CA2002879A1 - Poly(aryl ether)-poly(aryl carbonate) block copolymers and their preparation - Google Patents

Abstract

ABSTRACT

A method for preparing poly(aryl ether)-(poly aryl carbonate) block copolymers by the decarboxylation of copolycarbonates prepared by the condensation of two different aromatic dihydroxy compounds and a carbonate precursor such as phosgene. At least one of the aromatic diols must have at least one electron-withdrawing group located in a position ortho or para to at least one of its hydroxy groups and at least one of the diols must not have any electron-withdrawing groups in a position ortho or para to either of its hydroxy groups. The method is particularly effective in making crystalline block copolymers. The copolymers of the present invention exhibit high temperature stability and excellent thermoplastic engineering properties as well as superior solvent resistance. The copolymers are particularly useful for producing molded plastic components for the automotive and electrical housings markets.

35,395-F

Description

POLY(ARYL ETHER)-POLY(ARYL CARBONATE) BLOCK COPOLYMERS AND THEIR PREPARATION

This invention relates to a process for preparing polyether-polycarbonate copolymers. More particularly, the invention relates to a process for preparing poly(aryl ether)-poly(aryl carbonate) block copolymer~ and to block copolymers prepared thereby.
Polycarbonates are well-known commercially available resinous materials having a variety of application~. They are typically prepared by the reaction of dihydroxy compounds and a carbonate precursor, such as phosgene. The polycarbonates are high temperature, high performance thermoplastic engineering polymers with a good combination of thermal ard mechanical properties, especially when the polymer is prepared frsm one or more aromatic diols. However, the polycarbonates do exhibit poor hydrolytic stability, particularly when exposed to humid environments for prolonged times and/or elevated temperatures and poor ~olvent resistance.
Attempts to modify the properties of polycarbonate resins by blending with other polymeric 35,395-F _l_ materials are quite often unsatisfactory because of the incompatibility of the polycarbonates with other resinous materials. To overcome these problems, it has been proposed to polymerize other resinous materials into the polycarbonate molecule. Thus, random, block and graft copolymers of polycarbonates and other polymers, such as polyethers, are known. For example, polyether sulfone has been interpolymerized into the polycarbonate molecule by (1) preparing a hydroxyl-terminated polyether sulfone and condensing thehydroxyl-terminated polysulfone oligomer with 2,2-bis-(4-hydroxyphenyl)propane (Bisphenol A) and phosgene in the presence of pyridine; (2) preforming both a hydroxyl-terminated polyether sulfone oligomer and a Bisphenol A-polycarbonate oligomer and extending the oligomers to a high molecular weight by phosgenation in a common solvent; and (3) by the pyridine-catalyzed reaction of chloroformate-terminated polycarbonate oligomers with hydroxyl-terminated polyether sulfone oligomers in a common solvent. In each of these methods, a carbonate radical is linking the polycarbonate and polyether sulfone blocks.
The present invention relates to a process for preparing poly(aryl ether)~poly(aryl carbonate) block copolymers wherein at least some of the poly(aryl ether) block~ are joined to the poly(aryl carbonate) blocks through an ether oxygen atom; and such copolymers prepared according to the process of the present invention. More specifically, the present invention is directed to a method for making poly(aryl ether)-poly aryl carbonate) block copolymers, which ccmprises heating copolycarbonate which contains units having the structure~:

35,395-F -2-, ~A-0 C0~0~ and ~B-0-C0-03 wherein A i3 an activating aromatic radical having at least one electron-withdrawing group located in a position ortho or para to its carbonate linking group;
and B is a nonactivating aromatic radical which is characterized by the absence of an electron-withdrawing group located in a position ortho or para to its carbonate linking group.
A and B are desirably C6-C30 aromatic radicals, which optionally may contain one or more substituent monovalent Cl-C20 aliphatic radicals, halo radicals, alkoxy radicals, aryloxy radicals, thioalkoxy radicals or thioaryloxy radicals, or divalent Cl-C20 aliphatic radicals, alkoxy radioals, aryloxy radicals, thioalkoxy radical~ or thioaryloxy radicals.
In accordance with the present invention, poly(aryl ether)-poly(aryl carbonate) block copolymers are prepared by the decarboxylation of copolycarbonates formed from the reaction of at least two different aromatic dihydroxy compounds and at least one carbonate precursor, such as phosgene, wherein at least one of the aro~atic diols (the aromatic position of which is identified as an "A" group herein) contains an electron-withdrawing group in a position ortho or para, preferably para, with respect to at least one of the hydroxy groups on such diol, and wherein the other of the aromatic diols (the aromatic portion of which is identified as a "B" group herein) does not contain an electron-withdrawing group located in a position ortho or para with respect to any of its hydroxyl groups. The 35,395-F -3-.:' . ~

