Improved properties of ternary polymer/filler composites
10.1002/spepro.002680
Improved properties of ternary polymer/filler composites Qingkun Shang
A polymer matrix containing two inorganic fillers exhibits significantly enhanced mechanical and thermodynamic properties compared with both pure high-density polyethylene and binary composites. High-density polyethylene (HDPE), one of the most popular polymers, is often used in structural materials and mixed with natural minerals to enhance its stiffness, toughness, dimensional stability, and electrical-insulating properties.1, 2 Calcium carbonate (CaCO3 ) and organic montmorillonite (OMMT) may be used to further enhance its mechanical properties. Using CaCO3 as a filler enhances the composite’s Young’s or tensile modulus (which is used to measure the stiffness of elastic materials) and impact strength. However, this is usually accompanied by a reduction in tensile strength, whose level depends on the particle content, size distribution, and extent of dispersion and bonding with the polymer matrix.3–5 On the other hand, OMMT can be used as a filler to increase tensile strength and thermostability of composites, depending on the filler’s exfoliation extent and the type of ion modifier involved.6–8 In general, one type of organic filler particle is added to polymers to change their properties. In contrast, we have prepared a ternary composite containing HDPE and two inorganic particles (CaCO3 and OMMT). We observed a synergistic effect for CaCO3 and OMMT on tensile and impact strength as well as the thermal properties of the composite. The mechanical properties of composites filled with untreated and stearic-acid (SA)-treated CaCO3 particles are listed in Table 1. Compared with neat HDPE, the properties of binary composites are changed significantly. Almost all mechanical properties of HDPE/untreated CaCO3 are reduced. On the other hand, addition of 12.33% (by weight, wt%) of treated CaCO3 can enhance most mechanical properties of the binary composite, except the elongation at break. Figure 1 shows that the tensile strength of the binary composites increases upon OMMT addition. The best overall tensile properties were displayed by composites with 3wt% of OMMT. Therefore, we used this level of OMMT content to produce and test the mechanical properties of binary and ternary composites (see Table 1). On the one hand, adding 3wt% OMMT has a significant effect (>100% increments) on the
Figure 1. Tensile strength of binary composites filled with different organic montmorillonite (OMMT) contents. wt%: Fraction by weight.
composite’s tensile strength (which changes from 15.07 to 31.10MPa) and Young’s modulus (from 160.22 to 321.00MPa). The flexural properties are also enhanced, although the associated increments are similar to those resulting from addition of CaCO3 . The reduction in impact strength (from 437.1 to 309.4J/m) is apparent, just like that related to the elongation at break (from 201.8 to 123.9%). We find that it is impossible to improve all mechanical properties of our binary composites by simply adding SA-treated nano-CaCO3 or OMMT to HDPE. Some properties are enhanced despite addition of treated CaCO3 or OMMT (tensile strength and Young’s modulus). To produce a perfect polymer, we added both SA-treated nano-CaCO3 and OMMT to the HDPE. Table 1 also includes the mechanical properties for this ternary HDPE/OMMT/CaCO3 composite (with 12.33wt% CaCO3 and 3wt% OMMT). One important result is that all mechanical properties, except the elongation at break, are enhanced compared with pure HDPE, HDPE/treated CaCO3 , or HDPE/3wt% OMMT binary composites, but they differ in detail. For example, the tensile
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10.1002/spepro.002680 Page 2/2
Table 1. Mechanical composite properties. HDPE: High-density polyethylene. CaCO3 : Calcium carbonate. Component
HDPE (600g) HDPE/12.3wt% untreated CaCO3 HDPE/12.3wt% treated CaCO3 HDPE/3wt% OMMT HDPE/3wt% OMMT/12.3% treated CaCO3
Tensile strength (MPa) 15.07 10.25 17.36 31.10 33.85
strength of the ternary composite is 33.85MPa, which is significantly greater than that of HDPE/treated CaCO3 (17.36MPa) or pure HDPE (15.07MPa), but close to that of the HDPE/3wt% OMMT binary composite (31.10MPa). This implies that the main contribution to the tensile strength is provided by the 3wt% OMMT. Similarly, the impact strength mainly comes from the SA-treated CaCO3 . Table 1 also reveals that a large Young’s modulus (twice that of the binary) is obtained for the ternary composite. This suggests that the two fillers work together efficiently to improve the tensile modulus of the ternary composite. We obtained a similar result for the flexural modulus, a 8.59% increment over that of HDPE/treated CaCO3 and a 10.31% increment with respect to that of HDPE/3wt% OMMT. The elongation at break of the ternary composite is less than that of the 3wt% OMMT as a single additive but more than that of the HDPE/treated CaCO3 binary. These results imply that different inorganic fillers affect the system properties differently. While CaCO3 filling seems to affect impact strength more strongly, OMMT seems to have a strong impact on tensile strength. The simultaneous addition of both fillers has a synergistic effect. We will next investigate the heat resistance (flame retardancy) of our new ternary composite. We also want to test the mechanical and thermodynamic properties of the output pipe materials enabled by this new composite. These materials have potential for use in many fields.
