The influences of incorporating compatibilizers E-EA-MAH, E-MA-GMA, E-AM, SEBS KRATON G, or PP-g-MAH on the thermal properties of mixed (polypropylene/ethylene propylene rubber)/acrylonitrile butadiene styrene (PP/EPR)/ABS have been investigated. DSC investigations have revealed that the incorporation of 5% of ABS in the copolymer (PP/EPR) does not fundamentally affect the thermal properties of the basic copolymer; additionally, the addition of 1.5% of each of the compatibilizers in the basic mixture does not significantly alter the crystallization temperature values and the melting of the -P- sequences. There is a variation of melting enthalpy values of the -P- sequences of 18.23% using SEBS KRATON G and of 10.38% using E-AM-GMA. When the rate of each of the compatibilizers increases to 5%, overall crystallization enthalpies of -P- sequences are almost kept unchanged, except for the case of using the compatibilizer E-AM-GMA with a variation of 8.42%. There is a minor variation of the melting enthalpy of -P- sequences with higher levels of compatibilizer. The incorporation of 5% ABS copolymer in the PP/EPR does not significantly alter the thermal properties of the basic structure of (PP/EPR)/ABS.
Polymer industries have known fantastic development in the middle of the last century, where many manufactures have developed new plastic kinds. The production of new polymers such as thermoplastics, thermosets, or rubbers required large investments in research to find the way to produce them chemically. The design of new chemical vessels, the synthesis of new monomers prepared via complex chemical ways and methods, and the finding of new type of catalysts have contributed to the expansion of the plastic industry [
The present work studies the effect on a thermal point of view of commercial compatibilizers in mixture with copolymers PP/EPR and ABS. It starts with Introduction which is followed by Materials and Methods. The third section deals with the results. The next two sections are Discussion and Conclusions.
The ABS used was a thermoplastic elastomer compound technology (butadiene) dispersed and grafted as minor phase in a thermoplastic matrix of the copolymer of styrene and acrylonitrile SAN [
ABS characteristics.
Properties | Values | Unit | Test method |
---|---|---|---|
Density | 1.05 | — | — |
Melt flow index | 10 | g/10 min | MFI |
Young’s modulus | 1 | GPa | Traction |
Deformation at yield | 2 | % | Traction |
Maximum stress | 20 | MPa | Traction |
DSC curve of the copolymer PP/EPR used.
DSC curve of the copolymer ABS used.
Lotader AX8900 is an ethylene (E)/methyl acrylate (MA)/glycidyl methacrylate (GMA), which contains 8% in weight of GMA. Lotader AX3210 is a terpolymer of ethylene (E), acrylic ester (AE), and Maleic Anhydride (MAH). It contains 3% in weight of Maleic Anhydride. It is marketed by Atofina; its characteristics are presented in Table
Characteristics of compatibilizer E-EA-MAH.
Specifications | Values | Unit | Test method |
---|---|---|---|
Melt flow index |
5 | g/10 min | ASTM D 1238/ISO1133 |
Percentage of copolymer | 9 | % | IR |
Density to 23°C | 0.94 | g/cm3 | ASTM D 1505 |
Fusion point | 107 | °C | DSC |
Vicat softening point |
80 | °C | ASTM D 1525/ISO306 |
Flexural modulus | 120 | MPa | ASTM D 790/ISO178 |
Deformation at yield | 600 | % | ASTM D 638/ISOR527 |
LOTRYL 20MA08 ECH is an ethylene/acrylate methyl (E-AM), containing 20% acrylate methyl in weight. It is soluble in chloroform CHCl3. Ethylene is compatible with the polypropylene and acrylate methyl is compatible with the styrene portion of the ABS. SEBS KRATON G is a triblock copolymer poly(styrene-b-ethylene-co-butylene-b-styrene). It is compatible with ABS and polypropylene; it is also soluble in chloroform CHCl3. OREVAC CA 100 is a polypropylene chemical function containing a high percentage of Maleic Anhydride. Its characteristics are shown in Table
Characteristics of the compatibilizer PP-g-MAH.
Specifications | Values | Unit | Test method |
---|---|---|---|
Melt flow index (190°C/325 g) | 10 | g/10 min | — |
Fusion point | 167 | °C | DSC |
Vicat softening point (1 kg) | 147 | °C | ISO306 (9.81 N) |
Flexural modulus | 880 | MPa | ISO 178 |
Yield stress | 22 | MPa | — |
Percent elongation | 12 | % | — |
Point of embrittlement |
|
°C | ASTM D 726 |
The HAAKE PolyLab System mixer is connected to a computer. The “PolyLab” software controls the experimental procedure (screw types, mold temperature, screw speed, and holding time, etc.) and it records automatically all the data.