"A" aromatic units are referred to herein as activated, and the "B" aromatic units are said to be nonactivated.
Such copolymerization of two or more different aromatic diols in the presence of a carbonate precursor will result in a carbonate copolymer, which may have a random or ordered structure depending upon polymerization procedure and conditions and which contains units represented by the formulae ~A-0-C0-0~ and ~B-O~C0-03 The term "ordered structure" is intended to include either a simple alternating structure (ignoring the 0-C0-0 linkage) such as:
~A-B-A-B-A-B~nl ; or a block copolymer such as ~A-A-A-B-B-B3nl wherein n' is the number of repeating units of 2 or more. Such a copolycarbonate will contain carbonate linkages of three different decarboxylation activities.
Carbonate linkages between two activated aromatic radicals ~A-0-C0-0-A~ will be most active and will decarboxylate to -A-0-A- segments most rapidly.
Carbonate linkages between an activated aromatic linkage and a nonactivated linkage ~A-0-C0-0-B~ will be less active, but will still be subject to decarboxylation and will be substantially completely decarboxylated if decarboxylation is continued long enough. The carbonate linkages between two nonactivated aromatic groups ~B-0-C0-0-B~ will be highly resistant to decarboxylation 35,395-F -4-, , , at the same conditions and will decarboxylate to an insignificant degree, if at all.
Our experience reveals that even when one decarboxylates an alternating copolycarbonate as described above, one obtains a block poly(aryl ether)-poly(aryl carbonate). This is strikingly surprising.
While this invention should not be limited to a particular theory, it is believed that the rapidly decarboxylating "A-carbonate" radicals tend to combine with one another to form ether block segments while "B-carbonate" radicals liberated from A-B combinations tend to combine with other B-carbonate units or segments of units. In order to obtain block segments of meaningful lengths, e.g., from 5 to 15 units, it has been found preferable to continue decarboxylation until the decarboxylation of A-carbonate units approaches 100 percent. Further, in order to obtain meaningful poly(aryl ether) segment lengths, the activated aromatic carbonate units should preferably comprise at least 20 percent of the copolycarbonate chain. The most interesting poly(aryl ether)-poly(aryl carbonate) block copolymers tend to be made from copolycarbonates having from 20 to 80 percent activated aromatic carbonate unit~, thereby yielding poly(aryl ether)-poly(aryl carbonate) block copolymers having from 20 to 80 percent poly(aryl ether) units.
It i3 found that the length of the poly(aryl 3 ether) segments tends to be from 5 to 15 unitsO This length is determined not only by the percentage of activated aromatic carbonate in the starting copolycarbonate, but also by the difference in the decarboxylation rate of the -A-O-CO-O-A- linked groups and the -A-O-CO-O-B carbonate groups. The greater the 35,395-F -5-- . :
': ~ ~; -' rate difference, the greater the length of the poly(aryl ether) block segments.
In the decarboxylation of a copolycarbonate comprising 50 percent activated aromatic carbonate units and 50 percent nonactivated aromatic carbonate units, the length of the poly(aryl carbonate) block segments will be approximately the same as the length of the poly(aryl ether) block segments. If the percentage of nonactivated aromatic carbonate units is greater, then the length of the poly(aryl carbonate) block segments will be correspondingly longer. In other words, the relative lengths of the poly(aryl ether) and poly(aryl carbonate) segments tends to be proportional to the percentages of their respective precursors in the copolycarbonate.
The poly(aryl ether)-poly(aryl carbonate) block copolymers prepared according to this invention comprise a first segment having recurring units of the structure ~A-03 and a second segment having recurring units of the structure ~B-0-C0-03;
at least some of which segments are linked to each other through an ether oxygen to form poly(aryl ether)-poly(aryl carbonate) block copolymers which can becharacterized in a general way as having recurring units of the structure (~A-03k ~B~~C~O~m)n;

35,395-F -6-wherein A and B are previously described, K represents the number of recurring poly(aryl ether) units in the poly(aryl ether) block, preferably from 2 to 10,000, more preferably from 2 to 200, most preferably form 30 to 200, m represents the number of recurring units in the poly(aryl carbonate) blocks, preferably from 2 to 10,000, more preferably from 2 to 200, most preferably from 30 to 200 and n represents the overall degree of polymerization, preferably from 2 to 100, more preferably form 15 to 100, most preferably from 15 to 50. The k and m values are proportional to the respective percentages of activated aryl carbonate units and nonactivated aryl carbonate units in the starting copolycarbonate.
The foregoing general formula does ignore the fact that there may be a percentage of -A-0-C0-0- units left in the block copolymer chain. In order to obtain longer chain lengths, this percentage will be quite small.
The above general formula also a~sumes that half of the linkages between poly(aryl ether) segments and poly(aryl carbonate) segments will be ether linkages, and the remainder will be carbonate linkages.
This in fact may not be the case, depending on how long the operator allows decarboxylation to continue. Thus 7 a more precise structural formula would be as follows:

3 (~A-O~k ~C~~x ~B-0-CO~O~(m_1) ~B-0~ ~C0-0~x,)n wherein X, K, m and n are as previously defined; X is le~s than and never equals 1; and X' is from 0 to 1.

