Abstract
The effect of extension ratio on the structure and property of expanded polytetrafluoroethylene (ePTFE) has been decisively studied. ePTFE is unique with its porous fibrillar network structure connected by nodes and also with its degree of orientation which increases with increases in extension ratio. It is found that the Poisson’s ratio of ePTFE is negative, and it is reduced dramatically with increased extension ratio. At the extension ratio of 30, the Poisson’s ratio reaches − 10.00. By changes of extension ratio from 1 to 10, the segmental mobility of polymer chains becomes harder, and the dynamic glass transition temperature (T g) is increased. Broad glass transition regions are revealed in tan δ versus temperature curves in polytetrafluoroethylene specimens stretched 20- (S20) and 30-fold (S30). As the extension ratio is increased, the thermal conductivity of the specimens is decreased. The thermal conductivity coefficient is dropped to 0.051 W m−1 K owing to the appearance of more pores and low degree of crystallinity at higher extension ratio. The properties of ePTFE modified by carbonyl iron powder (CIP) have been investigated. CIP has affected the structure and properties of modified ePTFE. CIP-modified ePTFE also exhibits a negative Poisson’s ratio which is larger than ePTFE at the same extension ratio. The modified ePTFE reveals higher thermal conductivity coefficient than ePTFE itself.
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References
Brandel B, Lakes RS (2001) Negative Poisson’s ratio polyethylene foams. J Mater Sci 36:5885–5893
Alderson KL, Evans KE (1992) The fabrication of microporous polyethylene having a negative Poisson’s ratio. Polymer 33:4435–4438
Alderson KL, Webber RS, Kettle AP, Evans AE (2005) Novel fabrication route for auxetic polyethylene, part 1: processing and microstructure. Polym Eng Sci 45:568–578
Alderson KL, Alderson A, Smart G, Simkins VR, Davies PJ (2002) Auxetic polypropylene fibres, part 1: manufacture and characterization. Plast Rubber Compos 31:344–349
Gao Z, Dong X, Li N, Ren J (2017) Novel two-dimensional silicon dioxide with in-plane negative Poisson’s ratio. Nano Lett 17:772–777
Ma P, Chang Y, Jiang G (2016) Design and fabrication of auxetic warp-knitted structures with a rotational hexagonal loop. Text Res J 86:2151–2157
Aldred P, Moratti SC (2005) Dynamic simulations of potentially auxetic liquid-crystalline polymers incorporating swivelling mesogens. Mol Simul 31:883–887
Suzuki Y, Cardone G, Restrepo D, Zavattieri PD, Baker TS, Tezcan FA (2016) Self-assembly of coherently dynamic, auxetic, two-dimensional protein crystals. Nature 533:369–373
Ingrole A, Hao A, Liang R (2017) Design and modeling of auxetic and hybrid honeycomb structures for in-plane property enhancement. Mater Des 117:72–83
Wang H, Ding S, Zhu H, Wang F, Guo Y, Zhang H, Chen J (2014) Effect of stretching ratio and heating temperature on structure and performance of PTFE hollow fiber membrane in VMD for RO brine. Sep Purif Technol 126:82–94
Huang J, Lee YH (2001) Evaluation of uni-axially expanded PTFE as a gasket material for fluid sealing applications. Mater Chem Phys 70:197–207
Lin JH, Huang CL, Li TT, Lee YM, Wu ZH, Lou CW (2015) Extended PTFE fabrics used as high-temperature filter clothes: manufacturing technique and chemical stability evaluation. J Text Inst 106:793–799
Zhong Z, Xu Z, Sheng T, Yao J, Xing W, Wang Y (2015) Unusual air filters with ultrahigh efficiency and antibacterial functionality enabled by ZnO nanorods. ACS Appl Mater Interfaces 7:21538–21544
Bota PCS, Collie AMB, Puolakkainen P, Vernon RB, Sage EH, Ratner BD, Stayton PS (2010) Biomaterial topography alters healing in vivo and monocyte/macrophage activation in vitro. J Biomed Mater Res A 95:649–657
Alderson A, Alderson KL (2007) Auxetic materials. Proc Inst Mech Eng Part G J Aerosp Eng 221:565–575
Choi JB, Lakes RS (1991) Design of a fastener based on negative Poisson’s ratio foam. Cell Polym 10:205–212
Scarpa F, Ruzzene M, Soranna F (2002) Wave beaming effects in bi-dimensional cellular structures. Proc SPIE Int Soc Opt Eng 4697:63–77
Shan S, Kang SH, Zhao Z, Fang L, Bertoldi K (2015) Design of planar isotropic negative Poisson’s ratio structures. Extreme Mech Lett 4:96–102
Cassady AI, Hidzir NM, Grøndahl L (2014) Enhancing expanded poly(tetrafluoroethylene) (ePTFE) for biomaterials applications. J Appl Polym Sci 131:1–14
Ranjbarzadeh-Dibazar A, Barzin J, Shokrollahi P (2017) Microstructure crystalline domains disorder critically controls formation of nano-porous/long fibrillar morphology of ePTFE membranes. Polymer 121:75–87
Huang C, Chen L (2016) Negative Poisson’s ratio in modern functional materials. Adv Mater 28:8079–8096
Jin C, Zhong C (2013) Application of Fourier transform in nanofiber orientation measurement. J Text Res 34:34–38
Caddock BD, Evans KE (1989) Microporous materials with negative Poisson’s ratios, I: microstructure and mechanical properties. J Phys D Appl Phys 22:1877–1882
Han ZW, Zhang DZ, Yang QX, Wang BF (2011) Textbook of polymer science. East China University of Science and Technology Press, Shanghai
Ju B, Tang R, Zhang D, Yang B, Yu M, Liao C, Yuan X, Zhang L (2016) Dynamic mechanical properties of magnetorheological elastomers based on polyurethane matrix. Polym Compos 37:1587–1595
Yang H, Wei B, Yan G, Xiao Y (2005) Analysis of influence factor of polymer thermal conductivity. Plast Ind 33:1–4
Smith DS, Alzina A, Bourret J, Nait-Ali B, Pennec F, Tessier-Doyen N, Otsu K, Matsubara H, Elser P, Gonzenbach UT (2013) Thermal conductivity of porous materials. J Mater Res 28:2260–2272
Liu X, Zheng C, Huang C (2009) Analysis of influencing factors of thermal conductivity of porous. Low Temp Arch Technol 31:121–122
Choi KJ, Spruiell JE (2010) Structure development in multistage stretching of PTFE films. J Polym Sci B Polym Phys 48:2248–2256
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This work was supported by the National Natural Science Foundation of China (Grant no. 51003209).
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Xu, C., Tu, Y., Yu, R. et al. Expanded polytetrafluoroethylene as an auxetic material: effect of extension ratio on its structure and properties. Iran Polym J 27, 49–56 (2018). https://doi.org/10.1007/s13726-017-0581-6
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DOI: https://doi.org/10.1007/s13726-017-0581-6