Post on 28-Dec-2015
Functional Polymers From Renewable Resources
S. Shang, A. Ro, S. J. Huang and R. A. Weiss
Polymer ProgramUniversity of Connecticut
Storrs, CT
New England Green Chemistry Consortium Annual MeetingUniversity of Maine
Orno, MEMay 31, 2006
Monomers From Renewable Resources
Polymers based on renewable resources
crops, grasses, agricultural byproducts Raw materials are sustainable;
Polymers can be designed to be biodegradable
Lactic Acid
HO OH
CH3
O
Itaconic Anhydride
O
O
O
Stearyl Methacrylate
OO
Fermentation of agricultural by-products (carbohydrates),
e.g., corn starch
Pyrolysis of citric acid, or
Fermentation of carbohydrates to form itaconic acid, followed by dehydration
Derived from fatty acid from animal or vegetable fats or oils
Poly(lactic acid), PLA
HO
OH
O
CH3 Azeotropic Distillation
- H2O
O
*
O
CH3
n
O
OH
O
CH3
n
Prepolymer Mn ~ 5000
Condensation-H2O
Depolymerization
O
O
O
O
CH3
H3C
Lactide
Ring Opening Polymerization(SnOct2 with coinitiator)
High Molecular Weight PLA*
HSnOct2
Drumwright, R. E.; Gruber, P. R.; Henton, D. E. Adv. Mater. 2000. 12. 1841.
Applications: Fibers, films, moldable thermoplastics (Tm ~ 175C), sutures
Deficiencies: Low Tg (~ 60C), Narrow melt processing window, Brittle plastic, hydrophobic; incompatible with other polymers (blends)
IonomersPredominantly hydrophobic polymers that contain
modest amounts of bonded acid or salt groups (~ 15 mol%)
Interchain association of salt groups significantly alters thermal properties, mechanical properties and rheology.
PS1.82 NaSPS3.44 NaSPS5.81 NaSPS
Applications: coatings, fibers, thermoplastics, adhesion promoters, compatibilizers, viscosifiers, permselective membranes, hydrogels…
Research GoalsSynthesize and Characterize Ionomers Derived from Lactic
Acid, Itaconic Anhydride and Stearyl Methacrylate
Random Ionomer
- +
- +
- +
- +
Telechelic Ionomer
- +
- +
- +
O
H2C
CH2
O
O
C
CH3
C
O
CH2
O
H2C
O
CHH2C
CH3
O
O
x
H
O
H2C
CH2
O
O
C
CH3
C
OO
n mnm
a b
ITA
SM
ITA
ITA
PLA
PLA
Radical copolymerizaton of ITA and SM
IR evidence for copolymerizaiton: 1862, 1782 cm-1: ITA (anhydride) 5 member ring shift of C=O in SM from 1720 to 1731 cm-1 indicating reaction of C=C disappearance of peak at 1601 cm-1: reaction of C=C
OO O
+
O
(CH2)17CH3
O
O
O
O
O
(CH2)17CH3
O
AIBN, 80oC
Ethyl Acetate
n m
ITA SMco(ITA/SM)
Wavelength (cm-1)
10001500200025003000
Abs
orpt
ion
0
1
2
3
4
5
6
Copolymer
Mixture
ITA
SM
1862
17821730No peak
166016801700172017401760178018000.0
0.5
1.0
1.5
2.0
1731
1720
1601
Mixture
Copolymer
rITA = r1 = 0.53
rSM = r2 = 0.12
RandomCopolymers
Copolymerization of ITA and SM
Mn (25k – 60kDa) decreased with increasing fITA
f I TA
0.0 0.2 0.4 0.6 0.8 1.0
FIT
A
0.0
0.2
0.4
0.6
0.8
1.0
22221
211
212
111 2 frfffr
fffrF
J. Wallach, PhD Dissertation, Univ. Conn., 2000
Thermal behavior of ITA-co-SM copolymers
Increasing SM composition fITA Mn (kDa) Tm (C)
H (J/g SM)
0 57.1 30.2 62.8
0.29 45.1 31.2 83.0
0.40 33.0 32.1 77.0
0.53 34.8 44.7 87.9
0.54 29.1 48.2 50.9
0.45 24.1 45.6 21.3
Crystallinity is due to the SM side chain packing
Melting temperature increased with increasing ITA
content!
Effect of ITA on crystallinity was complicated.
No glass transition was observed (Tg(ITA) ~ 130C).
DSC: 1st scan after ppt from soln.
