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89 Cards in this Set

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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 competitors
PPO
PC
High temperature eng. plastics
@ room temp - comparable to Nylon
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