The purpose of this study is to develop a better understanding of the main mechanisms controlling the foaming of poly(ε-caprolactone) (PCL), a semi-crystalline biodegradable polymer, using batch processing and CO 2 as the physical blowing agent. A detailed study of the dissolution of CO2 is conducted in order to establish its impact on the transition temperatures of PCL. In a following step, particular attention is paid to the effects of crystallization on cell structure. This foam structure is subsequently linked to the processing window, expressed in terms of the processing temperature with respect to the shifted crystallization temperature and modified crystallization kinetics of PCL. The effects of talc addition on PCL crystallization and foam structure are also investigated, as talc is expected to modify the nucleation rate of crystallites and cells.
Alavi, S.H., Rizvi, S.S.H. and Harriott, P. (2003). Process Dynamics of Starch-Based Microcellular Foams Produced by Supercritical Fluid Extrusion. II: Numerical Simulation and Experimental Evaluation, Food. Res. Int., 36(4): 321—333.
2.
Constant, D.R. (1999). Crystallization Effects on Foamability of Polyethylenes-Relating Crystallization Kinetics to Processing of Low Density Foams, FOAMS, Parsippany, NJ, pp. 111—129.
3.
Witten, N. (1998). Extending the Conventional Boundaries of Crosslinked Polyolefin Foam Production, FOAMPLAST, May 19—20, Teaneck, New Jersey, USA, pp. 71—85.
4.
Baldwin, B.F. , Shimbo, M. and Suh, N.P. (1995). The Role of Gas Dissolution and Induced Crystallization During Microcellular Polymer Processing: A Study of Poly(ethylene terephthalate) and Carbon Dioxide Systems, J. Eng. Mater. Tech., 17(1): 62—74.
5.
Colton, J.S. (1989). The Nucleation of Microcellular Foams in SemiCrystalline Thermoplastics, Mtls. Manuf. Proc. , 4(2): 253—262.
6.
Doroudiani, S., Park, C.P. and Kortschot , M.T. (1996). Effect of the Crystallinity and Morphology on the Microcellular Foam Structure of Semicrystalline Polymers, Polym. Eng. Sci., 36(21): 2645—2662.
7.
Migozuchi, K. , Hirose, T., Maito, Y. and Kamiya, Y. (1987). CO2-Induced Crystallization of Poly(ethylene terephthalate), Polymer, 28(8): 1298—1302.
8.
Takada, M., Tanigaki, M. and Ohshima, M. (2001). Effects of CO2 on Crystallization Kinetics of Semi-crystalline Polymers, PPS-17, Montreal, Canada, paper 58.
9.
Schultze, J.D. , Engelmann, A.D., Boehning, M. and Springer, J. (1991). Influence of Sorbed Carbon Dioxide on Transition Temperature of Poly(p-Phenylene Sulphide), Polym. Adv. Technol., 2(3): 123—126.
10.
Handa, Y.P. , Zhang, Z. and Wong, B. (1997). Effect of Compressed CO2 on Phase Transition and Polymorphism in Syndiotactic Polystyrene, Macromolecules,30(26): 8499—8504.
11.
Handa, Y.P. , Zhang, Z. and Roovers, J. (2001). Compressed-Gas-Induced Crystallization in Tert-butyl Poly(ether ether ketone), J. Polym. Sci. Part B Polym. Phys., 39(13): 1505—1512.
12.
Di Maio, E., Iannace, S., Di, Y., Del Giacomo, E. and Nicolais, L. (2003). Heterogeneous Bubble Nucleation in PCL/Clay Nanocomposites Foams, Plast. Rubber Compos. Process Appl., 32(7): 313—317.
13.
Di Maio, E., Mensitieri, G., Iannace, S., Nicolais, L., Li, W. and Flumerfelt, R.W. (2005). Structure Optimization of Polycaprolactone Foams by Using Mixtures of CO2 and N2 as Blowing Agents , Polym. Eng. Sci., 45(3): 432—441.
14.
Xu, Q., Ren, X., Chang, Y., Wang, J., Yu, L. and Dean, K. (2004). Generation of Microcellular Biodegradable Polycaprolactone Foams in Supercritical Carbon Dioxide, J. Appl. Polym. Sci. , 94(2): 593—597.
