migration of pvc plasticizers into alcohols

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Migration of PVC plasticizers into alcohols

ARTICLE · JANUARY 1975

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Fotis Rigas

National Technical University of Athens

129 PUBLICATIONS 943 CITATIONS

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M i g r a t i o n o f P V p l a s tic i ze r s in t o a l c o h o l s

E m m a n u e l M . K a m p o u r i s F . R e g as S . R o k o t a s S . P o l y c h r o n a k i s a n d M . P a n ta z o g l o u

Laboratory o f Special Chem ical Technology, National Technical University of A thens, Athe ns 147,

Greece

(Received 14 A pr il 1975, evised4 July 1975)

Th e use of labe l led p las t ic ize rs and radioac t iv i ty measurements in conjunc t ion w i th w e ight loss can

g i v e q u a n t i t a t i v e i n f o r m a t i o n o n t he am oun t of migra ted p las tic ize r and on t he am oun t o f t he

l i qu id m ed ium tha t d i f fuses i n to t he po l ym e r du r i ng t he migrat ion process. In the case of PVC

plast ic ized wi th d ibu t y l ph tha la te and d ioc ty l phtha la te and immersed in alcohols the spec imens

soon become he te rogeneous due to loss in c o mp a t i b i l i t y b e t w e e n t h e p o l y me r a n d t he m ix tu res

o f p l a s t i c i z e r - a l c o h o l h igh in a lcoho l . These mix tures a r e fo r me d in the po lym er as a resu l t o f

con t i nuous migra t ion and d i f fus ion processes . The fo l lowing fac tors a f fec t ing the migra t ion

process were examined: na ture of a lcohol na ture of phtha la te p las t ic ize r am ou nt of p las tic ize r

m olecu la r w e i g h t o f po lym er th ickness o f specimens presence of ep ox y plast ic izers plast ic izat ion

process presence of s tab i l ize rs tem pera ture and t ime .

I N T R O D U C T I O N

The problem of p las t ic izer migra t ion is of spec ia l in te res t

in the c a se o f po lym e rs mod i f i e d w i th c ons ide ra b le a mou n t s

o f p l a st i ci z e rs . O f the c om mo n po lyme rs PV C i s t he one

used in the la rges t volum e as f lexib le or p las t ic ized PVC.

The re fo re a ny s tudy on the p l a s ti c i z at ion a nd mig ra t ion

p roc e ss e s ma y be o f p ra c t i c a l impor t a nc e fo r t he PV C

indus t ry .

In a l l appl ica t ions a p las t ic ized poly me r is in con tac t

w i th s ome k ind o f s u r round ing me d ium . U nde r the s e con -

di t ions the p las t ic izer mus t s tay in p lace during the useful

l i fe of the formed plas t ic i tem, o therwise i t migra tes wi th

the resul t th a t (a ) the p olym er, because o f loss of p las tici -

zer , s t i f fens and be com es less des irable , and (b) the sur-

round ing me d ium i s c on ta m ina te d by the p l a s ti c i ze r .

Thus there a r ises the need for a thorough s tudy of fac-

tors a ffec t ing the migra t ion process , and for a s imple and

a c c u ra t e me tho d o f me a s u ring a mo un t s o f p l a s ti c i ze r w h ic h

may be present in a g iven medium.

The poss ib le fac tors which can a ffec t the migra t ion pro-

cess can be classified in relation to: (a) the polymer, i .e .

na ture , molecular weight , c rys ta l l in i ty ; (b) the p las t ic izer ,

i .e . ~a ture , am oun t , poss ib le in te rac t ions (espec ia l ly in the

case of mixe d plas t ic iza t ion sys tems); (c ) the o t her com -

ponents usua l ly present in the p las t ic ized polymer, i .e .

s tabi lizers , lubricants , f i l le rs; (d) the p las t ic iza t ion pro-

c es s a nd c ond i t ions , a nd the re fo re the hom oge ne i ty o f

the s y s t e m; (e ) t he s u r round ing me d ium, i .e . na tu re ,

c omp a t ib i l i ty w i th the p l a s t i c iz e r , e f fe c t on po lym e r ; ( f )

the c ond i t ions o f t he t e s t , i .e . t ime , t e m pe ra tu re , t ype o f

c on ta c t .

The p las t ic izer tha t migra tes can be es t imated as : the

a mo un t l e av ing the po lym e r , o r t he a mou n t e n te r ing in to

the l iquid . In the f i rs t case the amo unt can be measured

by weight 1 or radioac t iv i ty 2 loss. In the sec ond case the

a mo un t o f p la s t ic i z e r c a n be me a s u re d by c h roma to g ra phy 3,4,

s p e c t r o m e t r ys , impulse-polarography6, and radioac t iv i ty7,8.

