CA1114097A - Crosslinked sulfonated polystyrenes and process for the preparation thereof - Google Patents

Abstract

#1013 CARMINE P. IOVINE, 18 Foxwood Drive, Somerset, New Jersey 08873 DILIP K. RAY-CHAUDHURI, 484 Rolling Hills Road, Bridgewater, New Jersey 08876 Crosslinked Sulfonated Polystyrenes And Process For The Preparation Thereof Abstract of the Disclosure Polystyrene and styrene copolymers are simultaneously crosslinked and sulfonated in a homogeneous reaction mixture by incorporation of from 0.1 to 5 mole percent of specific cross-linking reagents in the polymer sulfonating solution. The crosslinking reagents are selected aryl compounds having at least two -CH2X radicals where X is hydroxyl, chlorine or bromine.

Description

4~7 .1 1 l . .' BACKGROUND OF TIIE_INVENTION
I Field of the Invention: This invent~on relates to new cross-linked sulfonated polymers of polystyrene and styrene copolymers l and to a process for the production thereof. More particularly, jl the invention relates to a process for producing crosslinked ¦sulfonated polystyrene or styrene copolymers employing selected ¦ crosslinking agents during the sulfonation reaction so as to ~j achieve crosslinking and sulfonation of the polymer simultaneouslyl ¦and efficiently in a homogeneous system. The process yields cross-l.O I linked sulfonated styrene polymers undisclosed in the prior art. I -II, Brief Desc~iption of the Prior Art: Prior art procedures I . ,.
I for preparing crosslinked sulfonated polystyrene or styrene Il copolymers involve the sulfonation of polymers which have been ¦~previously crosslinked with difunctional reagents or which contain I copolymeriæed alkenyl halides within the backbone o~ the polymer itsel~ The crosslinking may then be achieved during formation ,1 of the polymer as i8 the case when styrene divinyl aryl compounds ¦
li are sul~onated, Alternatively, the styrene polymers may contain therein an alkenyl halide together with a Friedel-Crafts type 0 ~ catalyst, which, upon e~posure to elevated temperatures during i sulfonation, will effect crosslinking so as to produce the sul-fonated crosslinked polymer. The latter method is described in I U.S. Patent 2,628,193, ¦ The methods of the prior art thus, in all cases, require the presence of specific components within the backbone of the polymer thereby limiting the choice of molecular weight and final ¦ structure of the sulfonated polymer. Moreover, in cases wherein ~ !I the polymer is crosslinked prior to sulfonation, the degree of I I! crosslinking desired in the final polymer must be incorporated O ¦l into the starting polystyrene copolymer. Often, however, a high : `

- 2 - ~

' :. ' ' -I4~ J7 ; . .

~crosslinking density i6 desired in the final product and this ¦Inecessiates working with a styrene polymer which is insoluble in ,, the sulfonation medium resulting in incomplete or partial jisulfonation. Similarly, incomplete sulonation is achieved when alkenyl halides or the like are incorporated into the polymer since the aromatic sites available for sulfonation are propor-tionately reduced.
SUMMARY OF_THE INVENTION
~ In following the present invention, polystyrene L0 ¦ or styrene copolymers of molecular weight 800 to 4,000,000 can !l be crosslinked to any degree of water solubility during sulfona-1, tion from a homogeneous reaction mixture by incorporation of from ! 0.1 to 5 mole V/o of specific crosslinking reagents in the styrene polymer sulfonating solution. These crosslinking reagents are I not par~ of the polymer backbone and are activated only by the ,~ sulfonating reagent. Consequently, these reagents do not interact with the styrene polymer until the latter enters the sulfonation zone, thereby effecting simultaneous sulfonation and crosslinking a homogeneous system wherein the polymer itself is soluble ~ li throughout the reaction. I
¦1 The resultant crosslinks are covalent carbon bonds which ! are heat-stable, reproducible and not subject to hydrolysis;
properties dificul~ to obtain using procedures of the prior art.
Moreover, since the crosslinking agent is not part of l the polymer backbone, the same styrene substrate can be used to Il produce soluble chain extended sulfonates, insoluble sulfonates ; l or sulfonates having any degree of solubility between these j extremes simply by adjusting the amount of crosslinking reagent Il used. For the same reason, sulfonated polystyrenes can be 0 ll prepared over a wide range of molecular weights from the same .
! - 3 -. ;l I
,, ' ': ' ' ~' -' '''. ',, .

