Polymer Chemistry
Guangxi University School of Chemistry & Chemical Engineerin
g
Li Guang Hua (李光华)
Lab:材料楼—409#,321# E-mail : [email protected] phone: 15978133590
CHAPTER 10
Thermosetting Polymers :
Fusible & soluble polymer Crosslinking
Infusible & insoluble polymer Thermosetting polymer
Thermoplastic polymer
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1. Phenolic Resins2. Amino resins
4. Epoxy Resins5. Polyurethanes
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3. Unsaturated Polyester Resins
1. PHENOLIC RESINS (I)
Phenolic Resins (Phenolics) F
á Commercialization : in 1909 (Bakelite company)
Phenol-formaldehyde (PF) resins
O O O O
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f = 3
OH OH
CH2OH
CH2OH
HOH2C
OH
CH2OH HCHO
OHCH2OH
CH2OH
HCHOHCHO
1. PHENOLIC RESINS (II)
OH
CH2OHHOH2C
OH
CH2OH+
OHCH2OH2CHOH2C
OH OHCH2HOH2C
OHCH2OH
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CH2OH2CHOH2C
OHCH2HOH2C
OH
CH2HOH2C CH2OH
-HCHO
1. PHENOLIC RESINS (III)
Ø NovolacsConditions : formaldehyde : phenol = 0.8 :1
Catalyst : acid (H2SO4, oxalic acid)
OH
+ HCHO
OHCH2
OHCH2
CH2
OH
CH2
OH
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Novolacs (MW : 700 ~ 1000)
OHOH
CH2
OH
CH2n
CH2
OHCH2
OH
1. PHENOLIC RESINS (IV)
Novolacs
OHOH
CH2
OH
CH2n
N
N
NN
Phenolic resin
Molding powder
Filler
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N
N
NN
6 HCHO + 4NH3
hexamethylenetetramine Catalysis & crosslinking
1. PHENOLIC RESINS (V)
Ø ResolesConditions : formaldehyde : phenol = 1.25 :1
Catalyst : base (NaOH, NH3)
OH
+ HCHO
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OHCH2HOCH2
OHCH2
CH2OH CH2
OHCH2OH
CH2OH
OHCH2OH
Resoles (MW : 500 ~ 1500)
Phenolic resin
Ø Properties of Phenolics
á Have good chemical and thermal resistance, dielectric strength, and dimensional stability.
á Most phenolics contain fillers or reinforcements
◎ General-grade phenolics are filled with mica, clay, mineral flour, cellulose, and chopped fabric
1. PHENOLIC RESINS (VI)
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◎ Engineering-grade phenolics are reinforced with glass or organic fibers, elastomers, graphite
á Products made with these resins are inherently low in flammability, are creep resistant, and have low moisture absorption
á AdhesivesEx., the manufacture of plywood and fiberboard
á Coatings
Ø Applications of Phenolics
Ex., coatings on cans, drums, metal pipe, electrical insulation, varnishes, and metal primers
1. PHENOLIC RESINS (VII)
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á PlasticsEx., printed-circuit boards, gears, cams protective, decorative surfaces
for tables and furniture, switches, pump housings, and cutlery handles
á OthersEx., friction materials (brake lining, transmission bands), foam insulation,
and carbonless copy paper
2. AMINO RESINS (I)
Amino ResinsFurea-formaldehyde (UF) resins
melamine-formaldehyde (MF) resins
N NNH2H2N
NH2
NH2 C NH2
O
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N NH2H2N2 2
urea (f = 4) melamine (f = 6)
O CNH2
NH2
HCHO+
O CNHCH2OH
NH2
O CNHCH2OH
NHCH2OH
2. AMINO RESINS (II)
H2NCHNHCH2OHO
H
H2NCNO
CH23
H2NCNO
CH2 + H3O
N
N
N CNH2
OH2NC
O
CNH2O
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N CH2OH H N CH2OH+
N CH2OH + NHOCH2
N CH2 + H2ON + HCHO
N CH2 N CH2OH + H2O
N CH2 O CH2 + H2ON
N CH2O H + NHOCH2
2. AMINO RESINS (III)
CH2 NH CO N CH2 NH CO NH
CO NH CH2 N CO NH CH2NHCH2
CH2 NH CO N CH2 NH CO NHCH2
CH2
O
Methylene bridge
Methylene ether bridge
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CO NH CH2 N CO NH CH2NHCH2
N
N
N COCO
CO
NH CH2NH
NHCH2
N
Cyclic bridge
2. AMINO RESINS (IV)
Ø Properties of Amino Resins
á They are harder than phenolics but have somewhat lower impact strength and resistance to heat and moisture
á A distinct advantage of the amino resins over the phenolics is clearer and colorless
á The melamine resins have better hardness, heat resistance, and moisture resistance than the ureas
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Ø Applications of Amino resinsá Adhesives (better performance than the phenolic resin)
Ex., the manufacture of plywood and fiberboard
á Melamine resins are used to produce colored dinnerware and dinnerware with decorative patterns.
