Note: Descriptions are shown in the official language in which they were submitted.
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40,9 1 3A-I~
POLYCARBONATE AND POLYESTER COMPOSITIONS
This invention relates to polycarbonates, polyesters, and polyestercarbonates
prepared from at least one aromatic diol, wherein a portion or all of the aromatic diol used in
5 their preparation is a stilbene diol.
Certain polymers derived from stilbene diols are known and are described, for
example, in Cebe et al., Polym. Preprints, Vol. 33, p. 331 (1992), Bluhm et al., Mol. Crvst. Liq.
Cryst., Vol.239, p.123 (1994), and Cheng et al., Macromolecules, Vol. 27, p. 5440 (1994), which
describe the preparation of mixed aromatic-aliphatic polycarbonates based on stilbene diols
10 and Cl-12 alpha,omega-alkanediols. Percec et al., J. Polym. Sci. Polym. Lett., Vol. 22, p. 637 (1984)
and J. Polym. Sci. Part A: Polym. Chem., Vol. 25, p. 405 (1987) report the synthesis of mixed
aromatic-aliphatic polyethers via the reaction of 4,4'-dihydroxy-alpha-methylstilbene with C",
alpha,omega-dibromoalkanes. Blumstein et al., Mol. Cryst. Liq. Crvst., Vol. 49, p. 255 (1979) and
Polym. Journal, Vol.17, p. 277 (1985) describe mixed aromatic-aliphatic polyesters from stilbene
diols and alpha,omega-alkanedicarboxylic acids. Roviello and Sirigu, Makromol. Chem., Vol.
180, p. 2543 (1979), Makromol. Chem., Vol.183, p. 409 (1982) and Makromol. Chem., Vol.183,
p. 895 (1982) reportthe preparation of mixed aromatic-aliphaticthermotropic liquid crystalline
polyesters from 4,4'-dihydroxy-alpha-methylstilbene and C8 14 alpha,omega-alkanedicarboxylic
acids. Sato, J., Polym. Sci.: Part A: Polym. Chem., Vol. 26, p.2613 (1988) reports the synthesis of
2() mixed aromatic-aliphatic polyesters using 4,4'-dihydroxy-alpha,alpha'-diethylstilbene and
adipoyl chloride, sebacoyl chloride, and mixtures of adipoyl and sebacoyl chlorides. However,
the physical properties and melt characteristics of such polymers may be less than desirable for
certain applications.
In one aspect, this invention is a polycarbonate, polyester, or polyestercarbonate
2S composition prepared from a reaction mixture comprising at least one diol and at least one
carbonate precursor or ester precursor, wherein
(a) at least 95 mole percent of the carbonate precursor or ester precursor present
in the reaction mixture is selected from
(i) dialkyl carbonates, diarylcarbonates, carbonyl halides, or bis(trihaloalkyl)3() carbonates;
(ii) aromatic dicarboxyiic acids, hydroxybenzoic acids, hydroxynaphthoic acids,
hydroxybiphenyl acids, hydroxycinnamic acids, or the halides or metal salts of such acids; or
(iii) oligomers and polymers of (i) or (ii) containing carbonate or ester groups,
which are prepared by contacting an excess over stoichiometry of at least one compound
3 c; selected from (i) or (ii) with at least one monol or diol under reaction conditions sufficient to
form the corresponding oligomer or polymer; or
A ~ ~r~ Inrn C~l IrrT
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(b) at least 95 mole percent of the diol present in the reaction mixture consists of
one or more aromatic diois, at least 10 mole percent of which consists of one or more stilbene
diols.
Applicants have discovered thatthe composition of the invention has an
5 advantageous thermal resistance, melting temperature, tensile and flexural properties, and/or
resistance to thermal embrittlement. Moreover, those polymers of the invention which are
thermotropic liquid crystalline also have an advantageous temperature range for liquid
crystallinity, melt processibility, coefficient of thermal expansion, ignition resistance, solvent
resistance, and/or barrier properties. These and other advantages of the invention will be
10 apparent from the description which follows.
The polymeric composition of the invention may be prepared by any method
suitable for the preparation of polycarbonate, polyester, or polyestercarbonate polymers, so
long as at least 95 mole percent of the diol present in the polymerization reaction mixture
consists of one or more aromatic diols, and at least 10 mole percent of the aromatic diols
15 consists of one or more stilbene diols. Such methods include interfacial, solution, and melt
polymerization processes. Further, the polymeric composition of the invention may be
prepared as a homopolymer, or as a random or block copolymer of the various monomers
described below. The term "reaction mixture" as used herein referstothe mixture of
monomers which are polymerized to form the composition of the invention, utilizing any of
20 the polymerization methods described in any of the references cited herein.
The composition of the invention preferably comprises repeating units of the
formulas:
-[R-O-X-O]- (I)
and optionally
Z5 -[R2-c(o) o] (II)
wherein R independently in each occurrence is the divalent nucleus of an aromatic diol, X is
selected from: -C(O)-, -C(O)-Rl-C(O)-, or a mixture thereof, R1 independently in each occurrence
is the divalent nucleus of a difunctional aromatic carboxylic acid, and R2 is the divalent nucleus
of an aromatic hydroxy carboxylic acid. As indicated by the above formulas, other monomers
30 such as hydroxy carboxylic acids may also be present in the polymerization reaction mixture, in
addition to the diols and carbonate precursors. The term "divalent nucleus" as used herein
refers to the compound described, minus its pendant hydroxyl and/or carboxyl groups.
When the polymeric composition of the invention is a polycarbonate, it may be
prepared by the reaction of an aromatic diol or mixtures of aromatic diols with a carbonate
35 precursor. The term "carbonate precursor" as used herein refers to carbonyl halides, diaryl
carbonates, dialkyl carbonates, bis(trihaloalkyl)-carbonates such as triphosgene,
bishaloformates, and other compounds which will react with hydroxyl groups to form
carbonate linkages (-O-C(O)-O-). Examples of suitable carbonyl halides include carbonyl
-2-
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bromide, carbonyl chloride ("phosgene") and mixturesthereof. Suitable haloformates include
the bischloroformates of dihydric phenols such as bisphenol A. Preferably, the carbonate
precursor is phosgene or diphenyl carbonate, and is most preferably diphenyl carbonate.
Examples of suitable methods for preparing polycarbonates are setforth in "Polycarbonates,"
Encyclopedia of Polymer Science and Enqineerinq (2nd Edition), Vol.11, pp. 648-718 (1988);
U.S. Patent Nos. 5,142,018; 5,034,496; 4,831,105; 4,543,313; 3,248,414; 3,153,008; 3,215,668;
3,187, 065; 3,028,365; 2,999,846; 2,999,835; 2,970,137; 2,964,974; and 1,991,273.
