Journal of Geoscience and Environment Protection, 2014, 2, 49-56
Published Online July 2014 in SciRes. http://www.scirp.org/journal/gep
http://dx.doi.org/10.4236/gep.2014.24008
How to cite this paper: Boussoum, M. O., & Belhaneche-Bensemra, N. (2014). Reduction of the Additives Migration from
Poly Vinyl Chloride Films by the Use of Permanent Plasticizers. Journal of Geoscience and Environment Protection, 2, 49-56.
http://dx.doi.org/10.4236/gep.2014.24008
Reduction of the Additives Migration from
Poly Vinyl Chloride Films by the Use of
Permanent Plasticizers
M. O. Boussoum1,2, N. Belhaneche-Bensemra2
1Faculté des Sciences de la Nature et de la Vie, Université de Tiaret, Algérie
2Ecole Nationale Polytechnique, BP 182, El-Harrach, Alger, Algérie
Email: idir_boussoum@yah oo.fr, nbelhaneche@yahoo.fr
Received April 2014
Abstract
This aim of this work is to study the partial replacement of the plasticizer ordinarily used di-octyl
phtalate (DOP) by the permanent plasticizers ethylene-vinyl-acetate (EVA) and acrylonytrile-bu-
tadiene-styrene (ABS) in order to reduce migration of additives initially contents in polyvinyl
chloride (PVC) stabilized with expoxidized sunflower oil (ESO). Migration tests with agitation to
40˚C in sunflower oil and ethanol at 15% were made. Migration phenomenon was studied on the
basis of the PVC samples mass variations, Fourier transform infrared spectroscopy (FTIR) and
scanning electron microscope (SEM) analysis. The results showed the effectiveness of the ap-
proach consisting in the partial substitution of DOP by plasticizers of polymeric nature. The fol-
lowing order concerning the migration of additives was found: DOP (40) > DOP:EVA > (30/10)
DOP:ABS (30/10). Furthermore, all the measured values of overall migrations were lower than the
maximum allowable overall migration: 10 mgdm2.
Keywords
PVC, Migration, DOP, Permanent Plasticizers, Mass Variation, FTIR Spectroscopy, SEM
1. Introduction
Poly (vinyl chloride) is a widely used polymer in the plastics industry due to its excellent properties. Neverthe-
less, the low thermal stability is one of its main disadvantages. It undergoes severe degradation via zip elimina-
tion of HCl at relatively low temperatures. To increase the heat stability of PVC, different metal soaps like Pb,
Cd, Ca and Zn carboxylates and some di- and mono-alkyltin compounds are used. Several inorganic lead com-
pounds and organic secondary stabilizers (epoxides, polyols, phosphites, β-diketones) are also used in industrial
recipes (Murphy, 2003). Furthermore, various additives such as plasticizers (phthalic and phosphoric acids, etc.)
and lubricants are generally incorporated. Such substances are necessary for achieving the desired chemical and
mechanical properties. For example, plasticizers are added to give elasticity (Murphy, 2003). But, despite their
high compatibility with PVC, these low molecular weight additives possess a high mobility. In contrast to the
macromolecules, these additives can migrate from the packaging material into the packed product causing qual-
M. O. Boussoum, N. Belhaneche-Bensemra
50
ity defects. These are shown as changes in odour and taste or as toxicological symptoms after ingestion (Figge,
1972). This problem of migration obviously has health consequences.
Plasticizers and phthalates in particular have been used in the production of flexible PVC for over 50 years for
applications ranging from cable and wire covers and children’s toys to medical devices and consumers products.
During the past 20 years, phthalates have come under considerable attention from media, legislative and envi-
ronmental concerns (Cadogan, 2002; Mersiowsky, 2002; Rahman & Brazel, 2004). Although no direct evidence
has been found of the toxic effect of phthalates to human beings, it has been proved that high dosage and long
term exposure of phthalates to rodents resulted in liver cancer and adverse effect on the reproductive develop-
ment for young male rats (Wilkinson & Lamb, 1990). In addition phthalates were suspected of increasing asth-
ma and bronchial obstruction in children (Oil, Hersong, & Madsen, 1997).