Crystalline structure of ITA-co-SM
Composition(mol% ITA) d (nm)
0 2.95
29.0 2.96
4552.8
3.983.18
53.8 3.55
100 --
Length of alkyl side chain = 2.5 nm
SAXS
WAXD
0.417 nmcharacteristic of n-alkyl
hexagonal packing,
27
3.9 nm
Zn-Stearate Bilayer Crystal
Side-Chain, Stearyl Methacrylate Crystals
LL
Intercalated Crystal
Bilayer Crystal
L
(Mn=33 kDa; 40 mol% ITA)
IR evidence of neutralization
Peak ~ 1550-1650 cm-1 due to COO-
ITA-co-SM Ionomers
Wavenumber (cm-1)
1400150016001700180019002000
1570
1570
I TA-co-SM (40% I TA)
Na+ Salt (100%)
Ca2+ Salt (50%)
1630
Ionomer Structure and Properties
Ionic aggregation was observed
Long spacing of SM crystals increased upon neutralization
Neutralization increased the elasticity of the polymer.
Temperature (oC)
0 20 40 60 80
Prob
e H
eigh
t
0.0
0.2
0.4
0.6
0.8
1.0
I TA- co- SM(40% I TA)
Ca- Salt (50%)
Na- Salt (100%)
TMA (F = 60 mN)
q (nm-1)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
Inte
nsi
ty
Na-salt (100%)
Ca-salt (50%)
I TA-co-SM (40% I TA)
Poly(SM)
SAXS
Chemical Recycling of PLA by Transesterification
Transesterification Uncatalyzed - slow process, reaction temperature 250-300C.
Catalyzed - lower time and temperature (J. Wallach, PhD Dissertation, Univ. Conn., 2000).
– SnOct2. FDA approved.
Mechanism
O
CH3
O
O
O
OH
O
SnOct2
O
CH3
O
O
O
OH
O
SnOct2
HO
R
O
CH3
OH
O
O
OH
O
SnOct2
OR+
OR
H
Synthesis of ω-carboxylate functionalized PLA
A. Synthesis of methacrylate-terminated PLA
B. Functionalization with itaconic anhydride
O
OOH +
HO
CH3
O
HOn
SnOct2
O
OO
O
CH3
OH
n
2-hydroxyethyl methacrylate poly(lactic acid) telechelic PLA A
ethyl acetate,120oC, SnOct2
O
OO
O
CH3
OH
n
+OO
O
O
OO
O
O
O
O
O
n
itaconic ahydrideTelechelic PLA A telechelic PLA B
H
O
OO
O
O
O
O
OH
n
Broad OH stretch Carboxylic C=O stretch
C-O-H in-plane bend and C-O stretch
C=C stretch
C=O stretch
O
OO
O
O
O
O
O
nM
Asymmetric carboxylate anion stretch
1H-NMR Spectrum of Functionalized PLA Oligomer
End group Analysis -Mn = 1930, with 25 LLA units
c d h
d
c h
q/a
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
Tg
(o C)
25
30
35
40
45
50
55c = 0.6 mol%
(M ~ 13,000 g/ mole)
c = 2.1 mol%M ~ 3,000 g/ mole
For higher molecular weight (M ~ 15,000 – 900,000), Tg was relatively insensitive to functionalization
Glass Transition Temperatures of PLA-ITA Telechelic Ionomers
Cations = Li+, Na+, K+, Ca2+, Zn2+, Y3+
YZnCaLiNaK
Acknowledgments
Funding by:
New England Green Chemistry Consortium
NSF/EPA
Petroleum-Based Polymers
Hydrophobic and resistant to biodegradation
Escalating prices of petroleum (only ~ 2% of petroleum is used for polymers)
* Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2003, U.S. Environmental Protection Agency, 2003.
Tullo, Chem. Eng. News. 2005, 83, 19.
*
Environmental Concerns
Plastic are the largest volume component in U.S. landfills (~
25%)
Existing petroleum resources are limited.
Plastics production has nearly doubled every 10 years for four decades.
Environmental Issue Sustainability Issue
Biodegradable Polymers
Aliphatic Polyesters from Hydroxyacids
Poly(3-hydroxybutyric acid)
Poly(lactic acid)
O
O CH3
n
O
CH3
O n
NatureWorks LLC
Itaconic Anhydride
• Ramos – PEG functionalization
• Biocompatible – citric acid distillation, fermentation of carbohydrates (Aspergillus terreus)
ROH
SnOct2
RO
O
OH
O
OH
O
RO
O
O
O
O
A
B
Ramos, M. Multi-component Hydrophilic-Hydrophobic Systems From Itaconic Anhydride. Ph.D. Thesis, University of Connecticut, Storrs, CT, 2002.