~ 7 styrene substrate by varying the amount of crosslinking reagent.
¦ In addition, since sulfonation occurs in a homogeneous phase 1! simultaneously with crosslinking, virtually complete substitution ¦¦ of the aromatic groups of the polymer with respect to sulfonic ~¦ acid groups can be achieved.
Il Thus, the process of the present inven~ion enables the I! production of a sulfonated, crosslinked polystyrene or styrene Il copolymer in which the final molecular weight, degree of cross-¦l linking and degree of sulfonation can be selected independently ¦¦ of each other. Moreover, the present invention provides a method ¦I for the production of polystyrene and styrene copolymers which 1~ are fully sulfonated with respect to the available aromatic groups;
¦I such fully sulfonated materials could not be produced using the ! methods of the prior art.
BRIEF DESCRIPTION OF T~E DRA~ING
The single FIGURE is a graph illustrating the wide variety of viscosities (and hence wide range of solubilities) obtainable from one speci~ic polystyrene substrate using control-~ led amounts of c~,o-'-dichloro-p-xylene, one of the crosslinking ¦ reagents disclosed herein.
1~ D~TAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
! The homopolymers and copolymers of styrene suitable for use herein include those polymers having a styrene content of at leflst about 5% by weight, preferably at ].east 25% by weight, 1, exhibiting solubility in the sulfonation solvent and having a molecular weight within the range of about 800 to 4,000,000.
~ 1I Copolymerizable comonomers suit:able for use with the ; I; styrene include, for example, alkyl (Cl-C18) acrylates and meth-11¦ acrylates, maleic anhydride, maleic acid esters, fumaric acid ~¦ esters, acrylonitrile and olefins, e.g, ethyl acrylate, methyl ,i ~ 4 -- 1. 1 - - . , . , ~. - . ., . . - .

14~7 1 ~

methacrylate, dimethyl meleate, isobutylene, butyl acrylate, etc.
¦; Additionally, aromatic comonomers capable of copoly-merizing with the styrene may be employed. Such comonomers include the vinyl aryl compounds such as vinyl naphthalene, vinyl diphenyl, vinyl fluorene, etc. and their nuclear-substituted l derivatives such as alkyl, aryl, alkaryl, aralkyl, cycloalkyl, ¦ alkoxy, aryloxy, chloro, fluoro, chloromethyl, fluoromethyl and trifluoromethyl nuclear derivatives, for example methyl-styrene, l¦etc; alpha-alkyl-vinyl substituted aromatic compounds such as I those substituted with isopropenyl or alpha-methyl-vinyl, alpha-lethyl-vi.nyl, alpha-propyl-vinyl radicals, etc. It will be ¦ recogniæed that when such aromatic comonomers are polymerized with ¦ the styrene and treated''as described, ' ' '' sulfonation o the aromatic groups of the comonomèrs in addition to sulfonation of the styrene will also occur. It will also be ' il recognized by those skilled in the art that by requiring the copolymers to be soluble in the sulfonating reagent, such previous 11 ly cros~linked polymers as-would result from copolymerization with di'functional compounds, such as diacrylates, divinyl aromatlcs ' ZO I and diallyl compounds, would be excluded from the scope of the ; ' ¦''p'resènt''disclosure.
¦ The specific crosslinking agents'to be employed are selected aryl compounds having at ; ~ ¦! leas~ two radlcals of the following structure:

wheeein~l~X is selected from the group consisting of -OH, -Cl' ~and~-Br. More particularly, the useful crosslinking agents are ' defined by the following ~eneric structures:
":

: 1 .::- - . . ., : - ~.

!l !

