Polymer Final

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Why is the solvent resistance of PPS special?: No known solvent at temperatures under 400F
What is the processing temperature of PPS?: 600-650F
What year did PPS become available on the market?: 1968
T/F PPS is self lubricated.: True
PPS is crystalline or amorphous?: Highly crystalline
PPS does what when it degrades?: Cross links
Cost of PPS high or low?: High $5-6/lb glass filled
Up to $70+/lb carbon fiber fill
PPS requires what for good impact strength?: Fillers (30-40% common)
PPS Applications: Automotive
Electrical
Metal/Ceramic Replacement
Coating Applications
PPS Trade Names and Suppliers: Suppliers:
Chevron Phillips
Ryton
Xtel
Trade Names:
Ticona
Celstran
Celstran S.
Fortron
Ryton
PPS is primarily used when ______ is anticipated.: High service temperatures.
How does PPS react with moisture?: PPS has exceptional moisture resistance.
PPS is subject to ____ and _____.: Warping and brittleness
PPS has _____ flammibility resistance.: High
What is a Mesogen?: Molecules with rod like shapes that have strong dipoles and/or easily polarized substituents.At least one aromatic ring.
Why are LCP's so easily injection molded?: Very low viscosity, nearly perfectly align.
Why are LCPs known as self reinforcing materials?: Individual chains become so stiff with the addition of the meosgens.
What are the two types of LCPs?: Main Chain LCPs
Side Chain LCPs
What is the processing temp for LCPs?: 540-850F
Do LCPs require oil mold heaters?: Yes
What are the two melt phases of LCPs?: Soild to liquid crystal
Liquid crystal to amorphous liquid.
LCPs are good for what injection molding applications.: Thin walled parts
Reinforements
LCPs show potential in what field and what is the current problem?: Optical displays, molecules align too slow.
What are three good properties of LCPs?: Low stretch/elongation
Resistance to cutting
Chem/solvent resistance
Excellent thermal properties
High strength
Low weight
High impact resistance
Applications of LCPs?: Sub hulls
Bulletproof vests
Helicopter blades
Rocet engine castings
LCP trade names: Vectra
Zydar
LCP comparable to:: Fiber reinforced polymers
How do you lower the Tg of LCPs?: Introduce multiple mesogens and orient as random copolymer iwth spacers
Add kinks to the spacers in the Main Chain LCPs.
Why are LCPs difficult to cut?: Becuase of the director axis which acts like wood grain.
Why is suspension polymerization good for producing fluoropolymers?: Creates a powder, good for sinter molding, a common form of processing fluoropolymers.
Why is PTFE so difficult to process?: The melting temperature is slightly below the decomposition temperature.
What does decomposition of PTFE produce?: Toxic fluorine gas.
What are alternatives to PTFE?: PEEK
Nylon
Applications of PTFE: Gortex
Industrial Rollers
Process Dies
Kitchen Utensils
Tank/Pipe Linings
Wire Coverings
Gaskets
Medical Applications
PTFE accounts for ____% of fluoropolymer sales.: 90%
What is the benefit of fluoroelastomers?: Remain elastic at high temperatures, won't break down like natural elastomers.
Making fluoropolymers is a endo/exothermic process.: Exothermic
How does Teflon stick to the pan?: Sand blast the pan first.
Lay a primer layer
Add Teflon, then apply pressure.
Fluorine is the most ____ element on the periodic table.: Electronegative
Fluoropolymers have _____ coefficient of friction and ____ high lubricity.: Low coefficient of friction
High lubricity
Fluoropolymers have a ____ resistance to solvents.: High
Two main kinds of acetals.: Homopolymer
Copolymer
Acetal trade names.: Delrin
Celcon
Hostaform
How does acetal degrade?: Similiar to PVC by unzipping.
Competing materials with acetal.: Nylon
Acetal applications.: Moving mechanical parts
Snap fits
Hose fittings
Wiperblade fittings
Chain linkages
Acetal is or is not self lubricating.: Is self lubricating
Acetal is crystalline or amorphous?: Very crystalline
T/F Acetal is thermally stable.: False
Acetal has a high or low UV resistance.: Low UV resistance.
Copolymer acetal is the copolymerization of what two things?: Formaldehyde with ethylene oxide.
Homopolymer acetal is created by what two things?: Formaldehyde and acetic anhydride.
What happens when acetal degrades?: Gives off toxic fumes.
What is really important when processing acetal?: Uniform mold heating to insure uniform crystallinity.
What is PBIs trade name?: Celazole
What are the advantages of PBI?: Excellent thermal properties
Low CTE
High ionic purity
What are the disadvantages of PBI?: PRICE
Difficult to process
Water absorption
Competitors to PBI: Polyimides
Ceramics
Metals
Polyamidimides
PBI applications.: Figherfighter turnout coats
Astronaut space suits
High temperature gloves
Welder's apparel
Racecar driver suits
PBI comes in what forms?: Powder
Pellet
Filament
Solutions
Why can't you injection mold pure PBI?: No melting point, very high processing temperatures.
Commonly blended with PEEK.
Glass transistion of PBI?: 800F
PBI is manufactured using what technique?: Step growth polymerization
What was PBI first used for?: NASA applications
T/F PBI does not have good creep resistance.: False.
PBI has excellent creep resistance.
PBIs compressive strength is _____.: Very high. Highest compressive strength of any unfilled plastic (56000 psi)
What unique thing will not stick to PBI?: Other plastics will not stick to PBI.
When being manufactured, PBI undergoes a ____ process.: Dry spinning.
What contributes to PBIs flame retardedness?: LOTS of benzene rings.
What are the three properties that make polycarbonate very vulnerable if they are not treated?: Poor weather resistance
Poor abrasion resistance
Poor chemical resistance
What property gives polycarbonate such high impact strength?: Rotation of the oxygen bonds
What are the three properties of PC considered the most important?: Clarity
Impact strength
High thermal stability
How is PC produced?: Through a condenstation reaction
What happens when PC absorbs water?: Causes drool
PC trade names:: GE - Lexan
Dow - Calibre
Bayer - Makrolon
Competitive Materials for PC: Acrylic
ABS
PC applications: Safety equipment
Power tools
Electronics
CD/DVDs
Food safe
Automotive
How do you overcome the drawbacks of PC?: Hard coats and primers are used.
PC has up to ___% clarity.: 90% clarity
When was PC first introduced.: 1953
What is PC alloyed with?: ABS
PET
PBT
P'sulfone
Styrenics
Acrylics
What is PC blended with?: P'esters
P'urethans
PBT
PET
What happens when PC is weathered?: Yellows in weather
PC: Polycarbonate
PBI: Polybenimidazole
PTFE: Polytetrafluoroethylene
LCPs: Liquid Crystal Polymers
PPS: Polyphenylene Sulfide

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