35,395-F -7-In the foregoing formula, X and X' can both be substantially reduced, and perhaps even brGught to zero by continuing decarboxylation for a sufficient length of time. Almost certainly, at least some of the poly(aryl ether) segments will be bonded to adjacent poly(aryl carbonate) segments through an ether bond, resulting in the statement in the above formula that X is less than, and never equals, one. If X were zero and X' were one, then the more general formula for the polymer set forth above would result.
In less preferred embodiments of the invention, as little as 20 percent of the activated aromatic carbonate linkages are decarboxylated. This leaves a significant portion of activated aromatic carbonate units in the polymer chain. The presence of these units tends to cause the individual poly(aryl ether) block segments to be relatively small before being interrupted either by activated aromatic carbonate units or nonactivated aromatic carbonate units. If the degree of decarboxylation is too slight, the product retains too many of the characteristics of the copolycarbonate from which it is made. Further, the degree of decarboxylation necessary to effect a change in properties will vary depending on what percentage of the copolycarbonate is comprised of activated aromatic carbonate units. It has been found that the overall degree of decarboxylation, with reference to both activated and nonactivated aromatic carbonate units, should be at least 15 percent in order to begin effecting a ~ignificantly noticeable change in properties. In a 50/50 copolycarbonate, 10 percent decarboxylation overall will comprise 20 percent decarboxylation of the activated aromatic carbonate 35,395-F -8-':, ' , ' , .

linkages. On the other hand, in a 20/80 activated-nonactivated copolycarbonate, 10 percent decarboxylation as a whole comprises 50 percent decarboxylation of tne activated aromatic carbonate units. Thus, when discussing the degree of decarboxylation necessary to begin effecting a change in properties, it is best to refer to decarboxylation of the copolycarbonate as a whole, even though the nonactivated aromatic carbonate units cannot actually be decarboxylated.
A general formula which reflects the possibility of nondecarboxylated activated aromatic carbonate units is as follows:
(~A-O-C0-03j~A-03(k_j)~C0-03~B-O-CO-03(m_1)~B-03~CO-03X,)n where (k-j) is at least 10 percent o~ k + m.
It will be appreciated that the above formula is inherently somewhat imprecise in that the -A-O-CO-O-units may or may not form a block segment of their own,and indeed are more likely to be randomly interspersed between -A-O- units, between -A-O- and B-CO-O units, and probably between B-O-CO-O- units, to the extent that the~ were located between such B-O-CO-O- units in the starting copolycarbonate.
Substantially any aromatic diol can be employed in forming the copolycarbonates which are decarboxylated to polymeric poly(aryl ether)-poly(aryl carbonate) 3 blocks in accordance with t'nis invention, providing that at least one of the aromatic diols has at least one electron-withdrawing group which is positioned ortho or para with respect to at least one hydroxy group of the aromatic diol and at least one other and different aromatic diol is present which does not have an 35,395-F _g_ .:

- l o -electron-withdrawing group positioned ortho or para with respect to either of its hydroxy groups. Electron-withdrawing groups can be, without limitation to those specifically recited, divalent groups such as -SO2-, -SO-, -CO-, -CONH-, -CONR-, -+NR2-, -+PR2-, -+SR-, -P(O)R-, -C(CF3)2-, -CHCH-, -NN-, -CHNNCH-, wherein each R is a Cl-C12 hydrocarbyl radical; and monovalent groups such as -CN, -NO2, -CHO, -CO2R, -co2NH2~ -P(O)(OR)2, -P()R2, -+PR3, -+NR3, -~SR2~ wherein R again is a C1-C12 hydrocarbyl radical. Also functioning as an electron-withdrawing divalent group are heterocyclic compounds such as imidazoles, oxazoles, pyrazoles, isoxazoles and oxapyrazoles.

Some specific examples of suitable aromatic diols containing electron withdrawing groups which are properly positioned are shown below:

35,395-F -10-, .