Young’s modulus (MPa) 160.22 91.21 307.54 321.00 645.26
Elongation at break (%) 201.8 76.3 84.7 123.9 94.1
Flexural strength (MPa) 19.47 31.64 32.80 31.64 33.85
Flexural modulus (MPa) 535.04 658.32 783.23 771.03 850.53
Impact strength (J/m) 437.1 320.5 564.2 309.4 556.2
References 1. H. S. Katz and J. V. Milewski, Handbook of Fillers for Plastics, Van Nostrand Reinhold, New York, 1987. 2. J. Jancar, Structure-property relationships in thermoplastic matrices, Adv. Polym. Sci. 139, pp. 1–65, 1999. doi:10.1007/3-540-69220-7 1. 3. O. Fu, G. Wang, and C. Liu, Polyethylene toughened by CaCO3 particles: the interface behavior and fracture mechanism in high density polyethylene/CaCO3 blends, Polymer 36, pp. 2397–2401, 1995. 4. Z. H. Liu, X. G. Zhu, Q. Li, Z. N. Oi, and F. S. Wang, Effect of morphology on the brittle ductile transition of polymer blends: 5. The role of CaCO3 particle size distribution in high density polyethylene/CaCO3 composites, Polymer 39, pp. 1863–1868, 1998. doi:10.1016/S0032-3861(97)00370-4. 5. H. Huang, Structure development and property changes in high-density polyethylene/calcium carbonate blends during pan-milling, J. Appl. Polym. Sci. 74, pp. 1459–1464, 1999. doi:10.1002/(SICI)1097-4628(19991107)74:63.0.CO;2-D. 6. A. Osman, E. P. Rupp, and W. Suter, Tensile properties of polyethylenelayered silicate nanocomposites, Polymer 46, pp. 1653–1660, 2005. doi:10.1016/j.polymer.2004.11.112. 7. S. K. Swain and A. I. Isayev, Effect of ultrasound on HDPE/clay nanocomposites: rheology, structure and properties, Polymer 48, pp. 281–289, 2007. doi:10.1016/j.polymer.2006.11.002. 8. G. Liang, J. Xu, and W. Xu, PE/PE-g-MAH/Org-MMT nanocomposites. II. Nonisothermal crystallization kinetics, J. Appl. Polym. Sci. 91, pp. 3054–3059, 2004. doi:10.1002/app.13575.
Author Information Qingkun Shang College of Chemistry Northeast Normal University Changchun, China
c 2010 Society of Plastics Engineers (SPE)
Improved properties of ternary polymer/filler composites Qingkun Shang
A polymer matrix containing two inorganic fillers exhibits significantly enhanced mechanical and thermodynamic properties compared with both pure high-density polyethylene and binary composites. High-density polyethylene (HDPE), one of the most popular polymers, is often used in structural materials and mixed with natural minerals to enhance its stiffness, toughness, dimensional stability, and electrical-insulating properties.1, 2 Calcium carbonate (CaCO3 ) and organic montmorillonite (OMMT) may be used to further enhance its mechanical properties. Using CaCO3 as a filler enhances the composite’s Young’s or tensile modulus (which is used to measure the stiffness of elastic materials) and impact strength. However, this is usually accompanied by a reduction in tensile strength, whose level depends on the particle content, size distribution, and extent of dispersion and bonding with the polymer matrix.3–5 On the other hand, OMMT can be used as a filler to increase tensile strength and thermostability of composites, depending on the filler’s exfoliation extent and the type of ion modifier involved.6–8 In general, one type of organic filler particle is added to polymers to change their properties. In contrast, we have prepared a ternary composite containing HDPE and two inorganic particles (CaCO3 and OMMT). We observed a synergistic effect for CaCO3 and OMMT on tensile and impact strength as well as the thermal properties of the composite. The mechanical properties of composites filled with untreated and stearic-acid (SA)-treated CaCO3 particles are listed in Table 1. Compared with neat HDPE, the properties of binary composites are changed significantly. Almost all mechanical properties of HDPE/untreated CaCO3 are reduced. On the other hand, addition of 12.33% (by weight, wt%) of treated CaCO3 can enhance most mechanical properties of the binary composite, except the elongation at break. Figure 1 shows that the tensile strength of the binary composites increases upon OMMT addition. The best overall tensile properties were displayed by composites with 3wt% of OMMT. Therefore, we used this level of OMMT content to produce and test the mechanical properties of binary and ternary composites (see Table 1). On the one hand, adding 3wt% OMMT has a significant effect (>100% increments) on the
Figure 1. Tensile strength of binary composites filled with different organic montmorillonite (OMMT) contents. wt%: Fraction by weight.
