Lombardi, Lorenzo (2023) Foam-enhanced polymer devolatilization. From single bubble analysis to high-efficiency devolatilizer. [Tesi di dottorato]
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| Item Type: | Tesi di dottorato |
|---|---|
| Resource language: | English |
| Title: | Foam-enhanced polymer devolatilization. From single bubble analysis to high-efficiency devolatilizer |
| Creators: | Creators Email Lombardi, Lorenzo lorenzo.lombardi@unina.it |
| Date: | 10 March 2023 |
| Number of Pages: | 162 |
| Institution: | Università degli Studi di Napoli Federico II |
| Department: | Ingegneria Chimica, dei Materiali e della Produzione Industriale |
| Dottorato: | Ingegneria dei prodotti e dei processi industriali |
| Ciclo di dottorato: | 35 |
| Coordinatore del Corso di dottorato: | nome email D'Anna, Andrea anddanna@unina.it |
| Tutor: | nome email Maffettone, Pier Luca UNSPECIFIED Tammaro, Daniele UNSPECIFIED |
| Date: | 10 March 2023 |
| Number of Pages: | 162 |
| Keywords: | devolatilization, separation, polymers, foams, bubbles |
| Settori scientifico-disciplinari del MIUR: | Area 09 - Ingegneria industriale e dell'informazione > ING-IND/26 - Teoria dello sviluppo dei processi chimici |
| Date Deposited: | 21 Mar 2023 09:42 |
| Last Modified: | 10 Apr 2025 12:42 |
| URI: | http://www.fedoa.unina.it/id/eprint/15070 |
Collection description
Most polymerization products must undergo a devolatilization process designed to remove solvents and residual monomers to comply with environmental regulations. Under very stringent process conditions such as high temperature and vacuum, a multiphase gas-liquid system occurs, such as a foam. Although nonaqueous foams have recently received attention, the influence of volatile components lacks the fundamental understanding to control foam properties. In this dissertation, the process of static devolatilization of polymers is treated in its design aspects. A new tabletop static devolatilizer is presented to measure separation efficiency under various operating conditions. The measurement capabilities of the equipment are demonstrated by varying the initial concentration of volatiles, the degree of vacuum, and the design of the equipment. Work was also done to improve the current understanding of the thermodynamics and kinetics of gas sorption in commercial elastomers commonly found in devolatilization processes. Experimental sorption isotherms were interpreted using the non-random lattice fluid equation of state. Absorption kinetics were also studied and interpreted using a Fick's model that determines values of mutual diffusivity as a function of temperature and mixture composition. Another study was performed as part of this dissertation to investigate the physical mechanism leading to foam stabilization and liquid film drainage in binary mixtures with volatile compounds. Using an improved interferometry apparatus, we show that the foamability of polymer-volatile mixtures can be assessed by single bubble experiments. Two different solvents with different degrees of volatility were investigated, shedding light on surface bubble stabilization mechanisms.
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