HO ~--C ~EI ~ N ~ OH

li~-S~-OI~

NO~--N=N~--Oll ~o~3~ ~ \~OH

~ N-A-OH ~ ~ R-OH
HO C/ HO W

W=S, O, N-R

wherein R is a C1_12 alkyl radical or an aromatic C6_30 radical The polycarbonates which are derived at least in part from 4,4'-dihydroxybenzophenone (Bisphenol K) are particularly de~irable starting material~ because of 35,395-F ~11-, the crystalline nature of the products containing such residues.
The polycarbonates which are decarboxylated in accordance with this invention can be produced by any of the conventional processes known in the art for the manufacture of polycarbonates. Generally speaking, aromatic carbonate polymers are prepared by reacting an aromatic dihydric phenol with a carbonate precursor such as phosgene, a haloformate or a carbonate ester. The dihydric phenols are mononuclear or polynuclear aromatic compounds containing two hydroxy groups, each of which is attached directly to a carbon atom of an aromatic nucleus. In forming the copolycarbonates which are decarboxylated in accordance with the invention, there will be employed at least one activated dihydric phenol, th~t it, a dihydric phenol which contains at least one electron-withdrawing group in an ortho or para position to either or both of the hydroxy groups, for example, Bisphenol K, and at least one nonactivated dihydric phenol, that ls, a dihydric phenol, which does not contain an electron-withdrawing group in an ortho or para position to either of the hydroxyl groups, for example, Bisphenol A.
A preferred method for preparing the copolycarbonates suitable for use in the practice of this invention involves the use of a carbonyl halide, such as phosgene, as the carbonate precursor. This 3 method involves passing phosgene gas into a reaction mixture containing the activated dihydric phenol, the nonactivated dihydric phenol and an acid acceptor, such as a tertiary amine, for example, pyridine, dimethyl analine, qunioline and the like. The acid acceptor may be used undiluted or diluted with inert organic 35,395-F -12-solvents, such as methylene chloride chlorobenzene or 1,2-dichloroethane. Tertiary amines are advantageous since they are good solvents as well as acid acceptors during the reaction.
The temperature at which the carbonyl halide reaction proceeds may vary from below 0C to 100C. The reaction proceeds satisPactorily at temperatures from 20C to 50C. Since the reaction is exothermic, the rate of phosgene addition may be used to control the temperature of the reaction. The amount of phosgene required will generally depend upon the amount of dihydric phenols present. Generally speaking, one mole of phosgene will react with one mole OI' dihydric phenol to form the copolycarbonate and two moles of HCl. The HCl is in turn attacked or taken up by the acid acceptor present. The foregoing are herein referred to as stoichiometric or theoretic amounts.

Another method for preparing the carbonate polymer comprises adding phosgene to an alkaline aqueous suspension of the mixture of activated and nonactivated dihydric phenols. This preferably done in the presence of inert solvents such as methylene chloride 1,2-dichloroethane and the like. Quaternary ammonium compound~ may be employed to catalyze the reaction.
Yet another method for preparing such carbonate copolymers involves the phosgenation of an agitated suspension o~ the anhydrous alkali salts of the activated and nonactivated diols in a nonaqueous medium ~uch as benzene, chlorobenzene and toluene. The reaction is illustrated by the addition of phos~ene to a slurry of the sodium salts of Bisphenol A and Bisphenol K in an inert polymer solvent such a~

35,395-F -13--, chlorobenzene. The organic solvents should preferably be a polymer solvent but need not necessarily be a good solvent for the reactants.
Generally speaking, a haloformate such as the bis-haloformate of Bisphenol A may be substituted for phosgene as the carbonate precursor in any of the methods described above.
When a carbonate ester is used as the carbonate precursor in the polymer forming reaction, the materials are reacted at temperatures of from 100C or higher for time varying from 1 to 15 hours. Under such conditions, ester interchange occurs between the carbonate ester and the dihydric phenol used. The ester interchange is advantageously consummated at reduced pressures on the order of from 10 to 10U millimeters of mercury, preferably in an inert atmosphere such as nitrogen or argon.
Although the polymer forming reaction may be conducted in the absence of a catalyst, one may, if desired, employ the usual ester exchange catalyst, such as metallic lithium, potassium, calcium and magnesium.
Additional aatalysts in variation in the exchange methods are discussed in Grogans, Unit Processes and Or~anic Synthesis, (4th Edition, McGraw-Hill Book Company 19, 1952), pages 616-20. The amount of such catalyst, if used, is usually small, ranging from O.OO1 to O.1 percent, based on the moles of the dihydric phenols employed.
The carbonate ester useful in this connection may be aliphatic or aromatic in nature, through aromatic esters such as diphenyl carbonate are preferredO

35,395-F ~14-Additional samples of carbonate esters which may be used are dimethyl carbonate, diethyl carbonate, phenyl methyl carbonate, phenyl tolyl carbonate and di(tolyl) carbonate.
In the solution methods of preparation, the carbonate copolymer emerges from the reaction in either a true or pseudo solution whether aqueous base or pyridine is used as an acid acceptor. The copolymer may be precipitated from the solution by adding a polymer 0 nonsolvent, such as heptane or isopropanol.
Alternatively, the polymer solution may be heated to evaporate the solvent.
Another method for preparing the 5 copolycarbonate resins which are decarboxylated in accordance with the invention comprises passing a carbonyl halide such as phosgene into a slurry comprising a suspension of solid particles in a single liquid phase, the suspension of solid particles comprising a mixture of activated and nonactivated dihydric phenols and at least two moles, per mole of dihydric phenol, of at least one acid selector selected from the group consisting of a hydroxide, a carbonate and a phosphate of an alkali or alkaline earth metal and a single liquid phase comprising an inert organic liquid which i~ a solvent for the carbonate copolymer9 but a nonsolvent for the dihydric phenols and the acid acceptor, to form a reaction mlxture having a solid 3 phase and a single liquid phase comprising a solution of the copolycarbonate polymeric material in the inert organic liquid, and separating the liquid phase from the solid phase.