The blends are prepared by means of an internal mixer HAAKE PolyLab System. A computer is controlling the rotation of the screw and the heating temperature. The variation of the torque exerted by the screws “rollers” mixer is expressed as function of time. The rotation of the screw is adjusted to 40 RPM (round per minute) at a temperature of 180°C during 20 minutes. Thermal tests are performed by DSC according to a controlled procedure. A DSC test is performed on the copolymer PP/EPR to get the initial values of the thermal constants. The second step consists in mixing PP/EPR with 5% of ABS and getting its thermal constants using the same experimental procedure. To highlight the effects of the addition of ABS to the copolymer PP/EPR, one can simply compare the thermal constants of the two mixtures. If these results are relatively equal, it can be considered that the addition of 5% ABS copolymer does not alter the thermal properties of the latter. The same experimental procedure is applied to determine the thermal effect of the five above-mentioned compatibilizers on mixtures (PP/EPR)/ABS containing 5% ABS, with a rate of 1.5% or 5% compatibilizer. The dispersion of low mass rate not exceeding 4% of compatibilizers in the mixture is widely enough to generate physical or chemical interactions required at the interface between the two phases of the mixture, which may cause good properties impact of material [
Composition of blends (PP/EPR)/ABS/compatibilizer at a rate of 1.5% of one of the five compatibilizers.
Mixtures | PP/EPR | ABS | E-AM-GMA | E-EA-MAH | PP-g-MAH | SEBS | E-AM |
---|---|---|---|---|---|---|---|
(PP/EPR)/ABS/E-AM-GMA | 93.5% | 5.0% | 1.5% | — | — | — | — |
(PP/EPR)/ABS/E-EA-MAH | 93.5% | 5.0% | — | 1.5% | — | — | — |
(PP/EPR)/ABS/PP-g-MAH | 93.5% | 5.0% | — | — | 1.5% | — | — |
(PP/EPR)/ABS/SEBS | 93.5% | 5.0% | — | — | — | 1.5% | — |
(PP/EPR)/ABS/E-AM | 93.5% | 5.0% | — | — | — | — | 1.5% |
Composition of blends (PP/EPR)/ABS/compatibilizer at a rate of 5% of one of the five compatibilizers.
Mixtures | PP/EPR | ABS | E-AM-GMA | E-EA-MAH | PP-g-MAH | SEBS | E-AM |
---|---|---|---|---|---|---|---|
(PP/EPR)/ABS/E-AM-GMA | 90.0% | 5.0% | 5.0% | — | — | — | — |
(PP/EPR)/ABS/E-EA-MAH | 90.0% | 5.0% | — | 5.0% | — | — | — |
(PP/EPR)/ABS/PP-g-MAH | 90.0% | 5.0% | — | — | 5.0% | — | — |
(PP/EPR)/ABS/SEBS | 90.0% | 5.0% | — | — | — | 5.0% | — |
(PP/EPR)/ABS/E-AM | 90.0% | 5.0% | — | — | — | — | 5.0% |
For all the tests, the samples were subjected twice to the following thermal cycle: −100°C to 200°C with a heating rate of 10°C/min and an isothermal holding at 200°C for 2 minutes and then to cooling from 200°C to −100°C with a cooling rate of −10°C/min with an isothermal holding for 2 minutes at −100°C. All the data are automatically recorded. The thermal transitions of the sample are identified according to an internal reference subjected to the same temperature cycles. The sample and the reference are in the same furnace and the temperature varies linearly with time. Once the sample reaches a transition, the difference in temperature between the sample and the reference is compensated by the heating device. This appears on the DSC curve as a small drop of the base line for minor transition as glass transition temperature or a broad endothermic peak for the fusion. The DSC set-up is composed of a measurement chamber and a computer. Two pans are heated in the measurement chamber. The sample pan contains the material being investigated. A second pan, typically empty, is used as a reference.
The experiment is carried out in inert atmosphere (argon) to avoid a material reaction with air. The measurements are performed with a DSC 30 maintained by Mettler-Toledo SA system. The equipment is calibrated with indium, zinc, and lead: the calibration check is done with indium (
The DSC curves of PP/EPR and ABS, respectively, are represented in Figures
Thermal characteristics of copolymers PP/EPR and ABS and their mixture (PP/EPR)/ABS.
Mixtures |
|
|
|
|
|
|
|
---|---|---|---|---|---|---|---|
PP/EPR | — | 115.33 | 170.5 | 93.66 | 125.16 | −103.78 | 106.17 |
ABS | 105.7 | — | — | — | — | — | — |
(PP/EPR)/ABS | 105.7 | 116.16 | 170.83 | 93.00 | 124.83 | −104.84 | 106.59 |
Variation of the torque exerted by the screws “rollers” internal mixer HAAKE PolyLab System on mixtures (PP/EPR)/ABS/compatibilizers at a rate of 1.5% of the five compatibilizers.
