Vinyl-type polymers containing phosphorus

JOURNAL OF POLYMER SCIENCE VOL. VIII, NO. 5, PAGES 495-502

Vinyl-Type Polymers Containing Phosphorus

C. S. MARVEL and JOHN C. WRIGHT,* Noyes Chemicul Laboratory, University of Illinois, Urbana, Illinois

The reaction of an aldehyde or ketone with phosphorus trichloride fol- lowed by hydrolysis with acetic acid and water is a satisfactory method of introducing a hydroxyphosphonic acid residue into an organic molecule. This communication describes the application of this general reaction to vinyl-type copolymers containing carbonyl groups to yield phosphorus containing products.

One series of copolymers used in this work was made in typical free radi- cal systems from methyl vinyl ketone and each of the following: styrene, methyl acrylate, methyl methacrylate, acrylonitrile, and butadiene. The other series was made from styrene and each of the following: methyl isopropenyl ketone, methylacrolein, benzalacetone, benzalacetophenone,2 and cinnamaldehyde. These various copolymers were treated for an a p propriate time with phosphorus trichloride, and then the mixture was treated f is t with acetic acid and then with water. Phosphorus-containing polymers were obtained in every case, but the amounts of phosphorus in the cases of the acrylonitrile-methyl vinyl ketone copolymer, the styrene- benzalacetone copolymer, and the styrene-benzalacetophenone copolymer were so small as to indicate they were due to contamination rather than reaction. It seems probable that solubility difficulties prevented a reaction in the case of the acrylonitrile-methyl vinyl ketone copolymer, and steric factors probably account for the failure of the reactions in the other two cases. This view is supported by the fact that the aldehyde copolymers gave better reactions than ketone copolymers and that methyl vinyl ketone copolymers gave better reactions than methyl isopropenyl ketone copolymers in the cases tested.

In a few cases an attempt was made to hydrolyze the phosphorus trichloride addition product directly with water, but thia, always led to a lower phosphorus content in the resulting polymer than was obtained if the acetic acid treatment was used before the water treatment.

The copolymers containing the hydroxyphosphonic acid groups seem to * Present address: Hercules Powder Company, Wilmhgton, Delaware.

495

TABL

E I

PHO

SPH

OR

US-

CO

NTA

ININ

G

POL

YM

ER

S FR

OM

TH

E R

EACT

ION OF

PH

OSP

HO

RUS TR

ICH

LO

RID

E

AN

D C

AR

BON

YL-

CO

NTA

ININ

G

POLYMERS

,

No.

1

2 3"

4Q

5 6 7 8 9 10

11

12

13

14

Cop

olym

er ue

ed

Styr

ene-

met

hyl v

inyl

ket

one

Styr

ene-

met

hyl v

inyl

ket

one

Styr

ene-

met

hyl v

inyl

ket

one

Styr

ene-

met

hyl v

inyl

ket

one

Met

hyl v

inyl

ket

one

(lOO

oJo)

B

utad

iene

-met

hyl v

inyl

ket

one

Met

hyl a

cryl

ate-

met

hyl v

inyl

ke-

Met

hyl m

etha

cryl

ate-

met

hyl v

inyl

Acr

y lo

nitr

ile-m

ethy

l vin

yl k

eton

e St

yren

e-m

eth y

lacr

olei

n

St yr

ene-

cham

alde

hyde

St

yren

e-m

ethy

l iso

prop

enyl

ket

one

St yr

ene-

benz

alac

eton

e St

yren

e-be

mal

acet

ophe

none

tone

keto

ne

Inhe

rent

vi

ixxa

ity

3.40

3.

72

3.72

3.

72

0.60

0.82

4.78

-

-

0.45

0.81

1.

46

1.47

1:

30

Ben

zene

13

B

enze

ne

24

Ben

zene

24

B

enze

ne

24

Chl

orof

orm

10

0 36

Chl

orof

orm

19

-

Chl

orof

orm

32

24

Chl

orof

orm

29

-

Ben

zene

12

Ben

zene

28

B

enze

ne

11

Ben

zene

29

%P

in

prod

uct

0.. 9

6 1.

