Download Chapter 23 - Organic Chemistry

23
C h a pt e r
Organic Chemistry
Chemistry 4th Edition
McMurry/Fay
Dr. Paul Charlesworth
Michigan Technological University
Orbital Hybridization
2Formed
3 Formed
SP
Formed
by
bymixing
mixing
one
ones,s,and
and
one
two
pporbitals
orbitals
totoform
form
three
• SP
by mixing
one
s,
and
three
p two
orbitals
equivalent
sp 2orbitals
orbitalsand
andtwo
one
3 orbitals. pporbital.
unhybridized
orbital.
form four
equivalent
spunhybridized
to
12
Prentice Hall ©2004
Chapter23
Alkanes
•
Slide 2
01
Alkanes: Have the general formula Cn H2n + 2,
where n = 1, 2, . . . . Each carbon has a tetrahedral
arrangement.
•
These are saturated hydrocarbons:They contain
the maximum number of atoms that can bond to a
carbon atom.
Prentice Hall ©2004
Chapter23
Slide 3
1
Alkanes
Prentice Hall ©2004
02
Chapter23
Slide 4
Alkanes
03
Methane
CH 4
Undecane
CH 3(CH 2)9CH 3
Ethane
Propane
CH 3CH 3
CH 3CH 2CH 3
Dodecane
Tridecane
CH 3(CH 2)10CH 3
CH 3(CH 2)11CH 3
Butane
Pentane
CH 3(CH 2)2CH 3
CH 3(CH 2)3CH 3
Icosane
Henicosane
CH 3(CH 2)18CH 3
CH 3(CH 2)19CH 3
Hexane
Heptane
CH 3(CH 2)4CH 3
CH 3(CH 2)5CH 3
Docosane
Tricosane
CH 3(CH 2)20CH 3
CH 3(CH 2)21CH 3
Octane
Nonane
CH 3(CH 2)6CH 3
CH 3(CH 2)7CH 3
Triacontane CH 3(CH 2)28CH 3
Tetracontane CH 3(CH 2)38CH 3
Decane
CH 3(CH 2)8CH 3
Prentice Hall ©2004
Hectane
CH 3(CH 2)98CH 3
Chapter23
Alkanes
Slide 5
04
•
Nomenclature is based on the International Union
of Pure and Applied Chemistry (IUPAC) system.
•
Parent name is the longest continuous chain.
•
Side chain numbering gives the lowest total count.
•
A prefix such as: di-, tri-, or tetra- indicates the
number of identical chains.
Prentice Hall ©2004
Chapter23
Slide 6
2
Alkanes
•
05
–NH2
–F
–Cl
–Br
–I
–NO2
–CN
–CH=CH2
There are often many
different substituents.
•
If we cannot resolve
them numerically, we
may do so
alphabetically.
Prentice Hall ©2004
amino
fluoro
chloro
bromo
iodo
nitro
cyano
vinyl
Chapter23
Slide 7
Alkanes
•
Alkyl substituents
derive their names
from their parent
alkanes.
06
Methyl
–CH 3
Ethyl
–CH 2CH 3
n-Propyl
–CH 2CH 2CH 3
n-Butyl
–CH 2CH 2CH 2CH 2CH 3
CH 3
•
The n- means
attachment on end. Isopropyl
•
The iso- means on t-Butyl (tertiary butyl)
a central atom.
Prentice Hall ©2004
C H
CH 3
CH 3
C CH 3
CH 3
Chapter23
Cycloalkanes
•
Slide 8
01
Cycloalkanes are joined in rings and have the
general formula Cn H2n.
Prentice Hall ©2004
Chapter23
Slide 9
3
Cycloalkanes
•
02
Cyclic structures are simplified by using polygons
and lines. At every line junction it is understood
that a carbon and the correct number
of hydrogen atoms exist.
Prentice Hall ©2004
Chapter23
Slide 10
Cycloalkanes
•
03
Start numbering substituted cycloalkanes with the
group that has “alphabetical priority.”
