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Polyphosphites as polyvinylchloride (PVC) stabilizers
1206
V. KH. KADYROVAeta/.
10. 11. 12. 13. 14. 15.
C. E. BAWN, A. LEDWITH and B. R. MacFARLANE, Polymer 1O: 653, 1969 E. A. MELVIN-HUGHES, Physical Chemistry Izd. inostr, lit., 1962 (Russian translation) K. P. MISHCHENKO and A. M. SUKHOTIN, Zh. fiz. khim. 27: 81, 1953 A. J. PARKER, Chem. Rev. 69: 3, 1969 H. C. ROBERTSON and S. F. ACREE, J. Am. Chem. See. 37: 1902, 1915 G. GEE, W. C. E. HIGGINSON, P. LEVESLEY and K. J. TAYLOR, J. Chem. See., 1338, 1959 16. F. PATAT and E. WITTMANN, Z. Naturforsch. A18: 169, 1963 17. A. A. SOLOV'YANOV, K. S. KAZANSKII and S. G. ENTELIS, Vysokomol. soyed. BII: 169, 1969 (Not translated in Polymer Sci. U.S.S.R.)
POLYPHOSPHITES AS POLYVINYLCHLORIDE (PVC) STABILIZERS * V. :KH. :KADYROVA,P. •. KIRPICHI~IKOV, 1~. A. ~/[UKMENEVA, N. S. •OLYUBAKI17A, G. T. :FEDOSEYEVA a n d iK. S. VETOSHKII~A S. M. Kirov Institute of Chemical Technology, Kazan (Received 1 October 1970) PROS~HO~C acid esters are generally r e c o m m e n d e d as n o n - p i g m e n t i n g p o l y m e r stabilizers [1]. Monophosphites, however, do n o t m e e t the requirements in some cases, so t h a t poly-organophosphorus c o m p o u n d s , i.e. the p o l y p h o s p h i t e s (PP) h a v e been o f considerable interest for this purpose. T h e y h a v e higher t h e r m a l stability, are non-volatile, resistant to hydrolysis, a n d are also c o m p a t i b l e with a wider r a n g e o f polymers. The P P h a d been used so far as stabilizers in p o l y a m i d e s a n d rubbers [2], p o l y c a r b o n a t e [3], a n d low-pressure p o l y e t h y l e n e [4]. The work described here deals with the s t u d y o f t h e stabilizing action of P P of different s t r u c t u r e s in PVC. EXPERIMENTAL
The study object was a PVC with a Fikentscher constant /¢F~ 74; it was synthesized by a suspension polymerization at 65°C, using azoisobutyrie acid dinitrile (AIBN) as initiator. The various PP (Table 1) were colourless, transparent and viscous liquids, or powders, which were very soluble in organic solvents. The effects of the polyesters and their mixtures were studied on PVC in powder or film form. The amount of barium or cadmium stearate was 3 parts by weight (PBW) in studies of powder compositions (1 : 1 ratio). The compositions of the plasticized or unplastieized samples are given in Table 2 and 3 respectively, and the plasticizer was dioctyl phthalate (I)OP). The components were mixed 45 rain at 90°C (for plasticized PVC) and 30 rain at 70°C (unplastieized PVC). The film samples were produced by milling the compositions on rollers * Vysokomol. soyed. AI4: No. 5, 1081-1086, 1972.
1207
Polyphosphites as polyvinylchloride stabilizers
at 165°C for 7 min (unplasticized) or 10 min (plasticized). The stabilizing action of the PP in PVC was assessed on the basis of the induction period v (thermostability time), the rate ofdehydrochlorination, the eolour and transparency of the PVC samples. The assessment of the colour stability was visual, that of transparency by means of speetrophotometer SF-4A after treatment at 175°C for 3 hr in an oven in the presence of air. RESULTS
Certain principles e m e r g e d f r o m the e x p e r i m e n t a l findings of using P P as a stabilizer in PVC. The s t u d y of t h e effects of p h o s p h o r u s - c o n t a i n i n g polyesters with P V C powders showed t h a t most o f these r e d u c e d the d e h y d r o c h l o r i n a t i o n rate of t h e p o l y m e r (Fig. la). W h e r e h e a t stabilizers (barium or c a d m i u m stearate) were present, all t h e polyesters, regardless o f s t r u c t u r e , prolonged ~ a n d r e d u c e d the rate o f d e h y d r o c h l o r i n a t i o n w h e n c o m p a r e d with compositions R1
R1 TABLE
1. T H E P P
PP, * No.
