Polymer Physics – Insight into Polyurethane Structure/Property ...€¦ · Polymer Physics –...
Transcript of Polymer Physics – Insight into Polyurethane Structure/Property ...€¦ · Polymer Physics –...
Polymer Physics – Insight into Polyurethane
Structure/Property Relationships
Steve Seneker, Ph.D. Anderson Development Company
Outline n Elastomer Structure (Morphology) n Effect of Hard-Segment Structure
• Diisocyanate Symmetry n TDI n H12MDI
• Diol Extenders – Mixed • Unsymmetrical Urea Hard Segments
n Effect of Soft-Segment Structure • Brittleness Temperature or Tg • Polyol MW Distribution and Crystallizability • Polyol Compatibility
Elastomer Structure (Morphology)
n Three Basic Components • Diisocyanate • Chain Extender • Polyol
n These three components react together and form two phases. • Hard-segment phase • Soft-segment phase
Elastomer Structure (Morphology)
n Hard-Segment Phase • Diisocyanate • Chain Extender
n Soft-Segment Phase • Polyol
Elastomer Structure (Morphology)
n Two Types of Hard-Segment Phases
• Symmetrical Diisocyanates (MDI, H12MDI, NDI,PPDI, TODI) reacted with symmetrical diol curatives.
n Phase separation driven by order or crystallinity. n Results in “macro” phase separation.
• Unsymmetrical Diisocyanates (TDI, IPDI) need aromatic diamine curatives resulting in urea linkages.
n Phase separation driven by hydrogen bonding of urea linkage n Results in “micro” phase separation.
Urethane and Urea Linkage: H-Bonding
RN C
O
O
H
R RN C
O
N
H
HR
Urethane (One H-Bond)
Urea (Two H-Bonds)
Elastomer Structure (Morphology)
Elastomer DMTA Curve
Effect of Hard Segment Structure
n Diisocyanate Symmetry • H12MDI • TDI
n Diol Extenders - Mixed n Unsymmetrical Urea Hard Segments
Aliphatic Diisocyanates
N NC C
O O
CH3
CH3 CH3
N
NC
C OO
Dicyclohexylmethane Diisocyanate
(H12MDI)
Isophorone Diisocyanate (IPDI)
CH2CH2
CH2CH2
CH2CH2
NN C
C
O
O
Hexamethylene Diisocyanate
(HDI)
H12MDI Isomers
H12MDI/PTMEG-2000/1,4-Butanediol
Physical Property 20% t,t -‐H12MDI 97% t,t-‐H12MDI
Hardness, Shore 26D 41D Bashore Rebound, % 39 58
ElongaIon, % 370 720 Tensile Strength, psi 2680 3690
Die C Tear, pli 340 740 Compression Set, % 42 27
Toluene Diisocyanate (TDI) CH3
N
N
CO
CO
CH3N
CO
NC
O
2,4-TDI 2,6-TDI
TDI/PTMEG/1,4-Butandiol
2,4-TDI Content Hardness Tensile Die C Tear Split Tear (wt %) (Shore) (psi) (pli) (pli)
100 60A 1700 170 11
80 51A 800 90 50
0 82A 3200 280 200
Potlife: TDI Isomer Effect
2,4-TDI Content Potlife (wt %) (minutes)
100 12 80 7 65 5 40 3.5 20 3.5 0 3
Toluene Diisocyanate (TDI) CH3
N
N
CO
CO
CH3N
CO
NC
O
2,4-TDI 2,6-TDI
MDI and Mixed Extenders
MDI/PTMEG and Mixed Extenders Curative(s) Ratio Hardness (A) Rebound (%) Clarity
DiHEDS 92 58 Slightly hazy DiHEDS/BDO 75/25 78 47 Clearish DiHEDS/BDO 50/50 81 55 Hazy/Opaque
BDO 90 66 Opaque
DiHEDS 92 58 Slightly hazy DiHEDS/DEG 75/25 75 48 Clear DiHEDS/DEG 50/50 74 45 Clear
DEG 83 56 Opaque
DiHEDS 92 58 Slightly hazy DiHEDS/HDO 75/25 86 56 Hazy DiHEDS/HDO 50/50 84 53 Slightly hazy
HDO 86 63 Opaque
MDI/Polyester and Mixed Extenders
Curative(s) Ratio Hardness (A) Rebound (%) Clarity DiHEDS 88 28 Clearish
DiHEDS/BDO 75/25 69 12 Clear DiHEDS/BDO 50/50 71 12 Clearish
BDO 85 32 Opaque
DiHEDS 88 28 Clearish DiHEDS/DEG 75/25 63 10 Clear DiHEDS/DEG 50/50 60 8 Clear
DEG 75 17 Clear
DiHEDS 88 28 Clearish DiHEDS/HDO 75/25 76 21 Mostly Clear DiHEDS/HDO 50/50 75 20 Clear
HDO 80 30 Hazy/Opaque
Aliphatic – Urea n Prepolymer:
• 2,4-TDI/PPG Diol - 3.0% NCO • Aliphatic Diisocyanate (NBDI, Des W, IPDI, TMXDI) • % NCO: 4.0 and 8.0
n Curative: Curene 89 LC (low color DETDA) n Casting Conditions:
• Prepolymer @ 60 C, Curative @ R.T. • Molds preheated @ 100 C • Stoichiometry: 0.95
n Curing Conditions: 16 hours @ 100 C n Samples conditioned at least 2 weeks prior to
testing.