R
, CH2X
llwherein at least one R is selected from the group consisting of:

-CH~X, ~ and 0 11 . R'~ R' ~¦ -(Q)P-Z-(Q)P' ( ~ CH2X
j¦ R' `R' ~! where X is -OH, -Cl or -Br; Q i9 oxygen or sulfur;
I! P and p' are independently selected integ~rs havlng the.value O or ¦¦ l; Z is a radical containing from 1 to 10 carbon atoms inclusive ~l and is selected from the group consisting of straight and branched ¦¦ chain alkyl radicals; and the remaining R and R' are selected l from the group consisting of hydrogen, ClC3 alkyl ~dCl-C3 alkoxy I radicals; and 0 (ii) polynuclear aryl compounds containing at least two Il -CH2X groups wherein X is as defined.above, which compounds may I be further substituted with substituent groups selected from the I A IKy/en~
i S l group consisting of -0~, Cl-C3 nlleyl radicals and Cl-C3 alkoxy¦
radicals.
It is to be noted that the posi.tioning of the functiona~
C~2X groups on the above-described reagents is not critical to the efficacy of the crosslinkin~ reagent Illustrative crosslinking reagents include:

- , ~ , - .

a~7 ~CH2Cl CH2Cl CH2C

~.6~'-dichloro-xylenes: ~ ~ ~ CH2Cl ~ CH2Cl CH2Cl , 2,4,6-tris-chloromethyl mesitylene ~0 ~

CH~Cl . I

~ C~12Cl 1,4-bis-chloromethyl durene: ~

.1 CH2Cl I

1,4-bis-hydroxymethyl benzene: HOCH2- @ CH20H

.

4,4'-bis-bromomethyl-diphenoxy ethane:

BrCH~ OCH2CH2-0- ~ CH2Br .~ .
.

` ix :

4,4'-bischloromethyl diphenyl methane:

ClCH2 ~CH2~ CH2Cl 4,4'-bis-chloromethyl biphenyl: ClCH2- ~ - ~ CH2C

1,6-bis-chloromethyl naphthalene: ~ CU2Cl (p-chloromethyl phenyl)-2-(p-chloromethyl thiophenoxy)-ethane:
¦I C1CH2_~(CH2)2-S--~O~H2C1 I 'I Cl H2H
1,6-bLs-hydroxymethyl anthracene:

, 4~7 ~;
The a~ount of the crosslinking reagent employed will vary depending upon a number of factors including thP nature of the specific reagent and of the copolymer substrate, the molecular weight desired in the final product and the level of solubility or insolubility desired in the final product. In l general, levels of 0.1 to 5 mole V/o of the crosslinking agents ¦ based on the aromatic content of the styrene component may be employed, although levels of less than about 1.5% are preferred.
The lower levels of crosslinking will result in water-soluble o ~ polymers while the higher levels will result in water-insoluble ~ulfonated polymers useful, for example, as ion exchange resins.
l Any sulfonation reagent conventionally employed for the I ~ sulfonation of styrene-containing polymers may be used. Suitable i ~ reagents include sulfur trioxide, oleum, halosulfonic acids and sulfur trioxide addition compounds. Among the applicable addi-tion compounds of sulfur trioxide are included the complexes of sulfur trioxide with complexing agents such as pyridine, trialkyl amines, dimethyl formamide, ethers, e.g. bis-2-chloro-¦ ethyl ether and dioxane, trialkyl phosphates and phosphites.
¦ These reagents are well known to those skilled in the art and are described in variou~ texts dealing with aromatic sulfonation, I e.g. E.E. Gilbert "Sulfonation and Related Reactions", Inter-science Publishers, N.Y. (1965). The preferred class of sulfona-tion reagents is derived from the addition compounds of sulfur l trioxide and trialkyl (Cl-C18~ phosphates. The preparation of I such addition products and the sulfonation therewith are described in U.S. Patents 3,072,703 and 3,072,618, respectively.
`~ The amount of sulfonating reagent employed will also vary o~er a wide range dependlng upon a number of factors such _ 9 _ ~ I ~

