoms may be added to the hydrocarbon to make it saturated
Isomerism
Isomerism is the phenomenon in which more than one compounds have the same chemical formula but different chemical structures.
polymerization
polymerization is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks.
polyethylene
polyethylene is the most common plastic in use today. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, etc.).
molecular weight
molecular weight - The molecular mass is the mass of a given molecule: it is measured in daltons.
molecular weight distribution
formula
molecular weight distribution describes the relationship between the number of moles of each polymer species (Ni) and the molar mass (Mi) of that species
molecular weight calc
ex
degree of polymerization
The degree of polymerization (DP or Xn) is defined as the number of monomer units in the polymer. It is calculated as the ratio of molecular weight of a polymer and molecular weight of the repeat unit. Number average DP and weight average DP are the two main types used for measuring the DP.
molecular structures of polymers
polymer - molecular shape
Molecular Configurations for Polymers
Configurations
Tacticity
Tacticity is the relative stereochemistry of adjacent chiral centers within a macromolecule. The practical significance of tacticity rests on the effects on the physical properties of the polymer.
cis vs trans
isomerism
Copolymers
two or more monomers polymerized together
random -
alternating -
block -
graft -
copolymer - is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization.
polymer single crystals
semicrystalline polymer
Semicrystalline polymers are a mixture of both crystalline and amorphous structures.