81

0.27

0.

24

18.1

0 0.

28

2.67

4.09

0.07

7.

33

2.24

0.

97

0.01

0.

07

%'

Ext

ant o

f So

lu%

ity

reaction

in b

enze

ne

40

68

37

36

5"

100

5"

100

89

0 4 69

-

-

-

62

-

1.

10

0 14

100

100

19

78

1

100

2 10

0

Inhe

rent

b vi

saui

ty

1.75

1.

61

2.64

1.

49

Inso

lubl

e In

solu

ble

Inso

lubl

e

Insd

lubl

e

- 0.38

0.23

1.

10

1.48

1.

50

Wat

er w

as u

sed

dire

ctly

to h

ydro

lyze

the

phos

phor

us tr

ichl

orid

e ad

ditio

n co

mpl

ex w

ithou

t the

inte

rmed

iate

act

ion

of a

cetic

aci

d.

The

inhe

rent

vis

cosi

ties

repo

rted

wer

e m

easu

red

on s

olut

ions

con

tain

ing

0.1

g. o

f po

lym

er in

25

ml.

of t

he s

olve

nt n

oted

at 3

0'.

Solv

ent b

Chl

orof

orm

C

hlor

ofor

m

Ben

zene

B

enze

ne

-

-

-

-

-

Dim

ethy

l-

Ben

zene

C

hlor

ofor

m

Ben

zene

C

hlor

ofor

m

form

amid

e

VINYGTYPE POLYMERS CONTAINING PHOSPHORUS 4w

cross-link readily to yield insoluble products. This tendency is accelerated by reprecipitation from chloroform. It seems likely that this cross linking is due to anhydride formation between phosphonic acid groups in different chains since it has been shown before that phosphonic acids give anhy- d r i d e ~ ~ readily. Some of the phosphorus containing polymers were dis- colored. The resistance of the polymers to burning seemed to be directly proportional to the phosphorus content. If as much as 2% of phosphorus was present, inflammability was markedly decreased.

Some experiments with methyl vinyl ketone-styrene copolymers indicated that trivalent phosphorus compounds other than phosphorus trichloride will also add to the carbonyl group in such polymers but most of these reactions did not give unequivocal results, and the amounts of phosphorus introduced into the products were very smaU. Phenoxydichloro- phosphine did react to yield a phosphorus derivative without question.

The results of the experiments are summarized in Tables I and 11.

TABLE I1 TREATMENT OF STYRENE-METHYL VINYL KETONE COPOLYMERS WITH

TRIVALENT PHOSPHORUS COMPOUNDS %

Reaction Trivalent phosphorus '3, Carbonyl % P

compound used in polymer in product

Butoxydichlorophosphine ........... 29 0.04 1 Dibutyoxychlorophosphine ......... 29 0.06 2 Diphenoxychlorophosphine ......... 29 0.07 2 Phenyldichlorophosphine ........... 36 0.14 3 Phenoxydichlorophosphine .......... 29 0.39 10

P-)

Methyl Vinyl Ketone Copolymers: The methyl vinyl ketonsdpolymers were made in emulsion at 5 O O C . using the Mutual GR-S recGe4and a mon- omer charge of 20 g. with the other ingredients in proportion. Methyl vinyl ketone was used as an 85% azeotxope in water, and the water content of the recipe adjusted for this composition. The polymers were coagu- lated, filtered, and dried a t 70°C. The composition of the polymers was calculated from the carbon or nitrogen analysis. The polymers are described in Table 111.

Styrene Copolymers: Styrene copolymers with methyl isopropenyl ke- * We are indebted to Miss Elizabeth Peterson for all infrared data and their interprc-

EXPERIMENTAL* r(

tation, and to Miss Emily Davis for the microandytical results included here.

Met

h I

keto

nq

g. 2 4 5 5 5 4

viny

l O

ther

mon

omer

s G-

Styr

ene

18

Styr

ene

16

But

adie

ne

15

Met

hyl m

etha

cry l

ate

15

Met

hyl a

cryl

ate

15

Acr

y lon

itrile

" 13

TABL

E 11

1 M

ETH

YL VI

NYL K

ETO

NE CO

POLY

MER

S T

ime

of

poly

mer

- iz

atio

n.