35,395-F -15-., ~

.

The decarboxylation of the copolycarbonates to form the novel polymeric products containing poly(aryl ether)-poly(aryl carbonate) blocks or segments is carried out by heating the copolycarbonate, preferably in the presence of a high boiling solvenS and a catalyst, and more preferably, also in the presence of a dehydrating or azeotroping agent. The decarboxylation is effected at temperatures in the range from 150 to 350C, p~eferably 230 to 350C, and most preferably from 250 to 350C. The decarboxylation is effected at a time sufficient to prepare the poly(aryl ether)-poly(aryl carbonate) block copolymer, preferably for from 1 minute to 10 hours, more preferably from 5 minutes to 2 hours.
The pressure at which decarboxylation is effected is not critical and thus can be over a broad range from superatmospheric to subatmospheric.
The use of catalysts is recommended, particularly metal salts such as alkaline metal halides, carbonates, phenates, acetates and alcoholates.
Currently, the metal halides, particularly the metal fluorides such as cesium fluoride, are preferred. It has been found that the metal halide catalyst, especially the metal fluorides, provide a significant 2~
advantage over oxygen-containing catalysts, such as phenates and carbonates, in that their use does not lead to a loss of molecular weight in the final decarboxylated product. The currently preferred decarboxylation catalyst is cesium fluoride. The catalysts are employed in amounts in the range of from 0.001 to 10, preferably 0.01 to 2, and most preferably 0.1 to 0.5, percent by weight, relative to the copolycarbonate amount.

35,395-F -16-. -17-It can be advantageous, although it is not a requirement, to conduct decarboxylation in the presence of high boiling solvents such as benzophenone and diphenylsulfone and dehydrating agents, e.g., azeotroping agents, such as toluene or chlorobenzene.
In a particularly preferred embodiment, the polycarbonate and high-boiling solvent are combined with an azeotroping agent such as chlorobenzene to dewater the copolycarbonate before combining the copolycarbonate with the catalyst. As noted above, the degree of decarboxylation is at least 10 percent with respect to the total carbonate content of the copolycarbonate.
The invention is more easily understood by reference to a specific embodiment which is representative of the invention, it being understood that the specific embodiment is provided for purposes of illustration and understanding of the invention.
However, this specific embodiment does yield a surprisingly desirable block copolymer.
In accordance with the present invention, a poly(benzophenone ether)-poly[2,2-bis(4-hydroxyphenyl)-propane carbonate] block copolymer is obtained by the decarboxylation of the corresponding copolycarbonate according to the following reaction scheme, which is shown in a general way:

35,395-F -17-' ~ ~OH + m ' HO ~--OH

~ Base 1( _ o O _ - ~)--C ~-C -O ~ ~-C-O ~ n 11 ¦ CsF/320~C

2 ( 4~ ~ ~ n where k, m and n are as previously defined; and k' and m' are numbers proportional to k and m, respectively.
Thus, 4,4'-dihydroxybenzophenone ~Bisphenol K3, 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A~ and carbonyl chloride are reacted to form a copolycarbonate which can be ordered or random, depending on procedure followed. The benzophenone carbonate, i.e., Bisphenol K
carbonate, units are activated and the Bisphenol A
carbonate segments are nonactivated.
In the representative reaction in which Bi~phenol K and Bisphenol A are reacted in the pre~ence 35,395-F ~l8-of carbonyl chloride to form a copolycarbonate, the activation is accomplished by the carbonyl group from the Bispnenol ~ which is in a para position with respect to both hydroxy groups of the Bisphenol K compound.
While electron-withdrawing groups in either the ortho or para position are effective to activate the polycarbonate for decarboxylation, aromatic diols containing at least one electron-withdrawing group in a para position to at least one of the hydroxyl groups of ; 10 the aromatic diol are currently preferred.
The foregoing poly~Bisphenol K ether) poly (Bisphenol A carbonate) copolymer is a particularly preferred embodiment of this invention in that it exhibits both the high temperature, high performance thermoplastic engineering properties of polycarbonates, a~ well as excellent solvent resistance resulting from ;` the fact that surprisingly, this copolymer is crystalline in structure. This surprising crystalline structure is a particularly desirable re~ult.
, The copolymer prepared according to the present invention exhibit high temperature stability and excellent thermoplastic engineering propertie~ as well a~ superior solvent resistance. The copolymers are particularly u~eful for producing molded plastic components for the automotive and electrical housings markets.
The example~ which follow are intended solely to illustrate the embodiments of this invention and are not intended in any way to limit the ,~cope and intent of the invention.