This paper presents the resul ts , obta ined by radiometr ic

a nd w e igh t lo ss me thod s , o f a s tudy o f t he e f fe c t o f t he

fol lowing fac tors upon the m igra t ion o f phtha la te p las tic i-

zers f rom plas t ic ized PVC into a lcohols : na ture of a lcohol ,

mo le c u la r w e igh t o f t he p o lym e r , na tu re o f p l a s t ic i z e r,

a mo un t o f p l a s t i ci z e r, p re s e nc e o f e pox y p l a s t ic i z er s ,

presence of s tabi lizers , p las t ic iza t ion process , th ickness of

s pe c ime ns , t e mpe ra tu re , a nd t im e . .

E X P E R I M E N T A L

Synthesis o f labelled dibutyl p hthalate (DBP)

5 mg of labe l led n-butaho l (1-14C; 0 .25 mCi) were

d i lu t e d w i th n -bu ta no l (28 ml ) a nd a dde d to a fou r -ne c ke d

f l as k c on ta in ing pow de re d ph tha l i c a nhydr ide (49 g ) . The

flask was equipped with s t i r re r , ther mo me ter , N 2 in le t tube ,

and a s ide conde nser . The mix ture was hea ted a t 100°C

fo r 1 h , t he n n -bu ta no l (95 ml ) a nd c on c e n t ra t e d s u lphu r i c

a c id (0 .4 ml ) w e re a dde d , a nd the mix tu re w a s he a te d a t

130°C for 3 h . During th is per iod a s low s t ream of N 2 was

passed and n-bu tanol was per iodica l ly added to mak e up

for tha t d ist il ling. Afte r cool ing , the reac t ion prod uct

w a s d i lu t e d w i th e the r (500 ml ) a nd the e the re a l s o lu t ion

w a s w a s he d w i th 10 a que ous s od ium c a rbona te s o lu t ion ,

the n w i th w a te r , a nd f ina l ly e va po ra t e d to r e move e the r

a nd un re a c te d n -bu ta no l . The d i e s t e r w a s pu r if i e d by

vacuum dis t i l la tion (y ie ld 82 g of labe l led DBP of radio-

a c t iv i ty 4 .8 x 103 c oun t s /mg /m in ) . P roduc t s w i th low e r

radioac t iv i t ies were obta in ed by d i lu t io n with pure un-

labe l led DBP.

Synthesis of labelled d ctyl phthalate (DOP)

The p ro duc t w a s s yn the s iz e d a c c o rd ing to the l i t e ra tu re

m etho d s f rom labe l led phtha l ic anh ydride (7-14C) and 2-

e thy lhe xa no l .

Preparation o f specimens

Sus pe nsion po lym e r i z e d PV C w a s b le nde d a t 80°C w i th

the ca lcula ted amo unts o f p las t ic izers and s tabi l izers . No

8 4 0 P O L Y M E R 1 9 7 5 V o l 1 6 N o v e m b e r


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M i g r a t i o n o f P V C p l a s t ic i z e r s i n t o a l c o h o l s : Eo /14 K a m p o u r i s e t a L

Table I

E f f e c t o f t h e n a t u r e o f a l c o h o l u p o n th e m i g r a t i o n m g ) o f p l a s t i c i ze r s f r o m p l a s t i c i ze d PVC

2 - E t h y l -

M e t h a n o l E t h a n o l n - P r o p a n ol I s o p r o p a n o l n - B u t a n o l I s o b u t a n o l

h e x a n o l

T i m e

d a y s )

D B P D O P

D B P D O P D B P D O P D B P D O P D B P D O P D B P D O P D B P D O P

1 1 5 2 5 7 1 0 1 1 6 3 7 3 2 4 1 5 1 8 2 7 4 2 6 0 4 7 8 4 2 6 9 4

2 2 5 5 8 2 1 5 2 2 0 9 1 1 0 3 4 0 8 7 1 1 9 1 1 0 3 9 9 8 1 1 2 5 3 7 1 3 5

4 3 4 4 1 1 0 2 6 5 2 7 4 1 7 5 4 5 0 1 4 7 1 5 3 1 8 1 5 1 8 1 3 8 1 6 3 5 4 1 7 8

6 3 9 9 1 4 0 3 3 8 3 1 9 2 3 0 5 2 7 1 8 9 1 81 2 3 9 5 8 8 1 7 4 1 9 4 6 9 2 2 4

1 0 4 5 2 1 8 7 4 2 2 3 9 6 3 2 2 6 1 6 2 5 6 2 3 0 3 2 4 6 6 3 2 1 7 2 4 2 7 8 2 7 4

1 5 4 8 4 2 2 8 4 7 0 4 6 4 4 0 1 6 2 7 3 0 8 2 7 5 3 8 7 7 0 5 2 5 2 2 8 8 1 1 5 3 2 5