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j¦as the reagents and substrate employed, and the solubility and jldegree of sulfonation desired in the final product. If a fully substituted sulfonated styrene polymer or copolymer is desired, the amount of sulfonating reagent employed mustbe/least e~uimolar to the number of moles of available aromatic-containing components The sulfonation and crosslinking conditions are those conventionally employed in sulfonation reactions. Thus, any aliphatic hydrocarbons or chlorinated hydrocarbons which are not l reactive with the sulfonating reagent may be used as solvent. ¦
1 Preferably, 1,2-dichloroethane is used as a solvent medium but other solvents known to be useful in these sulfonating reactions may also be employed.
l Although reaction conditions may be ~aried and adapted i!to parti.cular industrial situations, the ollowing general-llpreparative procedure may be considered as illustrative. The ; ¦¦polystyrene or copolymer thereof is dissolved in 1,2-dichloro-¦¦ethane such that the concentration of the polymer in the solvent ; ¦¦is in the range of 1-50% by weight. To this solution is added a Isuitable amount of the crosslinking agent. The mixture is 20 11 agitated until the polymer and crosslinking agent dissol~e. The resultant polymer solution is then added simultaneously wlth the ¦sulfonating reagent to a reaction vessel containing precharged ~¦solvent and complexing agent if the sulfonating addition product is to be formed in situ. The reactions occur immediately and ¦the temperature is maintained at S-25C. by cooling. As the product forms, it precipitates from the reaction mixture.
The product is then isolated according to any of the llsuitable procedures described in the art as, for example, by il filtration or extraction with water if the acid form is desired 11, , 10- 1 . ,. I
,, ~ . . . . . , . . ., .. ~ - -4~97 ;, I

l'or by neutralizatLon ~f the salt form is desired or by s~abiliza-jltion with alkali metal carbonates and filtration.
Since the chemical nature of the crosslinking agent, l~the amount of crosslinking agent employed and the styrene substrat~
,lare all variables, it is not possible to represent the cross-¦¦linked sulfonated polystyrene or styrene copolymers by a single structure and they may only be considered to be defined by the process disclosed herein for their production. However, if a typical cros81inking agent is considered, then the basic type of structural units involved in the~new practice llmay be charac~erized.
¦I Thus, if polystyrene of average molecular weight 250,000 jl (degree of polymerization 2404) were crosslinked and sulfonated llu8ing 0.25 mole percent ~ dichloro-p-xylene in a sulfonating .. . . .... . .
, medium as here described, a typical resultant product could be represented by the following structure:
~ (~n-- CH~ (CH~ n . il S03H ~03H ~S03H

~S03~1 ~3So3~1 ~CI~ CH~-CH ~CH~ ~n ~I I

1 , . ..
~4~7 ll !
The examples which follow are illustrative and the scope of the invention is not to be considered as limited thereto.
In the examples, all parts are by weight unless otherwisè noted. I
EXAMPLE I ¦ I
~I This example illustrates a general process used to ! prepare the,new crosslinked ~sulfonated polystyrenes.
~¦ A one liter 3 neck flask equipped with a mechanical agitator, conden6er and drying tube, was charged with 900 gms. of Il 1,2-dichloroethane and 0.175 gms.cx,c~'-dichloro-p-xylene. With 1l stirring, 100 gms. o dry powdered polystyrene having a molecular ,I weight of 480,000 was added. The mixture was stirred until all ¦, the polystyrene had dissolved. This was designated solution "A".
The sulfonation vessel, a S-liter Morton flask equipped ¦ with an agitator, thermometer, condenser with drying tube and a ! gas inlet tube, was purged with dry nitrogen for one hour. To ¦ the reactor wa~ added 1250 gms. 1,2-dichloroethane at 0.009%
1~ H20 and 35 gms triethyl phosphate. The temperature of the reaction ¦ mixture was maintained at 15-20C. while 15.82 gms. S03 (liquid, l stabilized) was slowly added. This amount of S03 was sufficient I to form a l:l molar complex with the triethyl phosphate.
! When the temperature stabilized, the simultaneous addi-i tion of solution A (820 ml) and 77.5 gms. (42 ml) stabilized ¦¦ S03 was started. The addition rates were maintained at 20 ml/
minute for "A" and 1 mllminute for the S03. The temperature l during sulfonation was maintained at 15-21C. The sulfonated '~ ! polystyrene precipitated as it formed.
¦ As a control, this same procedure was repeated with the ~ ellmination of the 0.175 gms. of ~,C~'-dichloro-p-xylene from 1~ ~ j, the stock solution "A".
i~30 l~ Both polymers were evaluated to determine the extent of crosslinking by measuring thc Brookfield (RVF) viscosity o~

, i' , ..
. ~ .. ~ , .
. , .

