Fluorenone Polymers and Fibers - American Chemical Society

20 Fluorenone Polymers and Fibers

Downloaded by UNIV OF MICHIGAN ANN ARBOR on October 2, 2017 | http://pubs.acs.org Publication Date: August 29, 1984 | doi: 10.1021/bk-1984-0260.ch020

A. M. USMANI The Research Institute, University of Petroleum and Minerals, Dhahran, Saudi Arabia Fluorenone polymers as t y p i f i e d by bisphenol fluorenone copolyester of terephthalic and isophthalic acids have many outstanding properties, e.g., heat resistance and high glass t r a n s i t i o n temperature. They do not generate HCN during burning since the polymer structure does not contain nitrogen and t h i s is a p o t e n t i a l advantage i n f i r e - r e s i s t a n t f i b e r applications. Fluorenone polyesters can be toughened with minor percentages of ethylene/ v i n y l acetate/vinyl alcohol terpolymer. P o t e n t i a l l y they also can be toughened with small amounts of an acetylene terminated b i f u n c t i o n a l monomer of fluorenone which can react at high temperatures to form an improved thermally stable product. The synthetic f i b e r industry i s only about f i f t y years old yet the annual production i s i n b i l l i o n s of l b s . The development of f i b e r s resulted due to advances i n polymer synthesis and new spinning methods. At the present time nylons, polyesters, a c r y l i c s and polyo l e f i n s are major classes of synthetic f i b e r s . Fibers have also been made from polymers, e.g., polyvinylidene chloride and p o l y v i n y l alcohol but t h e i r commercialization has not materialized. Recently, we have made f i b e r s from fluorenone polyesters which have good potent i a l s and should be further developed. Fluorenone polyesters are made from isophthalic acid or terepht h a l i c acid/isophthalic acid and bisphenol fluorenone and a t y p i c a l formula i s as follows:

0097-6156/84/0260-0325$06.00/0 © 1984 A m e r i c a n C h e m i c a l Society

Arthur et al.; Polymers for Fibers and Elastomers ACS Symposium Series; American Chemical Society: Washington, DC, 1984.


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POLYMERS FOR FIBERS AND ELASTOMERS

Linear aromatic polyesters prepared from diphenols and dibasic acids have been reported i n some early patents Q-3). More recently, Morgan (4) has synthesized aromatic polyesters by i n t e r f a c i a l and solution methods from aromatic diacid chlorides and bisphenols that have e s s e n t i a l l y planar, doubly attached groups on the methylene units between the phenylene rings. Bier (5) has recently reviewed polyesters made from aromatic dicarboxylic acids and bisphenols and describes the preparation of some bisphenol monomers and polyesters made therefrom by i n t e r f a c i a l condensation, solution condensation, melt condensation, and r e - e s t e r i f i c a t i o n reaction methods. In t h i s paper we w i l l describe the chemistry and characterization of bisphenol fluorenone polyesters and copolyesters that were found to be suitable for conversion into f i b e r . We w i l l also describe the synthesis and u t i l i t y of acetylene terminated fluorenone to improve deficient properties of fluorenone polyesters. Fluorenone Polyesters Flourenone polyester synthesis has much l a t i t u d e . The r a t i o of dibasic acids (terephthalic and isophthalic) and bisphenols ( b i s phenol fluorenone and bisphenol A) can be varied depending upon desired properties. Molecular weight can also be regulated. We can expect good processability with fluorenone polyesters r i c h i n b i s phenol A whereas polyesters containing large amounts of bisphenol fluorenone w i l l have marginal processability. Marginal processabil i t y can be improved by using a reactive p l a s t i c i z e r . We have characterized fluorenone polyesters, e.g., bisphenol A/bisphenol fluorenone (90/10) polyterephthalate (FPE-1), bisphenol fluorenone polyisophthalate (FPE-2), bisphenol A/bisphenol fluorenone (20/80) polyisophthalate (FPE-3) and bisphenol fluorenone copolyester of terephthalic and isophthalic acid (50/50) (FPE-4) and evaluated their potential as f i b e r s . We also synthesized an acetylene terminated b i f u n c t i o n a l monomer of fluorenone which can p l a s t i c i z e fluorenone polyesters at moderately elevated temperatures and can react at high temperatures to form an improved thermally crosslinked network. Characterization of Polyesters F i r e reistance,chemical composition by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, thermal analyses, Clash-Berg moduli determination and dynamical mechanical analyses were determined. The fluorenone polyesters were spun as fibers from solution. They were blended with an acetylene terminated fluorenone monomer for p l a s t i c i z a t i o n and crosslinking at high temperatures to form an improved thermally stable product. Thermomechanical Analyses (TMA) were recorded on a DuPont thermal analyzer, Model 943 TMA f i t t e d with a penetrating t i p probe, at 2g load and 10°C/min temperature r i s e . V e r t i c a l displacement and the f i r s t derivative of that displacement with respect to time were recorded as a function of temperature. Dynamic Mechanical Analyses (DMA) were obtained on a DuPont 981 DMA instrument.