4% NCO Results
Aliphatic Isocyanate
Shore Hardness Rebound % Elongation %
Tensile Strength
psi Die C
Tear pli
Split Tear pli
IPDI 77A 62 770 3190 265 89
TMXDI 76A 59 820 2820 265 125
Des W 82A 59 840 3270 260 88
NBDI 78A 61 750 3140 260 86
8% NCO Results
Aliphatic Isocyanate
Shore Hardness Rebound% Elongation %
Tensile Strength
psi Die C
Tear pli
Split Tear pli
IPDI 97A, 46D 56 740 4280 440 242
TMXDI 97A, 47D 59 730 4360 430 238
Des W 98A, 54D 57 590 4140 515 243
NBDI 97A, 48D 59 650 4640 460 197
H12MDI/PTMEG-2000/DETDA
Physical Property 20% t,t -‐H12MDI 97% t,t-‐H12MDI
Hardness, Shore 47D 47D Bashore Rebound, % 53 57 ElongaIon, % 310 380 Tensile Strength, psi 4410 4410 Die C Tear, pli 510 590 Compression Set, % 50 55
Effect of Soft Segment Structure
n Polyol Effect on Tg/Brittleness Temperature
n Polyol MW Distribution n Polyol Compatibility
Polyether Polyols
CH2CH2
CH2CH2
OO H
H n
CH2CH
CH3
OO H
H
n
CH2CH2CH2
OH
OHn
Polypropylene Glycol (PPG)
Polytetramethylene Glycol (PTMEG) Polytrimethylene Glycol (Cerenol Polyol)
CH2CH
CH3
OO CH2
CH2O
HCH2CH2
OH
nx x
Hydroxyethyl capped Polypropylene Glycol
(EO capped PPG)
Polyester Polyols
O
O
O
OO
H OH
x
O
O
O
OO
H OH
x
O
OO
HO
O
OH
xx
Polyethylene Adipate
Polybutylene Adipate
Polycaprolactone (1,4-BDO initiated)
Brittleness Point – Polyol Effect
n PTMEG • 70A to 75D: -68C (-90F) to -55C (-67F)
n PPG • 70A to 75D: -45C (-49F) to -26C (-15F)
n Polyesters • 70A to 70D: -27C (-17F) to -13C (9F)
Ultra-Low Monol PPG versus PTMEG
Ultra-Low Monol PPG PTMEG
Chemical Structure
-O(-CH2-CH-O)x- I
CH3
Tg ≈ -75°C
-O(-CH2 CH2 CH2 CH2-O)x-
Tg ≈ -84°C
Hydroxyl Type (Reactivity)
Secondary Hydroxyl (Lower Reactivity)
Primary Hydroxyl (Higher Reactivity)
Molecular Weight Distribution (Viscosity)
Narrow: Mw/Mn = 1.02-1.15
(Acclaim 2200: 165 cps @ 40°C)
Broad: Mw/Mn = 1.7-2.4
(PTMEG-2000: 1200 cps @ 40°C)
Crystallizability Noncrystallizable (Liquid; Pour Point = -33°C)
Crystallizable (Waxy Solid; m.p. = 28 to 40°C)
Stress/Strain Curves – 80 Shore A Elastomers (MDI Prepolymers; BDO Cured)
Effect of Polyester Crystallizability on Stress/Strain Curves of 80 Shore A Elastomers (MDI Prepolymers; BDO Cured)
0
5
10
15
20
25
30
35
40
45
0 200 400 600 800 1000 1200 1400
Strain (%)
Stre
ss (M
Pa)
PBA PCL PEBA PMPA
PBA – Polybutylene Adipate PCL - Polycaprolactone PEBA - Polyethylene Butylene Adipate PMPA - Poly-2-Methyl-1,3-Propanediol Adipate
Polyol Molecular Weight Distribution
Ultra-Low Monol PPG versus PTMEG in Polyurethane/Urea Elastomers
(6% NCO 2,4-TDI Prepolymers; MBOCA Cured)