á Amino resins also find extensive as automotive parts; the cheaper ureas are used as primers while the melamines are used as topcoats
3. UNSATURATED POLYESTER RESINS (I)
Unsaturated Polyester (UP) ResinsF
CO
CO
O
+C
OCO
O
+ 2HOCH2CHOHCH3
O O CH3 CH3O O
toluene sulfonic acid150 ~ 200oC
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CC OCH2CHOO O CH3
CCH CHC OCH2CHOCH3O O
+ 2H2O
Unsaturated polyester (MW 1000 ~ 2000)
3. UNSATURATED POLYESTER RESINS (II)
OCCH CHCOO O
+ CH CH2
OCCH CHCOO O
OCCH CHCOO O
CH CH2peroxide
glass fiber
Glass fiber reinforced UP resin
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Ø Properties & Applications of UP resinsá Have a good combination of resistance to softening and deformation
at high temperature, electrical properties, resistance to corrosion, weak alkalies, and strong acids and possess very good weatherability
á Construction :
á Transportation and marine industries:Ex., tub and shower units, building facades, and specialty flooring
Ex., truck cabs, auto body repair, and boat hulls
Ø Epoxy Resins
4. EPOXY RESINS (I)
CHOCH3
CH3
OHH2C CHCH2ClO
+ (n+1)(n+2)
COCH3
CH3
OCH2CHCH2H2C CHCH2
O OH OCH2CO
CH3
CH3
OCH2CH
n
NaOH aq-HCl
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CH3 CH3n
n = 0 ~ 12 (MW = 340 ~ 3800)
O Ar O H2C CHCH2ClO
+ O Ar O CH2 CH CH2ClO
O Ar O CH2CH CH2
O+ ClO Ar O CH2 CH CH2
OO Ar O
O Ar O
4. EPOXY RESINS (II)
OCH2CHCH2 + NH2H2N R
RN
N
CH2 CH CH2
OH
CH2 CH CH2
OHCH2 CH CH2
OH
CH2 CH CH2
OH
CH3 CO
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COCH3
CH3
OCH2CHCH2
OH+
CR
CO
O
O
COCH3
CH3
OCH2CHCH2O
COCH3
CH3
OCH2CHCH2
O
CRC
O
O
4. EPOXY RESINS (III)
Ø Properties of Epoxy Resins
á A wide range of products varying in properties and curing temperature are obtained for specific applications by proper selection of the monomers, additives, and curing agents.