OF TYPE
X
R
C~H9
CH3 --e-
H(--O~--X--~O--P--)n
Mol.wt.
OC,H5
P content, Pto~
pa+
1650
8.85 8.80
8.35 8-50
7.93 8.18 7-01 7.24 5"43 5"37 8"90 8"85 6"90 6"72 8'87 8'82 8"18 8"03 8"85 8-76 5"72 5"90 6.40 6.25
7.87 7.53 6.35 6.25 4"67 4"80 8"70 8"62 6"54 6"38 8"80 8"75 7"60 7"43 8"69 8"72 5"47 5"56 5.98 6.02
Sulphur content,
l
CH8 2
iso-CsHI~
1680
3
C12H25
1630
4
C18I-I37
1690
5
C6H5
1570
6
n-C6H,CsHI~
1620
7
iso-C4H9
8
iso-CsHl~
1710
9
Cell5
1690
10
CsH17
1790
11
C6Hs
1780
--S--
1670
* PP numbers 1-9 had R I = R ~ = H ; P P - - 1 0 and 11 had R I f C H s , Rl=tert.C4H~.
8-97; 8"69 7"66 7.84 8-98 9"00
5"85 5.60 6-35 6.25
1208
V. Km KAn~ovA
e$ a&
containing only the stearates (Fig. lb). The stabilizing effect greatly depended on the P P concentration. Typical for the P P was t h a t t h e y had an optimal concentration above or below which t h e y were ineffective (Fig. 2). HCl,rag~9 pvc 8 a
12 \
11
c
X~.~8#6.10
/../. //×/,8
b
~~ 0
i
/2
8
60
120
Sy
#12
i
HOt,mq/g pvc
>.
i
5,11
180
60 120 t80 Time, rn[n F[O. 1. The kinetics of the PVC dehydrochlorination in an air stream at 175°0 in t h e presence of 0.6 × 10-3 mole/100 g PVC of PP: a---PVC--PP; b--PVC--PP-(Ba- and Cdstearates); c--PVC--(Ba- and Cd-stearates)- 3 pbw CI=H=5OH (the numbers with apostrophes are those for 3 pbw glycerol present); d--PVC--(Ba- and Cd-stearates)--40 pbw DOP. The numbers against the response lines are the same as those given in Table 1; they apply here and in Figs. 2 and 3. Line 12 is that for PVC without PP.
The P P were found to have a large inhibiting action when various additions of a plasticizing nature were made to the composition shown above ( P P + B a and Cd-stearate). Some of the alcohols used as lubricants are known to have a synergesic effect, when combined with metal-containing substances, on the thermal stability of PVC [5]. The study of compositions containing metal stearates, alcohols and P P showed t h a t optimal results were obtainable by using saturated alcohols with R/> Clo when added as 3% w/w to PVC. The PVC retained its original colour as a result, the rate of dehydrochlorination was much reduced and ~ became longer (Fig. lc). Similar results were got in the presence of monohydric alcohols, especially glycerol (Fig. lc). The thermal-oxidative degradation (TOD) of the PVC was also significantly reduced by compounding with Ba- and Cd-stearates, alcohols, polyarylene alkyl-
Polyphosphites as polyvinylchloride stabilizers T A B L E 2. T H E E F F E C T OF
PP
1209
CONCENTRATIONS OF GElqERAL FORMULA
H(--0~_j--S--~0--P--).0CsHs -
ON T H E COLOUR S T A B I L I T Y OF PLA.STICIZED P V C *
PP, No. 1 2 3 4 5 6 7
st 9t
iso-R
Stabilizer content c X 108 mole/1O0 g PVC
Colour stability, rain marked colour change 60 120 150 90 120 120 90 95 120
q
NoPP
C~H~ C,H9 C~Ho
0'06 0.2 0.6 0.06 0.2 0.6 0.2 0.6
CsH17
CsH17 CsH17 CsHl~ CsH17
FISMS
blackening 90 180 180 120 180 180 180 140 180
* Contents, pbw: 0.6 Ba stearate; 1-4 Cd separate; 50 DOP. t P P based on diphenylolpropane.
phosphites a n d e p o x y - c o m p o u n d s . F o r example, t h e use of Ba- a n d Cd-stearates, lauryl alcohol, P P a n d o e t y l e p o x y s t e a r a t e s t o p p e d HC1 liberation for t h e whole t~st period (180 rain) a n d t h e r e was h a r d l y a n y colour change.
