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Synthesis and Physical Properties of

Polyester Amides Derived from

Lipid-Based Components

By: Jiaqing Zuo

Trent Biomaterials Research Group

March 2011

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Outline

Introduction of polyester amide (PEA)

What is polyester amide

Applications

Advantage of Lipid-based components

Previous Examples of Lipid-based PEA

Objectives and Results

Conclusions

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Introduction

What is polyester amide (PEA)

Boc

HN COOH

Boc

HN

O O O O

HN

Boc

O OOO

TFA

HN O O O O

HN

O OOO

Cl Cl

O O

H2N O O O O NH2

O OOO

*

O

*

O

n

HO O O OH

O O

1

2

Ester linkage Amide linkage

Ester linkage: Biodegradability

Amide linkage: Thermal Stability, Mechanical Strength

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Applications

Biomedical applications:

Stent-coatings for drug delivery

Absorbable surgical materials

Material requirements:

Biodegradable

Good processing property

Safely metabolized by human bodies

References:

1. Lee, S.H., et al., Coronary Artery Disease, 2002. 13(4): p. 237-241.

2. Legashvili, I., et al., Journal of Biomaterials Science-Polymer Edition, 2007. 18(6): p. 673-685.

3. Guo, K. and C.C. Chu, Journal of Polymer Science Part a-Polymer Chemistry, 2005. 43(17): p. 3932-3944.

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Advantage of Lipid-based

components

Functional groups:

Carboxylic group

Double bonds

Advantages:

Economically friendly

Environmentally friendly

Potentially have good performance

as petroleum based materials

References:

1. Hojabri, L., X.H. Kong, and S.S. Narine,. Biomacromolecules, 2009. 10(4): p. 884-891.

2. Williams, C.K. and M.A. Hillmyer,. Polymer Reviews, 2008. 48(1): p. 1-10.

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Previous Examples of Lipid-based PEA

PEA derived from:

Pongamia glabra oil Linseed oil

Disadvantages:

Not all building blocks are from sustainable materials

Not suitable for biomedical applications

References:

1. Ahmad, S., S.M. Ashraf, and F. Zafar,. Journal of Applied Polymer Science, 2007. 104(2): p. 1143-1148.

2. Zafar, F., et al.,. Journal of Applied Polymer Science, 2005. 97(5): p. 1818-1824.

3. Ahmad, S., et al.,. Progress in Organic Coatings, 2003. 47(2): p. 95-102.

O

O

O

O

R

R

O

R

O

HN

OH

OH

+ N

OH

OHR

O

OH

O

HO

O

NaOCH3

Diethanolamine

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Objectives

1. Synthesis of PEAs with different ester/amide

ratios

PEA (I) with ester: amide= 1:1

PEA (II) with ester: amide= 2:1

PEA (III) with ester: amide= 3:1

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Hypotheses:

1. The increase of ester to amide ratios in the PEA

structure will result in a decrease of thermal stability

2. The increase of ester to amide ratio in PEA structure

will decrease the glass transition temperature

3. The increase of ester to amide ratio in PEA will result in

increased elasticity

4. The increase of ester to amide ratio in PEA structure

will diminish the mechanical strength of the polymer

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Step 1: Synthesis of different diols from oleic acid

1, 9-Nonanediol

Synthesis of the PEA

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Di-ester diol

Tetra-ester diol

Step 1: Synthesis of different diols from oleic acid

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Characterization of the diols

1H-NMR spectra

1, 9-Nonanediol Di-ester diol

Tetra-ester diol

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Step 2: Polyester amide preparation

PEA

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FT-IR spectra of PEAs

Characterization of PEAs

N-H stretching vibration:

3200–3500 cm-1

C-H stretching vibration:

2850-3000 cm-1

C=O stretching vibration:

1700–1740 cm-1

N-H bending vibration:

1560-1640 cm-1

( ) ( ) ( )

( ) ( ) ( )

: : 1: 2 :3ester I ester II ester III

amide I amide II amide III

A A A

A A A

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Characterization of the PEAs

Mn Mw PDI

PEA (I) 2.08e4 2.98e4 1.43

PEA (II) 2.09e4 3.44e4 1.64

PEA (III) 2.26e4 3.63e4 1. 61

GPC results

Mn: Number average molecular weight

Mw: Weight average molecular weight

PDI: Polydispersity index

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The hydrogen bonding structures

PEA(I)

PEA(II)

PEA(III)

PEA (I) PEA (II) PEA (III)

Molecular weight of the repeating unit

(g/mol)484 712 1025

Hydrogen bonding sites

86 58 44

Length of the repeating unit (Å)

31 48 73

Hydrogen bond density (1/Å)

0.065 0.042 0.028

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Physical Tests

1) Thermogravimetric Analysis (TGA)

• Thermal stability

• Weight changes vs. Temperature

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TGA Results

TD1 (oC) WL1

(%)TD2 (oC) WL2

(%)TD3

(oC)

WL3 (%)

TD4 (oC) WL4

(%)TD5 (

oC) WL5 (%)

PEA (I) 367 35.4 411 33.7 446 13.3 461 6.2

PEA (II) 371 35.6 402 29.8 432 25.6 444 4.3 458 3.7

PEA (III) 383 31.0 410 30.1 452 28.2 467 3.5

TD: Decomposition Temperature WL: Weight Loss

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2) Modulated Differential Scanning Calorimetry (MDSC)

• Melting temperature (Tm)

• Crystallization temperature (Tc)

• Glass transition temperature (Tg)

19Tg: Glass Transition Temperature

Tg

MDSC Results

PEA (I) PEA (II) PEA (III)

Tg (oC) (DSC) 3.4 -20.0 -34.1

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Tc1 (oC) Tm1 (oC) Tc2 (oC) Tm2 (oC)