2 0 5 0 6 2 5 4 4 9 1 5 1 6 4 4 4 7 1 8 3 4 9 3 0 7 4 3 3 7 3 6 2 8 0 3 2 9 1 3 3 3 6 1

2 5 5 2 1 2 7 2 5 0 6 5 5 1 4 7 5 7 4 2 3 7 6 3 3 2 4 6 4 7 5 4 3 0 8 3 5 0 1 4 7 3 9 0

3 0 5 2 8 2 8 2 5 1 4 5 7 5 4 9 7 7 5 1 3 9 2 3 5 4 4 8 5 7 6 2 3 3 2 3 7 1 1 61 4 1 2

lubricant was used. For stabilization Ba-Cd (1.5 phr) and

alkyl aryl phosphit e (0.5 phr) type stabilizers were used.

The dry blend was then plasticized by hot working for 7

min in the mixing head of a Brabender Plasticorder at

160°C and 30 rev/min. The plasticized mass was then

formed by hot rolling to a sheet from which specimens of

20 x 50 mm were cut.

Immersion

Each of the specimens was immersed in 250 ml of the

liquid medium contained in a 300 ml glass-stoppered

Erlenmeyer flask. The following alcohols were used as

liquids: methan ol, ethanol, 96 ethyl alcohol, n-propanol,

isopropanol, n-butanol, isobutanol, and 2-ethylhexanol.

All tests were made in duplicate, the flasks were kept at

temperatu res maintained to -+2°C, and the specimens were

selected with weight differences not exceeding 100 mg.

Measuremen t

The radioactivity of the liquid medium, at a given time

after immersion, was measured by transferring 0.5 ml of

the co nten t of the flasks to a glass measuring vial contain-

ing 10 ml of the scintillation solut ion, shaking to ensure

complete solution, and measuring the radioactivity by

means o f a Packard Tri-Carb 3385 liquid scintillation

spectrometer over a period of 10 min. The scintillation

solution was made b y dissolving 5 g of 2,5-diphenyloxazole

(PPO) and 300 mg of 2,2'-p-phenylenebis(4-methyl-5-phenyt-

oxazole)(Dimethyl-POPOP) in one litre o f toluene. From

each flask, two samples were taken thus each quoted result

represents the average of four measurements. Corrections

were made for background and quenching.

The radioactivity loss was calculated from radioactivity

measurements of the specimens before and after immersion.

In both cases about I0 mg of the specimens were dissolved

in 1 ml of tetrahydrofuran, 10 ml of the scintillation solu-

tion were added, and the radioactivity was measured in the

usual way. Efforts were made to obtain representative

samples; all measurements were made in fivefold and the

average obtained.

RESULTS AND DISCUSSION

Effec t o f the nature of alcohols

This effect was examined at 257C using k 65 PVC

plasticized with 50 phr DBP or DOP. The results obtained

are given in Tables and 2. As the data in Table indicate,

the amount of migrated DBP is high in the case of n-alcohols

Table 2

E f f e c t o f t h e n a t u r e

o f a l c o h o l u p o n t h e

m i g r a t i o n m g )

o f D B P a n d DOP f r o m p l a s t i c i ze d PVC: co m p a r i so n o f t h e r e su l t s

a f t e r 3 0 d a y s o f i m m e r s i o n

D B P D O P

Al co h o l I I I I I I IV I I I I I I IV

M e t h a n o l 5 4 5 5 2 8 2 8 9 2 3 9 2 7 5 2 8 2 1 2 4 1 5 8

E t h a n o l 5 3 8 5 1 4 2 2 7 2 8 7 5 8 2 5 7 5 3 1 7 2 5 8

n - Pr o p a n o l 5 0 7 4 9 7 1 9 2 3 0 5 7 3 1 7 5 1 4 2 8 3 2 3

I s o p r o p a n o l 4 1 7 3 9 2 16 4 2 2 8 3 7 2 3 5 4 1 2 6 2 2 8

n - B u t a n o l 4 9 3 4 8 5 2 0 2 2 8 3 7 4 5 7 6 2 4 2 0 3 4 2

I s o b u t a n o l 3 1 2 3 3 2 1 4 5 1 8 7 3 7 8 3 7 1 1 3 3 2 3 8

2 - E t h y l -

h e x a n o l 1 4 5 1 61 5 7 1 0 4 3 9 6 4 1 2 16 0 2 5 2

I = M i g r a te d p l a s t i c i ze r , b y r a d i o a c t i v i t y l oss ; II = m i g r a te d p l a s -

t i c iz e r b y r a d i o a c t i v i t y

o f t h e

a l co h o l ; I I I =

w e i g h t l o s s ;

IV ,=

d i f f e r -

e n c e

I I - - I I I d i f f u se d a l co h o l )

and much lower with iso-alcohols. In both cases the greater

the molecular weight of the alcohol, the lower is the amount

of plasticizer. In the case of DOP the greater migrat ion rates

also occur with n-alcohols, but the effect of the molecular

weight of is different. Now the greater the molecular weight

n- or iso-alcohols, the greater is the amou nt of migrated

plasticizer.

