Two compatibilizers consisting of styrene-acrylonitrile-glycidyl methacrylate (SAG) terpolymer with different contents of glycidyl methacrylate (GMA), SAG-001 (1 wt% of GMA) and SAG-005 (5 wt% of GMA), and styrene-acry-lonitrile-maleic anhydride terpolymer (SAM), SAM-002 (2 wt% of maleic anhydride ), were used to evaluate the role of compatibilizers in the PC/ABS alloy in terms of the mechanical properties, thermal stability and phase morphology. The tensile strength of SAG modified PC/ABS alloy slightly increased than that of SAM modified system, but the two compatibilizers barely affected the flexural strength of the system. On the other hand, the impact strength of SAG modified PC/ABS was improved. In addition, the MFR (melt flow index) of the SAG modified PC/ABS alloy reduced, implying that the viscosity or molecular weight of the system increased. The HDT (heat distortion temperature) also improved with SAG modified system. Moreover, the phase morphology of the SAG modified PC/ABS alloys much enhanced than that of SAM modified system. As a consequence, SAG compatibilized PC/ABS alloy showed better properties than those of SAM modified system, suggesting that the reaction between carboxylic or epoxy groups in SAG and terminal carboxyl group in PC would be the main factor to bring the enhancement in the mechanical, thermal and morphological properties of the PC/ABS alloy.
The enhanced properties of PC/ABS alloy were resulted from the combined characteristics of both PC and ABS. Compared to PC itself, the mobility and processability of PC/ABS alloy improved and the sensitivity to stress reduced. On the other hand, PC/ABS alloy possess excellent thermal stability compared to that of ABS. Thus, it can be widely applied to the various fields of household appliances, office equipments, communication equipments, camera and medical equipments, building and lightening appliances, aerospace, computers and optical fibers,etc. In particular, the property of high strength and heat resistance of PC/ABS alloy is applicable to the automobile interiors, exteriors and light systems [
In recent years, the market of PC/ABS alloy has continuously grown 10% per year. In the mean time, more attractive appearance and higher performance of PC/ABS alloy were demanded in the automobile industry and household appliances. As a result, the new class of PC/ABS alloys was appeared [
In this paper, two different compatibilizers with various contents were used in the PC/ABS (70/30) alloy and the role of compatibilizers on the properties of the PC/ABS system was evaluated. One is SAG (styrene-acrylonitrile-glycidyl methacrylate) terpolymer consisting of 1 and 5 wt% of glycidyl methacrylate (GMA) and other is SAM (styrene-acrylonitrile-maleic anhydride) terpolymer containing of 2 wt% of maleic anhydride (MAH). Thus, the effect of SAG and SAM on the mechanical properties, thermal stability and phase morphology of PC/ABS alloy was compared and the main cause of compatibilization between the compatibilizer and alloy matrix was suggested.
Materials. Polycarbonate (PC), as a lot number of 1100, was purchased from Honam Petrochemical Company, Korea and ABS, as a lot number of 8391, was purchased from Sinopec Shanghai Gaoqiao Company, China. Two styrene- acrylonitrile-glycidyl methacrylate (SAG) terpolymers, which are SAG-001 (1% of GMA content, Mw ≈ 80,000 - 100,000 g/mol) and SAG-005 (5% of GMA content, Mw ≈ 80,000 - 100,000 g/mol), are products of Fine-Blend Compatilizer Jiangsu Co., Ltd., China. Styrene-acrylonitrile-maleic anhydride (SAM) terpolymer, as a lot number of SAM-002 (2% of MAH content, Mw ≈ 100,000)is also a product of Fine-Blend Compatilizer Jiangsu Co., Ltd., China. Antioxidant, as a lot number of 168,245, is a product from the Ciba Specialty Chemicals, Swiss. All these ingredients are used as received.
Sample preparation. Both of PC and ABS resins were dried at 90˚C for 8h using an oven. PC and ABS were first mechanically mixed in the ratio of 70:30, respectively, with antioxidant, 168 (0.2 wt%), 245 (0.2 wt%), before the extrusion process. Then, this mixture was again mixed with different ratios of SAG and SAM using a high speed mixer. They were put into twin-screw extruder for melt mixing. The temperature for each stage was 180˚C, 200˚C, 220˚C, 235˚C, 240˚C, 245˚C, 250˚C from the head to the end of the extruder. Then, the extrusion, cooling and pelletizing processes were followed by. The pelletized granules were dried at 90˚C for 8h in an oven and injection molded to prepare the standard sample specimens. The sample size was the following; for tensile strength 165 × 13 × 3.2 mm according to the ASTM D638-2010, for bending 127 × 12.7 × 3.2 mm according to the ASTM D 790-2010, for Izod impact strength 63.5 × 12.7 × 3.2 mm according to the ASTM D256-2010.