35,395-F -19-, ': , .
: `:

:

Examples In Example 1 below, a random 50 percent Bisphenol A/50 percent Bisphenol K copolycarbonate was produced and subsequently decarboxylated in accordance with the method of the present invention. In Example 2, an ordered, alternating 50 percent Bisphenol A/
50 percent Bisphenol K copolycarbonate was made. Both were then subjected to the same analysis in Example 3 to compare the resulting block copolymer structures. In Analysis 1, the poly(Bisphenol K ether) poly(bisphenol A
carbonate) from each of Examples 1 and 2 was subjected to hydrolysis to separate te carbonate linkages. Acetic anhydride was added to react with the hydrolyzed fragments. The resulting mixture was subjected to distillation to remove the volatiles, consisting primarily of the diacetate of Bisphenol A. The acetylated ether oligomers remaining in the pot residue were subjected to NMR analysis to determine the ratio of Bisphenol K to Bisphenol A remaining in a polymer unit.
The results suggest that Bisphenol K ether blocks of approximately 5 units in length were formed and were connected to the poly(Bisphenol A carbonate) segments through an ether linkage. This was true for both the poly(Bisphenol K ether) and poly(Bisphenol A carbonate) polymer made in accordance with Example 1 and made in accordance with Example 2, the former being made from a random copolycarbonate and the latter being made from an alternating copolycarbonate. Thus, the ratio of residual Bisphenol K/Bisphenol A was 4.75 to 1 in the case of the Example 2 polymer and was 4.84 to 1 in the case of Example 1 polymer.
A similar series of tests was conducted in Examples 3 and 4 on a 50/50 Bisphenol A/Bisphenol S

35,395-F -20-[bis-(4-hydroxypehnol)sulfone] copolycarbonate. In Example 3, a random 50/50 Bisphenol A/Bisphenol S
copolycarbonate was decarboxylated. In Example 4, an alternating 50/50 Bisphenol A/Bisphenol S
copolycarbonate was decarboxylated. In Analysis 2, a sample of the polymer product of Exampie 4 was analyzed in a manner similar to the procedure of Analysis 1, except that the final separation technique was modified given the different characteristics of the chemicals involved. The Bisphenol S to Bisphenol A ratio determined by NMR procedures~was 5 to 1, again suggesting a poly(Bisphenol S ether) chain length of 5 units joined to the poly(Bisphenol A carbonate) chains through an ether linkage at one end.
The length of the polymer segments can be controlled to some extent by varying reaction conditions to thereby vary the decarboxylation rate difference between the -A-O-CO-O-A- carbonates and the -A-O-CO-O-B-carbonate groups. The specific process steps varied maybe different for different copolycarbonates. However, varying temperature usually affects the aforesaid rate differential and thereby affects the length of the polymer segments.
ExamDle 1 - Decarboxylation of Random 50/50 Bisphenol A/Bisphenol K Copolycarbonate A random copolycarbonate was prepared by dissolving an equimolar ratio of Bisphenol A and Bi~phenol K and 0.5 mole percent p-tert-butyl phenol as capping agent in CH2Cl2 along with a 20 percent molar excess of pyridine and a slight excess of phosgene. Ice bath cooling was employed to maintain a temperature below 20C. Excess phosgene was destroyed with MeOH.

35,395-F -21-, ,.