6O #0 2-0
z
/'0 1"25
3.75
6-2.5
[PPJ" [0s,mole/lOOgPVC FIG. 2. a--The thermostability period; b--the rate constants of dehydrochlorination at 175°C, as functions of the PP concentration. W h e r e plasticizers were present, especially D O P , all the e x a m i n e d P P v e r y effectively r e d u c e d t h e r a t e of d e h y d r o c h l o r i n a t i o n o f PVC a n d prolonged v (Fig. ld). T h e colour stability was m u c h better, however, w i t h p o l y a r y l e n e a l k y l than with polyarylenearyl-phosphites.
1210
V . K H . K A D Y R O V A et al.
TABLE 3.
T H E P R O P E R T I E S OF UI~PLASTICIZED P V C
FILMS I N T H E PRESENCE OF ~ O N O - OR
POLY-PHOSPHITES
(Standard compositions, pbw: 1 Ba-stearate, 2 Cd-stearatc, 3 octylepoxystearate) Light Colour stability, rain transmisAdditions Original sion (~) at T~ sample - - / a, mz min CO]OUr colour black- / - -C12H,50I-I, pbw mono- or poly-phosphites * change ening / 420 520
3 3
3 3
DY, TR Y, TU iso-(CeHsO),POCsH17 (3'0) DY, TU iso-(C6HsO)2POCsH17 (3"0) PY, TU P P 1 (0.2) DY, TR PP 2 (0.2) DY, TR P P 1 (0.2) C, TR PP 2 (0-2) C, TR m
15 15 100 60 120 125 180 180
> 180 >180 >180 180 > 180 >180 >180 >180
52 47 42 43 50 55 72 72.5
72 66 60 61 71 73 86 85.3
I28 130 ll0 110 165 165 175 175
Abbreviations: D Y - - d a r k yellow, Y--yellow, PY--pale yellow, C---eolourle~s, Tl~--transpareat, TU--turbid. * The numbers
in brackets
are the mono-
or poly-phosphite quantities added (c x l0 g mole/100 g).
S u b s e q u e n t investigations were carried out on plasticized and unplasticized PVC films. Those n a m e d first c o n t a i n e d the stearates and P P , which ensured a good initial colour a n d t r a n s p a r e n c y of t h e films; accelerated ageing in an oven for 3 hr a t 175°C g r e a t l y i m p r o v e d t h e colour stability. The use of sulphur-containing P P based on 4 , 4 - d i h y d r o x y d i p h e n y l sulphide was f o u n d to yield optimal stabilization a t P P concentrations n o t exceeding 0.2 × 10 -8 mole/100 g PVC, while t h e a m o u n t required o f t h e P P based on d i p h e n y l o l p r o p a n e was 0.6 × 10 -3 mole/ /100 g PVC (Table 2). P a r t i c u l a r l y interesting were t h e results o b t a i n e d with P P a n d unplasticized PVC. Table 3 shows t h a t monophosphites t o g e t h e r w i t h higher alcohols did n o t yield the desired colour stability and t r a n s p a r e n c y o f t h e PVC samples; it resulted, in some cases in a darkening and opaqueness of t h e samples. T h e use of P P instead of the mono-esters yielded t r a n s p a r e n t , t h e r m o s t a b l e a n d colourless films. The polyaxylene alkylphosphites were f o u n d to be superior to the P P containing o n l y a r o m a t i c radicals. W e were unable to establish a n y s t r u c t u r a l principles o f the alkyl radical affecting t h e stabilizing action. A molecular weight (mol.wt.) increase, especially with laP 2 (mol.wt. range 1100-2200), i m p r o v e d the efficiency o f the P P a t identical molar content. T h e stabilizing properties o f P P seem to be due to the same chemical reactions as with monophosphites [6]. This confirmed a n u m b e r of model reactions. T h e s t u d y of the P P reaction ~with h y d r o g e n chloride in p a r t i c u l a r showed t h a t t h e p o l y a r y l e n e alkylphosphites easily dealkylated a n d liberated alkyl halide; this was not d e t e c t e d with the polyarylene arylphosphite. A gas-liquid c h r o m a t o -
Polyphosphitos as polyvinylchloride stabilizers
1211
