Advances in Polycarbonates - American Chemical Society

Chapter 8

Copolycarbonate of Bisphenol and 4, 4'Dihydroxydiphenyl 1

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Downloaded by UNIV OF PITTSBURGH on February 11, 2015 | http://pubs.acs.org Publication Date: March 8, 2005 | doi: 10.1021/bk-2005-0898.ch008

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Alexander Karbach , Doris Drechsler , Claus-Ludolf Schultz , Ute Wollborn , Melanie Moethrath , Michael Erkelenz , James Y. J. Chung , and James P. Mason 2

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Bayer Industry Services GmbH & Company O H G , Analytics, 47829 Krefeld, Germany ([email protected]) Bayer Material Science A G , Innovation, 47829 Krefeld, Germany Bayer Material Science A G , Business Development, Pittsburgh, PA 15205 2

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A copolycarbonate (DOD-co-PC) (1) of bisphenol A and 4, 4'dihydroxydiphenyl (DOD) with defined amounts of D O D has an outstanding balance o f optical, mechanical, thermal and impact properties. In particular, it has high light transmission, high glass transition and heat-distortion temperatures, and high notched Izod impact strength at thick section and low temperatures. Furthermore, it is unusually resistant to embrittlement after heat aging. For further understanding o f the structure property relationships, DOD-co-PC with different amounts of D O D are investigated.

Introduction Certain copolycarbonates o f bisphenol A and 4, 4'-dihydroxydiphenyl (DOD) were reported in the literature to have high transparency and glass transition temperature (2, J), high surface hardness and electrical insulation properties (2). For samples with more than 60mol% D O D liquid crystalline 96

© 2005 American Chemical Society

In Advances in Polycarbonates; Brunelle, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2005.

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properties were obtained (4). Bayer Polymers recently carried out extensive evaluations of copolycarbonates o f bisphenol A with different amounts of D O D (Figure 1). In the present paper, experimental results of a copolycarbonate (DOD-co-PC) with defined amounts of D O D are discussed with those of a bisphenol A polycarbonate (BPA-PC) (5) of a comparable molecular weight. The copolycarbonate was synthesized by interfacial phosgenation (5). In the first chapter, the technical properties of DOD-co-PC are presented. The second chapter gives an overview on their morphology and their supramolecular structure; the results are discussed in combination with in situ deformation experiments.

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DOD-BPA-eo-PC X% BPA-PC 0%

100-X% 100%

Figure 1. Structures ofDOD-BPA-co-PC and BPA-PC.

Experimental Results The following experiments were carried out on DOD-co-PC with 30 mol% DOD.

Optical, Thermal, Physical and Mechanical Properties Optical Properties DOD-co-PC is transparent with a high light-transmission comparable to B P A - P C . A refractive index of DOD-co-PC is slightly higher than that of PC. Also, DOD-co-PC has a higher birefringence than B P A - P C as shown in Figure 2a. The birefringence of DOD-co-PC is more persistent during heat aging (annealing) than that of B P A - P C . For instance, annealing DOD-co-PC at 130 °C lower temperature (120 °C) for 8 days significantly reduced the birefringence.


Table L Optical properties of DOD-co-PC and BPA-PC. Refractive Yellow- Haze Index ness Index ASTM ISO 489-A ASTM

Theoretical Transmission Transmission at 1.0 mm at 4.0 mm ISO 5036- ISO 5036-1 1

r%] [%] Downloaded by UNIV OF PITTSBURGH on February 11, 2015 | http://pubs.acs.org Publication Date: March 8, 2005 | doi: 10.1021/bk-2005-0898.ch008

DODOD-coPC BPA-PC

1.599 1.585

3.05.0 1.83.0

[%1

0.5

86

89.91

0.3-0.8

88

90.26

Table II. Thermal properties of DOD-co-PC and BPA-PC. Vicat Softening Heat Glass Heat Temperature Transition Distortion Distortion Temperature Temperature Temperature ISO 306, ISO 11357-2, ISO 75, ISO 75, 50N/50K/h Method DMA Method Afatl.80MPa Afat0.45MPa °C °C °C °C 156 134 149 DOD-co-PC 163 147 141 BPA-PC 155 128

Thermal Properties In comparison to BPA-PC, DOD-co-PC has higher glass transition, heat distortion and Vicat softening temperatures by 6 to 9 °C.

Physical and Mechanical Properties Density, tensile and flexural properties of DOD-co-PC and BPA-PC are shown in Tables III, IV and V, respectively. DOD-co-PC has a higher density than PC. However, compared to BPA-PC, DOD-co-PC has a lower- tensile modulus, - yield stress, and - elongation at break, while its elongation at yield is higher. Similarly, theflexuralmodulus of DOD-co-PC is lower than that of the BPA-PC, and itsflexuralstrain at yield is higher.



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Figure 2. a) Injection molded samples of BPA-PC (top) and DOD-co-PC (bottom) shown under polarized light, b) Effect of boiling-water immersion on BPA-PC and DOD-co-PC (See page 1 of color insert)


100 Table III. Density of DOD-co-PC and BPA-PC. ISO 1183

Density fkg/dm ] 3


DOD-co-PC BPA-PC

1.217 1.200

Table IV. Tensile properties of DOD-co-PC and BPA-PC. ISO 527

DOD-co-PC BPA-PC

Tensile Yield modulus Stress [MPa] [MPa] 2200 60 2400 65

Stress at break fMPa]

Yield Strain

[%]

Strain at break

[%1 95 115

81 70

7.0 6.0

Table V. Flexural properties of DOD-co-PC and B P A - P C ISO 178

DOD-co-PC BPA-PC

Flexural modulus

Yield Stress M

[N

2200 2400

98 97

Flexural Strain [%] 8.1 7.0

Stressât 15% strain (MPa] 66 73

Notched hod Impact Strength Table VI. Notched Izod Impact Test (ISO 180/4A) with standard notch radius of 0.25 mm at various temperatures. Test 23 °C -10 °C -20 °C -30 °C -40 °C -50 °C -60 °C Temperature [kJ/m ] [kJ/m ] [kJ/m ] [kJ/m ] [kJ/m ] fU/m ] fkJ/m ] DOD-co-PC 82 60 57 56 52 52 50 BPA-PC 90 90 15 15

Advances in Polycarbonates - American Chemical Society

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