There have been many studies on the phenomenon of migration (Marin, Lopez, Sanchez, Vilaplana, & Jime-
nez, 1998; Belhaneche-Bensemra, Zeddam, & Ouahmed, 2002; Earls, Axord, & Braybrook, 2003; Marcilla,
Garcia, & Garcia-Quesada, 2004, 2007; Wang & Storm, 2005; Atek & Belhaneche-Bensemra, 2005; Boussoum,
Atek, & Belhaneche-Bensemra, 2006; Ito, Sechimi, Miura, Kawagushi, Saito, & Nakazawa, 2006; Zeddam &
Belhaneche-Bensemra, 2010; Atek, Belhaneche-Bensemra, & Turki, 2010), but few on reducing it. Various me-
thods have been proposed to reduce the migration of plasticizers and other additives from plastic food packaging
materials (Rahman & Brazel, 2004):
1) Surface modification: surface crosslinking, modification of surface hydrophilicity/lipophilicity; surface
coating; surface extraction.
2) Use of polymeric plasticizers and oligomers.
3) Use of alternative plasticizers.
4) Alternative polymers.
The aim of this work is to study the partial substitution of the commonly used plasticizer DOP by the perma-
nent plasticizers EVA and ABS in order to reduce the migration of the additives in PVC stabilized with epox-
idized sunflower oil, to identify the migrating substances and to compare the effectiveness of both permanent
plasticizers. Such permanent plasticizers can increase cohesion within the molecules, thus reducing the release
of additives into the food (Audic, Reyx, Brosse, & Poncin-Epaillard, 2000). Migration is negligible because the
plasticizers have a high molecular weight.
In this work, various formulations in the absence and presence of two permanent plasticizers (EVA and ABS)
were prepared.
The migration tests were carried out with stirring at 40˚C in two food simulants, namely, olive oil and 15%
aqueous ethanol.
The mass variation of the PVC samples with time was investigated. Migration phenomena were studied by
using various analytical methods such as Fourier transform infrared spectroscopy (FTIR) and scanning electron
microscopy (SEM).
2. Experimental
2.1. Materials
PVC resin with K-Wert value of 70 produced by CIRES (Portugal), dioctyl phthalate (DOP) from SGP (Tunisia),
ethylene-vinyl-acetate (EVA) from BASF (Germany), acrylonitrile-butadiene-styrene (ABS) from Chemtura
(USA), Zn and Ca stearates complex (Reapak BCV/3037) from IACN (Italy), and stearine produced by
SO.G.I.S.SPA (Italy) were commercial products used without preliminary purification. The epoxidized sun-
flower oil (ESO) was especially prepared as described previously (Benaniba, Belhaneche-Bensemra, & Gelbard,
2001). The level of oxirane oxygen was 5.2%. The olive oil used as food simulant was first characterized. Its
acidity index, iodine index, saponification index and peroxide index were measured, respectively, according to
the ISO 660, ISO 3961, ISO 3957 and ISO 3960. The following characteristics were measured:
Acidity index = 1.38; iodine index = 83.07; saponification index = 182.9; peroxide index = 7.5 and relative
density = 0.906.
Ethanol and tetrahydrofuran (THF) of high purity grade from Prolabo were used as received.
2.2. Preparation of PVC Fi lms
Samples were prepared according to the formulations given in Table 1. PVC and additives were mixed in a
M. O. Boussoum, N. Belhaneche-Bensemra
51
Table 1. Details on the prepared formulations (wt%).
F1 F2 F3 F4 F5 F6 F7 F8
PVC 100 100 100 100 100 100 100 100
Ca,
Zn
complex 2 2 2 2 2 2 2 2
ESO 10 10 10 10 10 10 10 10
Stearic acid 1 1 1 1 1 1 1 1
DOP 40
EVA 40
ABS 40
DOP:EVA
DOP:ABS 30:10 25:15 20:20 15:25 10:30
two-roll mill at 140˚C and melt compressed at 170˚C under a pressure of 300 kNm2.