When the polymeric composition of the invention is a polyester, it may be
prepared by the reaction of an aromatic diol or a reactive derivative thereof (such as the
10 corresponding diacetate), with an ester precursor The term "ester precursor" as used herein
refers to C8-40 dicarboxylic acids or reactive derivatives thereof (such as esters thereof or the
corresponding acid halides), which will react with hydroxyl groups to form ester linkages
(-O-C(O)-R1-C(O)-O-, wherein R1 is the divalent nucleus of the ester precursor). Preferably, the
ester precursor is an aromatic dicarboxylic acid.
A portion of the ester component in these polymeric compositions may optionally
be derived from hydroxycarboxylic acids or reactive derivatives thereof, either by reaction with
the other monomers or self-condensation, to provide repeat units olF Formula (Il~:
-[RZ-C(O)-O]-, wherein R2 is the divalent nucleus of a hydroxycarboxylic acid. Examples of
suitable methods for preparing polyesters are set forth in "Polyesters," Encvclopedia of
20 Polymer Science and Enqineerinq (Znd Edition), Vol.12, pp. 1-75 (1988); " Liquid Crystalline
l'olymers," Encyclopedia of Polvmer Science and Enqineerinq (2nd Edition), Vol. 9, pp. 1-61
1'1988); "Polyesters, Mainchain Aromatic," Encvclopedia of Polvmer Science and Enqineerinq
~2nd Edition), Vol. l, pp. 262-279; U.S. Patent Nos. 5,268,443; 5,237,038; 5,233,013; 5,221,730;
!"175,237; 5,175,326; 5,110,896; 5,071,942; 5,037,938; 4,987,208; 4,946,926; 4,945,150; and
25 ~,985,532.
Similarly, when the polymeric composition of the invention is a
polyestercarbonate, it may be prepared by the reaction of an aromatic diol with a combination
of a carbonate precursor and an ester precursor as described above. Suitable methods for the
preparation of pol~,e~Ler~dl bonates are described in U.S. Patent Nos 5,045,610; 4,398,018;
30 4,388,455; 4,374,973; 4,371,660; 4,369,303; 4,360,656; 4,355,150; 4,330,662; 4,287,787;
4,260,731; 4,255,556; 4,252,939; 4,238,597; 4,238,596; 4,194,038; 4,156,069; 4,107,143;
4,105,633; and 3,169,121; and articles by Kolesnikov et al. published in Vvsokomol Soedin as
E~9, p. 49 (1967); A9, p.1012 (1967); A9, p.1520 (1967); andA10, p.145 (1968).
In the preparation of the composition of the invention, at least 95 mole percent 35 of the carbonate precursor or ester precursor present in the reaction m ixture is
(i) dialkyl carbonates, diarylcarbonates, carbonyl halides, or bis(trihaloalkyl)carbonates;
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(ii) aromatic dicarboxylic acids, hydroxybenzoic acids, hydroxynaphthoic acids,
hydroxybiphenyl acids, hydroxycinnamic acids, and the halides or metal salts of such acids; or
(iii) oligomers and polymers of (i) or (ii) containing carbonate or ester groups,
which are prepared by contacting an excess over stoichiometry of at least one compound
selected from (i) or (ii) with at least one monol or diol under reaction conditions sufficient to
form the corresponding oligomer or polymer. The term "oligomer" as used herein includes
monoesters, diesters, monocarbonates, and dicarbonates of the monol or diol.
Suitable stilbene diols for use in the preparation of the polymeric composition of
the invention include those of the formula:
R4 R4
~ I I ~ OH
R4 R3 R3 R4
wherein R3 independently in each occurrence is selected from hydrogen, C18 alkyl, chlorine,
bromine, or cyano, but is preferably hydrogen or C18alkyl; R4 independently in each occurrence
is selected from hydrogen, halogen, alkyl, aryl, alkoxy, aryloxy, cyano, nitro, carboxamide,
carboximide, or R5-C(o)-, wherein Rs is C1 8 alkyl or aryloxy, but is preferably hydrogen or C1 8
alkyl. Preferably, the phenolic groups are in a "trans" configuration the double bond.
Preferably, the stilbene diol is4,4'-dihydroxystilbene; 4,4'-dihydroxy-alpha-methylstilbene;
4,4'-dihydroxy-alpha,alpha'-dimethylstilbene; or4,4'-dihydroxy-alpha,alpha'-diethylstilbene.
The stilbene diols described above may be prepared by any suitable method. For
example, the diol is prepared from a phenol and a carbonyl-containing precursor, using any of
the procedures described by S. M. Zaher et al., Part 3, J. Chem. Soc., pp.3360-3362 (1954); V.
Percec et al., Mol. Cryst. Liq. Cryst., Vol. 205, pp. 47-66 (1991); Singh et al., J. Chem. Soc., p. 3360
(1954), or Hefner et al., U.S. Patent No.5,414,150. If desired, color bodies, or color forming
bodies, may be removed from the stilbene diols by contacting them with an aqueous solution
of one or more compounds selected from alkali metal carbonates, alkali earth metal
carbonates, alkali metal bicarbonates (such as sodium bicarbonate), or alkaline earth metal
carbonates. The stilbene diol(s) used to prepare the composition of the invention preferably
have a 4,4'-isomeric purity of at least 95 mole percent, more preferably at least 98 mole percent
and most preferably at least 99 mole percent.
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in addition to the stilbene diol, one or more additional aromatic diols may also be
used to prepare the composition of the invention. Suitable aromatic diols include any aromatic
diol which will react with a carbonate precursor or ester precursor. P~ efer. ed diols include
, 2,2-bis(4hydroxyphenyl)propane ("bisphenol A"); 9,9-bis(4-hydroxyphenyl)fluorene;
hydroquinone; resorcinol; 4,4'-dihydroxybiphenyl; 4,4'-thiodiphenol; 4,4'-oxydiphenol;
4,4'-sulfonyldiphenol; 4,4'-dihydroxybenzophenone; 4,4"-dihydroxyterphenyl;
1 ,4-dihydroxynaphthalene; 1 ,5-dihydroxynaphthalene; 2,6-dihydroxynaphthalene;
bis(4hydroxyphenyl)methane ("bisphenol F"); and inertly substituted derivatives thereof, as
well as mixtures thereof. P~ e rerdbly, the diol is 2,2-bis(4-hydroxyphenyl)propane (" bisphenol
10 A ).
In the preparation of the composition of the invention, at least 95 mole percentof the diols present in the reaction mixture consist of one or more aromatic diols. Preferably, at
least 98 mole percent, and more pre rerably 100 mole percent of such diols are aromatic diols.