As the data in Table 2 indicate, the radioactivity loss

method can give results approx imately the same as

obtained by measurements of the radioactivity of the

liquid medium. Comparison between the results obtained

by the weight loss method and that of the radioactivity of

the liquid, for both DBP and DOP, indicates that in no case

can the weight loss method be used for the measurement

of the amount of migrated plasticizer. Correlation of the

results of the two methods, supposing no other matter

except plasticizer is migrated, can give quant itative infor-

mation on the amount of the alcohol diffused into the

polymer, during the migration process. In no case can the

amount of diffused alcohol be related with the molecular

weight. The only clear observation is that n-alcohols

diffused in greater amounts than iso-alcohols both in the

case of DBP and DOP. It also holds true that the lower

alcohols diffused faster in PVC plasticized with DBP,

while the higher alcohols diffused faster in PVC plasti-

cized with DOP.

In most cases the specimens gradually lose their trans-

parency and become opaque to white, during the migra-

tion process. This can be explained by the fact that the

plasticizer alcohol mixture, which plasticizes the polymer,

becomes gradually a non-solvent for the polymer and

P O L Y M E R , 1 9 7 5 , V o l 1 6 , N o v e m b e r 8 4 1


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Migra t ion o f PVC p las tic izers into alcoho ls : E M Kam pour is e ta /

hols exhib i t ing a se lec t ive ac t ion . As the da ta in Table 2

indica te , the lower a lcohols d i f fuse fas te r in PVC plas t i c ized

wi th DBP, whi le the h igher a lcohols do so in PVC plas t i c i -

z e d wi t h DOP.

Figure I

F o r m a t io n o f a lo n g h o le , a n u m b e r o f s m a l l o n e s , a n d

l in e s o f d i f f e r e n t ia t io n in t h e m a s s o f P V C p la st ic i ze d

w i t h 5 0 p h r

D B P a n d im m e r s e d in e t h a n o l ( × 3 5 )

T a b l e

E f f e c t o f t h e a m o u n t o f p la s tic iz e r u p o n t h e m ig r a t io n o f

D BP

f rom plast ic ized

P V C i n t o e t h a n o l a t 3 0 ° C

Mig rated plastic izer ( rag)

T i m e

( da y s) 2 0 p h r 4 0 p h r 6 0 p h r

2 1 4 1 0 8 4 5 1

4 1 9 1 5 9 6 1 4

6 2 5 2 0 9 6 8 8

10 3 3 301 757

1 5 4 0 3 5 2 8 0 1

2 0 4 6 3 8 3 8 2 7

2 5 5 0 4 1 5 8 5 2

3 0 5 6 4 3 8 8 7 2

4 0 6 0 4 6 1 8 9 9

5 0 7 0 4 8 2 9 2 4

6 0 7 6 4 9 8 9 3 5

7 0 8 5 5 1 2 9 4 3

8 0 9 3 5 2 3 9 4 7

Init ial plasticizer

c o n t e n t ( m g ) 4 6 4 8 0 2 1 0 5 0

Final plasticizer

c o n t e n t ( m g ) 3 7 1 1 7 9 1 0 3

Final plasticizer

c o n t e n t ( p h r ) 1 6 9 6

W e ig h t lo s s ( m g ) 7 8 1 8 0 5 1 7

D i f f u s e d a lc o h o l

( m g) 1 5 3 4 3 4 3 0

separa tes as a secon(1 phase in th e m ass . Thi s i s show n in

t h e m i c r o p h o t o o f

Figure 1

Effect of the nature of phthalate plasticizer

T h i s e f f e c t w a s e x a m i n e d f o r b o t h D B P a n d D O P , t w o

c o m m o n p l a s t ic i z e rs wi t h d i f f e r e n c e s in m o l e c u l a r we i g h t ,

v i s c o s i ty a n d v o l a t i li t y . I t i s o f t e n s t a t e d , i n e x a m i n i n g

t h e t e n d e n c y o f p l a s ti c i ze r s t o m i g r a t e , t h a t t h e g r e a t e r t h e

m o l e c u l a r we i g h t , t h e g r e a t e r t h e v i s c o s i t y , o r t h e l o w e r

t h e v o l a t i li t y , th e l o we r i s th e m i g r a t i o n r a t e a - l ° . Th e d a t a

in Table 1 indica te tha t there i s no f i rm re la t ionship be t -

ween molecular weight , v i scos i ty , or vola t i l i ty of p las t i c i -

z e r a n d th e r a t e o f t h e m i g r a t i o n p r o c es s . Ge n e r a l l y o n l y

i n th e c a s e o f c o n t a c t wi t h m e t h a n o l d o e s DB P m i g r a t e

f a s t e r t h a n D OP, wh i l e t h e o p p o s i t e i s t r u e i n t h e o t h e r

cases.

