Advisor : Assoc. Prof. Dr. Sarawut Rimdusit

Co-advisor: Dr. Suchada Tragoonwichian

Polymer Engineering Laboratory

Department of Chemical Engineering

Faculty of Engineering

Chulalongkorn University

Bangkok 10330, Thailand

by

Sunanta Klayposri

Controlled Molecular Weight Polycarbonate

Synthesis from Melt Transesterification of

Bisphenol-A and Diphenyl Carbonate

* C

CH3

CH3

O C

O

O *

n

Carbonate Group

• An important class of engineering thermoplastics.

• Containing recurring carbonate groups (-O-CO-C-)

in the main chain.

• The most popular PC is based on bisphenol-A.

Polycarbonate (PC)

Ref.: L. A. Utracki, “Commercial Polymer Blends,” Chapman & Hall, London, (1998). p.85.2

Properties of Polycarbonate

• High impact resistanceIzod, notched impact strength = 850 J m-1

• High heat resistanceMaximum use temperature = 100-135C

• Optical clarityLight transmittance, initial 85 % and after 3 yr 82 %

• Dimensional stability Tensile modulus = 2.38 GPa

Flexural modulus = 2.34 GPa

• Good electrical resistance

Ref.: D. J. Brunelle, “Encyclopedia of Polymer Science and Technology,” John Wiley & Sons, Inc., 2006J. E. Mark, “Polymer Data Handbook,” Oxford University Press, Inc., 1999.

3

Applications of Polycarbonate

• Optical Media

• Automotive Part

• Bottles & Packaging

• Electrical Part

• Glazing & Sheet

• Safety & Healthcare

• Diffuser Sheets for LCD Screens

Ref.: http://www.plasticseurope.org/, http://www.lgdow.com/products/application.htm, http://www.bayer.co.th/webphp/eng/production.php

4

Linear and Branched Polycarbonate

Linear Polycarbonate

OH

O

Branched Polycarbonate

monomers having two different

functional groups react through

condensation polymerization.

monomers having two different

functional groups react through

condensation polymerization, one

having at least 3-functional sites.

DPC

BPA

55.

Branched Polycarbonate

Mw = 5,000 g/mole

OH

O

DPC

BPA

Mw= Mc = 5,000 g/mole

Ref.: R. Dobkowski., Rheol Acta., 34, 578-585(1995).6.

Properties of Branched Polycarbonate

• Melt flow indexBranched polycarbonate ; Melt flow index = 2.5 g/10minLinear polycarbonate ; Melt flow index = 12.2 g/10min

• Optical clarityLight transmittance;Branched polycarbonate; 1 mm thick 88 %, 2 mm thick 87% and

4 mm thick 84%Linear polycarbonate; 3 mm thick 89 %

• Enhanced shear sensitivities Strong shear thinning

• Good processability from high melt strengthExtrusion blow molding, Injection stretch blow molding

Ref.: D. Karlik, H.P. Brack, H. Verhoogt, J.P. Lemmon, J.H. Kamps, W.L. Sederel, J.M.D. Goossens, U.S. Patent 6,504,002 B1 (2003).

7

1. To synthesize polycarbonate prepolymer with a critical molecular weight (Mc) of at least 5,000 to be used as PC precursor for further branched PC preparation.

2. To investigate the optimum conditions for the PC prepolymer preparation.

Objectives

8

Experimental Method

BPA DPC

Nitrogen Tank Vacuum PumpHeater

Trap

9

Stirrer

Gel Permeation Chromatography

Controller

PumpRefractive Index Detector

Column Container

Ref.: http://www.waters.com/waters/nav.htm?cid=10167568&locale=en_TH 10

Pores

Small permeating molecules

Large excluded molecules

Results & Discussion

HO C

CH3

CH3

OH O C O

O

n n

2n-1

Bisphenol-A Diphenyl Carbonate

Linear Polycarbonate Phenol

Melt Transesterification of Linear Polycarbonate

12

C O C

CH3

CH3

O C O

O

n

O

O

OH

175

180

185

190

195

200

205

0

100

200

300

400

500

600

700

800

0 50 100 150 200 250

Temperature

Pressure

Tem

pe

ratu

re(o

C)

Press

ure

(mm

Hg

)

Reaction Time(min)

760 mmHg

100 mmHg180oC

200oC

Synthesis Conditions of PC; without a Catalyst

13

FT-IR Spectra of Linear Polycarbonates

Commercial PC(Wonderilte110)