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Fluorenone Polymers and Fibers

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Monomer Synthesis Acetylene terminated monomers, e.g., acetylene terminated sulfone are known to exhibit high thermal s t a b i l i t y , good adhesion charact e r i s t i c s and high moisture resistance (6,7). Starting with b i s phenol fluorenone we synthesized acetylene terminated fluorenone (ATF) . ATF was prepared by the reaction route shown below. p-Fluorophenyl acetylene (6.00 g) was added to 9,9-bis(4-hydroxyphenyl) fluorenone (8.50 g) i n dimethylsulfoxide (230 ml) containing 25.8 g of potassium carbonate. The reaction was carried out under an inert atmosphere at 130°C f o r 4 days. The progress of the reaction was followed by monitoring disappearance of hydroxyl band at 3400 cm * and appearance of a c e t y l e n e band a t 3300 c m ~ l . The r e a c t i o n mass was then mixed with aqueous potassium hydroxide to remove -

any unreacted bisphenol and added to 900 ml d i e t h y l ether. The separated ether layer was washed several times with water to remove DMSO and inorganic materials. Ether was flashed o f f to recover crude ATF (7.1 g). ATF was c r y s t a l l i z e d from ethanol/water (90/10) to give a brownish yellow powder. The r e c r y s t a l l i z e d product showed an acetyl e n i c hydrogen peak at 3300 cm (IR) and 3.0 ppm (NMR). p-Fluorephenyl acetylene, used i n ATF synthesis, was prepared as follows: -1

o ci _(o>_{!cH3 + PCl -^ -- =CH R

F

5

F

C

2

p- f luoroocetophenone F

CI -

c


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TEMPERATURE PC)

Figure 3. Reproduced from Ref

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TGA of Samples FPE-1 and -4. 9.

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Copyright

1980 American Chemical Society.

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TEMPERATURE (°C)

Figure 4. Reproduced from Ref. 9.

TGA of Samples FPE-2 and -3. Copyright 1980 American Chemical Society.


20.

Fluorenone Polymers and Fibers

USMANI

Table I.

I n t r i n s i c V i s c o s i t i e s of Fluorenone Polyesters i n Methylene Chloride Sample

[n]

FPE-1 FPE-2 FPE-3 FPE-4 Downloaded by UNIV OF MICHIGAN ANN ARBOR on October 2, 2017 | http://pubs.acs.org Publication Date: August 29, 1984 | doi: 10.1021/bk-1984-0260.ch020

333

0.720 0.501 0.537 0.351

Preparation of Fibers from Solution. Fibers can be spun (wet or dry) from 10% polymer solution i n methylene chloride or tetrahydrofuran (THF). An advantage of THF i s that i t i s a good solvent for the ethylene terpolymer (E/VA/VOH) as well, which we used to modify the fluorenone polyesters. The fluorenone polyester f i b e r s formed were transparent (Figure 5). The polyesters can be blended with 10% E/VA/VOH and they formed s l i g h t l y cloudy films. Blending i n t h i s case was c a r r i e d out wi,th FPE-4 i n an attempt to toughen the polymer. However, the cloudy appearance of the films indicates that some phase separation occurs and toughening i s not l i k e l y to occur. Tensile data determination confirmed our speculation. Thermomechanical Analysis. The TMA scan on a molded FPE-1 f i l m i s shown i n Figure 6. A glass t r a n s i t i o n temperature (Tg) of 180°C was observed. FPE-4 did not mold w e l l so TMA was run on a sintered sample of FPE-4. A T of 270°C was observed (Figure 6). The TMA of FPE-4 blended with 10% E/VA/VOH i s also included i n Figure 6. Reduct i o n i n Tg to 238°C was noted for the polyblend. The polyblend should exhibit two d i s t i n c t glass t r a n s i t i o n temperatures. The ethylene terpolymer can engage i n t r a n s e s t e r i f i c a t i o n and crossl i n k i n g reactions with fluorenone polyesters under elevated temperature during TMA runs. The c r o s s l i n k i n g reactions are responsible for a single T . g

g

Dynamic Mechanical Analysis. The modulus loss tangent data for FPE-2 and -3 are shown In Figures 7 and 8. The data for FPE-2 were obtained from a compression molded f i l m and those for FPE-3 were obtained from a f i l m cast from methylene chloride. The glass t r a n s i t i o n s of FPE-2 and -3 (as indicated by loss modulus maxima, not shown) are 270 and 280°C, respectively. There are also various sub-Tg t r a n s i t i o n s apparent for each polymer. The peak damping value (tan 6 > 1.0) observed for FPE-3 i s comparable to that for polymers which exhibit a sharp t r a n s i t i o n from glassy to rubbery behavior. Clash-Berg Moduli. The Clash-Berg moduli obtained for FPE-1 and -4 over a temperature range of 0 to 280°C are shown In Figure 9. The Clash-Berg Tf, the temperature where the r i g i d i t y modulus equals 45,000 p s i , gives a measure of the low temperature l i m i t of a p p l i c a t i o n . Below t h i s temperature, the polymer w i l l be glassy. T575 i s the temperature where the r i g i d i t y modulus f a l l s to 675 p s i .


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Figure 5.

MOLDED FPE-4

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Photographs of FPE f i b e r s .

278°C

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480°C

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TEMPERATURE i*C) Figure 6.

TMA of FPE-1, -4 and FPE-4 Plus Ethylene Terpolymer Blend (90/10).

Reproduced from Ref. 9.

Copyright 1980 American Chemical Society.


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MODULUS

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Fluorenone Polymers and Fibers - American Chemical Society

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