PPG-1000 Acclaim® 4200/DEG
Andur® 2-92 AP
Hardness, Shore 83A 92A 92A Pendulum Rebound, % 15 55 46
Ultimate Elongation, % 340 310 410 Tensile Strength, MPa 9.3 21.7 48.2
Die C Tear Strength, kN/m 39 88 91
Andur® is a registered trademark of Anderson Development Company
Polyol Compatibility
n Krasol Polyols • Hydroxyl-terminated polybutadienes • Functionality close to 2.0 • Miscible with PPG and PTMEG polyols
Curatives Used for Compatibility Study – Aromatic Diamines
MBOCA
MCDEA
Cl Cl
NH2
NH2NH2
NH2
S CH3
CH3
SCH3
O
O
O
O (CH2)3
NH2 NH2
ClCl NH2NH2
H3CH2C
CH2CH3 H3CH2C
CH2CH3
Curene 107
• Versalink 740M
TDI-80/Krasol LBH-3000 (NCO:OH = 1.90; 2.04% NCO)
MBOCA MCDEA Curene 107 (Ethacure 300)
Versalink 740M
Potlife 6’ 00” 4’ 30” 6’ 00” 25’ Demold 40 min. 30 min. 35 min. > 60 min. Prepolymer Appearance Solid Flakes Clear Clear Opaque Elastomer Appearance Solid Flakes Clear Clear Opaque Shore Hardness ---- 73A 65A 65A Elongation, % ---- 290 350 350 Tensile Strength, psi ---- 1510 1560 1240 100% Modulus, psi ---- 750 540 510 300% Modulus, psi ---- ---- 1280 1100 Die C Tear, pli ---- 145 113 112 Split Tear, pli ---- 29 27 24
Hydrolytic Stability Data
n Test Solutions: • Water (90C, 3 weeks) • 50% Sodium hydroxide (RT, 3 weeks) • 60% Sulfuric acid (RT, 3 weeks) • Sodium hypochlorite (5% Cl) (RT, 5
weeks)
90C Water Immersion, 3 weeks H2O immersion, 90C for 3 weeks
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
140.0%
PPG/MBOCA PTMEG/MBOCA Krasol/PPG/MBOCA Krasol/MCDEA Krasol/Curene 107
Candidate
% R
eten
tion Hardness
Tensile100% ModulusElongation
60 % Sulfuric Acid Immersion (RT), 3 weeks H2SO4, RT, 3 weeks
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
140.0%
PPG/MBOCA PTMEG/MBOCA Krasol/PPG/MBOCA Krasol/MCDEA Krasol/Curene 107
Candidate
% R
eten
tion Hardness
Tensile100% ModulusElongation
Sodium Hypochlorite (5% Cl) (RT), 5 weeks
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
PTMEG/MBOCA Krasol/MCDEA Krasol/Curene 107
Candidate
% R
eten
tion
Tensile100% ModulusElongation
Outline n Elastomer Structure (Morphology) n Effect of Hard-Segment Structure
• Diisocyanate Symmetry n TDI n H12MDI
• Diol Extenders – Mixed • Unsymmetrical Urea Hard Segments
n Effect of Soft-Segment Structure • Brittleness Temperature or Tg • Polyol MW Distribution and Crystallizability • Polyol Compatibility
Acknowledgements
n Mobay Corporation (Bayer Material Science)
n ARCO Chemical (Lyondell Chemical)
n Anderson Development Company
n PMA (Polyurethane Manufacturer’s Association)
n CPI (Center for the Polyurethane Industry)