2.3. Migration Testing
Circular samples having a thickness of (2 ± 0.1) mm and a diameter of (22 ± 0.1) mm were cut from the selected
PVC films.
Migration tests were conducted using olive oil as fatty simulant and aqueous ethanol. The test conditions were
12 days at 40˚C (directive 82/711EEC). Twelve circular samples of plasticized PVC were immersed in 120 ml
of food simulant. A circular sample and 10 ml of food simulant were taken off every day. The rate of mass vari-
ation was calculated according to the following equation:
( )
( )
% 100
too
mmm
τ

=−×

( 1)
where: mo = initial mass before immersion and mt = mass of the sample at the time t.
The weights were measured to an accuracy of 104 g.
2.4. FTIR Analysis
Polymeric film was recovered and analysed with a JASCO FTIR-430 spectrophotometer.
2.5. SEM Characterization
The PVC samples were analysed after metallization by a scanning electron microscope PHILIPS type ESEM
XL.
3. Results and Discussion
3.1. Migration Testing
3.1.1. Rate of Mass Variation
The study of the rate of mass variation allows the identification of the interactions occurring between the PVC
samples and the food simulants (olive oil and aqueous ethanol). The decrease in the rate of mass variation means
that some amount of additives migrated from the PVC samples into the food simulant. The increase means a
gain in mass or penetration of the food stimulant in the PVC samples.
Figure 1 illustrates the evolution of the rate of mass variation with time of contact in the case of the three
considered formulations.
It is notable that in the case of aqueous ethanol the shape of the curves increases for the three formulations.
This indicates the penetration of ethanol in the free volume. This phenomenon is facilitated by the low mass and
low viscosity of ethanol.
M. O. Boussoum, N. Belhaneche-Bensemra
52
Moreover, in the case of olive oil, the shape of the curves decreases for the three formulations. This indicates
that some additives have migrated.
Triglycerides are likely to interact with the lipophilic polymers and are good solvents for additives. They are
weakly polar or apolar (Atek, Belhaneche-Bensemra, & Turki, 2010). The presence of DOP plasticizer reduces
the interactions between PVC chains and increases the free volume which increases the mobility of the additives
and then promotes their diffusion. On the other hand, the results obtained show that the partial substitution of
DOP plasticizer by both permanent plasticizers reduces migration. At the molecular level, the partial replace-
ment of DOP by permanent plasticizers increases the cohesion between the two polymers chains and thereby
reduces the free volume, which is unfavourable to the diffusion. This leads to a decrease in the migration of the
additives.
Furthermore, Figure 1 shows clearly the following order concerning the migration of additives: DOP (40) >
DOP:EVA (30/10) > DOP:ABS (30/10).
According to current legislation (Directive 90/128/EEC and its amendments; EEC 1990), the overall migra-
tion to a foodstuff from food contact plastics must be less than 10 mg of plastics compounds per dm2 of surface
area.
Table 2 shows the values of the overall migration in olive oil. They are lower than the maximum allowable
overall migration: 10 mgdm2. This means that migration has not affected the quality of the simulant (food).
Moreover, the lowest values of global migration were obtained in the case of the formulations where there is an
addition of a permanent plasticizer. This shows that this approach is effective in reducing the overall migration
of additives.
3.1.2. Migration Analysis by Infrared Spectroscopy
The spectrum of PVC alone and the spectra of the additives were compared with the spectrum of PVC with ad-
ditives. This allowed the identification of some characteristic bands which are related to the additives present in
the formulation. Table 3 shows these bands (Boussoum, Atek, & Belhaneche-Bensemra, 2006; Ito, Sechimi,
Miura, Kawagushi, Saito, & Nakazawa, 2006).
According to the phenomena of interaction between PVC samples and food simulants, the intensity of cha-
racteristic bands will change. An increase in the intensity corresponds to absorption of liquid through the PVC
samples and inversely, a decrease in intensity corresponds to a migration of one or more components in the food
simulants.
The comparison of the infrared spectra of the PVC films after various times of contact with the food simulants
allowed to study the migration phenomenon both in qualitative and semi-quantitative terms. The different cha
racteristic bands corresponding to the additives were identified.