H2
C
5
H 2C
4
3
CH
H2
C
1C H
CH 3
2
CH 2
H 3C
1-ethyl-3-methylcylcopentane
Prentice Hall ©2004
Chapter23
Alkenes
Slide 11
01
•
Alkenes: Contain at least one carbon–carbon
double bond. Alkenes have the general formula
Cn H2n.
•
Alkenes: Unsaturated hydrocarbons, which means
that they do not have the maximum number of
hydrogen atoms. These are taken up by double
bonds.
Prentice Hall ©2004
Chapter23
Slide 12
4
Alkenes
02
•
The names of compounds containing C=C bonds
end in -ene.
•
In naming alkenes we indicate the positions where
the carbon–carbon double bonds begin.
H2C
C
H
C
H2
CH3
H3C
1-butene
Prentice Hall ©2004
C
H
C
H
CH3
2-butene
Chapter23
Alkenes
Slide 13
03
•
Double bonds are rigid and do not allow rotation.
This creates geometric isomers.
•
Geometric isomers have the same chemical
formula, but a different structural arrangement.
•
The two main isomers are:
cis - meaning “on the same side.”
trans - meaning “on opposing side.”
Prentice Hall ©2004
Chapter23
Alkenes
Prentice Hall ©2004
Slide 14
04
Chapter23
Slide 15
5
Alkenes
•
05
Cis–trans isomerism occurs because the
electronic structure of the carbon–carbon double
bond makes rotation energetically unfavorable.
Prentice Hall ©2004
Chapter23
Slide 16
Alkynes
•
Alkynes: Contain at least one carbon–carbon triple
bond. They have the general formula Cn H2 n – 2.
•
Names of compounds with the carbon–carbon triple
bond end with -yne.
Prentice Hall ©2004
Chapter23
Aromatic Hydrocarbons
•
Slide 17
01
The base unit for all aromatic hydrocarbons is the
benzene ring. Its structure was proposed by Kekulé
in 1865 (often represented as Ar–H).
Prentice Hall ©2004
Chapter23
Slide 18
6
Aromatic Hydrocarbons
02
•
Benzene’s relative lack of reactivity is a result of its
electronic structure which contains six sp2hybridized orbitals.
•
Benzene has two resonance forms shown in (c).
Prentice Hall ©2004
Chapter23
Slide 19
Aromatic Hydrocarbons
•
03
The naming of substituted benzenes, in which one
hydrogen is replaced, is as follows:
CH3
CH2
ethylbenzene
F
Cl
Br
chlorobenzene
brom obenzene
Prentice Hall ©2004
NO2
fluor obenzene
nitrobenzene
Chapter23
Slide 20
Aromatic Hydrocarbons
•
04
Some benzene compounds have common names:
CH3
Tol uene
OH
Pheno l
Ph enyl
CH 3
O
CH 3
C
O
Acetophen one
Ani sole
Prentice Hall ©2004
N H2
CH2
Anisol
Ben zyl
OH
O
C
Benzoi c Aci d
Chapter23
O
OH
O
S
Benze nesulfoni c
acid
Slide 21
7
Aromatic Hydrocarbons
•
05
If more than one substituent exists, each has a
numbered position. Generally, the 1-position is
assigned arbitrarily.
•
The 1-position is, however, taken by functional
groups that are responsible for common names,
such as -CH3, - NH2, -NO2, and OH.
Prentice Hall ©2004
Chapter23
Slide 22
Aromatic Hydrocarbons
•
06
If more than one substituent exists, each has a
numbered position.
•
Generally, the 1-position is assigned arbitrarily.
•
The 1-position is, however, taken by functional
groups that are responsible for common names,
such as -CH3, - NH2, -OH, -COOH, and - COH.
Prentice Hall ©2004
Chapter23
Slide 23
Aromatic Hydrocarbons
•
07
D
A common designation
1
of the position of the
Ortho
Ortho
6
2
5
3
second substituent is
the use of the prefixes,
Meta
Meta
4
Para
ortho, meta, and para.