15.
Reignier, J., Gendron, R. and Champagne, M.F. (2004). Foaming of Poly(ε-caprolactone) in Batch Processing Using Carbon Dioxide, FOAMS, Wilmington, DE, October 5—6.
16.
TONE P787 Polymer, Technical data sheet, Dow Chemical Company , form No. 321-00052.
17.
Berens, A.R. and Huvard, G.S. (1989). Interaction of Polymers with Near-Critical Carbon Dioxide, Supercrit. FluidSci. Technol., 406(14): 208—223.
18.
Saltikov, S.A. (1967). The Determination of the Size Distribution of Particles in an Opaque Material from a Measurement of the Size Distribution of their Sections, Int. Cong. Stereology, Helias, New York.
19.
Cotugno, S. , Di Maio, E., Ciardiello, C., Iannace, S., Mensitieri, G. and Nicolais, L. (2003). Sorption Thermodynamics and Mutual Diffusivity of Carbon Dioxide in Molten Polycaprolactone, Ind. Eng. Chem. Res., 42(19): 4398—4405.
20.
Shieh, Y.T. and Liu, J.H. (2003). The Effect of Carbonyl Group on Sorption of CO2 in Glassy Polymers, J. Supercrit. Fluids, 25(3): 261—268.
21.
Kazarian, S.G. , Vicent, M.F., Bright, F.V., Liotta, C.L. and Eckert, C.A. (1996). Specific Intermolecular Interaction of Carbon Dioxide with Polymers, J. Am. Chem. Soc., 118(7): 1729—1736.
22.
Sarbu, T., Styranec, T.J. and Beckman, E.J. (2000). Design and Synthesis of Low Cost, Sustainable CO2-philes, Ind. Eng. Chem. Res., 39(12): 4678—4683.
23.
Crank, J. (1975). The Mathematics of Diffusion, Clarendon Press, Oxford, pp. 203—253.
24.
Crescenzi, V., Manzini, G., Calzotari, G. and Borri, C. (1972). Thermodynamics of Fusion of Poly-β-propiolactone and Poly-ε-caprolactone. Comparative Analysis of the Melting of Aliphatic Polylactone and Polyester Chains, Eur. Polym. J., 8(3): 449—463.
25.
Zhang, Z. and Handa, Y.P. (1997). CO2-Assisted Melting of Semicrystalline Polymers , Macromolecules,30(26): 8505—8507.
26.
Park, C.B., Cheung, L.K. and Song, S.W. (1998). The Effect of Talc on Cell Nucleation in Extrusion Foam Processing of Polypropylene with CO2 and Isopentane, Cell. Polym., 17(4): 221—251.
27.
Matuana, M.L. , Park, C.B. and Balatinecz , J.J. (1997). Processing and Cell Morphology Relationships for Microcellular Foamed PVC/Wood-Fiber Composites, Polym. Eng. Sci., 37(7): 1137—1147.
28.
Arora, K.A. , Lesser, A.J. and McCarthy, J. (1998). Preparation and Characterization of Microcellular Polystyrene Foams Processed in Supercritical Carbon Dioxide , Macromolecules,31(14): 4614—4620.
29.
Gendron, R. and Daigneault, L.E. (2003). Continuous Extrusion of Microcellular Polycarbonate, Polym. Eng. Sci., 43(7): 1361—1377.
30.
Baldwin, D.F. , Park, C.B. and Suh, N.P. (1996). A Microcellular Processing Study of Poly(ethylene terephthalate) in the Amorphous and Semicrytalline States, Polym. Eng. Sci., 36(11): 1437—1445.
31.
Handa, Y.P., Zhang, Z., Nawaby, V. and Tan, J. (2001). Gas Solubility in and Foamability of Various Forms of Syndiotactic Polystyrene, Cell. Polym., 20(4): 241—253.
32.
Reignier, J., Tatibouët, J. and Gendron, R. (2006). Batch Foaming of Poly(ε-caprolactone) Using Carbon Dioxide: Impact of Crystallization on Cell Nucleation as Probed by Ultrasonic Measurements, Polymer, 47(14): 5012—5024.
