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Crystallization of Polytetrafluoroethylene in a Wide Range of Cooling Rates: Nucleation and Diffusion in the Presence of Nanosilica Clusters. Molecules 2019; 24:molecules24091797. [PMID: 31075909 PMCID: PMC6539400 DOI: 10.3390/molecules24091797] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/06/2019] [Accepted: 05/06/2019] [Indexed: 11/17/2022] Open
Abstract
Polytetrafluoroethylene (PTFE) is a polymer that displays exceptional properties. This synthetic fluoropolymer is also known to crystallize very fast upon cooling. The present work highlights for the first time the influence of nanosilica clusters on PTFE crystallization at fast cooling rates (up to 5000 K·s−1). The silica was synthesized from aqueous silicate solution and the surface modification was performed using TriEthoxyFluoroSilane (TEFS). In order to understand the crystallization behavior of PTFE/silica nanocomposite at a fast cooling rate, the measurements were carried out by Fast Scanning Calorimetry (FSC). The data were consequently combined with the measurements performed by conventional Differential Scanning Calorimetry (DSC). Interestingly, the results displayed variation of the crystallization behavior for the nanocomposite at fast cooling rates compared to slow cooling rates. The differences in crystal morphologies were then observed by Scanning Electron Microscopy (SEM) after slow and fast cooling rates. Finally, the effective activation energies (Eα) obtained from the crystallization under various cooling rates were combined in order to obtain one set of Hoffman-Lauritzen parameters. This procedure allowed us to show that the crystallization of PTFE in the presence of silica is promoted or hampered according to the cooling rates employed.
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Unique behavior of in-situ generated nanosilica particles on physico-mechanical properties of fluoroelastomer. JOURNAL OF POLYMER RESEARCH 2018. [DOI: 10.1007/s10965-018-1629-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Zhang S, Li Q, Liu Y, Wu C, Guo W. Polytetrafluoroethylene (PTFE)/carbon black (CB) microporous membranes produced from PTFE/CB composite particles prepared by heterocoagulation process. HIGH PERFORM POLYM 2016. [DOI: 10.1177/0954008316629724] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Polytetrafluoroethylene (PTFE)/carbon black (CB) microporous membranes with excellent properties were successfully prepared via heterocoagulation process and mechanical stretching method. Heterocoagulation was achieved using PTFE emulsion with 26% solid content, an intermediate product of the commercial PTFE dispersions with 60% solid content, and CB dispersions to prepare PTFE/CB composite particles by mechanical stirring, which is the unique content in this article. Furthermore, in order to obtain uniform distribution of CB particles within the membrane matrix as well as improve color uniformity and mechanical strength of the microporous membranes, CB was pretreated by a titanate coupling agent (NDZ-201). The PTFE/CB composite particles were then used to prepare the PTFE/CB microporous membranes via mechanical stretching operation. Several important properties of the prepared PTFE/CB microporous membranes, such as tensile strength, porosity, contact angles, morphology, and dynamic mechanical properties, were investigated. Results showed that the fabricated PTFE/CB microporous membranes possessed color uniformity, high tensile strength, and high hydrophobicity.
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Affiliation(s)
- Shijie Zhang
- Shanghai key Laboratory of Polymeric Materials, Key Laboratory of Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Qiuying Li
- Shanghai key Laboratory of Polymeric Materials, Key Laboratory of Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Yujin Liu
- Shanghai key Laboratory of Polymeric Materials, Key Laboratory of Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Chifei Wu
- Shanghai key Laboratory of Polymeric Materials, Key Laboratory of Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
| | - Weihong Guo
- Shanghai key Laboratory of Polymeric Materials, Key Laboratory of Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China
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