Variation of the torque exerted by the screws “rollers” internal mixer HAAKE PolyLab System on mixtures (PP/EPR)/ABS/compatibilizers at rate of 5% of each one of the five compatibilizers.
All the DSC curves of the copolymers PP/EPR and ABS with compatibilizer in mixture at the rate of 1.5% and 5% are reported from Figures
Thermal characteristics of the blends (PP/EPR)/ABS/compatibilizer at rate of 1.5% of each one of the five compatibilizers.
Mixtures |
|
|
|
|
|
|
|
---|---|---|---|---|---|---|---|
(PP/EPR)/ABS | 105.7 | 116.16 | 170.83 | 93.00 | 124.83 | −104.84 | 106.59 |
(PP/EPR)/ABS/E-AM-GMA | 105.7 | 119.33 | 170.33 | 95.83 | 125.83 | −93.96 | 104.69 |
(PP/EPR)/ABS/E-EA-MAH | 105.7 | 111.33 | 168.83 | 95.66 | 127.32 | −97.67 | 101.09 |
(PP/EPR)/ABS/PP-g-MAH | 105.7 | 118.16 | 170.16 | 95.33 | 126.33 | −105.41 | 97.43 |
(PP/EPR)/ABS/SEBS | 105.7 | — | 170.16 | 94.33 | 125.83 | −85.73 | 107.28 |
(PP/EPR)/ABS/E-AM | 105.7 | 112.66 | 171.00 | 94.33 | 126.5 | −92.68 | 109.05 |
Thermal characteristics of the blends (PP/EPR)/ABS/compatibilizer at rate of 5% of each one of the five compatibilizers.
Mixtures |
|
|
|
|
|
|
|
---|---|---|---|---|---|---|---|
(PP/EPR)/ABS | 105.7 | 116.16 | 170.83 | 93.00 | 124.83 | −104.84 | 106.59 |
(PP/EPR)/ABS/E-AM-GMA | 105.7 | — | 171.83 | 94.16 | 124.16 | −94.29 | 97.61 |
(PP/EPR)/ABS/E-EA-MAH | 105.7 | 109.00 | 171.33 | 90.83 | 125.66 | −101.32 | 108.35 |
(PP/EPR)/ABS/PP-g-MAH | 105.7 | 115.5 | 171.00 | 93.83 | 120.5 | −101.73 | 105.84 |
(PP/EPR)/ABS/SEBS | 105.7 | 118.16 | 171.83 | 95.83 | 125.5 | −96.88 | 103.24 |
(PP/EPR)/ABS/E-AM | 105.7 | 116.33 | 172.00 | 93.16 | 124.16 | −98.90 | 103.91 |
DSC curves in the direction of the endothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (93.5)/5/1.5, for the first thermal cycle. For about 15 mg of sample. 1 graduation
DSC curves in the direction of the endothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (93.5)/5/1.5, for the second thermal cycle. For about 15 mg of sample. 1 graduation
DSC curves in the direction of the exothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (93.5)/5/1.5, for the first thermal cycle. For about 15 mg of sample. 1 graduation
DSC curves in the direction of the exothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (93.5)/5/1.5, for the second thermal cycle. For about 15 mg of sample. 1 graduation
DSC curves in the direction of the endothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (95)/5/5, for the first thermal cycle. For about 15 mg of sample. 1 graduation
DSC curves in the direction of the endothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (95)/5/5, for the second thermal cycle. For about 15 mg of sample. 1 graduation
DSC curves in the direction of the exothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (95)/5/5, for the first thermal cycle. For about 15 mg of sample. 1 graduation
DSC curves in the direction of the exothermic transformations of components and mixtures (PP/EPR)/ABS/compatibilizer (95)/5/5, for the second thermal cycle. For about 15 mg of sample. 1 graduation
In amorphous statistical copolymers,
The verification by means of the Fox law confirms that the characteristics of the copolymer PP/EPR respect the standard. In fact, it was perfectly processed by the manufacturer that has fully respected the same ratio of -E- and -P- sequences. Figures
The miscible blends are only a minority of cases encountered [
The DSC curves of ABS (Figure
Figures Reduction of interfacial tension to facilitate the dispersion. Stabilization of the morphology to avoid changing it during processing steps and implementation of the material. Increased adhesion between phases in the solid state in order to promote in particular the stress transfer between the phases and thus improve the mechanical properties of the mixture.