graphic study of system P V C - P P identified the alkyl chloride which could have formed in a dealkylation of P P by HCI liberated from the PVC'in the absence of stearates. This could also have happened in the P P reaction with the unstable chlorine b y the Arbuzov reaction. The poor reactivity of the aromatic P P in the dealkylations could also be explained by a relatively lower inhibiting activity of the polyarylene arylphosphites present in PVC. 12
HC[ , mg/,.q PVC
5 BO
120
180 0
60
120
/80
Tlrne , rain
FIG. 3. The kinetics of the PVC dehydrochlorination at 175°C in an air stream: a--with 0.05 pbw FeC13 and 0.3 × 10-* mole PP/100 g PVC present; b--with 40 pbw DOP and 0-6 × 10-3 mole PP/100 g PVC present. Comparative studies of t he systems PVC-plasticizer and PV C-PP-pl ast i ci zer showed t h a t the found activation energies of these reactions were fairly small (about 12 kcal/mole), i.e. t h a t the P P could participate in the suppression of degenerate chain branching during an oxidative process of PVC. In addition to this the presence of hydr oxyl end groups in the P P molecules made t h e m also capable of terminating the kinetic chain of oxidation. CONCLUSIONS
(1) The polyphosphites (PP) were found to be effective stabilizers for PVC. Their stabilizing action was enhanced by the presence of metal stearates and various additions of a plasticizing nature, giving rise to a reduction of the dehydrochlorination rate, prolongation of the induction period, retention of the original colour and transparency of plasticized and unplasticized PVC films. Translated by K. A. ALLEN
REFERENCES
l. P. A. KIRPICIINIKOV and N. A. MI_~MENEVA, Sb.: Sintez i issledovanie offektivnosti khemikatov dlya polimernykh materialov (Ia: The Synthesis and Activity Study of Chemicals Used as Additives in Polymeric Materials). Nauch.-issled. inst. khim. polimer., No. 4, 111, Tambov, 1970 2. P. A. KIRPICHNIKOV and N. A. MUKMENEVA, Sb.: Starenie i stabilizatsiya polimorov (In: The Ageing and Stabilization of Polymers). p. 168, Izd. "Khimiya", 1966 \
1212
L. G. K A Z ~ Y A ~ e$ al.
3. P. A. KIRPICHNIKOV, V. Kh. KADYROV, I. I. LEVANTOVSKAYA, N. A. MUKMENEVA
et al., Plast. massy, No. 1, 44, 1971 4. P. A. KIRPICHNIKOV, N. S. KOLYUB~tKINA, N. A. ~ E V A , E. T. MUKMENEV and Ye. I. VORKUNOVA, Vysokomol. soyed. B12: 189, 1970 (Not translated in
Polymer Sci. U.S.S.R.) 5. B. PUKANSZKY, Myanyag es gumei (Hungarian Resin and Rubber) 6: 302, 1969 6. K. S. MINSKER, P. A. KIRPICHNIKOV, N. S. KOLYUB~KINA, G. T. FEDOSEYEVA,
N. A. ~ V A and L. V. VERIZHNIKOV, Vysokomol. soyed. A10: 2500, 1968 (Translated in Polymer Sci. U.S.S.R. 10: 11, 2904, 1968)
THE STRUCTURAL-MECHANICAL PECULIARITIES OF THE BEHAVIOUR DURING STRETCHING OF POLYIMIDE FILMS BASED ON 3,3',4,4'-TETRACARBOXYDIPHENYL DIOXIDE DIANHYDRIDE AND 4,4'-DIAMINODIPHENYL ETHER* L. G. KAZARYAN, YE. G. LUR'E, E. L. UCHiSTKn~A, 1K. D. FREI~'KEL', P. M. T A N U ~ A , L. N. YEMEL'YA~OVA and 1K. L. DOBROKHOTOVA Plastics Research and Development Institute (Received 2 October 1970)
THE recently synthesized polyimide based on 3,3',4,4'-tetracarboxydiphenyl dianhydride and 4,4'-diaminodiphenyl ether, (TCDPDO), is a very promising heat-resistant material. The structure of its monomer unit is:
In addition to the aromatic and imide rings ensuring high heat resistance, the polymer chain also contains ether group linkages which make the chain reasonably flexible. The TCDPDO will change to the highly elastic state and t h a t of viscous flow at certain temperatures [1]. The aim of the work described here was the study of the deformation and mechanical strength properties of the TCDPDO films within a wide temperature rang e. Si/nultaneous with the determination of the mechanical parameters went the study of structural changes in the film during stretching. * Vysokomol. soyed. A14: 1~o. 5, 1087-1092, 1972.