The viscous solution was washed with 1M HCl and water, followed by passage through a column of acidic ion exchange beads to dry the solution and remove any residual pyridine. The polymer was isolated by precipitation into hexane/acetone, followed by filtration and drying in a vacuum oven. The inherent viscosity was ~ound to be 0.98 dL/g (0.5 g/dL CH2Cl2 at 25C) The above polymer (15.00 g) was placed in a small glass resin kettle along with diphenylsulfone ; (36.00 g) and chlorobenzene (50 mL). The resin kettle was equipped with a capillary gas inlet, a short path distiller and a glass stirring paddle. Heat was provided by a molten salt bath. Nitrogen (40 mL/min) wa passed through the gas inlet and out the receiver of the still head. Carbon dioxide was trapped using a tube of 'Ascarite-II' on a sensitive balance. Residual water was removed by twice distilling off 50 mL chlorobenzene.
The catalyst (60.0 mg CsF) was then added and the resin ; kettle was immersed in a preheated 250C salt bath. The color changed from a very pale yellow to red, and C02 began to evolve after a 10 minute induction period.
After 419 minutes, 1.3056 g of C02 had evolved.
Methyl chloride (40 mL/min) was added to the nitrogen inlet ga~ to cap the polymer. After 10 additional minutes, the reaction was removed from the salt bath.
The polymer was removed from the resin kettle and broken 3 up into small pieces while it was till hot. The polymer was slurried in 150 mL CH2Cl2 plus 2 mL Ac20 overnight. This slurry was blended for 5 minutes and added to 250 mL acetone in a blender. The acetone allows the polymer to be filtered more easily. The polymer was then slurried with 300 mL 50 percent (v/v) 35,395-F -22-, acetone/water for 4 hours and filtered. The light tan product was dried overnight in a vacuum over at 140C.
A tough, crystalline film was obtained by compression molding at 330C. Pressing at 345C resulted 5 in a tough, amorphous film which was annealed at 285C
for 30 minutes to a crystalline film. Differential scanning calorimetric analysis on the 345C molding showed a glass transition temperature of 155C, an exothermic crystallization peak maximum at 235C, followed by melting endotherm at 338C. Integration of the latter peak gave 21 J/g which represents 16 percent crystallinity, assuming a 130 J/g heat of fusion which has been determined for poly(ether ether ketone) ~5 (D. J. Blundell and B. N. Oxborn, PolYmer, Vol. 24, p 953 [ 1983] ) .
ExamDle 2 - Decarboxylation of Alternating Bisphenol A/Bisphenol K Copolycarbonate An alternating copolycarbonate was prepared using the method described in Example 1, with the exception that the Bisphenol K and 4-t-butylphenol capping agent (2 mole percent) were added after treating 25 the Bisphenol A with phosgene to convert it to the bis-chloroformate. 1 3C NMR was used to confirm the alternating structure. The inherent viscosity was determined to be 0.59 dL/g (0.5 g/dL in CH2Cl2 at 25C).
The decarboxylation was conducted as in Example 1 using 10.00 g polymer, 10.00 g diphenylsulfone and 67.5 mg CsF. After 72 minutes, ~23 mg of C02 had evolved. The reaction was stopped and worked up as in Example 1.

35, 395-F -23-,:, `
, , Analysis 1 - Analysis of Decarboxylated Bisphenol A/Bisphenol K Copolycarbonate A portion of the alternating copolycarbonate from Example 2 (2. 5755 g) was suspended in CH2C12 5 (30 mL) plus MeOH (30 mL) and treated with KOH (1.95 g) at ambient temperature under an N2 atmosphere overnight.
The next day the white suspension was acidified to pH 5 with 6M HCl and evaporated. Acetic anhydride ( 15 mL) plus 3 drops pyridine was added and the suspension was refluxed for 5 minutes. After evaporation to remove excess acetic anhydride, the volatiles (1.51 g consisting of the diacetate of Bisphenol A, a small amount of diphenylsulfone and traces of the diacetate of : ~5 Bisphenol K) were removed using bulb to bulb distillation. The acetylated ether oligomers remained in the pot residue ( 1.4595 g). This material was dissolved in refluxing C12CHCHC12 (slight amount of insolubles) and analyzed by lH NMR at 100C. The ratio of Bisphenol K/Bisphenol A was determined to be 4.75 to 1.00 and the number average molecular weight was 780 g/mole.
A similar analysis of a polymer from ; 25 decarboxylation of random 50/50 Bisphenol K/Bisphenol A
- copolycarbonates has been performed to yield number average molecular weight of the ether blocks of ; 1279 g/mol and a Bisphenol K/Bisphenol A ratio of 4.84: 1.00.
: 30 Example 3 - Decarboxylation of Random 50/50 Bisphenol A/Bisphenol S Copolycarbonate - A random copolycarbonate was prepared from an equimolar ratio of Bisphenol A and Bisphenol S plus 35.395-F -24-1.5 mole percent p-tert-butyl phenol as capping agent as described in Example 1. The inherent viscosity was found to be 0.52 dL/g (0.5 g/dL CH2C12 at 25C).
The method described in Example 1 was used to 5 decarboxylate this copolycarbonate. The above polymer (25.00 g) was placed in a small glass resin kettle along with diphenylsulfone (25.00 g) and toluene (100 mL).
Residual water was removed by distilling off the toluene. The catalyst (134.8 mg CsF) was then added and 10 the resin kettle was immersed in a preheated 250C salt bath. The color changed from a very pale yellow to red, and C02 began to evolve after an 8 minute induction period.
After 190 minutes, 1.9980 g of C02 had evolved.
The polymer dissolved in 100 mL C12CHCHC12 after overnight stirring. This solution was washed twice with 50 mL deionized water. Each washing required more than 20 an hour for phase separation. The polymer was precipitated in 1L MeOH in a blender. Filter and wash twice with 100 mL MeOH and twice with 100 mL hexane.
Dry at 150C in a vacuum oven overnight. The inherent viscosity was found to be 0.93 dL/g (0.5 g/dL Cl2CHCHCl2 25 at 25C).
A rough, clear, colorless film prepared by compres~ion molding at 270C. Differential scanning calorimetric analysis on this molding showed a glass 30 transition temperature of 165C.
Example 4 - Decarboxylation of Alternating Bisphenol A/Bisphenol S Copolycarbonate An alternating copolycarbonate of Bisphenol A
and Bisphenol S was prepared by condensing the bis-35,395-F -25-.. .