Further, at least 10 mole percent of the aromaticdiol present in the reaction mixture consists of
15 one or more stilbene diols. Preferably, at least 25 mole percent, and more preferably at least 50
mole percent of such aromatic diols are stilbene diols.
Examples of aromatic dicarboxylic acids which may be used to prepare polyester
or polyestercarbonate compositions of the invention include terephthalic acid; isophthalic
acid; 2,6-naphthalenedicarboxylicacid; 1,4-naphthalenedicarboxylicacid; 1,5-naphthalene-
20 -dicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,4'-biphenyldicarboxylic acid;
4,4'-terphenyldicarboxylic acid; 4,4'-stilbenedicarboxylic acid; 4,4'-dicarboxy-alpha-
-methylstilbene; inertly substituted derivatives thereof, as well as mixtures thereof.
Examples of hydroxycarboxylic acids that may be used to prepare the polyester
and polyestercarbonate polymeric compositions of the present invention include
25 4-hydroxybenzoic acid; 3-hydroxybenzoic acid; 6-hydroxy-2-naphthoic acid; 7-hydroxy-2-
-naphthoic acid; 5-hydroxy-1-naphthoic acid; 4-hydroxy-1-naphthoic acid; 4-hydroxy-4'-
-biphenylcarboxylic acid; 4hydroxy-4'-carboxydiphenyl ether; 4-hydroxycinnamic acid; inertly
substituted derivatives thereof, as well as mixtures thereof.
Processes for the preparation of polycarbonates, polyesters, and
30 polyestercarbonates typically employ a cha in stopping agent during the polymerization step to
rontrol molecular weight. The amount of chain stopping agent has a direct effect on both the
molecular weight and the viscosity of the polycarbonate, polyester, or polyestercarbonate
prepared. Chain stopping agents are monofunctional compounds which react with a
carbonate or ester precursor site on the end of the polymer chain and stop the propagation of
35 the polymer chain. Examples of suitable chain stopping agents include monofunctional
aromaltic alcohols, thiols, and amines, as well as mixtures thereof. Preferably, the chain
~stopping agent is a monofunctional aromatic alcohol, thiol, amine, aliphatic alcohol, aromatic
carboxylic acid, aliphatic carboxylic acid, or a mixture thereof.
-5-
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The compositions of the present invention are preferably of the following
formula:
F-O-(-R-O-X-O-)n-R-0-6
and optionally contain repeat units of Formula (Il): (-R2-C(O)-O-)r~; and/or end groups of the
5 formulas:
-R2-C(O)-O-G; or F-O-R2-
wherein R, X, R1 and R2 have the descriptions hereinbefore provided; n is a whole number from
5 to 300; and F and G are, independently, either hydrogen or other terminating groups
common to polycarbonates, polyesters carbonates, or polyesters. Preferably, F and G are
10 repl~sented bytheformulas:
R6-O-C(O)-; or R6-C(O)-
wherein R6 is hydrogen, halogen, or the nucleus of an alkyl, aryl, or alkyl-substituted aryl
alcohol or carboxylic acid.
The polymers of the present invention preferably have a weight average
15 molecular weight (Mw, determined by size exclusion chromatography using a bisphenol A
polycarbonate calibration curve) of at least 10,000, more preferably at least 20,000. P. ~ ret I ed
polymers according to the present invention have inherentviscosities, measured in methylene
chloride (for an amorphous polymer) at 0.5 grams per deciliter (g/dL) and 25C, or in
pentafluorophenol (for a crystalline or liquid crystalline polymer) at 0.1 g/dL and 45C, of at
20 least 0.2 dL/g and more preferably at least 0.35 dL/g.
Liquid crystalline polymeric compositions may be identified using one or more
standard techniques, such as heating the composition on a dirrer~nlial scanning calorimeter
and characterizing it in the melt state by optical microscopy under cross-polarized light.
Thermotropic liquid crystalline polymers will exhibit optical anisotropy upon melting. Other
25 techniques which may be used to characterize the polymer as liquid crystalline include scanning
electron microscopy, X-ray diffraction, visible light s~dll~ri. ,g techniques, electron beam
diffraction, infrared spectroscopy, and nuclear magnetic resonance. If the composition is liquid
crystalline, it preferably has nematic ordering in the liquid crystalline melt state.
As mentioned above, the compositions of the invention advantageously have a
30 relatively high thermal resistance, melting temperature, tensile and flexural properties, and/or
resistance to thermal embrittlement. Moreover, those polymers of the invention which are
thermotropic liquid crystalline also advantageously possess a broad temperature range for
liquid crystallinity, good melt processibility, a low coefficient of thermal expansion, a high
ignition resistance, high solvent resistance, and/or good barrier properties. The thermal
35 resistance of the composition may be characterized by its Vicat softening temperature and the
temperature at which it may be distorted under load, as illustrated in Example 2. The tensile
and flexural properties of the composition may be characterized and measured in accordance
with ASTM D-638, as illustrated in the examples. The composition's resistance to thermal
-6-
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W~96r~3539 PCTAUS95113869
emLr~ ei l lent refers to its tendency to become brittle at elevated temperature~ and may be
characterized by measurement of its postyield stress drop, as illustrated in Example 7.
The composition of the invention, when thermotropic liquid crystalline, also
preferablyhasthermalcha~dcl~ri~licswhichpermitittobereadilyprocessedintheliquid
5 crystal state when heated above its melt temperature. The temperature range over which such
polymers may be processed above their melt temperature in the liquid crystal state is preferably
as broad as possible, but is preferably at least 25C, more preferably at least 50C, and is most
pr~fe,dbly at least 100C. In most instances, the cornposition will become isotropic above this
range, in which case the range may be e,.,ur e~ed as the difference b~lween the clearing
10 temperature (TCI) and the melttemperature (Tm) of the composition. The clearing temperature
is the temperature at which the composition undergoes a transition from the anisotropic liquid
crystalline state to an isotropic state (see, for example, The Encvclopedia of Polymer Science
and Enqineerinq, Vol.9, p. 55 (1988).
The melt processibility of the polymeric composition may be characterized by its15 melt temperature and its melt viscosity, as ill ustrated in the examples. The melt temperature of
the composition (Tm~ as determined by Differential Scanning Calorirnetry) when thermotropic
liquid crystalline, is preferably at least z00C~ more preferably at least 250C, but is preferdbly
no greater than 350C.