Per

cent

hn.

canv

ersi

on

16

95

16

95

18

30

24

90

24

90

-

24

Inhe

rent

vi

sooe

ity

of p

olym

er

Solv

ent

3.40

Ben

zene

3.72

Ben

zene

4.78

C

hlor

ofor

m

0.82

Chl

orof

orm

Inso

lubl

e -

Ana

l. fo

und.

%C

Com

poei

tion

of'p

olym

er ~

al~

d.

89.39

13 M

ethy

l vi

nyl

keto

ne/

87 S

tyre

ne

86.51

24 M

ethy

l vi

nyl

keto

ne/

76 S

tyre

ne

81.52

36 M

ethy

l vi

nyl

keto

ne/

64 B

utad

iene

62.74

32 M

ethy

l vi

nyl

keto

ne/

68 M

ethy

l met

hacr

ylat

e 58.23

19 M

ethy

l vi

nyl

keto

ne/

81 M

ethy

l acr

ylat

e 20.03 (N)

24 M

ethy

l vi

nyl

keto

ne/

76 A

cryl

onitr

ile

a T

his p

olym

eriz

atio

n w

as c

arrie

d ou

t in

wat

er s

olut

ion using 0.2 g. o

f am

mon

ium

per

sulf

ate,

0.06

g. o

f sod

ium

bis

ulfit

e, 3 d

rops

of d

odec

yl m

erca

p-

It w

as in

solu

ble i

n di

oxan

e, c

hlor

ofor

m,

Bot

h C

=O (1710 c

m.-l

), an

d C

=N (2245 c

m.--

l) ba

nds w

ere

obse

rved

ta

n, a

nd 55

ml.

of w

ater

at 3

0°C

. be

nzen

e, a

nd p

hosp

horu

s tri

chlo

ride.

in

the

infr

ared

spe

ctru

m.

The

pol

ymer

whi

ch se

para

ted

was

was

hed

with

wat

er, e

than

ol, a

nd e

ther

. It

was

solu

ble

in d

imet

hylfo

rmam

ide.

VINYLTYPE POLYMERS CONTAINING PHOSPHORUS 499

tone, methacrolein, cinnamaldehyde, benzalacetone, and benzalacetophenone were prepared in the Mutual GR-S recipe4 at 50°C. for eighteen hours.

The polymers are described in Table IV.

TABLE IV STYRENE COPOLYMERS

Par cent Analysis

Styrene, conver- Inherent c-++ g. Other monomers Grams sion vismsity Solvent '% C yo H comptron

15 Methyl isopro- 5 75 1.46 Benzene

15 Methamoleinb 5 95 0:45 Chloro- form

15 Bemalacetone" 5 80 1.47 Benzene

15 Benzalacetophen- 5 85 1.30 Benzene

15 Cinhamaldehyde" 5 30 0.81 Benzene

penyl ketone"

oned

86.43 8.34 72% Sty- rene

rene

rene 90.62 - 71% Sty-

rene 91.11 7.67 88% Sty-

rene

85.46 7.93 71% Sty-

91.16 7.41 89% Sty-

a This polymer was reprecipitated twice by dissolving it is dioxane and pouring this solution into water. Infrared absorption at 1698 cm.-1 indicated the presence of ketone carbonyl.

b This polymer was only 33y0 soluble in benzene. soluble portion in chloroform and pouring into methanol to give 6 g. of b e n z e n a s z polymer. It softened at 155-162'. Infrared absorption at 1718 cm.-1 indicated a lds

It softened at 235-239".

It was purified by dissol

byde mbonyl.

this solvent and DmDitation with methanol. 8 This white, fluffy polymer was soluble in chloroform and was purified by solution in

Infrared ab- It softened at 229-233'. so tion at 1675 ern.-' indicated ketone carbonyl.

white. fluffy polymer which was soluble in chloroform, was reprecipitated by solution in this solvent and addition of methanol. It'softened at 229-234". Infrared a h tion at 1709 cm.-l indicated ketone carbonyl.

