Rigid, fused-ring molecules were investigated as nano-sized reinforcements for engineering polymers. Because of the high specific surface area associated with their small size, it was expected that they would provide greater enhancement of modulus than equally stiff reinforcements of millimeter and micron dimensions. The expected enhancement was not realized, a result attributed to the bulky alkyl substituents on the rings, placed there to make the fused-ring molecules soluble and dispersible at the molecular level in engineering polymers. It was concluded that the free volume introduced to the nanocomposites by these substituents counteracted the stiffening effect of the fused-ring structure in the molecules. The results point out the inherent trade-off with fused-ring molecules as reinforcements; the types of substituents required to make the molecules dispersible in a polymer matrix are also those that reduce its modulus.
Fornes, T.D. , Yoon, P.J., Hunter , D.L., Keskkula, H. and Paul, D.R. (2002). Effect of Organoclay Structure on Nylon 6 Nanocomposite Morphology and Properties , Polymer, 43: 5915—5933.
2.
Zeng, Q.H., Yu, A.B., Lu, G.Q. and Paul, D.R. (2005). Clay-based Polymer Nanocomposites: Research and Commercial Development, J. Nanosci. Nanotechnol., 5: 1574—1592.
3.
Schadler, L.S. , Giannaris, S.C. and Ajayan, P.M. (1998). Load Transfer in Carbon Nanotube Epoxy Composites, Appl. Phys. Lett., 73: 3842—3844.
4.
Ajayan, P.M. , Schadler, L.S., Giannaris , C. and Rubio, A. (2000). Single-walled Carbon Nanotube-polymer Composites: Strength and Weakness, Adv. Mater. , 12: 750—753.
5.
Qian, D., Dickey, E.C., Andrews, R. and Rantell, T. (2000). Load Transfer and Deformation Mechanisms in Carbon Nanotube-polystyrene Composites, Appl. Phys. Lett., 76: 2868—2870.
6.
Ito, S., Wehmeier, M., Brand, J.D., Käbel, C., Epsch, R., Rabe, J.P. and Mullen, K. (2000). Synthesis and Self-assembly of Functionalized Hexa-peri-hexabenzocoronenes, Chem. Eur. J., 6: 4327—4342.
7.
Mallory, F.B. , Butler, K.E., Evans , A.C. and Mallory, C.W. (1996). Phenacenes: A Family of Graphite Ribbons. 1. Synthesis of Some [7]Phenacenes by Stilbene-like Photocyclizations , Tetrahedron Lett., 37: 7173—7176.
8.
Mallory, F.B. , Butler, K.E., Evans , A.C., Mallory, C.W., Yang, C. and Ellenstein, A. (1997). Phenacenes: A Family of Graphite Ribbons. 2. Synthesis of Some [7]Phenacene and an [11]Phenacene by Stilbene-like Photocyclization, J. Am. Chem. Soc., 119: 2119—2124.
9.
Mallory, F.B. , Butler, K.E., Berube , A., Luzik Jr, E.D.Mallory, C.W., Brondyke, E.J., Hiremath, R., Ngo , P. and Carroll, P.J. (2001). Phenacenes: A Family of Graphite Ribbons. Part 3. Iterative Strategies for the Synthesis of Large Phenacenes, Tetrahedron, 57: 3715—3724.
10.
Godt, A.J. (1997). Synthesis of Unsymmetrical 1,4-Diarylbutadiynes by Stille Coupling, Org. Chem., 62: 7471—7474.
11.
Casado, A.L. and Espinet, P. (1998). Mechanism of the Stille Reaction. 1. The Transmetalation Step. Coupling of R1I and R 2SnBu3 Catalyzed by trans-[PdR1IL 2] (R1 = C6Cl2F3; R 2 = Vinyl, 4-Methoxyphenyl; L = AsPh3), J. Am. Chem. Soc., 120: 8978—8985.
12.
Tsai, S.W. (1966). Mechanics of Composite Materials, Report No. AFML-TR-66—149 , Air Force Materials Laboratory, Wright Patterson Air Force Base, OH.
13.
Halpin, J.C. and Tsai, S.W. (1967). Environmental Factors in Composite Materials Design, Report No. AFML TR 67—423, Air Force Materials Laboratory , Wright Patterson Air Force Base, OH.
14.
Tsai, S.W. and Pagano, N.J. (1968). In: Tasi, S.W. and Fagano, N.J. (eds), Composite Materials Workshop, pp. 233—352, Technomic Publishing Co., Lancaster, PA.
15.
Lavengood, R.E. and Goettler, L.A. (1972). Stiffness of Nonaligned Fiber Reinforced Composites, Report No. 886372, National Technical Information Service , Springfield, VA.
16.
Nielsen, L.E. (1974). Mechanical Properties of Polymers and Composites , Vol. 2, Ch. 8, Marcel Dekker , New York.
Gibson, R.F. (1994). Principles of Composites Material Mechanics, Chs . 3 and 6, McGraw-Hill, New York.
19.
Halpin, J.C. and Pagano, N.J. (1969). The Laminate Approximation for Randomly Oriented Fibrous Composites, J. Compos. Mater. , 3: 720—724.
20.
Christensen, R.M. and Waals, F.M. (1972). Effective Stiffness of Randomly Oriented Fibre Composites, J. Compos. Mater., 6: 518—532.
21.
Weng, G.J. and Sun, C.T. (1979). In: Tsai, S.W. (ed.), Composite Materials: Testing and Design (Fifth Conference), pp. 149—162, ASTM STP 674, American Society for Testing and Materials , Philadelphia.
22.
Christensen, R.M. (1976). Asymptotic Modulus Results for Composites Containing Randomly Oriented Fibers, Int. J. Solids Structures, 12: 537—544.
23.
Wu, T.T. (1966). The Effect of Inclusion Shape on the Elastic Moduli of a Two-Phase Material, Int. J. Solids Structures, 2: 1—8.
24.
Pauling, L. (1948). Nature of the Chemical Bond, 2nd edn, Chs 3 and 5, Cornell University Press, Ithaca, NY.
25.
Moser, F.H. and Thomas, A.L. (1963). Phthalocyanine Compounds, Reinhold Publishing Company, New York.
26.
Tackley, D.R. , Dent, G. and Smith, W.E. (2001). Phthalocyanines: Structure and Vibrations, Phys. Chem. Chem. Phys., 3: 1419—1426.
27.
Badger, R.M. (1943). A Relation Between Internuclear Distance and Bond Force Constants, J. Chem. Phys., 2: 128—131.
28.
Badger, R.M. (1935). The Relation Between the Internuclear Distances and Force Constants of Molecules and Its Application to Polyatomic Molecules, J. Chem. Phys., 3: 710—714.
29.
Ubbelohde, A.R. and Lewis, F.A. (1960). Graphite and Its Crystal Compounds, Ch. 2, Oxford University Press, London.
30.
Kelly, B.T. (1981). Physics of Graphite, Applied Science, Englewood, MI.
31.
Van Lier, G. , Van Alsenoy, C., Van Doren, V. and Geerlings, P. (2000). Ab Initio Study of the Elastic Properties of Single-walled Carbon Nanotubes and Graphene, Chem. Phys. Lett., 326: 181—185.
32.
Yu, M.F. , Files, B.S., Arepalli , S. and Ruoff, R.S. (2000). Tensile Loading of Ropes of Single Wall Carbon Nanotubes and their Mechanical Properties, Phys. Rev. Lett., 84: 5552—5555.