The coefficient of thermal expansion of the composition of the invention may be
20 measured in accordance with ASTM D-2236, as illus1:rated in the Examples below. The ignition
resistance of the polymers may be measured by determining the Limiting Oxygen Index of the
composition, by testing the composition in accordance with Underwriters Laboratories' test
number UL-94, or by measuring the char yield of the composition by thermal gravimetric
analysis. The solvent resistance of the composition of the invention may be characterized as
25 shown in the examples
The barrier properties of the composition of the invention may be measured in
accordance with ASTM D-3985 (oxygen transmission rate) and ASTM F-372 ~carbon dioxide and
water vapor transmission rate).
The composition of the invention may be subjected to post-condensation in the
30 solid phase (also known as solid-state advancement), preferably under reduced pressure, at a
temperature in the range from 150C to 350C. After 1 to 24 hours, the molecular weight has
increased and the resulting polymers exhibit further improved properties. The composition of
the present invention may be fabricated using any of the known thermoplastic molding
procedures, including cornpression molding, injection molding, and extrusion to provide
35 fabricated articles, including moldings, boards, sheets, tubes, fibers, and films. Procedures that
may be employed to maximize the orientation of the liquid crystal moieties contained in
fabricated articles from the polymers of the invention are summarized in U.S. Patent No.
5,300,594, as well as the references cited therein.
--7 -
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The composition of the present invention can also be employed with other
thermoplastic polymers to prepare thermoplastic polymer blends. Suitable thermoplastics for
this purpose include polycarbonates, polyesters, polyethers, polyetherketones, polysulfides,
polysulfones, polyamides, polyurethanes, polyimides, polyalkylenes such as polyethylenes and
5 polypropylenes, polystyrenes, copolymers thereof and mixtures thereof. The polymers of this
invention may, in addition to being used for molding purposes, be employed as the base for
preparing thermoplastic molding compositions by being compounded with antioxidants,
antistatic agents, inert fillers and reinforcing agents such as glass fibers, carbon fibers, talc,
mica, and clay, hydrolytic stabilizers, colorants, thermal stabilizers, flame retardants, mold
10 release agents, plasticizers, UV radiation absorbers, and nucleating agents as described in
U.S. Patent Nos. 4,945,150 and 5,045,610 and the other references cited above.
The following examples are given to illustrate the invention and should not be
interpreted as limiting it in any way. Unless stated otherwise, all parts and percentages are
given by weight.
15 Example 1 - Preparation of Polycarbonate of 4,4'-Dihydroxy-alpha-methylstilbene (DHAMS)
The polymerization was run in a 1 L single-neck round-bottom flask fitted with atwo-neck adapter upon which were mounted a glass paddle stirrer and a 13 centimeter (cm)
Vigreaux distillation column, distillation head with a thermometer, condenser and a receiver.
DHAMS (1.79 mol,403.6 9) and diphenylcarbonate (1.93 mol,412.7 9) were added to the
20 reaction flask. The apparatus was evacuated and refilled with nitrogen three times. The flask
was immersed in a molten salt bath preheated to 220C. When the solid reactants had melted
to form a molten reaction mass, stirring was started and an aqueous solution of lithium
hydroxide (0.82 mL,0.06 M) was added as a catalyst. The reaction temperature was raised to
290C over a period of 1 hour and the pressure was reduced from atmospheric pressure to
,z5 2x10-3 atmospheres. The latter pressure was maintained for one hour at 290C. After an
additional 5 minutes the reaction mass formed a ball on the stirrer shaft. The vacuum was then
released under nitrogen and the reaction vessel was removed from the salt bath. The reaction
apparatus was cooled and disassembled. The distillation receiver contained 337 9 of phenol.
The flask was broken away from the opaque chalk-white polycarbonate plug. The plug was
30 sawed into chunks and then ground in a Wiley mill. The product was dried in a vacuum oven at
100C for 2 hours to give 408 9 of product (91 percent yield).
The polycarbonate had an inherent viscosity (IV) of 2.6 dL/g, measured at 45C
using a solution of 0.1 9 of polycarbonate in 100 mLof pentafluorophenol. Differential
scanning calorimetry (DSC), conducted at 20C/minute using a Du Pont Instruments DSC 2910,
35 showed a peak melting point of 273C (first heating scan, run from 25C to 320C) and a
crystallization temperature of 202C (first cooling scan, run from 320C to 50C). A second
heating scan showed a peak endotherm at 272C, and a second cooling scan showed a
crystallization temperature at 194C. When the initial heating scan was run from 25C to 400C,
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a second endotherm was observed at 375C. Examination by hot stage cross-polarized
microscopy (described hereinafter) indicated that the first endotherm was a solid crystailine to
nematic liquid crystalline transition, and the second endotherm was a nematic liquid crystalline
to isotropic liquid clearing transition.
The 1 H NMR and 13C NMR spectra of the DHAMS poly~arbonate are determined in
pentaflurophenol at 45C. The 1H NMR (300 MHz) spectrum of the homopolycarbonateshowed the presence of aliphatic, aromatic and vinylic hydrogen atoms. The infrared spectrum
showed the presence of C=O, C=C, and C-O groups. Apparent molecularvrei~ ,were
determined by gel permeation chromatography (GPC) using refractive index detection.
10 Calibration was done using both BA (BA) polycarbonate and narrow molecular weight
distribution polystyrene, with chloroform as the mobile phase. Sample preparation was done
by dissolution of 40 mg sample in 1 mL pentafluorophenol at 45C followed by addition of
10 mL chloroform. Using BA polycarbonate for calibration, the DHAMS polycarbonate sample
had Mw = 66,000 and Mn = 13,000. Using polystyrene as the calibration, the DHAMS15 polycarbonate had Mw = 154,000 and Mn = Z1
Chara~l~ri~dlion bv Optical Microscopv Under Crosspolarized Liqht
The apparatus used for determining optical anisotropy included a THM 600 hot
stage (Linkham Scientific Instruments LTD, Surrey, England) and a Nikon Optiphot Microscope
equipped with crossed-polarizers and a 35 mm camera (Nikon Instrument Group, Nikon, Inc.,
20 Garden City, N.Y). Observation of a bright field attemperatures above the melting point
indicated that the DHAMS polycarbonate melt was optically anisotropic. The sample was
placed on the programmable hot stage and a heating rate of 50Clminute was used initially
from25Cto180C,then10C/minutewasusedfrom180Cto250Candthen5C/minutewas
used from 250C to 300C. Observation of the samples showed a nematic phase at room
25 temperature and a nematic phase upon melting. The polymer formed a turbid melt that
showed strong shear opalescence. The following observations were made for this DHAMS
polycarbonate sample, using the polarizing microscope.