Th e n a t u r e o f p l a s t ic i z e r a f f e c t s th e d i f f u s i o n o f a l c o -

Effect of the amount of plasticizer

Th i s e f f e c t wa s e x a m i n e d i n t h e c a s e o f k 6 5 PVC p l a s -

t i c iz e d wi t h 2 0 , 4 0 a n d 6 0 p h r o f DBP. Th e t e m p e r a t u r e

o f t h e t e s t wa s 3 0 °C, t h e d u r a t i o n 8 0 d a y s , a n d t h e l i q u id

m e d i u m e t h a n o l . Th e r e s u l t s o b t a i n e d a r e g i v en i n

Table

3 . As th e d a t a i n d i c a t e t h e a m o u n t o f p l a s ti c i z e r s t r o n g l y

a f f e c t s th e m i g r a t i o n p r o c e s s a n d t h e g r e a t e r th e a m o u n t

o f p l a s ti c i z e r, t h e g r e a t e r i s t h e a m o u n t l o s t b y m i g r a t i o n .

Du r i n g t h e c o u r s e o f t h e p r o c e s s t h e m i g r a t i o n r a t e wa s

f a s t e r f o r t h e s p e c i m e n s p la s t i ci z e d wi t h t h e g r e a t e r a m o u n t s

of p las t ic izer . The resu l t was a reversa l of the orde r and

a f t e r a c e r t a i n t i m e t h e s p e c i m e n wi t h t h e g r e a t e r a m o u n t

o f p l a st i c iz e r en d s u p wi t h t h e l o we s t a m o u n t . Th i s b e -

h a v i o u r c a n b e e x p l a i n e d o n l y i n c a se s o f h ig h d i f f u s io n

ra tes . In the case exa min ed i t is ev iden t tha t the grea te r

t h e a m o u n t o f p l a s ti c i z e r, t h e g r e a t e r i s t h e a m o u n t o f

d i f f u s e d e t h a n o l . A t t h e e n d o f th e t e s t th e s p e c i m e n

p l a s ti c iz e d wi t h 2 0 p h r DBP b e c o m e s p l a s ti c iz e d w i t h

a b o u t 1 6 p h r o f a m i x t u r e c o n t a in i n g 4 e t h a n o l , th e

s p e c i m e n p l a s t ic i z e d wi t h 4 0 p h r b e c o m e s p l a s t ic i z e d

wi t h a b o u t 2 6 p h r o f a m i x t u r e c o n t a in i n g 6 5 e t h a n o l ,

a n d f i n a l ly t h e s p e c i m e n p l a s t i c iz e d wi t h 6 0 p h r DB P

b e c o m e s p l a s t i c i z e d wi t h a b o u t 3 0 p h r o f a m i x t u r e c o n -

ta in ing 80 e than ol .

Effect of the molecular weight of the polymer

Fo r t h i s t e s t f o u r s a m p l e s o f PVC ( k v a l u e s 5 5 , 6 5 , 7 0 ,

and 73 respec t iv e ly) were ]~last ic ized wi th 5 0 phr D BP and

i m m e r s e d in e t h a n o l a t 3 0 v C f o r 6 0 d a y s . Th e r e s u l ts o b -

ta ined a re g iven in Table 4 As t h e d a t a i n d i c a t e t h e m o l e -

c u l a r we i g h t o f t h e p o l y m e r a f f e c t s m i g r a t i o n a n d t h e

g r e a t e r th e m o l e c u l a r we i g h t , th e l o we r i s t h e a m o u n t o f

migra ted p las t i c izer .

Effect of th e th ickn ess of specimens

I n s o m e c a s e s ~° 'H s h o r t - t i m e t e s t s l e d t o t h e c o n c l u s i o n

t h a t t h e t h i c k n e s s o f s p e c i m e n s h a s li t tl e o r n o e f f e c t o n

the migra t io n of p las t ic izers . In th i s t es t spec imen s of k

Table 4 E f f e c t o r th e m o l e c u l a r w e i g h t o f p o l y m e r u p o n t h e

m ig -

ra t i on o f D BP f rom p las t i c i z ed PVC

i n t o e t h a n o l

a t 3 0 ° C

Migrated plast ic izer

rag)