As-synthesized PC

5001000150020002500300035004000

Ab

so

rba

nc

e

Wavenumber (cm-1)

C-H (Aromatic ring) (1506,757)

C-H (Methyl groups) (2969)

O- (C=O)-O (Carbonyl)) (1773)

C=C (aromatic ring)(1602,1465)

14

Molecular Weight Profile of Synthesized PC without a Catalyst @ DPC:BPA 1.05:1.00

15

0

0.5

1

1.5

2

2.5

0 50 100 150 200 250

Mo

lecu

lar

Wei

gh

t (M

w x

10

4)

Reaction Time (min)

Molecular Weight Profile of Synthesized PC without a Catalyst @ DPC:BPA 1.26:1.00

16

0

0.2

0.4

0.6

0.8

1

0 50 100 150 200 250

Mo

lec

ula

r W

eig

ht

(Mw

x104)

Reaction Time (min)

Molecular Weight Profile of Synthesized PC without a Catalyst at Various

DPC/BPA Mole Ratios

17

0

0.5

1

1.5

2

2.5

0 50 100 150 200 250

DPC:BPA 1.05:1.00

DPC:BPA 1.26:1.00

Mo

lecu

lar

Wei

gh

t (

Mw

x 1

04)

Reaction Time (min)

DSC Thermograms of PC Products

Heating rate at 10oC/min

MwTg

(oC)

2,747

10,599

13,144

14,475

101

130

133

136

18

40 60 80 100 120 140 160 180 200

Mw 14,475

Mw 2,747

Mw 10,599

Mw 13,144

Hea

t F

low

(m

W)

Exo

Up

Temperature (oC)

Conclusions

19

The obtained FTIR absorption bands suggested the formation of PC by condensation of BPA with DPC.

The reaction of PC prepolymer of varied Mw could be performed at 200oC without adding catalyst, and by varying mole ratio of DPC/BPA reactants.

The PC prepolymer prepared using the initial DPC/BPA mole ratio of 1.26:1.00 was found to be appropriate for the preparation of the PC precursor to provide a molecular weight in a range that suitable for branched PC production.

The Tg significantly increased with increasing molecular weight of the synthesized PC.

Innovation and Technology Department, PTT

Phenol Co., Ltd.

Higher Education Research Promotion and

National Research University Project of Thailand

Office of the Higher Education Commission

(AM1076A).

Acknowledgements

20

21

Diphenyl Carbonate (DPC)

• Molecular weight; 214.216 g/mol

• Comonomer for BPA polycarbonate

• White solid (flakes)

• Melting point 78oC

• Boiling point 320oC

• Methods for DPC synthesis Transesterification of DMC to DPC Oxidative carbonylation of phenol

O C O

O

Structural formula of DPC

11Ref.: www.inchem.org, W. B. Kim, U. A. Joshi, and J. S. Lee, Ind. Eng. Chem. Res., 43, 1897-1914(2004).

22

Branching Agent: THPE

HO

CH3

OH

OHStructure formula

Formula; C20H18O3

Molecular weight; 306.355 g/mol

Melting point; 246-248oC

Physical form; solid

Ref.: www.chemicalbook .com /Chemicalproductproperties_EN_CB7458874.htm12

1,1,1,-tris(4-hydroxyphenyl)ethane (THPE)

232

Branching Agent Branching Agent

Structure formula

OHO

O

O

HO

HO

Formula; C9H6O6

Molecular weight; 210.14 g/mol

Purity; ≥98%

Melting point; 240-245 °C

Solubility; 83 g/l (30 °C)

Ref.: www.biotechsci.co.th www.indiamart.com

Trimellitic acid

2413

S. P. Kim and J. S. Lee (1999)

Literature Reviews

Synthesis of branched polycarbonate and properties of blends with linear polycarbonate

Results:

15Ref.: S.P. Kim, J.S. Lee, S.H. Kim, B.H. Lee, S.H. Kim, and W.G. Kim, Ind. Eng. Chem. Res., 5, 268-273(1999).

At 0.35 mol% of THPE- Aromatic proton peaks;(THPE) not detected.At 2 mol% of THPE- Aromatic proton peaks;(THPE) at 6.6-6.7 ppm.- Methyl proton peaks; (THPE) at 1.65 ppm.- Hydroxyl groups;(BPA+THPE) at 4.9 ppm.