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Temperature (C) Observations
white opaque soiid
150 white opaque solid
180 compressed between coverslip and siide
260 highly birefringent, nematic texture, viscous fluid
290 highly birefringent, nematic texture, flow directed .
domains
300 anisotropic melt, still passes crosspolarized light
The sample remains anisotropic above 300C, indicating that DHAMS
10 polycarbonate was liquid crystalline. Clearing (lldn,ilion from liquid crystalline to isotropic
phase) was not observed until 370C.
Solubilitv Characterization
The thermotropic liquid crystalline DHAMS polycarbonate prepared in this
example was insoluble in conventional organic solvents both at room temperature and
15 elevated temperatures. Solvents that do not dissolve this polycarbonate include methylene
chloride, chloroform, carbon tetrachloride, tetrahydrofuran, acetone, N,N-dimethylacetamide,
dimethylsulfoxide, pyridine, and trifluoroacetic acid/methylene chloride (4/1 volume ratio).
The polycarbonate was soluble in pentafluorophenol at high dilutions (0.1g/dL).
MeltViscositv Determination
The melt viscosity of the DHAMS polycarbonate sample was determined using an
Instron 3211 capillary rheometer with capillary length of 1.0087 inch, capillary diameter of
0.05005 inch, a shear rate range of 3.5 to 350 sec-', and a temperature of 290C. The samples for
the rheometer were prepared by placing a pre-dried, (100C vacuum oven dried) polymer
sample (1 g) in a stainless steel die, pl essing in a hydraulic press at a platen pressure of 3,000
Z5 pounds for a few minutes and obtaining cylindrical pellets. The melt viscosity of DHAMS
polycarbonate was determined to be 810 poise at 100 sec-l and 250 poise at 400 sec'.
ThermoqravimetricAnalvsis (TGA)
T6A is run using a Du Pont 2100 thermal analyzer, a temperature scan range from
25C to 1000C, a heating rate of 10C/minute, and a nitrogen purge. The residue remaining at
30 1000C, also known as the char yield, is 38 percent for DHAMS polycarbonate. The significance
of char yield and its relation to ignition resistance were discussed by Van Krevelen, Properties
of Polvmers, p.731 (Third Edition,1990).
Example 2 - Injection Molding and Properties of DHAMS Polycarbonate
DHAMS polycarbonate, prepared according to the procedure of Example 1, was
35 ground in a Thomas-Wiley model 4 laboratory mill, dried at 100C in a vacuum oven for 2 hours,
and then injection molded using an Arburg injection molding machine. Standard 0.125 inch
thick test specimens were injection molded at a barrel temperature of 300C, a mold
temperature of 125C, and using 275 bars of injection pressure. Tensile strength at break (Tb),
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tensile modulus (TM), elongation at break (Eb), flexural strength (FS), and flexurai modulus
(FM) were determined according to American Society for Testing and Materials (ASTM) test
method D-638. The notched Izod impact strength was determined according to ASTM D-256
wherein a 0.01 inch notch radius was employed. Vicat softening temperature for the polymer
5 was determine~ according to ASTM D-1525 using a 1 kg load. The coefficient of linear thermal
expansion (CLTE) in the flow direction was measured according to ~STM D-2236. Limiting
oxygen index (LOI) was determined according to ASTM D-2863-87. UL-94 determinations of
flammability resistance was conducted as specified by Underwriters Labordl~,ries. Water
absorption was measured at 25C after 24 hours immersion time. Specific gravity was measured
10 according to ASTM D-570. These results were as follows: Specific Gravity - 1.27; H2O
Absorption (percent) - 0.002; LOI (percent oxygen) - 37; UL-94 Rating V-0;
CLTE (ppm/C) - 25 to 35; Vicat (C) - 188; Tb (psi) - 15,970; TM (psi) 575,800; Eb (percent) - S;
FS (psi) - 18,970; FM (psi) - 656,600; N. Izod (ft-lb/in) - 8.8. The thermal resistance of DHAMS
polycarbonate was also evaluated using a 0.025 inch diameter probe carrying a load of 10 g.
15 Penetration of the sample was not observed until a temperature of 270C was reached.
Example 3 - Solid State Advancement of DHAMS Polycarbonate
A sample of DHAMS polycarbonate having an IV of 0.42 dL/g (measured in
pentafl uorophenol at 0.1 g/dL and 45C) was synthesized by the general proced ure of
Example 1. DSC analysis showed a melting temperature of 231C and a crystallization
20 temperature of 157C, determined during the first heating and cooling cycles according to the
procedure described above. The DHAMS polycarbonate was then solid state advanced with
stirring at 220C under a reduced pressure of 2x10-4 atmospheres for 48 hours, resulting in an
increase in IV to 2.2 dL/g, a melting point at 271C, and a crystallization temperature of 192C.
Example 4 - Preparation of Mixture of DHAMS Polycarbonate and Glass Fibers
DHAMS polycarbonate (prepared as in Example 1) (417 g) was dry mixed with
Owens-Corning glass fibers (125 9, 0.125 inch nominal length, #492). The mixture was then
compounded using a Brabender conical twin screw extruder (counter-rotating) at40 rpm screw
speed, with the feed zone at 255C and all other zones at 300C. The mixture was starve-fed to
the extruder using a K-Tron volumetric screw, having a feeder setting at 10.0, venting under
30 vacuum of any volatiles from the polymer melt, and a die was maintained. The measured
torque was approximately 2,500 meter-gram and the head-pressure was less than 2,000 psi. As
the mixture exited the die it was quenched with a water spray and cut into pellets with a
ronventional strand cutter. The resulting pellets were dried for approximately 16 hours in a
vacuum oven set at 100C and then were injection molded into standard test specimens (as
35 specifiedbyASTMD-638fordeterminingtensileproperties)onanArburgmoldingmachine
using a barrel temperature of 300C, a mold temperature of 125C, and 275 bars of injection
pressure.