Prentice Hall ©2004
Chapter23
Slide 24
8
Aromatic Hydrocarbons
Br
08
NO2
NO2
Br
1,3-dibromobenzene
meta-dibromobenzene
Prentice Hall ©2004
1,2-dinitrobenzene
ortho-dinitrobenzene
Chapter23
Slide 25
Aromatic Hydrocarbons
Br
1
CH3
1
6
2
6
3
5
Br
4
1,3-di bromo benze ne
4
3-bromo to lue ne
3-bromo ani line
Prentice Hall ©2004
2
3-b romoph enol
O
C
H
1
6
2
3
4
Br
4
OH
5
3
5
C
1
6
Br
Br
4
3
5
6
3
O
2
OH
1
2
5
N H2
1
6
09
Br
3-bro mo ben zoic Acid
2
3
5
4
Br
3 -bromob enzal dehyd e
Chapter23
Slide 26
Functional Groups: Alcohols
01
•
Alcohols: Contain the hydroxyl functional group, –
OH which replaces an –H in the alkane.
•
Alcohols are named by replacing the “-e” ending of
the alkane with a “-ol” ending. The carbon of
attachment is indicated with the smallest number.
•
methane, CH 4, gives methanol, CH 3OH
•
ethane, C 2H 6, gives ethanol, C 2H 5OH
•
Propane, CH3 CH2 CH3 , gives 2-propanol, CH3 CH CH3
Prentice Hall ©2004
Chapter23
OH
Slide 27
9
Functional Groups: Alcohols
•
Primary Alcohols have their –OH bonded to a
terminal carbon that is bonded to one carbon and
two hydrogens. A common preparation is given
below.
Prentice Hall ©2004
Chapter23
Functional Groups: Alcohols
•
02
Slide 28
03
Secondary alcohols have their –OH bonded to a
carbon that is bonded to two other carbons and one
hydrogen. A common preparation is given below.
Prentice Hall ©2004
Chapter23
Functional Groups: Ethers
Slide 29
01
•
Ethers: Contain the R–O–R’ linkage, where R and
R’ are a hydrocarbon group.
•
Their names derive directly from the two alkyl
groups, R and R’, attached to the oxygen.
•
•
CH 3OCH 3 dimethyl ether
•
CH 3CH 2OCH 3 ethylmethyl ether or methylethyl ether
Ethers are inert chemically and make good
solvents.
Prentice Hall ©2004
Chapter23
Slide 30
10
Functional Groups: Ethers
•
02
Ethers can be produced from two alcohols:
H2SO 4
CH 3OH + HOCH 3
Prentice Hall ©2004
Catalyst
CH 3OCH3 + H 2O
Chapter23
Slide 31
Functional Groups: Amines
•
01
Amines: Are organic bases with the general
formula R3 N where R may be H or a hydrocarbon
group. Their names are derived from the alkyl
groups attached to the nitrogen.
H3 C
N
H3 C
H
Methylamine
(Primary)
Prentice Hall ©2004
N
CH3
H3 C
H
H
N
CH3
CH3
N,N-dimethylamine N,N,N-trimethylamine
(Secondary)
(Tertiary)
Chapter23
Functional Groups: Amines
•
Slide 32
02
Amines are bases like ammonia.
CH3 NH2 + H2 O → CH3 NH3 + + OH–
•
They are easily protonated (neutralized) in acid
solution to form soluble amine salts.
(CH 3CH2) 2 NH + HCl → (CH3 CH2) 2NH2 Cl(aq)
Prentice Hall ©2004
Chapter23
Slide 33
11
Functional Groups: Carbonyl
•
01
Carbonyl (Pronounced Car–bo–neel): Has a
carbon–oxygen double bond (C=O).
Prentice Hall ©2004
Chapter23
Slide 34
Functional Groups: Carbonyl
•
02
Aldehydes: Have the terminal carbonyl functional
O
group, -CHO,
R C
H
•
They are named by replacing the -e ending of the
alkane by an -al ending. Numbering begins with the
aldehyde carbon.
