Exam 2 Flashcards
What are the 3 main processes of radical chain growth?
Initiation, propagation, and termination
What is kintetics?
The rate of chemical reactions.
What are the 4 polymer reaction systems?
Bulk, solution, suspension, and emulsion
What is 1 pro and 1 con of Bulk polymerization?
Pro: High Yield
Con: difficult to stir
What is 1 pro and 1 con of Solution polymerization?
Pro: product easily removed
Con: small yield
What is 1 pro and 1 con of suspension polymerization?
Pro: High purity
Con: small yield
What is 1 pro and 1 con of Emulsion Polymerization?
Pro: low viscosity
Con: separation is difficult
What is degree of polymerization?
Average number of repeating units in each chain
What is viscoelasticity?
Viscosity: ability to flow
Elasticity: ability to stretch
What are 3 unique properties of polymers?
1: chain entanglement
2: summation of intermolecular forces
3: time scale of motion
What is chain entanglement?
Entangled chains inside a polymer that once molten allow to slide past on another.
What is summation of intermolecular forces?
Polymers are made up of large molecules whos intermolecular forces are compounded due to size
What is time scale of motion?
Polymers move slower than small molecules do.
What are 4 molecular structures for polymers?
Linear, branched, cross-linked, network
What is a linear molecular structure?
Repeat units joined end to end in single chains
What is a branched molecular structure?
Side branched chains connected to a main chain
What is a cross-linked molecular structure?
Adjacent chains joined at positions by covalent bonding
What is a network molecular structure?
Three or more covalent bonds in a small molecule
What is tacticity?
The spa jam arrangements of monomeric units along a polymer chain
What are the 3 types of tacticity?
Isotactic, syndiotactic, and atactic
What is isotactic?
All side groups facing the same way
What is syndiotactic?
side groups alternate in orientation
What is atactic?
Side groups oriented in a random manner
What is stereoregularity?
Configuration of polymer chains
What are the 2 types of stereoregularity?
Cis and Trans
What is Cis stereoregularity?
Substitutents on the same side
What is Trans stereoregularity?
Substitutents on the opposite side
What are 3 factors that affect crystalinity?
Chain entanglement, chain length, and inter chain bonding
What are 3 high crystalline polymers?
Polyethylene, polypropylene, and PET
What are 3 high amorphous polymers?
Polystyrene, PMMA, and PVC
What is a Thermoset?
Network structures that can’t be re-molded once set.
Typically stronger than thermoplastic
3 examples of thermosets
Epoxy resin, polyurethane, and Bakelite
What is a Thermoplastic?
Linear polymers with minor branching and flexible chains
3 examples of thermoplastics
PE, PVC, and PP
Are elastomers thermosets or thermoplastics?
They can be either, as well as a rubber
What is glass transition temperature?
Temperature AMORPHOUS polymers transition from rubbery solid to brittle, glassy amorphous solid.
What is vitrification?
when an amorphous solid transitions to a glassy solid
What is polydispersity?
Polydispersity refers to the distribution of molecular weight
What instrument can you use to determine polydispersity?
Size Exclusion Chromatography (SEC)
Gel Permeation Chromatography (GPC)
What are 4 common spectroscopic techniques?
FTIE, RAMEN, NMR, SAX/WAX
What does FTIR and RAMEN identify?
Functional Groups
What does NMR identify?
Microstructure
What does SAX/WAX Identify?
Arrangement of atoms or molecules in a material
What are 3 Thermal Analyses?
TGA, DSC. DMA
What are 3 Mechanical analyses?
DMA, MTS, and Rheology
What is rheology?
Study of deformation and flow of matter
What are 3 things TGA measures?
Degradation temp, thermal stability, Oxidative Stability
What does DSC measure?
Exothermic and Endothermic transitions
What does DMA measure?
Thermomechanical behavior
What does MTS measure?
Physical Properties and tinsile strength
What does rheology measure?
Flow or movement of liquids and solids