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ExamPle 5 - Preparation of a Mixture of DHAMS Polycarbonate and BA PolycarbonateDHAMS polycarbonate with an IV of 1.5 dL/g (measured in pentafluorphenol at
0.1 g/dL and 45CC) and BA polycarbonate with a Condition O melt flow rate of 10 9/10 minutes
were each separately cryogenically ground to a fine powder. A portion (0.5011 g) of the
5 DHAMS polycarbonate and a portion (4.50 g) of the BA polycarbonate were combined and
mixed. The resulting mixture (4.76 9) was added over an 8 minute period to the stirred
reservoir of an injection molder which was preheated to 260~C. After addition of the mixture
was completed, the stirred mixture was maintained for an additional 12 minutes at the 260C
temperature prior to shutting off the stirring. The mixture was then injected into a 3 inch by
10 0.5 inch byO.125 inch stainless steel mold which was preheated to 260'~C.
The resulting molding was allowed to slowly cool to 23C before removing it fromthe molding machine. The molded specimen was opaque when it was removed. The flashing
recovered from the edges of the injection molded mixture was examined by optical microscopy
under cross-polarized light at both 75X and 300X magnifications. For the flashing, birefringent
fibers were observed at both magnifications and were oriented in the flow direction in an
isotropic matrix A sample of the residual mixture remaining in the reservoir of the injection
molder was removed and heated to 260C using a hot stage and then examined by optical
microscopy under cross-polarized light. B irefringent f ibers were observed at both
magnifications and these fibers were randomly oriented in an isotropic matrix.
20 Example 6 - Preparation of DHAMS/BA Copolycarbonates Using Melt Transesterification
The copolymerization was run in a zso mL, single-neck, round-boteom flask, fitted
with a two-neck adapter upon which were mounted a glass paddle stirrer and a 13 centimeter
~cm) Vigreaux distillation column, distillation head with a thermometer, condenser and a
receiver. DHAMS (0.11 moles, 24.1~ grams), 3A (0.012 moles, 2.71 grams) and
25 diphenylcarbonate (0.12 moles, 25.46 grams) were added to the reaction flask. The apparatus
was evacuated and refilled with nitrogen three times. The flask was immersed in a molten salt
bath preheated to Z20C. When the solid reactants were melted to form a molten reaction
mass, stirring was started and an aqueous solution of lithium hydroxide was added as a catalyst
(0.36 mL, 0.06 M).
The reaction temperature was raised to 265C over a period of one hour from
atmospheric pressure to 2x10 3 atmospheres. The latter pressùre was maintained for 1 hour at
265C. After an additional 5 minutes the reaction mass formed a ball on the stirrer shaft. The
vacuum was then released under nitrogen and the reaction vessel was removed from the salt
bath. The reaction apparatus was cooled and disassembled. The flask was broken away from
35 an opaque chalk-white copolycarbonate plug. The plug was sawed into chunks and then
ground in a Wiley mill. The copolycarbonate had an inherent viscosity of 0.91 dL/g which was
measured at 45C using a solution of 0.1 g of polycarbonate in 100 mL of pentafluorophenol.
The peak melting point was 250C on the first heating scan as measured by differential
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scanning calorimetry (DSC) on a sample run at 10C/minute. A second heating scan showed
only a Tg at 84C and no melting point lrd~iliOn is observed.
The copolycarbonate was characterized by optical microscopy under cross-
-polarized light. Observation of a bright field at temperatures above the melting point
5 indicated that ~he copolycarbonate melt was optically anisotropic.
Additional copolycarbonates of DHAMS and BA were prepared according to the
general procedure described above. These copolycarbonates were based on DHAMS/BA moiar
ratios of 90/10 to 50/50. The copolycarbonates were characterized by DSC for the¢letermination of glass transition temperature (Tg) and melting temperature (Tm), lV, TGA
10 I~percent char), and optical microscopy under cross-polarized light as described above. These
~esults are shown in Table 1.
Table I
DHAMS/BA IV Tg Tm TGA
Molar Ratio (dL/q) (C) ~C) % CharNematlc Melt
15 90/10 o.9la 84 250 35 Yes
75/25 0.36 105 216b 31 Yes
70/30 0.59 1Z4 213b 31 No
65/35 0.38 130 21 ob 30 No
20 60/40 0.59 134 218b 30 No
50/50 0.31 137 --' 29 No
a Run in pentafluorophenol at 45C.
b After annealing 2 to 12 hours at 175C under nitrogen.
c No melting transition observed.
Example 7 - Preparation of DHAMS/BA (50/50 and 25/75 Molar Ratio) Copolycarbonates Using
Solution Process
The following procedure was used to prepare a DHAM5/BA (50/50 molar ratio)
copolycarbonate. A 2 L four-neck, round-bottom flask, equipped with a thermometer,
condenser, phosgene/nitrogen inlet, and a paddle stirrer connected l:o a Cole Parmer
servodyne was charged with DHAMS (26.80 g,0.118 mol), BA (27.04 g, 0.118 mol),
4_tertbutylphenol (0.71 9,4.7 mmol, a chain terminator), pyridine (48.5 g,0.614 mol), and
methylene chloride (0.5 L). The mixture was stirred at 250 rpm and slowly purged with
nitrogen as phosgene (24.8 g, 0.251 mol) was bubbled in over 28 minutes while maintaining
the reactor temperature at 17C to 26C. The reaction mixture was worked up by adding
methanol (5 mL) and then a solution of 20 mL conc. HCI in 60 mL water.
35 After stirring for 15 minutes at 200 rpm, the mixture was poured into a 2 L
separatory funnel. The methylene chloride layer was separated and washed further with a
solution of 5 mL conc. HCI in 100 mL water, followed by 100 mL water, and then passed through
a column (0.2 L bed volume) of macroporous cation-exchange resin. The product was isolated
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by adding the clear methylene chloride solution to a mixture of hexane (2 L) and acetone (0.2L)
in an explosion resistant blender. The product was filtered, dried in a hood overnight, and then
dried for 48 hours in a vacuum oven at 110qC. ~he dried product weighed 55.6 9 and had an IV
of 0.846 dL/g (determined in methylene chloride at 0.5 g/dL and Z5C). DSC analysis (first scan,
20C/minute heating rate, scan from 50C to 250C) showed an extrapolated onset glass
transition temperature (T ) of 144qC. The second scan showed a Tg at 141 C. The 1 H NMR
spectrum of the product was in agreement with the target copolycarbonate composition. Size
exclusion chromatography using narrow fraction polystyrene standards gave the following
molecularweightanalysis: Mw = 98,446and MWlMn = 2.361.
The general procedure of this example was used to prepare additional
DHAMS/BA copolycarbonates having DHAMS/BA molar ratios of 50/50 and 25/75.