Depending on the chosen method of accounting and the type of compatibilizer used, each of the three previous objectives can be more or less achieved. The two most frequently used strategies in the compatibilization of immiscible polymer blends strategies are the following [ The addition of a preformed copolymer, nature, and suitable structures capable of interacting with each of the phases present. In situ formation of a copolymer by chemical reaction at the interface between the phases during preparation of the mixture.
For blends compatibilized, the choice of compatibilizer is based on the miscibility of the sequences of the latter with the mixture components. Similarly, the low molecular weight chains of the compatibilizer will facilitate their diffusion in the molten medium (high viscosity) and will focus their accessibility and their concentration on the areas of interaction, that is, the interface between the two-phase mixture [
It is observed that with 1.5% of compatibilizer the homogenization of the blend takes a mean time of four minutes. But, with 5%, the homogenization is accelerated and occurs in three minutes or less. This variation of the mean time for the homogenization shows that the compatibilizer promotes effectively and efficiently the blending of the mixture.
Figures
For the rest of the experiments (variation of the compatibilizers concentration, first and second thermal cycles) these previous remarks and differences remain almost true.
Figures
For the endothermic transformations, the predominant peaks tend to have the most important enthalpy values of fusion for -P- sequences as reported in the tables. This might be due to the fact that blends have almost the same melting temperature, and then the thermal power is mainly governed by the melting enthalpy values of the -P- sequences regardless of PP-g-MAH.
Observing our results, a small increase in crystallization temperature for all mixtures at a low rate of compatibilizer emerges. In our maximum rate, the behavior is completely random. In the case of the exothermic transformations and regardless of the thermal cycle, the lower rate of compatibilizer tends to perfectly align the crystallization temperatures of the blend. On the contrary, the opposite effect can be observed when the compatibilizer rate is increased.
It can be still noticed that, in general, the DSC curves keep their global initial aspect. Then it can be stated that the incorporation of 5% of ABS in the copolymer PP/EPR does not significantly affect the thermal properties of the basic copolymer; the addition of 1.5% of each compatibilizer in the basic mixture does not significantly alter the crystallization temperature values and melting of the -P- sequences. However, there is a variation of the melting enthalpy values of the -P- sequences of 18.23% using SEBS KRATON G and of 10.38% using the E-AM-GMA; with regard to the crystallization enthalpies of the -P- sequences, only the PP-g-MAH allows observing a variation of 8.59%. At last, when the rate of each compatibilizer increases by 5%, the overall crystallization enthalpy of the -P- sequences remains almost unchanged, except for the case when using the compatibilizer E-AM-GMA with a variation of 8.42%. It has also been observed that, for the presence of high concentration of compatibilizer, the melting enthalpy of the -P- sequences varies less. The addition of 5% of ABS copolymer to PP/EPR does not affect significantly the thermal properties of the basic (PP/EPR)/ABS mixture.
This work has been devoted to the effects of the addition of compatibilizers on the thermal properties of the polymeric mixture (PP/EPR)/ABS. The addition of 5% of ABS to the PP/EPR copolymer does not significantly affect the thermal properties (enthalpies, melting temperatures, and crystallization) of the basic copolymer. In the same time, the addition of 1.5% of each compatibilizer in the basic mixture does not affect significantly the crystallization temperature values. The same kinds of observations have been made for the melting temperatures of the -P- sequences. However, a variation of the melting enthalpy values of the -P- sequences of about 18.23% when using SEBS KRATON G and 10.38% when using the E-AM-GMA is still observable. For the crystallization enthalpies of the -P- sequences, only the PP-g-MAH allows variation of 8.59%. When the rate of each compatibilizer increases up to 5%, the overall crystallization enthalpies of the -P- sequences remain almost unchanged except in the case when the E-AM-GMA compatibilizer is used with a variation of 8.42%. It has also been observed that, with high levels of compatibilizer, the melting enthalpy of the -P- sequences varies less; however, the compatibilizer E-AM-GMA is the one that causes the greatest variation with a value of 10%.
LOTADER AX3210
LOTADER AX8900
LOTRYL ECH 20MA08
OREVAC CA 100
PP108MF97 marketed by SABIC.
Polypropylene (isotactic)
Ethylene propylene rubber
Styrene copolymer/acrylonitrile
Acrylonitrile butadiene styrene
Triblock Ethylene Ester-Acrylic Maleic Anhydride
Ethylene/Acrylatemethyl/Glycidyl Methacrylate
Ethylene Acrylate Methyl copolymer
Triblock Copolymer poly(styrene-b-ethylene-co-butylene-b-styrene)
Polypropylene-g-Anhydride copolymer Maleic Anhydride
Differential Scanning Calorimetry.
The authors declare that there is no conflict of interests regarding the publication of this paper.