V. KH. KADYROVAeta/.
10. 11. 12. 13. 14. 15.
C. E. BAWN, A. LEDWITH and B. R. MacFARLANE, Polymer 1O: 653, 1969 E. A. MELVIN-HUGHES, Physical Chemistry Izd. inostr, lit., 1962 (Russian translation) K. P. MISHCHENKO and A. M. SUKHOTIN, Zh. fiz. khim. 27: 81, 1953 A. J. PARKER, Chem. Rev. 69: 3, 1969 H. C. ROBERTSON and S. F. ACREE, J. Am. Chem. See. 37: 1902, 1915 G. GEE, W. C. E. HIGGINSON, P. LEVESLEY and K. J. TAYLOR, J. Chem. See., 1338, 1959 16. F. PATAT and E. WITTMANN, Z. Naturforsch. A18: 169, 1963 17. A. A. SOLOV'YANOV, K. S. KAZANSKII and S. G. ENTELIS, Vysokomol. soyed. BII: 169, 1969 (Not translated in Polymer Sci. U.S.S.R.)
POLYPHOSPHITES AS POLYVINYLCHLORIDE (PVC) STABILIZERS * V. :KH. :KADYROVA,P. •. KIRPICHI~IKOV, 1~. A. ~/[UKMENEVA, N. S. •OLYUBAKI17A, G. T. :FEDOSEYEVA a n d iK. S. VETOSHKII~A S. M. Kirov Institute of Chemical Technology, Kazan (Received 1 October 1970) PROS~HO~C acid esters are generally r e c o m m e n d e d as n o n - p i g m e n t i n g p o l y m e r stabilizers [1]. Monophosphites, however, do n o t m e e t the requirements in some cases, so t h a t poly-organophosphorus c o m p o u n d s , i.e. the p o l y p h o s p h i t e s (PP) h a v e been o f considerable interest for this purpose. T h e y h a v e higher t h e r m a l stability, are non-volatile, resistant to hydrolysis, a n d are also c o m p a t i b l e with a wider r a n g e o f polymers. The P P h a d been used so far as stabilizers in p o l y a m i d e s a n d rubbers [2], p o l y c a r b o n a t e [3], a n d low-pressure p o l y e t h y l e n e [4]. The work described here deals with the s t u d y o f t h e stabilizing action of P P of different s t r u c t u r e s in PVC. EXPERIMENTAL
The study object was a PVC with a Fikentscher constant /¢F~ 74; it was synthesized by a suspension polymerization at 65°C, using azoisobutyrie acid dinitrile (AIBN) as initiator. The various PP (Table 1) were colourless, transparent and viscous liquids, or powders, which were very soluble in organic solvents. The effects of the polyesters and their mixtures were studied on PVC in powder or film form. The amount of barium or cadmium stearate was 3 parts by weight (PBW) in studies of powder compositions (1 : 1 ratio). The compositions of the plasticized or unplastieized samples are given in Table 2 and 3 respectively, and the plasticizer was dioctyl phthalate (I)OP). The components were mixed 45 rain at 90°C (for plasticized PVC) and 30 rain at 70°C (unplastieized PVC). The film samples were produced by milling the compositions on rollers * Vysokomol. soyed. AI4: No. 5, 1081-1086, 1972.
1207
Polyphosphites as polyvinylchloride stabilizers
at 165°C for 7 min (unplasticized) or 10 min (plasticized). The stabilizing action of the PP in PVC was assessed on the basis of the induction period v (thermostability time), the rate ofdehydrochlorination, the eolour and transparency of the PVC samples. The assessment of the colour stability was visual, that of transparency by means of speetrophotometer SF-4A after treatment at 175°C for 3 hr in an oven in the presence of air. RESULTS
Certain principles e m e r g e d f r o m the e x p e r i m e n t a l findings of using P P as a stabilizer in PVC. The s t u d y of t h e effects of p h o s p h o r u s - c o n t a i n i n g polyesters with P V C powders showed t h a t most o f these r e d u c e d the d e h y d r o c h l o r i n a t i o n rate of t h e p o l y m e r (Fig. la). W h e r e h e a t stabilizers (barium or c a d m i u m stearate) were present, all t h e polyesters, regardless o f s t r u c t u r e , prolonged ~ a n d r e d u c e d the rate o f d e h y d r o c h l o r i n a t i o n w h e n c o m p a r e d with compositions R1
R1 TABLE
1. T H E P P
PP, * No.