CH3
O
CH3 C
CH3 CH
H
ethanal
Prentice Hall ©2004
O
C
H2
C
H
3-methylbutanal
Chapter23
Functional Groups: Carbonyl
•
Slide 35
03
Aldehydes are prepared by oxidizing primary
alcohols. An example is given below where
methanal (formaldehyde) is prepared from
methanol.
Prentice Hall ©2004
Chapter23
Slide 36
12
Functional Groups: Carbonyl
•
04
Ketones: Have the carbonyl functional group
bonded between two hydrocarbon units.
C
•
Slide 37
05
Ketones are prepared by the oxidation of
secondary alcohols as the example below shows
for the preparation of propanone (acetone).
Prentice Hall ©2004
Chapter23
Slide 38
Functional Groups: Carbonyl
06
Carboxylic Acids:Contain the carboxyl functional
group, –COOH or –CO2 H.
O
C
•
C
Chapter23
Functional Groups: Carbonyl
•
C
Ketones are named by replacing the -e ending of
the alkane with the -one ending and prefixing the
name with the number of the carbonyl carbon.
Prentice Hall ©2004
•
O
OH
They are named by replacing the -e ending of the
alkane with the -oic ending.
O
H 3C
C
Ethanoic Acid
(Acetic Acid)
Prentice Hall ©2004
O
CH 3 O
OH
H 3C
H2
C
C
H
C
OH
2-methylbutanoic ac id
Chapter23
C
OH
Benzoic Acid
Slide 39
13
Functional Groups: Carbonyl
•
07
Carboxylic acids are prepared by the oxidation of
aldehydes or primary alcohols.
O
H 3C CH 2 O H
•
O2
H3 C
O
C
O2
H
H3 C
C
OH
Carboxylic acids dissociate as weak acids to give
the carboxylate anion and the hydronium ion.
CH 3CO2H + H2O → CH 3CO2– + H3O+
Prentice Hall ©2004
Chapter23
Slide 40
Functional Groups: Carbonyl
•
08
Esters: have the general formula R’COOR or
R’CO2 R, where R’ can be H or a hydrocarbon
group and R is a hydrocarbon group.
O
R
•
C
O
R'
They are the product of a reaction between a
carboxylic acid and an alcohol, eliminating water
and forming the “organic salt,” the ester.
O
O
H
R
C
O
H + H
O
Prentice Hall ©2004
R'
R
C
O
R'
Chapter23
H
O
Slide 41
Functional Groups: Carbonyl
•
+
08
Ester names are derived from the acid name where
the -oic ending is replaced by the -oate ending and
prefixing this with the name of the attached alkyl
group (which comes from the alcohol).
O
H3 C
C
O CH 3
Methyl Ethanoate
(methyl acetate)
Prentice Hall ©2004
O
H3C
O
C
H C
O
CH 2 CH 3
Ethyl Ethanoate
(ethyl acetate)
Chapter23
O
CH 2 CH 3
Ethyl Methanoate
(ethyl formate)
Slide 42
14
Functional Groups: Carbonyl
•
09
Esters are commonly found or used in:
•
Medicines (aspirin)
•
Anesthetics (benzocaine )
•
Polymers (Polyesters, Dacron, Mylar)
•
Fragrant odors of food and flowers
Prentice Hall ©2004
Chapter23
Slide 43
Functional Groups: Carbonyl
10
•
Amides: Often known in the peptide bond, it
consists of a carbonyl and an amine group on the
same carbon.
•
Formed when an acid and a basic amine react.
O
O
C
C
OH H
N
N
+
H 2O
H
H
Acid
Amine
Prentice Hall ©2004
Amide
Chapter23
Functional Groups: Carbonyl
•
Slide 44
11
Amides are named by replacing the -oic ending of
the acid by the -amide ending and then prefixing
this name with the N-alkyl groups on the amine.