PEA (I) 66.1 87.8

PEA (II) 14.2 49.3 56.0 77.4

PEA (III) 31.9 54.9 58.8 76.0

Tm: Melting Temperature; Tc: Crystallization Temperature

MDSC Results

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• Viscoelastic properties

• Measuring glass transition temperature

3) Dynamic Mechanical Analysis (DMA)

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DMA ResultsStorage Modulus at 37 oC

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PEA (I) PEA (II) PEA (III)

Tg (oC) (DMA) 17.9 -1.6 -15.0

Tg (oC) (DSC) 3.4 -20.0 -34.1

Tg (DMA) is reported from the peak value of tan δ

DMA Results

/Tan E E

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Tg (DMA) versus Structures

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4) Tensile analysis

• Ultimate strength

• Elongation

• Young’s Modulus

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Ultimate Strength(MPa)

Maximum Strain(%)

PEA (I) 19.6±0.5 12±1

PEA (II) 10.2±0.2 14.3±0.4

PEA (III) 8.5±0.2 12±2

Tensile Analysis

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Ultimate Strength versus Structures

Biodegradability increases

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Young’s Modulus (MPa)

PEA (I) 535.1

PEA (II) 319.2

PEA (III) 239.8

Tensile Analysis

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Young’s Modulus versus Structures

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X-ray Diffraction

2θ (º) d-spacing (Å)

α-form(helical

conformation)

16.8 5.23

19.0 4.65

23.2 3.84

β-form(planar

conformation)

6.9 12.72

21.1 4.19

24.7 3.64

Scattering Angle (2θ, Degree)

Co

un

ts

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Sources and Structures TD (oC) Tg (oC) Tm (oC)

Tensile

strengthElongation Features

From

fatty

acids

PEAs in our research

300 3 87.8 19.6MPa 12%

Derived from oleic acid300 -20 77.4 10.2MPa 14.3%

300 -34 76.0 8.5MPa 12%

Linseed oil,

diethanolamine DEA

and diacid

163-220

(5%)155 Anticorrosive coatings

Pongamia glabra oil,

DEA and diacid

275

(10%)Anticorrosive coatings

Nahar seed oil, DEA

and adipic acid

Surface coating

applications

Gallic acid, amino

acid

249-305

(5%)141-168 180 Highly branched, aromatic

Castor/soyabean oil,

DEA, adipic acid and

Zn(OH)2

260 120Potental antibacterial

activities

Comparison of lipid-based polyester amides

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Sources and Structures TD (oC) Tg (oC) Tm (oC) Tensile strength (MPa) Elongation (%)

From

petroleum

Cyclohexyl diol, diacyl chloride,

cyclohexyl sebacamide250 -36 to -7 68 to 97 20 950

Di-p-nitrophenyl sebacate and p-

toluenesulfonic acid salt of L-

phenylalanine butane-1,4-diester

30 109.2

1,6-hexanediamine, sebacic acid

octadecanedioic acid, and ε-

caprohctone

231 to 391 -24 to 48 64 to 218

Different aromatic diols, diacids and

4-acetamidophenol (AP)80, 87 3.18GPa, 3.94GPa < 4

Glucitol(diol), amino acid, aliphatic

dicarboxylic acid40 to70 124,164

Copolymer 280 to 366 80 to82 240 to 250

α-amino acids, diols and fatty

dicarboxylic acids

6.7 to

32.80.02 to 12.08 65 to 882

Copolymer -45 to -5 83 to140 4 to 26 50 to 870

Random combination of polyester

and nylon

Around

380-15 to -6 29 to 57 10 to 22

BAK 1095

Caprolactam (Nylon 6)

Butanediol, Adipic acid

125 220 400

BAK 2195

Nylon 6,6; Diethylene glycol

Butanediol, Adipic acid

177 550 120

Comparison with petroleum-based polyester amides

Conclusions

Three PEAs with different ratios of ester and amide

linkages were synthesized from lipid-based components

The PEAs were fully characterized

Functionality of the PEAs were investigated from a

structural perspective

PEA’s had superior properties to all other lipid-based

PEAs

PEA’s had comparable and sometimes superior

properties to petroleum-based PEAs

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Hypothesis #1: The increase of ester to amide ratio in the PEA structure

resulted in a decrease of thermal stability

a. The increase of ester to amide ratio did not impact dramatically the thermal

degradation of the PEAs

b. The increase of ester to amide ratio decreased the thermal stability at the

melting behaviour level

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Hypothesis #2: The increase of ester to amide ratio in PEA structure

decreased dramatically the glass transition temperature

a. The increase of ester to amide ratio in PEA structure decreased

dramatically the glass transition temperature

b. This is an improvement as materials with lower Tg can be used flexible in a

wider range

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Hypothesis #3: The increase of ester to amide ratio in PEA resulted in an

increased elasticity

From the result of tan Delta, the elasticity of PEA increased when ester to

amide ratio increased at room temperature

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Hypothesis #4: Mechanical strength of the polymer was diminished

when ester to amide ratio in PEA structure was increased

The tensile strength and the Young’s Modulus are both decreased

when ester to amide ratio increased

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Future Work

Investigate the biodegradability of PEAs with varying ratios of ester to amide groups

Increase the molecular weights of the synthesized PEAs to further improve the thermal and mechanical properties (such as changing the amino acid to polypeptide or increasing the reaction temperature)

Study the effects of crystallinity on the physical properties of the PEAs

Prepare a PEA with an ester to amide ratio of 4:1 in order to model the trend observed in the physical properties versus ester to amide ratio

Acknowledgment

• Ontario Soybean Growers / Grain Farmers of Ontario

• Elevance Renewable Sciences

• NSERC

• GPA- EDC

• Industry Canada

• Trent University

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Thank You !