chloroformate of Bisphenol A (Preparative Methods inPolymer Chem., Sorenson and Campbell p. 128, 25.000 g, 71.598 mmol) with Bisphenol S (17.832 g, 71.24 mmol) plus 4~t-butylphenol (0.1076 g, 0.716 mmol) in CH2C12 (150 mL) in the presence of excess pyridine (12.66 g, 160 mmol). 13C NMR was used to confirm the alternating structure. The inherent ~iscosity was determined to be 0.40 dL/g (0.5 g/dL in C12CHCHC12 at 25C).
The decarboxylation was conducted as in Example 1 using 10,00 g polymer, 10.00 g diphenyl sulfone and g6.0 mg CsF. After 128 minutes, 539.4 mg of C2 had evolved. The reaction was stopped and worked up as in Example 4. The inherent viscosity of the product was 0.66 dL/g (0.5 g/dL in C12 CHCHC12 at 25C).
Analysis 2 - Analysis of Decarboxylated Bisphenol A/Bisphenol S Copolycarbonate A portion of the alternating copolycarbonate from Example 4 (1.717 g) was suspended in CH2C12 (12 mL) plus MEOH (12 mL) and treated with KOH (1.26 g) at ambient temperature under an N2 atmosphere overnight.
The next day a viscous gel had formed which was acidified to pH 5 with 6M HCl. The white suspension was filtered and evaporated. The residue was washed with acetone, leaving behind a small amount of insolubles.
The acetone solution was evaporated and placed under vacuum overnight (1.2729 g). This solid was washed four times with 25 mL boilin~ deionized water to remove Bisphenol A and Bisphenol S. The insoluble material was acetylated by brief boiling with acetic anhydride. The resultant amber solution was placed under vacuum and 35,395-F -26-gently warmed until a constant weight (623 mg) was obtained.
This material was dissolved in CDCl3 and analyzed by 1H NMR. The ratio of Bisphenol S/
Bisphenol A was determined to be 5.0 to 1.0 and the number average molecular weight was 1490 g/mole.
In view of the above description, those of ordinary skill in the art may envision various modifications which would not depart from the inventive concepts disclosed.

3o 35,395-F -27-

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:

l. A method for making poly(aryl ether)-poly(aryl carbonate) block copolymers which comprises heating in the presence of at least one decarboxylation catalyst, a copolycarbonate recurring containing units having the structure:
?AO-CO-O? and ?B-O-CO-O?, wherein A is an activating aromatic radical having at least one electro-withdrawing group located in a position ortho or para to its carbonate linking group;
and B is a nonactivating aromatic radical which is characterized by the absence of an electro-withdrawing group located in a position ortho or para to its carbonate linking group.
2. A method of Claim 1 wherein the copolycarbonate is heated at a temperature of from 150°C
to 350°C.
3. A method of Claim 1 wherein the copolycarbonate is heated for from 1 minute to 10 hours.
4. A method of Claim 1 wherein the electron-withdrawing group comprises at least one of -SO2-, -SO-, -CO-,-CONH-, -CONR-, -+NR2-, -+PR2-, -+SR-, -P(O)R-, -C(CF3)2-, -CHCH-, -NN-, -CHNNCH-, -CN, -NO2, -CHO, -CO2R, -CO2NN2, -P(O) (OR)2, P(O)R2, -+PR3, 35,395-F -28--+NR3, -+SR2, an imidazole, oxazole, pyrazole, isoxazole and oxapyrazole, wherein R is a difunctional or monofunctional hydrocarbyl radical having from one to 12 carbon atoms.
5. A method of Claim 1 wherein the catalyst is selected from alkaline metals, halides, carbonates, phenates, acetates and alcoholates.
6. A method of Claim 5 wherein the catalyst is cesium fluoride.
7. A method of Claim l wherein the catalyst is employed in amounts of from 0.001 to 10 percent by weight relative to the copolycarbonate amount.
8. A Method of Claim 1 wherein the copolycarbonate contains from 20 to 80 percent of the copolymeric units containing the activating aromatic carbonate units.
9. A method of Claim 1 wherein the copolycarbonate is a Bisphenol K/Bisphenol A
copolycarbonate or a Bisphenol S/Bisphenol A
copolycarbonate.
10. A poly (aryl ether)-poly(aryl carbonate) block copolymer prepared according to the method of

Claim 1.

35,395-F -29-