8 polymer isolated as a yellow sticky gum was converted to a white fibrous polymer by solution in chloroform and precipitation with methanol. This gave 6 g. of soluble polymer which softened at 180-184". Infrared absorption at 1719 cm.-1 indicated aldehyde carbonyl.

Reaction of Carbonyl Containing Polymers with Phosphorus Trichloride I n general, 2 to 4 g. of the carbonyl-containing polymer dissolved in 150

ml. of anhydrous dioxane was shaken with 4 to 8 ml. of phosphorus trichloride at room temperature from ten to twenty-four hours. Then 10 ml. of glacial acetic acid was added and shaking continued for twenty-four to forty-eight hours. The mixture was next poured into a large volume of water. The polymer which precipitated was filtered, re-dissolved in dioxane, and again precipitated by pouring into.water. The treated polymers usually had lower inherent viscosities than the starting materials.

Polymer 1, Table I : From 2 g. of the styrene (87)-methyl vinyl ketone (13) polymer there was obtained a phosphorus-containing poIymer completely soluble in chloroform, dioxane, and dimethylformamide. This polymer softened at 257-262°C. but was not flameproof.

500 C. S. MARVEL AND J. C. WRIGHT

Polymer 2, Table I: From 2 g. of the 'styrene (76)-methyl vinyl ketone (24) polymer there was obtained a phosphorus-containing polymer which was completely soluble in chloroform, 8670 soluble in dimethylformamide and 36% soluble in benzene. When the polymer was dissolved in chloroform and precipitated with methanol, the solubility in dimethylformamide dropped to 56%, and it was no longer completely soluble in chloroform. It softened with decomposition at 24OOC.

Polymer 3, Table I : Two grams of the copolymer of styrene (76)-methyl vinyl ketone (24) was prepared by direct hydrolysis of the solution of 150 ml. of dioxane and 5 ml. of phosphorus trichloride after twelve hours reaction time. The polymer was completely soluble in chloroform, benzene, dioxane, and dimethylformamide.

Polymer 4, Table I : One gram of.the styrene (76)-methyl vinyl ketone (24) copolymer was dissolved in 25 ml. of phosphorus trichloride, shaken for seven hours and then poured cautiously into a large excess of water. The filtered polymer was dried at 70OC. and was completely soluble in benzene. Solution in dioxane and reprecipitation with water gave a polymer only 91% soluble in benzene. Solution in chloroform and reprecipitation with methanol gave a polymer which was 870 soluble in dimethylformamide, 19% soluble in benzene, and 28% soluble in chloroform.

Polymer 5, Table I : A solution of 5 g. of the polymer of methyl vinyl ketone in 100 ml. of dioxane was treated with 10 ml. of phosphorus trichloride and then hydrolyzed with acetic acid and water. The product was brownish and insoluble in chloroform and dimethylformamide. The product swelled but did not dissolve in 15% aqueous ammonia. It did not soften at 32OOC. and was very resistant to burning.

Polymer 6, Table I : This polymer, which was soluble in dioxane, was purified by solution in this solvent and reprecipitation with water. It was not resistant to burning.

Polymer 7, Table I : This polymer was greenish in color and insoluble in chloroform and dioxane. It softened at about 310°C. and did not burn, although it decomposed when heated in a direct flame.

Polymer 8, Table I: This polymer was greenish in color and only partially soluble in dioxane. It did not soften at 310°C. and was extremely difficult to ignite.

Polymer 9, Table I : Since the acrylonitrile-methyl vinyl ketone copolymer was not soluble, it was treated directly with a large excess of phosphorus trichloride and then after several hours with water. It is doubtful if any reaction occurred.

Polymer 10, Table I: This polymer was not soluble in benzene and only partially soluble in chloroform. It did dissolve in dimethylformamide, and the inherent viscosity was determined in this solvent. It softened with decomposition at 210°C. It was difficult to ignite and burned only when held in the direct flame.