Compression Moldinq and Properties of DHAMS/BA Copolycarbonates
Compression molded plaques of approximately 6 inch x 6 inch x 0.125 inch were
prepared at molding temperatures 100C above Tg using a Tetrahedron MTP-14 press. These
transparent plaques were machined into test specimens. Tensile strength at yield (Ty),
elongation at yield (Ey), and post-yield stress drop (PYSD) are determined according to
ASTM D-638. A reduction in PYSD had been correlated with enhanced resistance to physical
aging and fatigue, resulting in improved long-term property maintenance: see R.8ubeck et
al., Polym. Enq. Sci., Vol.24, p.1142 (1984). IV, Tg, and notched l~od were determined as
20 described above. These results are shown in Table ll.
Table ll
DHAMS/BA IV TgN.lzod Ty Ey PYSD
Molar Ratio (dL/q) (C) (ft-lb/in) ~pSj) (cC) (%)
25/75 0.71 15013.3 7,802 7.8 14.6
50/50 0.64 13511.2 7,45g 7.6 8.1
50/50 , 0.76 13812.7 7,354 8.9 6.2
Example 8 - Preparation of DHAMS/BA (75/25 Molar Ratio) Copolycarb~nate Using Solution
Process
The same equipment as described in Example 7 was charged with DHAMS
(40.30 9, 0.178 mol), BA (13.55 9,0.059 mol),4-tertbutylphenol (0.71 9,4.7 mmol), pyridine
(48.7 9, 0.616 mol), and methylene chloride (0.5 L). The mixture was stirred at 250 rpm and
slowly purged with nitrogen as phosgene (24.4 9,0.247 mol) was bubbled in over 21 minutes
while maintaining the reactor temperature at 18C to 26qC. The product began to precipitate
from the reaction solution when 13 9 of phosgene was added. The same workup procedure as
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shown in Example 7 was followed, except that the product was not passed through a column of
ion exchange resin. For this composition the product was a slurry in methylene chloride rather
than a solution.
The product was isolated by adding the slurry to 3 L of methanol in an explosion5 , e~ dnt blender. The product was filtered, dried in a hood overnight, and then dried for 48
hours in a vacuum oven at 11 0C. The product weighed 59.6 g and was insoluble in the
following solvents that dissolve BA polycarbonate: methylene chloride, chlol c,f~r" "
tetrahydrofuran, dimethylformamide, and sym-tetrachloroethane. A compression molded
~laque (approximately 0.0Z inch thickness) prepared at 250C (3 minutes molding time, 10,000
10 pounds platen pressure) was well-fused, opaque, creasable, insoluble in the solvents listed
above, and does not stress crack when flexed and exposed to acetone. DSC analysis of the
product showed a first scan Tg of 1 35C and a melting endotherm from 1 75C to 220C with a
l,dn~ilion peak at 194C. A sample of this copolycarbonate was characterized by optical
microscopy under crosspolarized light as described above. The sample was applied between a
15 qlass slide and a glass coverslip and then placed on the programmable hot stage of the
rnicroscope. A heating rate of 1 0C/minute was employed and the following results were
obtained:
l~emperature (C) Observations
20 3o birefringent crystalline solid
145 slight softening observed when compressed between coverslip and
slide
168 fuses to highly birefringent, opaque, viscous fluid as compressed
184 highly birefringent, viscous fluid
200 highly birefringent, viscous fluid, stir opalescent, nematic texture,
orients with shear to give flow directed domains
245 some isotropic fl uid observed
285 isotropic fluid containing scattered birefringent regions
291 isotropization complete
Example 9 - Preparation of DHAMS/9,9-Bis(4-hydroxy-phenyl)fluorene (BHPF)
Copolycarbonate
The general procedure of Example 7 was used to prepare DHAMS/BHPF (75/25
molar ratio) copolycarbonate. The resulting copolycarbonate was insoluble in methylene
chloride. DSC analysis showed a Tg at 1 73C (first scan, 20C/minute heating rate).
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~xample 10 - Preparation of Polyestercarbonate from DHAMS, Diphenyl Terephthalate, and
Diphenyl Carbonate
The polymerization was run in a 250 mL single-neck, round-bottom flask, fitted
with a two-neck adapter upon which are mounted a glass paddle stirrer and a 13 cm Vigreaux
5 distillation column, distillation head with a thermometer, condenser and a receiver. Diphenyl
terephthalate (0.0143 mol,3.64 g, an ester derivative of terephthalic acid), DHAMS (0.11 mol,
25.84g),anddiphenylcarbonate(0.10mol,22.02g)wasaddedtothereactionflask. The
apparatus was evacuated and refilled with nitrogen three times. The flask was immersed in a
molten salt bath preheated to 220C. When the solid reactants had melted to form a molten
10 reaction mass, stirring was started and lithium hydroxide (0.36 mL of 0.06 M aqueous solution)
was added.
The reaction temperature was raised to 265C over a period of one hour and the
pressure was reduced from atmospheric pressure to 2x10-3 atmospheres. The latter pressure
was maintained for 1 hour at 265C. After an additional 5 minutes the reaction mass formed a
ball on the stirrer shaft. The vacuum was then released under nitrogen and the reaction vessel
was removed from the salt bath. The reaction apparatus was cooled and disassembled. The
volumeofphenolrecoveredwas20.1mL. Theflaskwasbrokenawayfromanopaquechalk-
white product. The plug was sawed into chunks and then ground in a Wiley mill. The
polyestercarbonate had an inherent viscosity of 1.05 dL/g (pentafluorphenol, 45C,0.1 g/dL).
20 DSC analysis, conducted at a scan rate of 10C/minute, showeds a melting Lrdr,~iLion at 213C.
Example 11 - Preparation of Polyester from 4,4'-Diacetoxy-alpha-methylstilbene (DAAMS) and
Terephthalic Acid
The following procedure was used to convert DHAMS to DAAMS. To a single-
-neck, 500 mL, round-bottom flask, equipped with a condenser and nitrogen inlet, were added
25 DHAMS (0.133 mol,30 g) and acetyl chloride (0.665 mol,48 mL) in methylene chloride (200 mL).
The reaction mixture was refluxed for 3 hours and a clear solution was obtained, at which point
by High Pressure Liquid Chromatography (HPLC) analysis the reaction had reached completion.
The reaction mixture was cooled, and then concl:"L~dled to remove excess methylene chloride
and unreacted acetyl chloride, leaving a white powder as the product. The crude product was
30 recrystallized from methyl isobutyl ketone, resulting in 20.16 g of DAAMS as a white crystalline
solid having a melting point of 126C.