., I .
,, 5% solutions in water: j -Viscosity De~ree of Sulfonation Control 100 cps 0.943 Crosslinked2080 cps 0.939 1, , EXAMPLE II
!j This example illustrates how this process lends itself !~ to the preparation of sulfonated polystyrenes having widely differ ent solution properties by simply adjusting the level of cross- !
linking agent used in the sulfonation of the same base polystyrene .
The results obtained in this example are illustrated by the graph in the FIGURE.
General Procedure A stock solution for 8ulfonation was prepared by ! dis801ving 220 ~ns . of polystyrene (molecular weight 250,000) and ,¦ the de8ired amount of ~ dichloro-p-xylene in 1980 gms . 1,2-dichloroethane containing 0.008% water.
A five-liter Morton ve9sel equipped with stainless 9teel ~¦ agitator, thermometer, condenser with drying tube and a gas inlet '¦ adapter, was purged for one hour with dry nitrogen. Thereupon, 1 2500 gm~ 1,2-dichloroethane and 23.3 gms. triethyl phosphate was !1 added to the reactor and the temperature lowered to 15C.
¦ With cooling~ 11,14 gms. stabilized S03 was dropped ¦ into the reac`tor in order to form a 1:1 complex with the phosphat~.
When th~ temperature stabilized, the addition of 2000 gms.
¦ (1640 ml) of the stock solution containing polystyrene and jl crosslinker was started. Simultaneously, the addition of 154.6 i gms~ (83.5 ml) of stabilized S03 was also started. The rate o ¦ the stock solution was 20 ml/min. ancl ~he S03 rate was adjusted i to 1 ml/min. During the additions, the temperature was maintainec I
i I :

i - 13 - ~
. ' ,~ I .
~: , . . .

l i Il I .' at 15-20~C. by cooling. As the crosslinked sulfonated polystyrene~
forms, it precipitated from solution.
When the sulfonation was completed, 143 gms. of llpulverized sodium carbona~e monohydrate was added to the reactor ¦land the mixture stirred for 1 hour. The stabilized product was isolated by filtration and drying at 60C. for 2 hours. The llsulfonated polymer was characterized by preparing a 1~/~ aqueous 'Isolution and measuring the Brookfield viscosity at room temperature.
¦IThe data is tabulated in Table I and plotted in the FIGURE.
ll TABLE I
,¦ Mole % Brookfield ¦'Experiment_ _Crosslinker Viscosity at 1% Type I
¦ A 0 35 cps Clear Solution B 0.10 250 ~ Clear Solution C 0.20 1,350 " Clear Solution .
¦ D 0.25 3,000 " Clear Solution Il E 0.35 11,680 " Slight Grain ¦¦ F 0,50 5,800 " Moderate Grain I! G 0.60 590 " Heavily Grained ¦I EXAMPLE III . .
This example illustrates the wide selection in the choice of polystyrenes and crosslinking agents. - :
. The general procedure described in Example II was ! repeated using a variety o~ polymers and copolymers in the amounts shown in Table II, The polymers employed were designated -¦I a~ follows: ~
:~ ~ . .
~' I . .

I - 14 - ! `
jl .
.
;l . . .
,, ~ . . .

!l , I .

Polymer A Polystyrene (MW 250,000) Polymer B Polystyrene (MW 3 x 106) Polymer C Polystyrene (MW 30,000) Polymer D Copolymer of styrene and acrylonitrile (75~/O styrene, 300,000) IlPolymer E Copolymer of styrene and methylmethacrylate (70%
¦I styrene, MW 287,000) llPolymer F Copolymer of styrene and maleic anhydride (76. l~/o ¦1 styrene, MW 2,000) o ~¦Polymer G Polystyrene (MW 500,000) Polymer H Copolymer of styrene and p-t-butyl styrene (39.6%
' styrene, ~ 750,000) ¦I The viscosity results obtained are tabulated in Table II
EXAMPLE IV
¦ This example illustrates the preparation of an insoluble !crosslinked sulfonated polystyrene, i I A stock solution is prepared by dissolving 2~0 gms. of ¦ polystyrene (molecular weight 250,000) and 5 gms. of 2,4,6-tris-~ ¦ (chloromethyl)-mesitylene in 1980 gms. of 1,2-dichloroethane ,0 containing 0.008% in water.
,; .
five liter reactor as described in Example II is `~ purged for one hour with dry nitrogen, Thereupon, 2500 gms., ¦ 1,2-dichloroethane is added to the reactor and the temperature . ~ . I . , . I
¦ lowered to 15C.
; . , ..
I The addition of 2000 gms. (1640 ml) of the stock ~ solution containing polystyrene and crosslinker is started.
;. , :
; i ~Simultaneously the addition of 1546 gms. (83.5 ml) of stabilized ;;~5O3~is~aLso started. The rate of the stock solution is 20 mllmin.
DurLng the~additions the temperature is maintained at 15-20C. by ~;o~ cooling. A9 the crosslinked sulfonated polystyrene forms, it ! precipitates from solution, il 15 ., . . . ~ . .

