exam 1

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1

Nylon applications

Jackets, coolers, string

2

Wallace H. Carothers

Worked @ Dupont

responsible for Neoprene, Nylon 6,6 and polyesters

3

When did Nylon go into production? what war did it affect?

1939, in ww2 Nylon production, was changed to military purposes( parachute and canopies).

4

First major application of Nylon for common use?

NYLONS: Nylon leggings, stockings, medias. so popular people were fighting over them.

5

What year did Hermann Studinger win the Nobel Prize? and why?

1953, For his discoveries in macromolecular chemistry.

6

Synthetic polymer examples

LPDE, HDPE- (plastic bags)

Nylon - parachutes

ABS - dashboards, tv and computer monitors

Epoxy resins- adhesives

Silicon - heart valves, breast implants

teflon - tape and coatings

7

Biopolymers examples

wood, DNA, Keratin (hair), Chitin ( nails & shells), proteins.

8

Fields of study involved in polymer R&D

Chemistry, Chemical engineering, engineering, physics, biology, biochemistry, medicine, dentistry

9

What is a monomer?

Mono = one

mer = unit

monomer is a any substance that can be converted into a polymer.

10

What is a Dimer?

made of two monomers, usually linear

11

What are Trimers, tetramers, pentamers?

several monomers. linear or cyclic

12

Oligomers

low molecular weight polymerization products (dimers, trimers, etc)

13

polymers

high molecular weight substances

14

low molecular weight polymer?

10,000-20,000 g/mol (Dalton)

15

high molecular weight polymer

20,000 - millions g/mol (Dalton)

16

Linear polymer

a long chain of skeletal atoms to which substituent groups are attached.

-soluble in some solvents

17

Branched polymer

A linear polymer with branches of the same structure has a limit to "stacking". soluble in the same solvent as linear polymer.

-lower tendency to crystallize and different solution viscosity than linear polymers.

18

Crosslinked polymer

a polymer in which chemical linkages exist between chains. Swell but DO NOT dissolve.

physical crosslinks easier to break than chemical crosslinks

19

cyclomatrix polymers

polymers in which ring systems are linked to form a 3d matrix.

-Highly insoluble, rigid, high mp, stable at high temperatures.

Ex: Cement, graphite

20

Cyclolinear polymers

linear polymers formed by linking ring systems. solubility is low. tendency for crystallization might be high. Rigid... flexibility limited.

ex: poly( p-phenylene) and polybenzimidazaole

21

Copolymers

polymer made from two different monomers

22

Random copolymers

No definite sequence. properties different than homopolymers often formed from olefins by free radical polymerization.

ABBBAABAAAAAABBBBBBBBB

23

Alternating copolymers

regular alternating sequences

olefins through ionic or coordination polymerization properties different than homopolymers.

ABABABABABAB

24

Block copolymers

block of one monomer connected to a block of other monomer.

olefins through ionic polymerizations.

physical characteristics are similar to corresponding homopolymers.

AAAAABBBBAAAAAAAAAABBBBBBBBBBB

25

Graft copolymers

one polymer is grafted to another.

two routes of formation ( A and B polymer, B to A polymer)

irraadiation (xray & gamma ray), mechanical shearing and synthesis

26

polymer additive

chemical compounds added to polymers to modify their properties

organic or inorganic

27

anticounterfeiting

optical brighteners absorb UV and re-emit at higher wavelength, as a blue glow

"money"

28

antimicrobials

prevent deterioration of plastics by microorganisms, attack by microorganisms produces staining, discoloration, odor, loss of electrical and mechanical properties.

29

antioxidants

prevent polymer reaction with oxygen (oxidation), from thermal oxidation or light-induced oxidation. oxidation produces lower mechanical properties.

30

Antistatic agents

prevent the build up of static electrical charge

31

plasticizers

additives that increase the plasticity or decrease viscosity liquids with low volatility or solids. decrease attraction between polymer chains to make them more flexible. DOMINANT APPLICATION FOR PVC.

32

lubricants

added to prevent damage during processing

33

blowing agents

added to form gases during processing, resulting in a foam structure.

34

fillers/extenders

additives that improve strength and lower the cost

usually inorganic compounds

talc, calcium carbonate...... bedframes, 18 plastic cab

35

flame retardants

prevent ignition or flame spreading. used in electrical, construction and transportation phosphorous and halogen based.

36

impact modifiers

allows to absorb impact without cracking. useful for PVC, PS, AND PP

37

UV absorbers

stabilize the polymer from exposure to UV light

38

pigments

compounds that add color

39

reinforcements

additives that improve tensile strength usually fiber based

40

MWD

molecular weight distribution. molecular weights are averages

41

bread MWD

less prone to crystallize, lower solidification temperatures, shorter chains plasticize the bulk of the polymer

42

Crystallinity

most polymers show characteristics of crystalline and amorphous solids. difficult to have 100% crystalline polymers.

43

fringed micelle theory

small sized ordered crystalline regions (crystallites).

embedded in an unordered amorphous matrix.

44

folded chain lamella

accordion-like manner observed in polymer single crystal from solution or the melt.

45

chain folding

is maximized for polymers crystallized slowly near the crytalline mp.

fast cooling yields chaotic crystallization

46

simple structure

allow packing, the regular structure allows packing.

47

chain fidelity

decreases packing, crystallinity; polysiloxanes, natural rubber.

48

Young's modulus

resistance to deformation; initial stress divided by delta l/l

49

tensile strength ( ultimate strength)

stress required to rupture

50

tensile strain ( ultimate elongation)

elongation suffered to rupture

51

elastic elongation

reversible elongation

52

polystrene

poly = prefix

styrene = monomer

53

multiworded monomer

use parenthesis on the monomer IF multiworded

poly = prefix

monomer= vinyl chloride

poly(vinyl chloride)

54

CRU

constitutional repeating unit (smallest possible repeating unit)

55

SRU

structural repeating unit