Lesson 1, 2: History, Molecular Origin Flashcards
(161 cards)
Macromolecule (long molecules) built of small covalently bonded units called monomers
Polymer
Monomers in greek word is ___ means ____
“mer”, part
Small units repeated throughout the macromolecule chain
Monomers
The macromolecules are bonded together by ___ or ___
weak Van der Waals and hydrogen (secondary bonds), or additional covalent cross-links
Most polymers are ___ and formed from ___
Organic, hydrocarbon molecules
Each C atoms has ___ electrons that participate in covalent bonding, each H has ___ bonding electron
4, 1
A single covalent bond exists when ____
Each of the 2 bonding atoms contribute one electron
Double and triple bonds between 2 carbon atoms
Involve the sharing of 2 and 3 pairs of electrons
Molecules that have double, and triple covalent bonds are termed
Unsaturated
Unsaturated means
Each carbon us not bonded to maximum (4) other atoms
For saturated hydrocarbon
All bonds are single ones, and no new atoms may be joined w/o the removal of others
Molecule that combines with other mol of the same/different type to form polymer
Monomer
Oligomer is
Low molecular weight polymer, contains atleast 2 monomer units
Oligomer of polyethylene
Hexatriacontane
Specifies the length of polymer molecule
Degree of polymerization
In DOP, n means
Number of repeating units strung together in the polymer chain (mol)
A ___ degree of polymerization is normally reqd for a matl to develop useful properties
High
Dimensionless quantity given by the sum of the atomic weights in the mol formula
Molecular weight
Relation between DOP and MW of the same macromolecule is…
M=(DP)Mo
Mo= formula weight of the repeating units
Classification of Polymers
Based on origin
Based on polymer structure
Based on polymerization mechanism
According to thermal processing behavior
Based on preparative technique
Classification of polymer Based on origin
Natural vs synthetic polymers
Wood, rubber, cotton, leather, wool, silk, protein, enzymes, starches, cellulose is an example of
Natural polymers
Fibers , elastomers, plastics, adhesives
Synthetic polymers
Classification based on polymer structure
A. Linear, Branched or cross-linked, network vs functionality
B. AMORPHOUS OR CRYSTALLINE
C. HOMOPOLYMER OR COPOLYMER
D. FIBERS, PLASTICS, OR ELASTOMERS