T i m e

( d a ys ) k 5 5 k 6 5

k 7 0 k 7 3

2 256 203 156 90

4 3 3 0 2 7 5 2 0 5

1 3 5

6 377 327 244 170

1 0 4 1 0 3 7 0

2 8 5 1 9 9

1 5 4 3 5 4 0 1

3 2 4 2 3 5

20

4 5 0 4 1 9 3 4 8

2 6 0

25

4 5 9 4 2 5

3 6 0 2 7 6

30

4 6 4 4 3 5 3 7 0 2 8 4

3 5 4 6 9 4 4 0 3 7 6 2 9 8

4 0 4 7 3

4 4 5 3 8 1

3 1 0

4 5 4 7 6 4 5 0 3 8 5 3 1 9

5 0

4 8 0 4 5 3

3 9 2 3 2 6

5 5 4 8 3 4 5 7 3 9 8 331

6 0 4 8 6 4 8 0 4 0 5 3 3 5

8 4 2 P O L Y M E R , 1 9 7 5 , V o l 1 6 ,

N o v e m b e r


5/6

Migra t ion o f PV C p las t ic i ze rs in to a l coho ls : E M Kam pour i s e t aL

Table Ef f ec t o f t he t h i c k nes s o f s pec im ens upon t he m ig ra t i on o f

D B P f r o m p l a s t ic i z e d P V C i n t o e t h a n o l

M ig ra t ed p las t i c i z e r (m g)

T i m e

(day s ) 3040 m g 2381 m g 1785 m g 1483 m g

1 317 295 292 287

2 531 442 386 338

4 688 530 463 361

6 7 3 8 5 7 2 4 8 8 3 7 7

10 778 599 502 406

1 5 7 9 6 6 3 3 5 1 5 4 1 9

2 0 8 1 4 6 5 7 5 2 6 4 3 5

2 5 8 3 4 6 7 5 5 3 8 4 4 7

3 0 8 4 3 7 01 5 4 7 4 6 0

I n i t i a l p l as t i c i z e r

c o n t e n t ( m g) 1 0 0 0 7 8 3 5 7 8 4 8 8

F ina l p l as t i c i z e r

c on t en t ( rag ) 157 82 31 28

F ina l p l as t i c i z e r

c on t en t ( ph r ) 7 . 7 5 . 2 3 . 5 3 . 6

ranged f rom 2 .5 to 15 min . As the da ta in

Table 7

indica te ,

d i f f e r e n c e s i n t h e p l a s t i c i z a t io n p r o c e s s ( d u e t o v a r i a t i o n s in

p l a s t i c iz a t i o n t i m e ) a f f e c t m i g r a t i o n a n d t h e g r e a t e r t h e wo r k -

i n g ti m e , t h e l o w e r i s t h e a m o u n t o f m i g r a t e d p l a s ti c iz e r .

El]Oct o f s tabi l iza t ion

Th i s e f f e c t wa s e x a m i n e d f o r k 6 5 PVC p l a s t i c iz e d wi t h

6 0 p h r DBP o r DOP a n d i m m e r s e d i n 9 6 e t h a n o l f o r 3 0

d a y s a t 2 5 °C . I n t h e c a s e o f n o n - s t a b il i z e d PVC, p l a s ti c i z e d

wi t h 6 0 p h r DOP, t wo s e r i e s o f s a m p l e s we r e p r e p a r e d wi t h

di f fe ren t p las t i c i za t ion t imes , i .e . 7 and 15 ra in . The resul t s

in Table 8 indica te tha t s t ab i l i za t ion a f fec t s s t rongly the mi -

g r a t i o n p r o c e s s , a n d t h e g r e a t e r a m o u n t s a r e m i g r a t i n g f r o m

the s t abi l ized spec ime ns . In the case of uns tab i l i zed spec i -

m e n s t h e e f f e c t o f t h e p l a s t i c i z a ti o n t i m e i s g r e a t e r t h a n i n

the case of s t ab i l i zed ones .

Ef fe c t o f t e m pe r a tur e

Th e e f f e c t o f t e m p e r a t u r e wa s s t u d ie d i n t h e c a s e o f k 6 5

PVC p l a s t ic i z e d wi t h 5 0 p h r DBP a n d i m m e r s e d i n e t h a n o l

Table 6

E f f e c t o f e p o x y p l a s t i c iz e r u p o n t h e m i g r a t i o n o f D B P

a n d D O P f r o m p l a s t ic i z e d P V C i n t o e t h a n o l

M ig ra t ed D BP ( rag )

M ig ra t ed D OP (m g)

T i m e

(day s ) 0 ph r 6 ph r 0 ph r 6 ph r

2 186 219 178 223

4 244 269 240 297

6 2 7 0 2 9 6 2 8 2 3 4 7

10 302 331 327 402

1 5 3 1 7 3 6 0 3 4 9 4 3 7

20 327 373 360 451

25 333 381 377 460

3 0 3 4 2 3 8 4 3 8 3 4 6 9

6 5 PVC p l a s t i c i z e d wi t h 5 0 p h r DBP we r e u s e d i m m e r s e d

i n e t h a n o l a t 3 0 °C . Fo r h i g h e r a c c u r a c y t h e we i g h t o f

2 0 x 5 0 m m s p e c i m e n s wa s u s ed a s a n i n d ic a t i o n o f t h ic k -

ness . The resul t s in Table 5 indica te tha t the grea te r the

t h i c k n e s s o f t h e s p e c i m e n s , t h e g r e a t e r is th e a m o u n t o f

m i g r a t e d p l a s ti c i z e r. A t t h e e n d o f th e t e s t t h e m a j o r p a r t

o f t h e p l a s ti c i z e r h a d m i g r a t e d a n d t h e a m o u n t r e m a i n i n g

wa s g r e a t e r f o r t h e t h i c k e r s p e c i m e n s .

