Ernesto Di Maio

Ernesto Di Maio
University of Naples Federico II | UNINA · Department of Chemical, Materials and Production Engineering

PhD

About

137
Publications
16,737
Reads
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3,252
Citations
Additional affiliations
June 2015 - present
University of Naples Federico II
Position
  • Professor (Associate)
January 2004 - February 2015
University of Naples Federico II
Position
  • Professor (Assistant)
September 2001 - January 2004
Italian National Research Council
Position
  • Research Associate

Publications

Publications (137)
Book
Foaming with Supercritical Fluids, Volume Nine provides a comprehensive description of the use of supercritical fluids as blowing agents in polymer foaming. To this aim, the fundamental issues on which the proper design and control of this process are rooted are discussed in detail, with specific attention devoted to the theoretical and experimenta...
Article
This study investigates the influence of air bubbles inclusion on the foaming of water blown and water-pentane blown rigid polyurethane and polyisocyanurate foams. It was observed that, when a large number of air bubbles were included in the reacting system during the mixing stage (fast mixing), no further bubble nucleation from water reaction or p...
Article
This study investigates the effect of liquid-type organofluorine additives (OFAs) on the morphology, thermal conductivity and mechanical properties of rigid polyurethane (PU) and polyisocyanurate (PIR) foams. Foams were characterized in terms of their morphology (density, average cell size, anisotropy ratio, open cell content), thermal conductivity...
Article
Full-text available
The incorporation of graphene-related materials as nanofiller can produce multifunctional foams with enhanced specific properties and density reduction. Herein we report on the preparation of microcellular thermoplastic polyurethane/graphene foams by batch foaming. Solution blending was first adopted to disperse graphene nanoplatelets (GNP) in the...
Article
Thermosetting polyurethane foams are nowadays produced with typical bubble size, d >150 μm, with plenty of room for improvement towards the cellular structure refinement, to gain, among others, in the thermal insulation performances. We herein report a first example of a microcellular thermosetting polyurethane foam, i.e. with bubble size below 5 μ...
Article
Full-text available
A seguito dell’epidemia da COVID-19, in Italia l’art. 15 del decreto-legge 17 marzo 2020 n. 18 ha permesso di produrre, importare e immettere in commercio mascherine chirurgiche in deroga alle vigenti disposizioni mediante l’invio all’Istituto Superiore di Sanità di una autocertificazione da parte dei soggetti interessati nella quale siano attestat...
Article
During COVID-19 pandemic crisis, Italian Government has approved Law Decree no. 18 of 17 march 2020, in which art. 15 allows enterprises to produce, import and commercialize surgical masks notwithstanding the current rules of product certification. It is just required that the interested enterprises send to the Italian National Institute of Health...
Patent
Full-text available
Processes for producing a polyurethane foam described herein include mixing a physical blowing agent with one or more of an isocyanate-reacting mixture and an isocyanate at a sorption pressure psorp for a time tsorp, reacting the isocyanate-reacting mixture and the isocyanate at a pressure p1 for a time t1, reducing the pressure to a pressure p2, m...
Article
The lattice fluid theory is used to develop transport property-structure correlations for glassy perfluoropolymers with dioxolane pendant rings, a new class of membrane materials for gas separation. Poly(perfluoro-2-methylene-1,3-dioxolane) (poly(PFMD)) and poly(perfluoro-2-methylene-4-methyl-1,3-dioxolane) (poly(PFMMD)) exhibit lower permeability,...
Article
Full-text available
A procedure for imaging the complex fluid dynamics in bubbles could greatly assist efforts to understand and exploit thin liquid films in applications ranging through medicine, industrial chemistry and engineering. Thin liquid films are ubiquitous in nature, found in such varied systems as soap bubbles, biological membranes, detergents, oils, insul...
Article
We developed a novel method to produce microcellular thermosetting polyurethane foaming by the gas-foaming technique using high-pressure physical blowing agents. In particular, to tackle the inherent difficulties of imposing a rapid pressure quench O(10^-2 s) to a material whose synthesis timing is much larger O(10^2 s), we utilized a two-stage foa...
Article
We developed a novel method to produce microcellular thermosetting polyurethane foaming by the gas-foaming technique using high-pressure physical blowing agents. In particular, to tackle the inherent difficulties of imposing a rapid pressure quench O(10^-2 s) to a material whose synthesis timing is much larger O(10^2 s), we utilized a two-stage foa...
Article
In tissue engineering, the use of supercritical CO2 foaming is a valuable and widespread choice to design and fabricate porous bioactive scaffolds for cells culture and new tissue formation in three dimensions. Nevertheless, the control of scaffold pores size, shape and spatial distribution with foaming technique remains, to date, a critical limiti...