Figure 1. Effect of the nature of the food simulant on the rate of mass variation τ.
M. O. Boussoum, N. Belhaneche-Bensemra
53
The following absorbance ratios were calculated:
A 1731/A 1426: ESO migration;
A 1719/A 1426: DOP migration;
A 1557/A 1426: Zn, Ca stearates complex migration;
A 1541/A 1426: Zn, Ca stearates complex migration;
A 1457/A 1426: Zn, Ca stearates complex, DOP, ESO and stearic acid migration.
The band at 1426 cm1 is present in all the spectra. It is caused by the vibration of the CH2 bond in PVC
(Krimm, Folt, Shipman, & Berens, 1963). Figure 2 shows the variations of these five ratios of absorbance as a
Table 2. Overall migration (mgdm2) in olive oil at 40˚C.
Formulations Overall migration (mgdm2)
DOP:EVA or ABS (40:00) 1.36
DOP:EVA (30:10) 0.57
DOP:ABS (30:10) 0.42
Figure 2. Variation of absorbance ratios as a function of time of contact with food simulants.
M. O. Boussoum, N. Belhaneche-Bensemra
54
function of time of contact with aqueous ethanol and olive oil for the three formulations studied.
There is a decrease in all absorbance ratios with time. This indicates that migration of ESO, Zn, Ca stearates
complex, DOP and stearic acid occurred in both liquid simulants. In the case of aqueous ethanol, it seems that
the penetration of the liquid simulant which was observed in the rate of mass variation favoured the migration of
additives. The lowest ratios of absorbance were obtained for the formulation plasticized with DOP; therefore al-
so, the lowest values of residual additives and the highest rates of migration. Furthermore, it appears clear that
the partial substitution of DOP by the permanent plasticizers EVA and ABS reduced the migration of DOP and
other additives.
According to the results obtained with rate of mass variation, the following order for the migration of addi-
tives estimated by FTIR spectroscopy was observed:
DOP (40) > DOP :EVA (30/10) > DOP:ABS (30/10).
3.1.3. Morphological Analysis by SEM
Figure 3 illustrates images of PVC samples of the three formulations analysed by scanning electron microscopy
Figure 3. Analysis of plasticized formulations after migration testing in olive oil by scanning electron mi-
croscopy (Gr ×800).
M. O. Boussoum, N. Belhaneche-Bensemra
55
Table 3. Characteristic bands of the used additives present in PVC film.
Wave number (cm1)
Assignments Additives
1 1731 C=O (ester) ESO, EVA
2 1719 C=O (ester) DOP
3 1557 COO (ester) Zn, Ca Complex
4 1541
2
CO
(carboxylic acid salt) Zn, Ca Complex
5 1457 CH2 (methyl, methylene) Zn, Ca Complex; DOP; ESO; EVA; ABS; stearic acid
before and after contact with olive oil during 10 days. The surfaces of the samples after migration testing were
rough compared to the control ones. The appearance of dark areas (holes) confirms that additives migration oc-
curred.
The holes observed are more important in the case of the formulation DOP (40) than for the formulations
DOP:EVA (30/10) and DOP:ABS (30/10) confirming that the additives migration is more important.
4. Conclusion
From the experimental results the following conclusions can be drawn:
- The preliminary study of the evolution of the rate of mass variations showed the presence of interactions
between plasticized PVC and food simulants. Indeed, additives migration in olive oil and penetration of
aqueous ethanol occurred. All the global migrations in olive oil found were lower than the allowable overall
migration: 10 mgdm2.
- The FTIR analysis has highlighted the migration of DOP and other additives using a semi quantitative esti-
mation based on the evolution of the absorbance ratios versus contact time.
- The scanning electron microscopy confirmed that there was migration of additives in olive oil.
- Finally, this study showed the effectiveness of the approach consisting in the partial substitution of DOP by
plasticizers of polymeric nature. All the results obtained with the various analytical methods used showed
the following order concerning the migration of additives: DOP (40) > DOP:EVA (30/10) > DOP:ABS
(30/10).
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