Ef fe c t o f t he e po x v p la s t i ci z e r

I n e x a m i n i n g t h e e f f e c t o f e p o x y p l a s ti c iz e r s u p o n t h e

m i g r a t i o n o f th e m a i n ( p h t h a l a t e ) p l a s t i ci z e r , s p e c i m e n s

we r e m a d e f r o m k 6 5 PVC p l a s t i c i z e d wi t h 5 0 p h r DBP o r

DOP a n d 6 p h r o f e p o x y p l a s t ic i z e r (a c o m m e r c i a l e p o x i -

d i z e d s o y a b e a n o il ). Th e s p e c i m e n s we r e i m m e r s e d in

e t h a n o l f o r 3 0 d a y s a t 2 5 °C . Th e r e s u lt s o b t a i n e d a r e g i v en

in

Table 6

As t h e d a t a i n d i c a te , t h e e p o x y p la s t ic i z e r a f f e c t s

m i g r a t i o n , p r o m o t i n g t h a t o f th e m a i n p l a s t ic i z e r. Th i s b e-

h a v i o u r s e e m s t o b e s e l e c t iv e : DOP m i g r a t e s t o a g r e a t e r e x -

tent than does DBP.

L f f e c t o f the p las t ic izat ion process

Th i s e f f e c t wa s s tu d i e d f o r k 6 5 PV C p l a s t ic i z e d wi t h 5 0

p h r DBP a n d i m m e r s e d in e t h a n o l a t 3 0 °C f o r 6 0 d a y s . Th e

plas t i c i za t ion process genera l ly used in th i s work was fo l -

l o we d wi t h v a r i a t i o n s in t h e t i m e o f h o t wo r k i n g wh i c h

Table 7

Ef f ec t o f t he p las t i c i z a t i on p roc es s upon t he m ig ra t i on o f

D B P f r o m p l a s t ic i z e d D B P e t h a n o l

ig ra ted p las t ic ize r

(rag)

T i m e

(day s ) 2 . 5 m in 5 ra in 10 m in 15 m in

2 2 3 0 2 1 3 2 0 8 2 0 2

4 3 2 7 3 0 7 2 8 0 2 6 2

6 370 352 321 297

10 421 392 368 335

1 5 4 4 5 4 1 6 3 9 2 3 8 0

2 0 4 5 2 4 3 0 4 1 7 3 9 8

3 0 4 6 2 4 4 1 4 2 5 4 1 5

4 0 4 6 7 4 4 9 4 3 1 4 2 4

5 0 4 7 2 4 5 9 4 3 7 4 3 2

6 0 4 7 7 4 6 1 4 4 2 4 3 7

W e igh t l os s (m g) 294 290 273 265

E t hano l d i f f us ed

(mg) 183 171 169 172

Table 8

Ef f ec t o f t he p res enc e o f s t ab i l iz e rs upon t he m ig ra t i on o f

D BP and D OP f rom p las t i c i z ed PVC in t o 96 a l c oho l

M ig ra t ed p las t i c i z e r

(rag)

T i m e

(days) I I I I I I IV V

2 222 80 153 79 67

4 283 136 228 123 114

6 333 173 263 164 148

10 379 227 312 207 175

15 424 257 358 246 211

20 451 273 383 276 230

2 5 4 6 9 2 8 2 4 1 0 3 0 3 2 5 1

3 0 4 8 3 2 9 1 4 2 5 3 2 8 2 6 7

I = N orm a l l y s t ab i l i z ed PVC p las t i c i z ed w i t h 6 0 ph r D BP ; I I = un-

s t a b i l iz e d P V C p l a s t i c iz e d w i t h 6 0 p h r D B P ; I I I = n o r m a l l y s t a b i li -

z e d P V C p l a s t ic i z e d w i t h 6 0 p h r D O P , p l a s t ic i z a t i o n t i m e 7 m i n ;