O
N-ethylbutanamide
N
H
O
N
H
Prentice Hall ©2004
N-methylethanamide
(N-methylacetamide)
Chapter23
Slide 45
15
Functional Groups: Carbonyl
•
The amide bond is the fundamental link used by
organisms to form proteins.
•
Some synthetic polymers and pharmaceutical
agents are amides.
Prentice Hall ©2004
Chapter23
C h a pt e r
12
Slide 46
23
Polymer Chemistry
Chemistry 4th Edition
McMurry/Fay
Dr. Paul Charlesworth
Michigan Technological University
What Is a Polymer?
01
•
Polymer: A molecular compound distinguished by
a high molar mass, ranging into thousands and
millions of grams, and made up of many repeating
units.
•
Polymers are classified in several ways:
1. Thermosetting/Thermoplastic
2. Addition/Condensation
3. Plastics, fibers, elastomers, coatings, adhesives.
Prentice Hall ©2004
Chapter23
Slide 48
16
Addition Polymerization
01
•
Simplest polymer is polyethylene, made from
“stringing together” ethylene (ethene) molecules.
•
The molecule consists of over 500 units. These
repeating units are represented below where one of
the two bonds in the double bond in CH2 =CH2 has
been broken and the two paired electrons split to
form two new bonds.
H H
*
Prentice Hall ©2004
C
C
H
H
*
n
Chapter23
Slide 49
Addition Polymerization
•
02
Polymer synthesis starts with monomers, the molecular
building blocks that create the repeating structure.
•
Polymerizing alkenes requires an initiator to break the p bond.
•
Once the p -bond breaks, chain propagation occurs until
some termination reaction stops it.
Prentice Hall ©2004
Chapter23
Slide 50
Addition Polymerization
•
Chain initiator: a peroxide decomposes under
heating to form two radicals.
2R O
R O O R
•
03
Initiation Step: Reaction of the radical.
H
R
O
+
H
Prentice Hall ©2004
H
C
C
R
H
Chapter23
O
H
H
C
C
H
H
Slide 51
17
Addition Polymerization
•
Chain initiator: benzoyl peroxide.
O
O
O
Heat
O
O
2
O
•
04
Initiation Step: Reaction of benzoyl radical.
O
O
O
+
H2 C
O
CH2
Prentice Hall ©2004
H2
C
CH2
Chapter23
Slide 52
Addition Polymerization
•
Chain Propagation: Addition of further ethylene.
R
•
05
O
H
H
H
H
C
C
C
C
H
H
H
H
n
H
+
H
C
H
C
R
O
H
H
H
H
H
C
C
C
C
H
H
H
H
n +1
Chain Termination: Reaction of two radicals.
R
O
H
H
H
H
C
C
C
C
H
H
H
H
n
O
+
Prentice Hall ©2004
R
R
O
H
H
H
H
C
C
C
C
H
H
H
H
n
O
Chapter23
Slide 53
Addition Polymerization
•
06
Chain Propagation: Addition of further ethylene.
O
O
•
R
H2
C
C
H2
H2
C
O
CH2
+
O
H2C CH2
H2
C
C
H2
n
H2
C
CH2
n+1
Chain Termination: Reaction of two radicals.
O
O
Prentice Hall ©2004
H2
C
C
H2
H2
C
n
O
CH2
+
O
O
O
Chapter23
H2
C
C
H2
H2
C
n
O
C
H2
O
Slide 54
18
Addition Polymerization
H
H
C
C
H3C
•
07
CH
H
CH2
Propene: Forms the
polymer polypropene or
polypropylene.
Prentice Hall ©2004
•
Styrene: Forms the
polymer polystyrene or
styrofoam .
Chapter23
Slide 55
Addition Polymerization
F
C
F
•
H
F
C
08
H
C
F
H
Tetrafluoroethene: Forms
the polymer polytetrafluoroethene. This polymer is
marketed as PTFE, Teflon,
and Goretex .
Prentice Hall ©2004
C
•
Cl
Chloroethene: Commonly
known as vinyl chloride this
forms the polymer
polyvinylchloride or PVC.