OF TYPE
X
R
C~H9
CH3 --e-
H(--O~--X--~O--P--)n
Mol.wt.
OC,H5
P content, Pto~
pa+
1650
8.85 8.80
8.35 8-50
7.93 8.18 7-01 7.24 5"43 5"37 8"90 8"85 6"90 6"72 8'87 8'82 8"18 8"03 8"85 8-76 5"72 5"90 6.40 6.25
7.87 7.53 6.35 6.25 4"67 4"80 8"70 8"62 6"54 6"38 8"80 8"75 7"60 7"43 8"69 8"72 5"47 5"56 5.98 6.02
Sulphur content,
l
CH8 2
iso-CsHI~
1680
3
C12H25
1630
4
C18I-I37
1690
5
C6H5
1570
6
n-C6H,CsHI~
1620
7
iso-C4H9
8
iso-CsHl~
1710
9
Cell5
1690
10
CsH17
1790
11
C6Hs
1780
--S--
1670
* PP numbers 1-9 had R I = R ~ = H ; P P - - 1 0 and 11 had R I f C H s , Rl=tert.C4H~.
8-97; 8"69 7"66 7.84 8-98 9"00
5"85 5.60 6-35 6.25
1208
V. Km KAn~ovA
e$ a&
containing only the stearates (Fig. lb). The stabilizing effect greatly depended on the P P concentration. Typical for the P P was t h a t t h e y had an optimal concentration above or below which t h e y were ineffective (Fig. 2). HCl,rag~9 pvc 8 a
12 \
11
c
X~.~8#6.10
/../. //×/,8
b
~~ 0
i
/2
8
60
120
Sy
#12
i
HOt,mq/g pvc
>.
i
5,11
180
60 120 t80 Time, rn[n F[O. 1. The kinetics of the PVC dehydrochlorination in an air stream at 175°0 in t h e presence of 0.6 × 10-3 mole/100 g PVC of PP: a---PVC--PP; b--PVC--PP-(Ba- and Cdstearates); c--PVC--(Ba- and Cd-stearates)- 3 pbw CI=H=5OH (the numbers with apostrophes are those for 3 pbw glycerol present); d--PVC--(Ba- and Cd-stearates)--40 pbw DOP. The numbers against the response lines are the same as those given in Table 1; they apply here and in Figs. 2 and 3. Line 12 is that for PVC without PP.
The P P were found to have a large inhibiting action when various additions of a plasticizing nature were made to the composition shown above ( P P + B a and Cd-stearate). Some of the alcohols used as lubricants are known to have a synergesic effect, when combined with metal-containing substances, on the thermal stability of PVC [5]. The study of compositions containing metal stearates, alcohols and P P showed t h a t optimal results were obtainable by using saturated alcohols with R/> Clo when added as 3% w/w to PVC. The PVC retained its original colour as a result, the rate of dehydrochlorination was much reduced and ~ became longer (Fig. lc). Similar results were got in the presence of monohydric alcohols, especially glycerol (Fig. lc). The thermal-oxidative degradation (TOD) of the PVC was also significantly reduced by compounding with Ba- and Cd-stearates, alcohols, polyarylene alkyl-
Polyphosphites as polyvinylchloride stabilizers T A B L E 2. T H E E F F E C T OF
PP
1209
CONCENTRATIONS OF GElqERAL FORMULA
H(--0~_j--S--~0--P--).0CsHs -
ON T H E COLOUR S T A B I L I T Y OF PLA.STICIZED P V C *
PP, No. 1 2 3 4 5 6 7
st 9t
iso-R
Stabilizer content c X 108 mole/1O0 g PVC
Colour stability, rain marked colour change 60 120 150 90 120 120 90 95 120
q
NoPP
C~H~ C,H9 C~Ho
0'06 0.2 0.6 0.06 0.2 0.6 0.2 0.6
CsH17
CsH17 CsH17 CsHl~ CsH17
FISMS
blackening 90 180 180 120 180 180 180 140 180
* Contents, pbw: 0.6 Ba stearate; 1-4 Cd separate; 50 DOP. t P P based on diphenylolpropane.
phosphites a n d e p o x y - c o m p o u n d s . F o r example, t h e use of Ba- a n d Cd-stearates, lauryl alcohol, P P a n d o e t y l e p o x y s t e a r a t e s t o p p e d HC1 liberation for t h e whole t~st period (180 rain) a n d t h e r e was h a r d l y a n y colour change.