composite’s tensile strength (which changes from 15.07 to 31.10MPa) and Young’s modulus (from 160.22 to 321.00MPa). The flexural properties are also enhanced, although the associated increments are similar to those resulting from addition of CaCO3 . The reduction in impact strength (from 437.1 to 309.4J/m) is apparent, just like that related to the elongation at break (from 201.8 to 123.9%). We find that it is impossible to improve all mechanical properties of our binary composites by simply adding SA-treated nano-CaCO3 or OMMT to HDPE. Some properties are enhanced despite addition of treated CaCO3 or OMMT (tensile strength and Young’s modulus). To produce a perfect polymer, we added both SA-treated nano-CaCO3 and OMMT to the HDPE. Table 1 also includes the mechanical properties for this ternary HDPE/OMMT/CaCO3 composite (with 12.33wt% CaCO3 and 3wt% OMMT). One important result is that all mechanical properties, except the elongation at break, are enhanced compared with pure HDPE, HDPE/treated CaCO3 , or HDPE/3wt% OMMT binary composites, but they differ in detail. For example, the tensile
Continued on next page
10.1002/spepro.002680 Page 2/2
Table 1. Mechanical composite properties. HDPE: High-density polyethylene. CaCO3 : Calcium carbonate. Component
HDPE (600g) HDPE/12.3wt% untreated CaCO3 HDPE/12.3wt% treated CaCO3 HDPE/3wt% OMMT HDPE/3wt% OMMT/12.3% treated CaCO3
Tensile strength (MPa) 15.07 10.25 17.36 31.10 33.85
strength of the ternary composite is 33.85MPa, which is significantly greater than that of HDPE/treated CaCO3 (17.36MPa) or pure HDPE (15.07MPa), but close to that of the HDPE/3wt% OMMT binary composite (31.10MPa). This implies that the main contribution to the tensile strength is provided by the 3wt% OMMT. Similarly, the impact strength mainly comes from the SA-treated CaCO3 . Table 1 also reveals that a large Young’s modulus (twice that of the binary) is obtained for the ternary composite. This suggests that the two fillers work together efficiently to improve the tensile modulus of the ternary composite. We obtained a similar result for the flexural modulus, a 8.59% increment over that of HDPE/treated CaCO3 and a 10.31% increment with respect to that of HDPE/3wt% OMMT. The elongation at break of the ternary composite is less than that of the 3wt% OMMT as a single additive but more than that of the HDPE/treated CaCO3 binary. These results imply that different inorganic fillers affect the system properties differently. While CaCO3 filling seems to affect impact strength more strongly, OMMT seems to have a strong impact on tensile strength. The simultaneous addition of both fillers has a synergistic effect. We will next investigate the heat resistance (flame retardancy) of our new ternary composite. We also want to test the mechanical and thermodynamic properties of the output pipe materials enabled by this new composite. These materials have potential for use in many fields.
Young’s modulus (MPa) 160.22 91.21 307.54 321.00 645.26
Elongation at break (%) 201.8 76.3 84.7 123.9 94.1
Flexural strength (MPa) 19.47 31.64 32.80 31.64 33.85
Flexural modulus (MPa) 535.04 658.32 783.23 771.03 850.53
Impact strength (J/m) 437.1 320.5 564.2 309.4 556.2
References 1. H. S. Katz and J. V. Milewski, Handbook of Fillers for Plastics, Van Nostrand Reinhold, New York, 1987. 2. J. Jancar, Structure-property relationships in thermoplastic matrices, Adv. Polym. Sci. 139, pp. 1–65, 1999. doi:10.1007/3-540-69220-7 1. 3. O. Fu, G. Wang, and C. Liu, Polyethylene toughened by CaCO3 particles: the interface behavior and fracture mechanism in high density polyethylene/CaCO3 blends, Polymer 36, pp. 2397–2401, 1995. 4. Z. H. Liu, X. G. Zhu, Q. Li, Z. N. Oi, and F. S. Wang, Effect of morphology on the brittle ductile transition of polymer blends: 5. The role of CaCO3 particle size distribution in high density polyethylene/CaCO3 composites, Polymer 39, pp. 1863–1868, 1998. doi:10.1016/S0032-3861(97)00370-4. 5. H. Huang, Structure development and property changes in high-density polyethylene/calcium carbonate blends during pan-milling, J. Appl. Polym. Sci. 74, pp. 1459–1464, 1999. doi:10.1002/(SICI)1097-4628(19991107)74:63.0.CO;2-D. 6. A. Osman, E. P. Rupp, and W. Suter, Tensile properties of polyethylenelayered silicate nanocomposites, Polymer 46, pp. 1653–1660, 2005. doi:10.1016/j.polymer.2004.11.112. 7. S. K. Swain and A. I. Isayev, Effect of ultrasound on HDPE/clay nanocomposites: rheology, structure and properties, Polymer 48, pp. 281–289, 2007. doi:10.1016/j.polymer.2006.11.002. 8. G. Liang, J. Xu, and W. Xu, PE/PE-g-MAH/Org-MMT nanocomposites. II. Nonisothermal crystallization kinetics, J. Appl. Polym. Sci. 91, pp. 3054–3059, 2004. doi:10.1002/app.13575.
Author Information Qingkun Shang College of Chemistry Northeast Normal University Changchun, China
c 2010 Society of Plastics Engineers (SPE)