1H NMR Spectra of branching agent

26

Md. M. Islam et al. (2011)

Literature Reviews

Synthesis and characterization of branched bisphenol-Apolycarbonates functionalized with siloxane

• At high frequencies, the

branched PC exhibited more

pronounced shear thinning

than BPA-PC (linear).

Complex viscosity curves

Results:

21Ref.: Md.M. Islam, D.W. Seo, H.H. Jang, Y.D. Lim, K.M. Shin, and W.G. Kim, Macromol. Res., 19,1278-1286(2011).

27

Literature ReviewsM. Y. Lyu et al. (2001)Study of mechanical and rheological behaviors of linear and branched polycarbonates blends Complex viscosity curves of linear and branched polycarbonates blends

Temperature at 260oC Temperature at 280oCRef.: M. Y. Lyu, J. S. Lee, and Y. Pae, J. Appl. Polym. Sci., 80, 1814-1824(2001).

28

19

Temperature at 300oC

Results:

• The viscosities increase as the

content of the branched

polycarbonate increases in the

blends at each measured

temperature.

• The temperature increases from

260 to 300oC, the viscosities

decrease and the range of the

shear rate for Newtonian regions

increases.

Ref.: M. Y. Lyu, J. S. Lee, and Y. Pae, J. Appl. Polym. Sci., 80, 1814-1824(2001).

2920

Literature ReviewsC. Liu and C. Li (2004)Influence of long-chain in branching on linear viscoelastic flow properties and dielectric relaxation of polycarbonates

Characteristics of the polycarbonates studied

COOH

COOH

HOOC

PC-B2

N

H

O

OH

CH3

OH

CH3

PC-B1 PC-B3

Ref.: C. Liu, C. Li, P. Chen, J. He, and Q. Fan, J. Appl. Polym. Sci., 45, 2803-2812(2004).

HO C CH3

OH

OH 3016

17

Results:

• Branched PC exhibits higher zero shear viscosity, more significant shear thinning, and much longer relaxation time than linear PC.

•The observed behaviors resulted from additional molecular chain entanglement of LCBs.

Ref.: C. Liu, C. Li, P. Chen, J. He, and Q. Fan, J. Appl. Polym. Sci., 45, 2803-2812(2004).

- Different branching agent may result in different degree of branching.

- Degree of branching inversely depends on the chain length of branches thus the flow behaviors of the branched PC. 

PC-B3PC-B2PC-B1PC-L

Effect of LCBs on the storage modulus for linear PC-L

and branched PC-Bs

Results:

• LCB PC shows greater

elasticity of melt e.g. storage

modulus, than SCB PC.

Ref.: C. Liu, C. Li, P. Chen, J. He, and Q. Fan, J. Appl. Polym. Sci., 45, 2803-2812(2004).18

1. To synthesize branched polycarbonate based on melt transesterification of diphenyl carbonate (DPC) and bisphenol-A (BPA).

2. To investigate effects of operating conditions and branching agents on physical, mechanical, and thermal properties of as-synthesized polycarbonate.

3. To recommend the academic data and technical data for the branched polycarbonate production using DPC and BPA.

Objectives

2233

1. Studying on the preparation of branched polycarbonate from BPA and DPC by melt transesterification.

2. Parameters to be studied. - Synthesis conditions

Temp. range: 180-300○C, P = 100 mmHg - Branching agents: 3 types;

1,1,1-tris(4-hydroxyphenyl)ethane, Trimellitic

acid, and 3,3-Bis(3-methyl-4-hydroxyphenyl) oxyindole

3. Synthesize branched polycarbonate by using Na2CO3 as branch-inducing catalyst.

Scopes of Study

2334

Scopes of Study

4. Characterize physical, mechanical and thermal properties of the as-synthesized branched polycarbonate.

- Chemical structure- Molecular weight- Rheological properties- Optical properties- Glass transition temp, Degradation

temp- Dynamic mechanical behaviors

2435

5. Benchmarking the obtained properties with commercial grades upon PPCL’s recommendation if applicable.

6. Summarizing the optimum processing condition and suitable branching agents of branched PC production based on the reaction of DPC with BPA.

Scopes of Study

2536

Experimental Method

BPA DPC

Nitrogen Tank Vacuum PumpHeater

Trap

26

Stirrer Branching Agent

37

Na2CO3

Sample Characterization

Thermal properties

Mechanical propertiesPhysical properties

• Glass transition temperature• Thermal degradation temperature

• Tensile properties• Storage and loss modulus

• Viscosity• Molecular weight• Chemical structure

2738