6O #0 2-0
z
/'0 1"25
3.75
6-2.5
[PPJ" [0s,mole/lOOgPVC FIG. 2. a--The thermostability period; b--the rate constants of dehydrochlorination at 175°C, as functions of the PP concentration. W h e r e plasticizers were present, especially D O P , all the e x a m i n e d P P v e r y effectively r e d u c e d t h e r a t e of d e h y d r o c h l o r i n a t i o n o f PVC a n d prolonged v (Fig. ld). T h e colour stability was m u c h better, however, w i t h p o l y a r y l e n e a l k y l than with polyarylenearyl-phosphites.
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V . K H . K A D Y R O V A et al.
TABLE 3.
T H E P R O P E R T I E S OF UI~PLASTICIZED P V C
FILMS I N T H E PRESENCE OF ~ O N O - OR
POLY-PHOSPHITES
(Standard compositions, pbw: 1 Ba-stearate, 2 Cd-stearatc, 3 octylepoxystearate) Light Colour stability, rain transmisAdditions Original sion (~) at T~ sample - - / a, mz min CO]OUr colour black- / - -C12H,50I-I, pbw mono- or poly-phosphites * change ening / 420 520
3 3
3 3
DY, TR Y, TU iso-(CeHsO),POCsH17 (3'0) DY, TU iso-(C6HsO)2POCsH17 (3"0) PY, TU P P 1 (0.2) DY, TR PP 2 (0.2) DY, TR P P 1 (0.2) C, TR PP 2 (0-2) C, TR m
15 15 100 60 120 125 180 180
> 180 >180 >180 180 > 180 >180 >180 >180
52 47 42 43 50 55 72 72.5
72 66 60 61 71 73 86 85.3
I28 130 ll0 110 165 165 175 175
Abbreviations: D Y - - d a r k yellow, Y--yellow, PY--pale yellow, C---eolourle~s, Tl~--transpareat, TU--turbid. * The numbers
in brackets
are the mono-
or poly-phosphite quantities added (c x l0 g mole/100 g).
S u b s e q u e n t investigations were carried out on plasticized and unplasticized PVC films. Those n a m e d first c o n t a i n e d the stearates and P P , which ensured a good initial colour a n d t r a n s p a r e n c y of t h e films; accelerated ageing in an oven for 3 hr a t 175°C g r e a t l y i m p r o v e d t h e colour stability. The use of sulphur-containing P P based on 4 , 4 - d i h y d r o x y d i p h e n y l sulphide was f o u n d to yield optimal stabilization a t P P concentrations n o t exceeding 0.2 × 10 -8 mole/100 g PVC, while t h e a m o u n t required o f t h e P P based on d i p h e n y l o l p r o p a n e was 0.6 × 10 -3 mole/ /100 g PVC (Table 2). P a r t i c u l a r l y interesting were t h e results o b t a i n e d with P P a n d unplasticized PVC. Table 3 shows t h a t monophosphites t o g e t h e r w i t h higher alcohols did n o t yield the desired colour stability and t r a n s p a r e n c y o f t h e PVC samples; it resulted, in some cases in a darkening and opaqueness of t h e samples. T h e use of P P instead of the mono-esters yielded t r a n s p a r e n t , t h e r m o s t a b l e a n d colourless films. The polyaxylene alkylphosphites were f o u n d to be superior to the P P containing o n l y a r o m a t i c radicals. W e were unable to establish a n y s t r u c t u r a l principles o f the alkyl radical affecting t h e stabilizing action. A molecular weight (mol.wt.) increase, especially with laP 2 (mol.wt. range 1100-2200), i m p r o v e d the efficiency o f the P P a t identical molar content. T h e stabilizing properties o f P P seem to be due to the same chemical reactions as with monophosphites [6]. This confirmed a n u m b e r of model reactions. T h e s t u d y of the P P reaction ~with h y d r o g e n chloride in p a r t i c u l a r showed t h a t t h e p o l y a r y l e n e alkylphosphites easily dealkylated a n d liberated alkyl halide; this was not d e t e c t e d with the polyarylene arylphosphite. A gas-liquid c h r o m a t o -
Polyphosphitos as polyvinylchloride stabilizers
1211