Polymer 11, Table I: This polymer was white and was completely soluble in benzene, chloroform, and dioxane. It softened with charring at 225-

It was nbt flameproof.

VINYLTYPE POLYMERS CONTAINING PHOSPHORUS 501

235°C. Solution in chloroform and precipitation with methanol reduced its solubility to about 50% in benzene. Although a fair amount of phosphorus was introduced, the treated polymer was not much improved in the burning test.

Polymer 12, Table I : This polymer was completely soluble in chloroform and dioxane and 78% soluble in benzene. After twice reprecipitating it from a dioxane solution by adding water, the product softened at 234- 237°C.

Polymer 13, Table I: This polymer was soluble in dioxane and after two reprecipitations from dioxane solution by adding water it softened at 224- 229OC. There was apparently no reaction with phosphorus trichloride.

Polymer 14, Table I : This polymer was like the one above except that it softened at 224-230OC. The low phosphorus content indicates there had been no reaction with phosphorus trichloride.

Carbonyl Containing Polymers and Other Trivalent Phosphorus Compounds Copolymers of styrene (71)-methyl vinyl ketone (29) in anhydrous diox-

ane were treated respectively, with butoxydichlorophosphine, dibutoxy- chlorophosphine, diphenoxychlorophosphine, and phenyldichlorophosphine. The reaction mixtures were treated with acetic acid for about twelve hours and then with water. As indicated in Table I1 little reaction appeared to have taken place.

When this polymer was treated with phenoxydichlorophosphine, the new product was only 40% soluble in benzene. It melted at 235-240°C. and was difficult to ignite, The phosphorus content indicated some reaction and a hydroxy phosphonic monoester appears to have been produced to some extent.

It showed some flame-resistant properties.

References

(1) W. Fossek, Monatsh., 5, 120, 627 (1884); ?,20 (1886); J. B. Conant and A. D. MacDonald, J. Am. Chem. Soc., 42,2337 (1920).

(2) C. S. Marvel, J. E. McCorkle, T. R. Fukuto, and J. C. Wright, J. Polymer Sci., 6, 776 (1951).

(3) C. S. Marvel and L. R. Drake, J . Org. Chem., 2, 387 (1937). (4) J. W. Wilson and E. S. Pfau, Ind. Eng. Chem., 4.0, 530 (1948).

Synopsis

Some copolymers which contain either aldehyde or ketone carbonyl groups have been’ treated with phosphorus trichloride and then in sequence with acetic acid and water. On the basis of phosphorus analyses of the resulting products, a-hydroxyphosphonic acid groups have been introduced in amounts ranging from zero to 100% of the theoreti- cal amount. These phosphorus containing polymers with 2% or more of phosphorus are somewhat flame resistant.

R6sum6

Certains copolymhres contenaqt un groupe carbonylique, soit aldhhydique, soit c6toni- que, ont 6t6 traitb a& trichlorure de phosphore, et ulthrieurement 1 l’acide achtique et l’eau. En se basant sur des analyses de phosphore au sein des produits finaux, on con-

502 C. S. MARVEL AND J. C. WRIGHT

state qu’il y a eu introduction des groupes a-hydroxyphosphoniques acides en des quantitb, variant de z h B 100% de la quantith thkorique. Ces polymsres contenant du phosphore, B teneur de 2% ou plus de phosphore, sont en quelque sorte r6sistanta B la Uamme.

Zusammenfassung

Einige Copolymere, die entweder Aldehyd- oder Keton-Carbonylgruppen enthalten, wurden mit Phosphortrichlorid und dann nacheinander mit Essigsaure und Wzwjer behandelt. A d Grund von Phosphoranalysen der erhaltenen Substamen wurde gefun- den, dass a-HydroxyphosphonGuregruppen im Bereich von Null bis 100% der theo- retischen Menge eingefiihrt worden waren. Diese Phosphor enthaltenden Polymere mit 2% oder mehr Phosphorgehalt sind einigermassen feuerbesttindig.

Received November 2, 1951

Documents

Vinyl-type polymers containing phosphorus