Conference Paper
Full-text available
In questo lavoro, sono state prodotte schiume poliuretaniche rigide microcellulari mediante utilizzo di CO2 come agente espandente fisico. In particolare, per affrontare le difficoltà che incorrono quando una rapida depressurizzazione O(10^-2 s) viene applicata ad un materiale il cui tempo di sintesi è molto più grande O(10^2 s), è stato sviluppato...
Conference Paper
Full-text available
This study investigates the effect of air bubbles inclusion on the foaming process of pentane blown polyurethane (PU) and polyisocyanurate (PIR) foams. A methodical approach was developed in order to in-situ monitor the bubble nucleation and growth mechanisms. Results revealed that when a significant number of air bubbles is introduced in the react...
Conference Paper
Full-text available
The aim of the present study was the introduction of a novel method to produce microcellular thermosetting polyurethane foaming by the gas-foaming technique, using high-pressure physical blowing agents. In particular, to tackle the inherent difficulties of imposing a rapid pressure quench O(10^-2 s) (where O stands for order of magnitude) to a mate...
Article
Graphene wetting by polymers is a critical issue to both the success of polymer-aided transfer of large size sheets onto specific substrates and to the development of well performing nanocomposites. Here we show for the first time that high temperature contact angle measurements can be performed to investigate the wettability of CVD graphene by mol...
Article
The effect of CO2 on the polyurethane synthesis between a polyol and an isocyanate was studied by in situ near infrared spectroscopy in a newly developed instrumented foaming equipment. In particular, first two solutions, namely a polyol/CO2 solution and an isocyanate/CO2 solution were formed at high pressure and then, upon mixing, the synthesis wa...
Conference Paper
Full-text available
The aim of the present study was the introduction of a novel method to produce microcellular thermosetting polyurethane foaming by the gas-foaming technique, using high-pressure physical blowing agents. In particular, to tackle the inherent difficulties of imposing a rapid pressure quench O(10-2 s) to a material whose synthesis timing is much large...
Article
Layered and graded foams have proven superior to their uniform counterparts in terms of structural, and functional properties. This is also suggested by nature, abundant with porous material structures whose attributes are far beyond any artificial foam. To date, advanced foamed structures are generated via advanced though complex/time consuming te...
Conference Paper
Digital holographic microscopy (DHM) has become a technique utilized widely for sample inspection, having many applications in different fields of science and technology. The capability for recovering the complex amplitude distribution scattered by the sample permits numerical refocus after acquisition and quantitative phase imaging. These are two...
Conference Paper
The dynamics of thin films and bubbles are of great interest in life sciences. Here we show an innovative holographic technique to evaluate the 3D topography and its temporal evolution in these systems.
Conference Paper
Computation tools allow to enforce 3D imaging through thus making digital holography a powerful metrology instrument in science and technology of liquid bubbles and films.
Article
Full-text available
The thickness of thin liquid films is of great interest to industrial processes and life science. However, there are not appropriate quantitative experimental tools for an adequate study of film evolution in case of not-ideal conditions. Here, we show the application of a holographic system for the evaluation of the 3D topography and thickness of e...
Preprint
The dynamics and stability of thin liquid films have fascinated scientists over many decades. Thin film flows are central to numerous areas of engineering, geophysics, and biophysics and occur over a wide range of length, velocity, and liquid properties scales. In spite of many significant developments in this area, we still lack appropriate quanti...
Article
In the underlying literature, bubble coalescence has been so far observed at the latest foaming stages, where bubble growing causes large extensional loads on the polymer film between two neighboring bubbles and eventually leads to the film rupture and to the merging of the two bubbles in a single one. This phenomenon is responsible for the coarsen...
Article
When a Newtonian bubble ruptures, the film retraction dynamics is controlled by the interplay of surface, inertial and viscous forces. In case a viscoelastic liquid is considered, the scenario is enriched by the appearance of a new significant contribution, namely, the elastic force. In this paper, we investigate experimentally the retraction of vi...
Conference Paper
Full-text available
In a newly developed sensorized pressure vessel, polyurethane synthesis under high-pressure carbon dioxide was studied by using in-situ near infrared spectroscopy. In particular, the equipment is capable of keeping the two components of the polyurethane reaction (polyol and isocyanate) separate during CO2 sorption, by making use of a rubber impelle...
Conference Paper
Thin-film drainage process has been studied by a digital holographic recording system. In this study, trajectories of three particles inside a bubble film are revealed by holographic 3D tracking during the bubble growth.