graphic study of system P V C - P P identified the alkyl chloride which could have formed in a dealkylation of P P by HCI liberated from the PVC'in the absence of stearates. This could also have happened in the P P reaction with the unstable chlorine b y the Arbuzov reaction. The poor reactivity of the aromatic P P in the dealkylations could also be explained by a relatively lower inhibiting activity of the polyarylene arylphosphites present in PVC. 12
HC[ , mg/,.q PVC
5 BO
120
180 0
60
120
/80
Tlrne , rain
FIG. 3. The kinetics of the PVC dehydrochlorination at 175°C in an air stream: a--with 0.05 pbw FeC13 and 0.3 × 10-* mole PP/100 g PVC present; b--with 40 pbw DOP and 0-6 × 10-3 mole PP/100 g PVC present. Comparative studies of t he systems PVC-plasticizer and PV C-PP-pl ast i ci zer showed t h a t the found activation energies of these reactions were fairly small (about 12 kcal/mole), i.e. t h a t the P P could participate in the suppression of degenerate chain branching during an oxidative process of PVC. In addition to this the presence of hydr oxyl end groups in the P P molecules made t h e m also capable of terminating the kinetic chain of oxidation. CONCLUSIONS
(1) The polyphosphites (PP) were found to be effective stabilizers for PVC. Their stabilizing action was enhanced by the presence of metal stearates and various additions of a plasticizing nature, giving rise to a reduction of the dehydrochlorination rate, prolongation of the induction period, retention of the original colour and transparency of plasticized and unplasticized PVC films. Translated by K. A. ALLEN
REFERENCES
l. P. A. KIRPICIINIKOV and N. A. MI_~MENEVA, Sb.: Sintez i issledovanie offektivnosti khemikatov dlya polimernykh materialov (Ia: The Synthesis and Activity Study of Chemicals Used as Additives in Polymeric Materials). Nauch.-issled. inst. khim. polimer., No. 4, 111, Tambov, 1970 2. P. A. KIRPICHNIKOV and N. A. MUKMENEVA, Sb.: Starenie i stabilizatsiya polimorov (In: The Ageing and Stabilization of Polymers). p. 168, Izd. "Khimiya", 1966 \
1212
L. G. K A Z ~ Y A ~ e$ al.
3. P. A. KIRPICHNIKOV, V. Kh. KADYROV, I. I. LEVANTOVSKAYA, N. A. MUKMENEVA
et al., Plast. massy, No. 1, 44, 1971 4. P. A. KIRPICHNIKOV, N. S. KOLYUB~tKINA, N. A. ~ E V A , E. T. MUKMENEV and Ye. I. VORKUNOVA, Vysokomol. soyed. B12: 189, 1970 (Not translated in
Polymer Sci. U.S.S.R.) 5. B. PUKANSZKY, Myanyag es gumei (Hungarian Resin and Rubber) 6: 302, 1969 6. K. S. MINSKER, P. A. KIRPICHNIKOV, N. S. KOLYUB~KINA, G. T. FEDOSEYEVA,
N. A. ~ V A and L. V. VERIZHNIKOV, Vysokomol. soyed. A10: 2500, 1968 (Translated in Polymer Sci. U.S.S.R. 10: 11, 2904, 1968)
THE STRUCTURAL-MECHANICAL PECULIARITIES OF THE BEHAVIOUR DURING STRETCHING OF POLYIMIDE FILMS BASED ON 3,3',4,4'-TETRACARBOXYDIPHENYL DIOXIDE DIANHYDRIDE AND 4,4'-DIAMINODIPHENYL ETHER* L. G. KAZARYAN, YE. G. LUR'E, E. L. UCHiSTKn~A, 1K. D. FREI~'KEL', P. M. T A N U ~ A , L. N. YEMEL'YA~OVA and 1K. L. DOBROKHOTOVA Plastics Research and Development Institute (Received 2 October 1970)
THE recently synthesized polyimide based on 3,3',4,4'-tetracarboxydiphenyl dianhydride and 4,4'-diaminodiphenyl ether, (TCDPDO), is a very promising heat-resistant material. The structure of its monomer unit is:
In addition to the aromatic and imide rings ensuring high heat resistance, the polymer chain also contains ether group linkages which make the chain reasonably flexible. The TCDPDO will change to the highly elastic state and t h a t of viscous flow at certain temperatures [1]. The aim of the work described here was the study of the deformation and mechanical strength properties of the TCDPDO films within a wide temperature rang e. Si/nultaneous with the determination of the mechanical parameters went the study of structural changes in the film during stretching. * Vysokomol. soyed. A14: 1~o. 5, 1087-1092, 1972.