I V = u n s t a b i li z e d P V C p l a s t i c iz e d w i t h 6 0 p h r D O P , p l a s t ic i z a t i o n

t i m e 7 m i n ; V = u n s t a b i l iz e d P V C p l a s t i c iz e d w i t h 6 0 p h r D O P ,

p las t i c i z a t i on t im e 15 ra in

POLY MER 1975 Vo l 16 Novem ber 843


6/6

Migrat ion of PVC plasticizers into alcohols: E M Karnpouris et aL

T a b l e

Ef fec t o f th e tem p er a tu r e u p o n th e m ig r a tio n o f D BP

from p lastic ized PVC in to ethanol

Migrated plasticizer rag)

T i m e

d a ys ) 1 0 C 3 0 C 6 0 ° C

2 5 4 2 3 4 4 4 2

4 7 8 3 3 4 5 3 0

6 1 0 0 3 8 8 5 7 2

1 0 1 3 2 4 3 0 5 9 9

1 5 1 6 4 4 5 7 6 3 3

2 0 1 9 9 4 7 3 6 5 7

3 0 2 1 3 4 8 4 70 1

b e e x p l a i n e d b y t h e s m a l l i n t e r v a l s o f t i m e . G e n e r a l l y t h e

g r e a t e s t m i g r a t i o n r a t e s o c c u r i n t h e f i r s t st a g e s o f t h e p r o -

c e ss . T h e y b e c o m e t h e n l o w e r a n d t e n d t o m i n i m i z e . F o r

l o n g e n o u g h p e r i o d s t h e t o t a l a m o u n t o f p l as t ic i z er c a n

m i g r a t e , l e a v i n g t h e p o l y m e r p l a s t i c i z e d , o r s w e l l e d , b y a

m i x t u r e c o n t a i n i n g l o w a m o u n t s o f p la s ti c iz e r .

A C K N O W L E D G E M E N T S

T h e a u t h o r s w i s h t o e x p r e s s t h a n k s t o D r G . A k o y u n o g l o u

a n d M r S . D a o u s i s o f th e B i o l o g y D e p t . o f N . R . C . D e m o c r i -

t o s f o r c o u n t i n g t h e s a m p l e s .

a t t e m p e r a t u r e s r a n g i n g f r o m 1 0 ° t o 6 0 °C . T h e r e s u l t s i n

Table 9 i n d ic a t e t h a t t h e t e m p e r a t u r e a f f e c ts s t r o n g l y t h e

m i g r a t i o n o f p l a s t i c iz e r ; a n y r i se i n t e m p e r a t u r e i n c r e a s e s

d r a s ti c a ll y t h e a m o u n t o f m i g r a t e d p la s ti c iz e r . T h u s 3 0

d a y s o f i m m e r s i o n a t 1 0 ° C g av e th e s a m e a m o u n t o f m i g r a-

t e d p l a s ti c i z e r , a s 2 d a y s a t 3 0 °C . S c h e m a t i c p r e s e n t a t i o n

o f t h e r e s u l ts l e a d s t o t h e c o n c l u s i o n t h a t t h e r e l a t i o n t e m -

p e r a t u r e / a m o u n t o f m i g r a t e d p l a s t ic i z er i s n o t a li n e ar o n e .

Effect of t ime

E x a m i n i n g t h e e f f e c t o f t i m e , i n a ll t h e a b o v e c a s e s , w e

c a n c o n c l u d e t h a t t h e r e i s n o l i n e a r r e l a ti o n b e t w e e n t h e

a m o u n t o f m i g r a t e d p l a s ti c iz e r a n d t i m e , o r t h e s q u a r e

r o o t o f t i m e . C o n t r a d i c t o r y r e s u l t s i n th e l i te r a t u re m a y

R E F E R E N C E S

1 Reed M.C. andHarding J. lnd. Eng. Chem.

1 9 4 9 ,4 1 ,6 7 5

2 Kamp ouris, E. and Rokotas, S. unpublished data

3 Rost, H. E.

Fette Seifen Anstrichm.

1970 , 72, 552

4 Rohleder, K. and Bruchhausen, B. V. Dsch. Lebensm-

Rundsch. 1972, 68,

5 Gutsalyul, V. G. and Samono va, N. S.

[zv. Akad. Nauk Kaz.

SSR Set. Khim.

1962, 2) , 95

6 W o g g o n ,H. and Koehler, U.

Kunststoffe

1967, 57, 583

7 F i g g e ,K. and Piater, H.

Dsch. Lebensm-Rundsch.

1971, 67,

235

8 Kam pouris, E.

4th Eur. Conf. Plast. Rubbers Paris

1974,

Paper 91

9 Knappe, W.

Kunststoffe

1962, 52, 387

10 Quackenbo s, H. M.

Ind. Eng. Chem.

1954, 46, 1335

11 Reed, M. C., Klemm , H. F. and Schultz, E. F.

Ind. Eng. Chem.

1954, 46, 1344

8 4 4 P O L Y M E R , 1 9 7 5 , V o l 1 6 , N o v e m b e r

migration of pvc plasticizers into alcohols

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