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After the sulfonation the polymer is filtered and washed once with methanol and then resuspended in water. The polymer is fully crosslinked and will exhibit no significant solution viscosity. ~ence, the resultant crosslinked material would be Il characterized by an appoximate D.S. of 0.90-0.95 which would ,¦ correspond to an exchange capacity of 0.5 meq/gm. (dry basis) rendering the polymer very well suited for ion exchange uses.
EXAMPLE V
I¦ This example illustrates the use of a diferent sulfonat-1¦ ing system in the production of the crosslinked sulfonated poly- ¦
¦ styrenes.~
A stock solution is prepared containing 220 gms. Polymer A, ¦ 1980 gms. 1,2-dichloroethane and 0.37 gms. ~ dichloro-p-xylene.
I A complexed sulfonating reagent is prepared as follows: ¦
; ! A 2 liter round bottom flask fitted with a glass/teflon ¦¦ agitator, nitrogen sweep, thermometer, condenser and drying tube is charged with 277.4 gms. of bis(beta chloroethylether) and ~1 1000 gms. 1,2-dichloroethane. With cooling so as to maintain the 1l temperature at 15-20C,, 155.3 gms. SO3 is added to the mixture over a 1 hour period.
A 5-liter Morton flask as described in Example I is I charged with 1000 gms. of 1,2-dichloroethane. With cooling, 1 2000 gms. of the polymer solution, and the sulfonating reagent ,' solution added simultaneously over a 2 hour period, The reaction 1~ temperature is maintained at 15-20CC. A~-ter the sulfonation, the ¦¦ mixture is stirred 30 minute3 and then 216 gms sodium carbonate added.

I!
~1 .
.

g7 The stabilized polymer is recovered by filtration and ,j drying. A 1% solution of the final product in water will exhibit l a Brookfield viscosity of approximately 235 cps compared to 35 ¦j cps for the control.
EXAMPLE VI
! Using the general procedure described in Example I the following polymers can also be sulfonated using the amount of reagents designated:
ll (a) 200 parts of 90/10 copolymer of methylmethacrylate ¦ and styrene with 2.22 parts 1,4-bis-chloromethyl durene and 22.4 parts of chlorosulfonic acid. The product will be cross-linked and water swellable.
(b) 100 parts of an 80/20 copolymer of isobutylene and styrene with 15.4 parts S03, 3.5 parts triethyl phosphate and 1,7 parts 2,2'-dichloro-p-xylene. The product will be crosslink-ed and water swellable.
As will be reco~nized to those skilled in the art, 1¦ varietions may be made in in~redie~t~, proportions and procedures ¦¦ as long as such variations are within the scope and spirit of the ~ollowing clslms.

1l1 ' .
, 11 . I

Claims (11)

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

1. A process for the simultaneous crosslinking and sulfonation of polystyrene and styrene copolymers containing at least 5% by weight styrene and having a molecular weight of 800 4,000,000 comprising the steps of:
a) dissolving the polystyrene or styrene copolymer in a sulfonating solvent;
b) adding thereto from 0.1 to 5 mole percent of a crosslinking reagent selected from the group consisting of:

(i) wherein at least one R is selected from the group consisting of -CH2X, and wherein X is -OH, -Cl or -Br; Q is oxygen or sulfur;
p and p' are independently selected integers having the value 0 or 1; Z is a radical containing from 1 to 10 carbon atoms inclusive and is selected from the group consisting of straight and branched chain alkylene radicals; and the remaining R and R' are selected from the group consisting of hydrogen, C1-C3 alkyl an C1-C3 alkoxy radicals; and (ii) polynuclear aryl compounds containing at least two -CH2X groups wherein X is as defined above, which compounds may be further substituted with substituent groups selected from the group consisting of -OH, C1-C3 alkyl radicals and C1-C3 alkoxy radicals; and c) adding the resultant solution to a sulfonating reagent while maintaining the reaction at a temperature of 5 to 25°C.; and d) recovering the resultant precipitated cross-linked sulfonated polymer.