á Possess high chemical and corrosion resistance, toughness and flexibility, good mechanical and electrical behavior, and outstanding adhesion to many different substrates
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Ø Applications of Epoxy resinsá Adhesives
Ex., military (missile casings, tanks), aircraft (rudders, wing skins), automobiles (drive shafts), and pipe
á Coatings : Ex., marine, maintenance, drum, and can coatingsá Structural composites :
Ex., electrical and electrons industries (circuit-board substrate) á Laminates :
Polyurethanes (PU)F
5. POLYURETHANES (I)
OCN +R NCO R' OHn nHO R NHCO R' nOCNHO O
diisocyanate glycol polyurethane
CH3
NCO CH
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2 NCO + R'' NH2H2N R'' NHCNHO
NHCNHO
urea linkages diamine
2,4-tolulenediisocyanate (TDI) methylene-4,4’-diphenyldiisocyanate (MDI)
NCO
NCO
OCN CH2 NCO
5. POLYURETHANES (II)
O
NH NH+ + OCN R' NCOCOO CO NH
C NHOR'NH C O
N COO
N CO NH
Allophanate
Biuret
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NCO3N
N
N
O
OO
trimerizationcatalyst
OCN NCO OCN NH2H2O
NHCNHO
OCN NHCOOH-CO2
Ø Elastomers
5. POLYURETHANES (III)
CH3
NCO
NHCO B OCNH CH3
NHCO B OCNH CH3
NCO
O O
O O
CH3
NCO
NCO
+ B
excessR' OHHOR'' NH2H2N or
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R'' NHCNHO
NHCNHO
NCOOCN
Crosslinked PU
C(CH2)4COCH2CH2OCH2CH2OOO
CH2CHOCH3
n nHHO HHO
B (MW = 1000 ~ 2000) :
poly(propylene glycol) poly(diethylene glycol adipate)
Properties of PU elastomersá Extremely good abrasion resistance and toughness, combined with
good elasticity and resistance to greases, oils, and solvents.
Applications of PU elastomersá Forklift tires & skateboard wheels
5. POLYURETHANES (IV)
¹
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Ex., bumpers, fenders, door panels, gaskets for trunk, windows, windshield, steering wheel, instrument panel
á Automobile parts
á Sporting goodsEx., golf balls, ski boots, football cleats
Ø Fibers
HO OH + OCN Ar NCO
OCN Ar NHCO
O OCNH Ar NHCO
O OCNHO O
Ar NCO
OCN Ar NCO H2N R NH2
B (MW = 2000 ~ 3000) excess
5. POLYURETHANES (V)
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CNH Ar NHCNHOO
R NH CNH Ar NHCOOO
O
OCN Ar NCO H2N R NH2
(unreacted)
“Hard” segment “Soft” segment
spinning
Crosslinked PU fibers
á Polyurethane fibers have unusually high elasticityLightweight foundation garments and swimsuits
5. POLYURETHANES (VI)
Ø Foams
HO OH
á They do suffer from limited resistance to hydrolysis
H O
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OCN Ar NCO
MW ~ 3000 excess
(unreacted)
OCN Ar NCO+HO OH
OH
or OCN NCO
OCN NH2
H2O
NHCNHO
OCN NHCOOH
-CO2
Flexible foams
Rigid foamsor
5. POLYURETHANES (VII)
Applications of PU foamsá Flexible foams
Ex., insulators, automobile crash panels, upholstery, bedding, carpet underlays, and synthetic sponges
¹
á Rigid foamsEx., commercial roofing, residential sheathing, and insulation for
water heaters, tanks, pipes, refrigerators, and freezers.
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water heaters, tanks, pipes, refrigerators, and freezers.
Ø Coatings
OCN Ar NCO
excessOCN Ar NCO+HO OH
OHOCN NCO
OCN NH2
atmospheric moisture
O
OCN NHCOOH-CO2
5. POLYURETHANES (VIII)
“one-pot” coatings
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OCN Ar NCO
(unreacted)NHCNHO “one-pot” coatings
á Have very good resistance to abrasion and solvent attack plus good flexibility, impact resistance and weatherability
Gymnasium and dance floors and bowling pins, in magnet wire coatings, etc.
á They can be applied by dip, spray, or brush and adhere well to a wide variety of materials