Conference Paper
The dynamics of thin liquid films are of great interest to industrial processes and life science. Here we propose a holographic system for the evaluation of the 3D topography and thickness of evolving thin liquid film.
Article
In this paper, we examine the state of the art of the physical foaming of polymers with supercritical fluids with a primary focus on carbon dioxide. We provide a critical analysis of the current research pathways and the main scientific open questions. We discuss the knowledge gaps along with technological challenges for further advances. Perspecti...
Article
Polyurethane foams are typically obtained by reacting a polyisocyanate with a polyol and the foamed structure derives from a blowing reaction concurrent to the polymerization reaction. The blowing stage makes use of chemical and physical blowing agents, among which ozone-depleting or flammable gases are being substituted with eco-friendly and safe...
Article
This paper presents insight in bubble nucleation in polymer foaming with physical blowing agent using a batch foaming technique. In our experiments the bubble nucleation is triggered by a sudden pressure drop that causes the supersaturation in the polymer gas solution. In fact, the pressure drop rate is an important process variable since it plays...
Article
In this work, we introduce the use of selective microwave heating to solve the problems of conventional heating systems, such as non-uniformity and thickness restriction, in classical thermoplastic foaming methods. To do so, carbon nanotubes (CNTs) are used as microwave absorbers in a transparent polymer media. When irradiated, CNTs are responsible...
Article
In this paper, we investigate the retraction of a circular viscoelastic liquid film with a hole initially present in its center by means of finite element numerical simulations. We study the whole retraction process, aiming at understanding the hole opening dynamics both when the hole does not feel any confinement and when it interacts with the sol...
Article
In this study, arabinoxylan extracted from barley husks was reacted with polyethylene glycol (PEG) of various molecular weights to introduce an internal plasticizer into the polymer matrix. A successful PEGylation reaction was identified using FTIR and elemental analysis. Thermal and mechanical properties were studied using dynamic mechanical analy...
Conference Paper
In this paper, we propose digital holography in transmission configuration as an effective method to measure the time-dependent thickness of polymeric films during bubble blowing. We designed a complete set of experiments to measure bubble thickness, including the evaluation of the refractive index of the polymer solution. We report the measurement...
Article
We herein report the design of an apparatus for studying the concurrent chemo-physical processes occurring during gas foaming of thermosetting polymers. In particular, to address the recent interest in combining the gas (physical) foaming with the classical (chemical) polyurethane foaming, a novel instrumented pressure vessel was designed for inves...
Article
Two types of lignin, alkali lignin and lignosulfonic acid sodium salt, are blended into thermoplastic zein through melt mixing in order to develop biodegradable insulator materials for multifunctional applications in electronics. The effects of lignin type and content on the dielectric properties of the resulting bio-nanocomposites are investigated...
Article
Bio-nanocomposite films based on the vegetable protein, zein, and natural fillers, lignin derivatives, are potential candidates to produce biodegradable dielectric materials for transient, temporary, electronics. The dielectric properties of the biodegradable dielectrics can be tuned by modulating the film formulation and the typology of Lignin der...
Article
In this work a design tool to control cell-opening in gas foaming of thermoplastic polymers is developed. The sequence of events following bubble nucleation, namely, bubble growth and impingement, are modeled to gain a comprehensive, perspective view on the mechanisms of bubble wall rupture and on the conditions for achieving a fully open-cell morp...
Article
The mechanical properties of a polyurethane-cement hybrid foam are investigated. The hybrid foam, based on the combined, synergic use of rigid polyurethane foam and portland cement, was introduced for application in the building field. Thermal and acoustic insulation properties, water vapor permeability, and the fire resistance of the material have...
Article
In this article, we reports the effects of the processing conditions on the morphological and hollow attributes of polystyrene micrometric hollow particles produced by the use of a recently developed technique based on the gas foaming of spherical, dense particles. By modulating the foaming temperature and saturation pressure, we produced hollow pa...
Article
In the present study, a Raman line-imaging setup was employed to monitor in situ the CO2 sorption at elevated pressures (from 0.62 to 7.10 MPa) in molten PCL. The method allowed the quantitative measurement of gas concentration in both the time-resolved and the space-resolved modes. The combined experimental and theoretical approach allowed a molec...
Article
In this work, we demonstrate the feasibility of micrometric asymmetric reservoirs made of thermoplastic polymers by using the gas foaming method, which has been recently introduced, and consists in forming bubbles in micro- or nano-metric bulk particles as is done with carbonated drinks. As this simplicity anticipates, this represents a breakthroug...