The polymerization was run in a 250 mL single-neck, round-bottom flask, fitted
with a two-neck adapter upon which were mounted a glass paddle stirrer and a 13 cm Vigreaux
distillation column, distillation head with a thermometer, condenser and a receiver.
35 Terephthalic acid (0.084 mol,13.99 g) and DAAMS (0.084 mol, 26.12 g) were added to the
reaction flask. The apparatus was evacuated and refilled with nitrogen three times. The flask
was then immersed in a molten salt bath preheated to 260C. The white suspension became a
slurry over the next 2 hours as the temperature was slowly raised to 360C. The pressure was
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slowly lowered to Zx10-3 atmospheres. After an additional 30 minutes, the apparatus was
cooled, and the vacuum was released under nitrogen. The isolated amount of opaque, pale
yellow polyester was 26 9. The receiver contained 9.7 mL of acetic acid. The polyester was
ground to a powder and was found to be insoluble in pentaflurophenol at 0.1 g/dL and 45C.
5 DSC analysis of the polymer resulted in no observable endotherms or exoll.erl..s in the analysis
range of 25C to 400C.
Example 12 - Preparation of Copolyester from DAAMS, IsophthalicAcid, 4-AcetoxybenzoicAcid
(ABA), and 2,6-NaphthalenedicarboxylicAcid (NDCA)
The polymerization was run in a 250 mL single-neck, round-bottom flask, fitted
10 with a two-neck adapter upon which were mounted a glass paddle stirrer and a 13 cm Vigreaux
distillation column, distillation head with a thermometer, condenser and a receiver. ABA
(0.10Zmol,18.232g),isophthalicacid(0.0169mol,2.80g),NDCA(0.017mol,3.65g),and
DAAMS (0.034 mol,10.46 g) were added to the reaction flask. The apparatus was evacuated
and refilled with nitrogen three times. The flask was immersed in a molten salt bath preheated
15 to 260C. When the solid reactant melt to form a molten reaction mass, stirring was started and
lithium hydroxide (0.36 mL of 0.06 M aqueous solution) was added. The reaction temperature
was raised to 340C over a period of 2 hours at atmospheric pressure. Then the pressure was
lowered to 2x10-3 atmospheres and this pressure was maintained for an additional hour at
340C. After an additional 5 minutes, the reaction mass formed a ball on the stirrer shaft. The
zO vacuum was then released under nitrogen and the r eaction vessel was removed from the salt
bath. The reaction apparatus was cooled and disassembled. The volume of acetic acid
recovered was 9.67 mL. The flask was broken away from the opaque yellow copolyester plug.
The plug was sawed into chunks and then ground in a Wiley mill. DSC analysis, conducted at a
scan rate of 10C/minute, showed a melting transition at 280C.
25 Example 13 - Preparation of Polycarbonate of 4,~'-Dihydroxy-alpha,alpha'-diethylstilbene
(DES)
This polycarbonate was prepared according to the general procedure of Example
1 using DES (0.14 mol,36.5 g) and diphenyl carbonate (0.15 mol,32.1 g). During the synthesis,
conducted from 2Z0 to 290C, the reaction mixture remained isotropic. Phenol (25 g) was
30 removed as a distillate during the synthesis. The isolated yield of DES polycarbonate is 37 g.
This polycarbonate had an IV of 0.37 dL/g (determined in chloroform at 25C). DSC analysis
showed a Tg at 87C and no indications of a melting transition in the scan range of Z5C to
300C. The polycarbonate was annealed at 125C for 12 hours under an atmosphere of
nitrogen. DSC analysis of the annealed sample showed a Tg at 92C, but no evidence of melting
35 transitionS.
Example 14- Preparation of DHAMS/DES (90/10 Molar Ratio) Copolycarbonate
This copolycarbonate was prepared according to the general procedure of
l xample 1 using DES (0.016 mol,4.19 g), DHAMS (0.14 mol,31.76 g), and diphenyl carbonate
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40,9 1 3A-F
(0.16 mol,33.41 9). During the synthesis, conducted from Z20C to Z90C, the reaction changed
from an isotropic liquid to an opaque molten state at 270C. Phenol (29 9) was removed as
distillate during the synthesis. The resulting copolycarbonate was obtained as a white
crystalline soiid in an isolated yield of 35 9. DSC analysis showed a Tg at 875C and a melting
5 transition at 237C during the heating scan and a crystallization exotherm at 112C during the
cooling scan. The polymerwas insoluble in methylene chloride and chloroform at 0.1 g/dL.
The polymer melt was optically anisotropic as determined by optical microscopy analysis
described above.
Example 15 - Preparation of DHAMS14,4'-Dihydroxystilbene (DHS) Copolycarbonate
DHAMS/DHS (90/10 molar ratio) copolycarbonate was prepared according to the
general procedure of Example 1 using DHS (0.02 mol, 3.35 9), DHAMS (0.14 mol,32.5 9), and
diphenyl carbonate (0.16 mol,34.2 9). DHS was prepared according to the procedure of
McMurry and Silvestri, J. Orq. Chem., Vol. 40, p. 2687 (1975). The polymerization was
conducted from 220C to 290C. The reaction mixture beamed opaque at 280C. Phenol (30 g)
was removed as a distillate during the synthesis. The resulting copolycarbonate,37 9, was
isolated as a white fibrous solid. The polymer was insoluble in methyiene chloride or
chloroform at 0.1 g/dL. DSC analysis showed a sharp melting transition at 283C and a
crystallization exotherm at 200C during the first heating and cooling scans. The second
heating and cooling scans of the sample showed a melting transition at 283C and a
20 crystallization exotherm at 196C. The melt was optically anisotropic as determined by the
methods described above.
Example 16 - Preparation of DHAMS/DHS (75/25 Molar Ratio) Copolycarbonate
This copolycarbonate was prepared according to the general procedure of
Example 1 using DHS (0.04 mol, 8.45 9), DHAMS (0.121 mol, 27.3 g), and diphenyl carbonate
25 (0.16 mol,34.5 9). The reaction was conducted from 220C to 320C and the reaction mixture
became opaque at 285C. Phenol (30 9) was removed as a distillate during the synthesis. The
resulting copolycarbonate, 35 9, was isolated as a white fibrous solid. The polymer was
insoluble in methylene chloride or chloroform at 0.1 g/dL. DSC analysis showed a sharp melting
transition at 299C and a crystallization exotherm at 228C. The melt was optically anisotropic
30 as determined by the methods described above.
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Al`'lE~l~ED S,'IEET