2. The process of Claim 1 wherein the styrene is present in an amount of at least 25% by weight of the polymer.

3, The process of Claim 1 wherein the crosslinking reagent is selected from the group consisting of .alpha.,.alpha.'-dichloro-xylenes, 2,4,6-tris-chloromethyl mesitylene, 1,4-bis-chloromethyl durene, 1,4-bis-hydroxymethyl benzene, 4,4'-bis-bromomethyl-diphenoxy ethane, 4,4'-bis-chloromethyl diphenyl methane, 4,4'-bis-chloromethyl biphenyl, 1,6-bis-chloromethyl naphthalene, 1-(p-chloromethyl phenyl)-2-(p-chloromethyl thiophenoxy)-ethane, and l,6-bis-hydroxymethyl anthracene.

4. The process of Claim 1 wherein the crosslinking reagent is used in an amount of 0.1 to 1.5 mole percent.

5. The process of Claim 1 wherein the sulfonation reagent is selected from the group consisting of sulfur trioxide, oleum, halosulfonic acids and sulfur trioxide addition compounds.

6. The process of Claim 1 wherein the sulfonation reagent is derived from the addition of sulfur trioxide and a trialkyl phosphate.

7. The process of Claim l wherein the amount of sulfonating reagent employed is at least equimolar to the number of moles of available aromatic containing component and wherein the resultant polymer is fully substituted.

8. The process of Claim 1 wherein the solvent employed is an aliphatic hydrocarbon or a chlorinated hydrocarbon.

9. The process of Claim 1 wherein the solvent is 1,2-dichloroethane.

10. A process for the simultaneous crosslinking and sulfonation of polystyrene and styrene copolymers having a molecular weight of 800-4,000,000, said copolymers prepared from polymerization of at least 5% by weight styrene with a comonomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, maleic anhydride, maleic acid esters, fumaric acid esters, acrylonitrile, olefins, vinyl aryl com-pounds and their nuclear substituted derivatives, and alpha-alkyl-vinyl substituted aromatic compounds, comprising the steps of:
a) dissolving the polystyrene or styrene copolymer in a sulfonating solvent;
b) adding thereto from 0.1 to 5 mole percent of a crosslinking reagent selected from the group consisting of:
(i) wherein at least one R is selected from the group consisting of:

-CH2X, and wherein X is -OH, -Cl or -Br; Q is oxygen or sulfur; p and p' are independently selected integers having the value 0 or 1;
Z is a radical containing from 1 to 10 carbon atoms inclusive and is selected from the group consisting of straight and branched chain alkylene radicals; and the remaining R and R' are selected from the group consisting of hydrogen, Cl-C3 alkyl and Cl-C3 alkoxy radicals; and (ii) polynuclear aryl compounds containing at least two -CH2X groups wherein X is as defined above, which compounds may be further substituted with substituent groups selected from the group consisting of -OH, C1-C3 alkyl radicals and Cl-C3 alkoxy radicals; and c) adding the resultant solution to a sulfonating reagent while maintaining the reaction at a temperature of 5 to 25°C. whereby crosslinked sulfonated polymer is immediately precipitated; and d) recovering the resultant precipitated crosslinkcd sulfonated polymer.

11. A crosslinked sulfonated polystyrene or styrene copolymer containing residues derived from reaction of the polystyrene or styrene copolymer with crosslinking reagents selected from the group consisting of (i) wherein at least one R is selected from the group consisting of:

-CH2X, and -(Q)p-Z-(Q)p, CH2X

wherein X is -OH, -C1 or -Br; Q is oxygen or sulfur;
p and p' are independently selected integers having the value 0 or 1; Z is a radical containing from 1 to 10 carbon atoms inclusive and is selected from the group consisting of straight and branched chain alkylene radicals; and the remaining R and R' are selected from the group consisting of hydrogen, Cl-C3 alkyl and Cl-C3 alkoxy radicals; and (ii) polynuclear aryl compounds containing at least two -CH2X groups wherein X is as defined above, which com-pounds may be further substituted with substituent groups selected from the group consisting of -OH, Cl-C3 alkyl radicals and Cl-C3 alkoxy radicals.