Chapter23
Slide 56
Addition Polymerization
H
H
H
CH3
C
C
H
•
C
C
H
C
O
O
CN
Cyanoethene: Commonly
known as acrylonitrile this
forms the polymer
polyacrylonitrile.
Prentice Hall ©2004
09
CH3
•
Methyl 2-methyl -2propenoate: Commonly
methyl methacrylate this
forms the polymer PMMA.
Chapter23
Slide 57
19
Condensation Polymerization
01
•
In condensation reactions, two molecules link by
forging bonds between their functional groups.
•
In the process a molecule of H2 O is formed.
•
Polymerization may take place between two
different functional groups, or two that are the
same.
Prentice Hall ©2004
Chapter23
Slide 58
Condensation Polymerization
•
02
Polyamides: Nylon-66 by Du Pont is of this type.
n HO
O
C
O
C
C
O
OH n H
H
N
N
H
H
N
C
O
N
H n
Prentice Hall ©2004
H
+ H2 O
Chapter23
Slide 59
Condensation Polymerization
03
H
•
Kevlar:
•
A Polyamide
where Hydrogen
N
O
bonds increase
strength.
H
N
H
H
N
N
O
N
H
H
N
H
O
O
O
N
H
H
N
O
Chapter23
H
N
O
O
N
H
N
H
Prentice Hall ©2004
O
O
N
N
N
H
H
N
O
H
O
O
O
N
O
Slide 60
H
20
Condensation Polymerization
•
04
Polyesters: Account for over 40% of the more than
4 billion kg of synthetic fibers in the USA.
O
O
HO
O
OH +HO
O
Terephthalic Acid
Prentice Hall ©2004
+ H 2O
O
OH
O
Ethylene Glycol
n
PET
Chapter23
Properties of Polymers
Slide 61
01
•
Plastics: A polymeric material that hardens on
cooling or on evaporation of solvent, allowing it to
be molded or extruded into specific shapes or
spread into thin films.
•
Plastics fall into two groups:
1. Thermoplastic – melt or deform on heating.
2. Thermosetting – retain structure on heating.
Prentice Hall ©2004
Chapter23
Properties of Polymers
•
Slide 62
02
Thermoplastic polymers:have very little or no
cross-linking between the polymer chains. Crosslinking provides the structure and thermal stability.
Prentice Hall ©2004
Chapter23
Slide 63
21
Properties of Polymers
•
03
Thermosetting Polymers: Have extensive crosslinking that is derived from either the component
molecules or from some secondary process
(vulcanization).
Prentice Hall ©2004
Chapter23
Slide 64
Properties of Polymers
•
04
Plasticizers: small molecules that improve the
flexibility of some plastics. Many plasticizers are
esters of phthalic acid.
O
O
OH
O
O
Phthalic Acid
C6H 6O4
Prentice Hall ©2004
O
O
OH
O
O
O
OCH3
OCH3
O
Dibutylphthalate Dimethoxyethylphthalate
C1 6H2 2O4
C 1 4H1 8O6
Chapter23
Properties of Polymers
Slide 65
05
•
Fibers: Thin threads of polymers made by forcing a
fluid thermoplastic material through tiny pores.
•
Most synthetic fibers are polyesters, polyamides, or
polyacrylonitrile.
•
Polar functional groups in these polymers produce
strong intermolecular forces that add significant
tensile strength to the material.
Prentice Hall ©2004
Chapter23
Slide 66
22
Properties of Polymers
•
06
Elastomers: A polymer that is flexible, allowing it to
be distorted from one shape to another.
Polyisoprene (natural rubber), polybutadiene, and
butadiene-styrene copolymers are important.
• All contain some C=C bonds.
•
Prentice Hall ©2004
cis -Isoprene
unit
Chapter23
trans - Isoprene
unit
Properties of Polymers
•
Slide 67
07
Polymer Stability: Increasing stability has good
and bad effects.
1. More resistant to chemical and physical attack.
2. More resistant to animal and insect damage.
3. Up to 15% of municipal waste is polymeric.
•
Modern methods are fine-tuning the stability.