Article
In this work we investigate the sorption of CO2 in a formulated polyether polyol, typically used to obtain rigid polyurethane foams when it reacts with isocyanates. In particular, by using a fully-experimental, coupled gravimetry-Axisymmetric Drop Shape Analysis, solubility, mutual diffusivity, specific volume and interfacial tension of polyol/CO2...
Article
We studied the foaming of polystyrene with CO2 as the physical blowing agent at large pressure drop rates (PDRs) and at different foaming temperatures, with a novel batch foaming apparatus, capable of reaching PDRs as high as 500 MPa/s (in the underlying literature, the maximum so far achieved is 100 MPa/s). Results show that, at each foaming tempe...
Article
Tissue engineering is one of the major challenges of orthopedics and trauma surgery for bone regeneration. Biomaterials filled with mesenchymal stem cells (MSCs) are considered the most promising approach in bone tissue engineering. Furthermore, our previous study showed that the multi-phase poly [ε-caprolactone]/thermoplastic zein-hydroxyapatite (...
Article
In this paper, we report the design of a new experimental apparatus for the study of the foaming process of thermoplastic polymers with physical blowing agents. The novel lab-scale batch foaming equipment is capable of achieving accurate control of the processing variables, namely, the temperature, the saturation pressure and the pressure drop rate...
Article
Full-text available
In this study, we evaluated the feasibility of producing bioplastics from blue maize (BM) and white sorghum (WS) flours by thermoplasticization using sorbitol and glycerol as plasticizers and by using extrusion and compression molding. The analyzed variables were screw speed rotation (50–70 rpm), extrusion temperature (100–140 °C), number of extrus...
Chapter
This chapter discusses the theoretical and experimental aspects related to the techniques for the preparation of scaffold by gas foaming of biodegradable polymers, of both natural and synthetic origin. Properties of polymer/gas solutions controlling nucleation and growth of gas bubbles are analysed in the first part of this chapter. In the second p...
Conference Paper
Abstract Different strategies to produce thermoplastic materials using starch and zein were studied, aiming to investigate their effect on the compatibility of starch and zein. The strategies comprised the use of two different plasticizers for starch, two different compatibilizing agents, and two blending procedures. The plasticizers were mixture...
Article
Recently, the specific volume of molten solutions of polycaprolactone and carbon dioxide (PCL/CO2) was measured by coupling gravimetric measurements with the observation of the swelling of a pendant drop. Quite interestingly, this approach highlighted a non-monotonic dependence of the specific volume of the solution on CO2 pressure. Herein, in orde...
Conference Paper
Full-text available
Background: Foams are high porosity and low density materials. In nature, they are a common architecture. Some of their relevant technological applications include heat and sound insulation, lightweight materials, and tissue engineering scaffolds. Foams derived from natural polymers are particularly attractive for tissue culture due to their biode...
Conference Paper
Mini-bioreactors have diverse applications in the field of biotechnology: screening of culture conditions, kinetic characterization of clones, and fundamental research in cell biology, among others. In this contribution, we illustrate the use of continuous mini-bioreactors for the culture of mammalian and yeast cells. In particular, we explore expe...
Conference Paper
We present proof-of-principle results of the use of continuous mini-reactors (1mL scale) for the production of monoclonal antibodies in adherent CHO cell cultures using zein-foams as the scaffold for cell adhesion. Zein foams were produced from thermo-plasticized zein exposed to supercritical CO2 foaming. CHO cells were able to colonize and proli...
Article
Full-text available
Different strategies to produce thermoplastic materials using starch and zein were studied, aiming to investigate their effect on the compatibility of starch and zein. Research strategies comprised the use of two different plasticizers for starch, two different compatibilizing agents, and two blending procedures. The plasticizers were mixtures of s...
Article
This paper presents the results of a first successful attempt to produce hollow micro- and nano-particles of a large variety of materials, dimensions, shapes and hollow attributes by using an environmentally friendly and cheap technology, common in polymer processing and known as gas foaming. The central role played by ad hoc polymeric hollow micro...
Conference Paper
The swelling behavior of molten poly(epsilon-caprolactone) in contact with carbon dioxide has been analyzed by using the pendant drop method. At subcritical pressures, the swelling kinetics of the polymer-gas solution follow the typical Fickian diffusion behavior, the volume approaching an equilibrium value after the initial transient. In supercrit...
Article
In this paper, we report data on PS foamed at 100 °C after CO 2 saturation at 10 MPa in a new physical foaming batch that achieves pressure drop rates up to 120 MPa/s. Results show how average cell size of the foam nicely fit a linear behavior with the pressure drop rate in a double logarithmic plot. Furthermore, foam density initially decrease...