All ingredients for PC/ABS alloy upon sample numbers are listed in
Equipments & experiments. High speed mixer, SH140Φ85 of Zhanghiagang Baixiongkemei Machinery Co. Ltd, China, twin-screw extruder (CTE50-TY3515, diameter 36 cm, length/diameter ratio 40/1, respectively) of Nanjing Corporation Machinery Co. Ltd., China, electronic universal testing machine, CMT6104, of Shenzhen Xingsansi Measurement Technique Co. Ltd, China, Izod impact testing machine, XJU-22, of Chengde Testing Machine Co. Ltd, China, melt flow indexer, RL-11B, of Shanghai Sierda Scientific Instrument Co. Ltd., China, injection molding machine, JN88-E, of Zhenxiong Machinery Co. Ltd., China and
Sample Number | 1# | 2# | 3# | 4# | 5# | |
---|---|---|---|---|---|---|
PC | 70 | 70 | 70 | 70 | 70 | |
ABS | 30 | 30 | 30 | 30 | 30 | |
SAG-001 (phr) | 0.3 | 0.5 | ||||
SAG-005 (phr) | 0.5 | |||||
SAM-002 (phr) | 0.5 | |||||
168,245 (phr) | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | |
scanning electron microscope, JSM-6360LV, of Japan Electronic Company were used.
Tensile strength was evaluated based on the standard ASTM D638-2010 at tensile speed of 5 mm/min. Flexural strength was tested according to ASTM D790-2010 using the flexural speed of 2 mm/min. The Izod impact strength was performed according to ASTM D256-2010 (1/4 inch specimen’s size: 63.5 mm* 12.7 mm*6.4 mm, 1/8 inch specimen’s size: 63.5 mm*12.7 mm*3.2 mm,). MFR was evaluated based on ASTM D1238-2010 at 260˚C and 5 kg of load. The standard ASTM D648-2007 was used to test the heat distortion temperature (HDT) at the load of 1.82MPa. Scanning electron microscopy (SEM) was used to study the morphological characteristics. Fractured surface was obtained after dealing with liquid nitrogen. The cross section was etched by K2Cr2O7-H2SO4 solvent and treated with spray-gold. The acceleration voltage was 60kV when the surface morphology of fault was observed by SEM.
The experimental values are the average of at least five measurements.
The effect of compatibilizers on PC/ABS alloy. As shown in
The compatibilizers, SAG-001, SAG-005 and SAM-002 were added in samples 2#-5#. As seen in
Since SAG contains of glycidyl methacrylate (GMA) group, GMA can react with the terminal hydroxyl group in PC as described in Scheme 1. On the other
Scheme 1. Schematic diagram of the reaction between PC terminal groups and GMA in SAG.
hand, MAH in SAM reacts with hydroxyl-terminated group in PC described in Scheme 2. Since five-member MAH group in SAM is more rigid than three- member epoxy group GMA in SAG, it was suggested that the reactivity of SAG
Scheme 2. Schematic diagram of the reaction between hydroxyl-terminated of PC and MAH in SAM.
would be higher than that of SAM, resulting in higher impact strength.
From the discussion of
The MFR (melt flow index) and HDT were measured for each specimen and the results are drawn in
As seen in
The phase morphology of PC/ABS alloy. The phase morphology of PC/ABS alloy with different compatibilizers was shown from
The data representing the effect of compatibilizers on the mechanical property of PC/ABS is listed in
Specimen No. Property | 1# | 2# | 3# | 4# | 5# |
---|---|---|---|---|---|
Tensile strength | 56 | 57 | 57 | 58 | 58 |
Flexural strength | 82 | 83 | 82 | 83 | 82 |
Impact strength (1/8”) | 514 | 584 | 602 | 628 | 594 |
Impact strength (1/4”) | 180 | 286 | 301 | 309 | 227 |
Melt index | 29 | 24 | 24 | 23 | 25 |
HDT | 118 | 121 | 121 | 122 | 120 |
the best among 5 samples, implying that GMA-contained SAG terpolymer is an excellent compatibilizer in PC/ABS (70/30) system. It can be explained that the micro morphology phase was optimized due to the introduction of SAG inducing the dispersed particle smaller and the distribution more homogeneous than with SAM. As a consequence, more energy can be absorbed and stored when the alloy was affected by external forces, which resulted in the increased impact strength and less sensibility to gaps [
The two compatibilizers consisting of styrene-acrylonitrile-glycidyl methacrylate terpolymer (SAG) with 1 and 5 wt% of glycidyl methacrylate (GMA) and one SAM (styrene-acrylonitrile-maleic anhydride terpolymer) with 2 wt% maleic anhydride (MAH) were used to evaluate the role as a compatibiulizer in PC/ABS (70/30) alloy based on the mechanical properties, thermal stability and phase morphology. The tensile strength of compatibilized PC/ABS alloy slightly increased, but the two compatibilizers barely affected the flexural strength of the system. On the other hand, the impact strength of SAG modified PC/ABS was improved, in particular, the specimen 4# with 0.5 phr of SAG-005 showed much enhancement. In addition, the HDT of the specimen 4# showed 3℃ increment. Moreover, the MFR of 4# alloy reduced, implying that the viscosity or molecular weight of the system increased due to the interaction between compatibilizer and PC/ABS alloy. Moreover, the phase morphology of the specimen 4# also showed the best indicating the small domain size and homogeneous dispersion of ABS in PC matrix, resulting in better compatibility. As a conclusion, the reactivity between GMA in SAG and terminal carboxyl group of PC would be the main factor for not only improving the mechanical and thermal property, but also enhancing the phase morphology of PC/ABS alloy.
Duan, H., Xin, M.-Q., Kim, K.-Y. and Tang, J.-J. (2017) The Role of Compatibilizers on the Properties of PC/ABS Alloy. Journal of Materials Science and Chemical Engineering, 5, 21- 30. https://doi.org/10.4236/msce.2017.56003