Prentice Hall ©2004
Chapter23
Properties of Polymers
Slide 68
08
•
Modulus of Elasticity: Measures how easily the
polymer deforms.
•
Rigid plastics are high modulus polymers.
•
Soft or rubbery plastics are low modulus polymers.
•
Under the same load, low modulus polymers will
deform more than high modulus polymers.
Prentice Hall ©2004
Chapter23
Slide 69
23
Properties of Polymers
Prentice Hall ©2004
Chapter23
Properties of Polymers
Prentice Hall ©2004
Chapter23
Properties of Polymers
Prentice Hall ©2004
Chapter23
09
Slide 70
10
Slide 71
11
Slide 72
24
Properties of Polymers
12
•
Glass Transition Temperature (Tg): This is the
transition of an amorphous state from glass-like to
rubber-like, as temperature increases.
•
Tg is a fundamental characteristic of polymer
properties and processing.
•
At the molecular level, there is an increase in longrange molecular motion, particularly chain rotation.
Prentice Hall ©2004
Chapter23
Properties of Polymers
1.
2.
3.
4.
13
If a 20.0 g mass made a sample of the rubber in
the previous slide increase by 12.0 cm at a
temperature of 25°C. How much will it increase if
the weight is reduced to 8.0 g?
How much will it stretch if the the temperature is
reduced to –50°C?
How much will the plastic sample of the same
dimensions stretch under the same conditions?
Polystyrene is used to make styrofoam coffee
cups. What can you say about Tg for this
polymer?
Prentice Hall ©2004
Chapter23
Properties of Polymers
•
Slide 73
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14
Some changes that take place:
1. Increased specific volume (measured by dilatometry).
2. Enthalpy change (measured by calorimetry).
3. Modulus decreases appreciably.
4. Refractive index.
5. Thermal conductivity.
Prentice Hall ©2004
Chapter23
Slide 75
25
Properties of Polymers
•
15
What Determines Tg?
1. Chemical structure is the most important.
2. Method of measurement.
3. Difficulties with reproducible results.
4. Time (polymers can “age”).
•
Discrepancies of up to 30°C for a given polymer
are not uncommon.
Prentice Hall ©2004
Chapter23
Slide 76
Properties of Polymers
•
16
Primary chemical structure factors that increase Tg
for polyvinyl polymers
*
H
S
C
C
H
H
*
n
Size of the substituent, S ( many exceptions )
• Branching of the substituent, S ( i-propyl > n-propyl)
• Polarity of the substituent, S ( -OH > -Cl > -CH 3 > H)
•
Prentice Hall ©2004
Chapter23
Slide 77
Properties of Polymers
•
•
•
•
•
•
•
•
•
•
•
The glass transition temperatures of some vinyl
polymers:
The R-group
T g (oC)
-H
–20
-CH 3
5
H
-CH 2CH 3
–24
-CH 2CH 2CH 3
–40
* C
-CH(CH3)2
50
-C(CH 3)3
64
-Cl
81
H
-OH
85
-C 6H 5
100
Prentice Hall ©2004
Chapter23
17
R
C
H
*
n
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Polymers
•
What are the monomer(s) used to produce each
addition polymer below?
•
1. -CH2 CH(CN)CH2 CH(CN)-
•
2. -CH2 CF2 CH2 CF2-
•
3. -CH(OH)CH(OH)CH(OH)CH(OH)-
•
4. -CH2 C(CN)(CH3)CH 2C(CN)(CH3)-
Prentice Hall ©2004
Chapter23
Slide 79
Polymers
•
What are the repeating units in the condensation
polymers formed from the monomer(s) below?
•
1. HO 2C(CH2) 2 CO2 H and
•
2. HOCH2 CH2 CO2 H
•
3. H2 N(CH 2) 2CO2 H
•
4. H2 NCH2 NH2 and HO2 CCH2 CO2 H
Prentice Hall ©2004
Chapter23
HOCH2OH
Slide 80
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