Polymer-based dielectric composites have become a hot topic in recent years due to their high-power density and high breakdown strength. However, some disadvantages still exist in some typical monopolymers, which are not conductive to improving the energy storage performances significantly, such as high energy loss of PVDF and low polarization of PMMA. Based on the good compatibility of PMMA and PVDF, this paper proposes a binary polymer blending strategy to improve the polarization and energy storage properties of the dielectric composite. The influences of volume content of PMMA in PVDF and heat treatment temperature during the fabrication process on the microstructure, polarization behaviors and energy storage performances of the PMMA blended PVDF composites (abbreviated as PMMA/PVDF) are systematically investigated. Fortunately, when the heat treatment temperature was 150 °C, the binary blending composite of PMMA/PVDF with a PMMA content of 50 vol% possessed an excellent storage density of 20.1 J cm−3 at 570 kV mm−1, and an energy storage efficiency of 63.5%. This study provides an effective method for designing polymer materials with excellent energy storage properties.

A blended binary composite of poly(vinylidene fluoride) and poly(methyl methacrylate) exhibiting excellent energy storage performances

https://hal.archives-ouvertes.fr/hal-02064079/document

On the miscibility of PVDF/PMMA polymer blends: Thermodynamics, experimental and numerical investigations

In this study, a new hybrid artificial intelligence approach is proposed to model the ultrasonic welding of a polymeric material blend. The proposed approach is composed of an ensemble random vector functional link model (ERVFL) integrated with a gradient-based optimizer (GBO). First, welding experiments were conducted on acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) blends produced by the injection molding method. The experiments were designed according to the L27 orthogonal array considering three process factors (applied pressure, welding time, and vibration amplitude) and two responses (average temperature and joint strength). Then, the obtained experimental data were used to train the developed model. To verify the accuracy of the model, it was compared with standalone ERVFL in addition to two fine-tuned ERVFL models (ERVFL-SCA and ERVFL-MRFO) in which ERVFL is incorporated with sine cosine algorithm (SCA) or Manta ray foraging optimization (MRFO). The four models were evaluated using five statistical tools. ERVFL-GBO has the highest coefficient of determination and the lowest root mean square error, mean relative error mean absolute error, and coefficient of variance compared with other models which indicate its high accuracy over other tested models.

Modeling ultrasonic welding of polymers using an optimized artificial intelligence model using a gradient-based optimizer

A PC/ABS blend was used to prepare hybrid composites reinforced with the use of a biocarbon/carbon fiber (BC/CF) system. The purpose of using blends of this type was to reduce the degradation of PC during the blending processes, which turned out to be effective already at 40% ABS in the blend structure. TGA analysis and rheological measurements confirmed that the addition of ABS in the matrix structure allowed reduction of PC hydrolytic degradation. The decrease in DTG peak value for the PC/20BC composite is even 50 °C, whereas for the ABS/20BC sample the peak values were the same as reference pure ABS. Izod tests showed that the impact resistance for ABS/BC composites was more than twice as high as PC/BC materials, 37 J/m to 13 J/m respectively. For PC/ABS composites, the addition of ABS in the structure also served to improve impact resistance. The main purpose of the hybridized reinforcement application was the reduction of thermal expansion in the material and homogenization of the fibrous CF structures. For reference PC/20CF samples the difference in CLTE values is over 1000%, while for PC/20(BC-CF) hybrid composites it is reduced below 300%. Detailed analysis of the expansion characteristics, carried out by TMA methodology, showed significant improvement in the isotropy of hybrid materials, which was also confirmed by structural observations. The improvement of process stability as well as excellent thermomechanical parameters indicates that biocarbon can be an excellent additive for standard fibrous reinforcement, limiting the phenomenon of structure anisotropy.

Development of hybrid composites reinforced with biocarbon/carbon fiber system. The comparative study for PC, ABS and PC/ABS based materials

Dielectric behaviour of the polymer nanocomposite (PNC) films comprise alumina (Al2O3) and silica (SiO2) nanoparticles (1, 3, and 5 wt%) dispersed in poly(methyl methacrylate) (PMMA) matrix was investigated in the frequency span of 20 Hz to 1 MHz at 30 °C and also with temperature variation (30–60 °C) for the 3 wt% nanofillers containing PNC films. Some changes in the dielectric permittivity and electrical conductivity were observed with the increase of nanofiller content, frequency variation, and rise in temperature of these films. Electric modulus spectra confirmed a broad relaxation peak at the lower frequencies for the Al2O3 loaded PNC films which attribute to the PMMA bulky side ester groups rotation, whereas this relaxation was not observed for the SiO2 filled PNC films in the same experimental frequency range. The UV–Vis absorbance, transmittance, and reflectance spectra of these PNCs showed a gradual variation with the increase of Al2O3 and SiO2 contents in the films. The energy bandgap decreases, whereas the Urbach energy, refractive indices, and optical conductivity enhance with the increase of filler concentration in these composites. The X-ray diffraction (XRD) study revealed the predominantly amorphous nature of these materials and the homogeneity of the hybrid was evidenced by their SEM images. The energy dispersive X-Ray (EDX) mapping revealed the purity of these hybrid composites. The results demonstrated that these PNC films are low permittivity polymeric nanodielectrics (PNDs), and their controllable optical parameters with the filler contents could be technologically important in the design and development of some advanced microelectronic and optoelectronic devices.

Dielectric and optical properties of alumina and silica nanoparticles dispersed poly(methyl methacrylate) matrix-based nanocomposites for advanced polymer technologies

In the challenging prospect of developing new materials by mixing different polymers to reach a synergetic performance, the present research focuses on the study of the miscibility of two polymers: The acrylonitrile butadiene styrene (ABS) composed of a dispersed elastomeric (polybutadiene rubber) polymer embedded in a SAN thermoplastic matrix, and the polycarbonate (PC). It shall be noted that obtaining miscible polymer blends is often a difficult task because of the large size of their molecular chains and the high interfacial tension between the polymer phases. Until now, the most numerous researches developed in this field involve polymer blends obtained by compatibilization techniques in order to improve the interfacial adhesion between initial polymers. The aim of this work is to study the miscibility between ABS and PC. First, two different methods were used to mix the polymers: the twin-screw extrusion and the dissolution in a common solvent tetrahydrofuran (THF). Then, physicochemical, microscopic observation and rheological characterization were performed on samples of mixtures obtained by both extrusion processing and dissolution method. The measurement of glassy transition temperature (Tg) by differential scanning calorimetry measurements (DSC) and dynamical mechanical thermal analysis (DMTA) have shown a partial miscibility between the two polymers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44975.

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Experimental study of the miscibility of ABS/PC polymer blends and investigation of the processing effect

This paper aims to study the coalescence phenomenon of two different polymers PVDF and PMMA. The paper is divided in two parts: the first part is devoted to the experimental work, and the second one focuses on the modeling of the coalescence phenomenon. The first step was a physicochemical and rheological characterization. Then, the coalescence tests have been performed on droplets derived from PVDF and PMMA polymers using a polarized light optical microscope combined with a hot stage. The effect of several significant parameters like temperature and particle size was investigated. The second part of this study is focused on the modeling of the coalescence phenomenon based on the well-known Bellehumeur model. The latter has been commonly used to describe the coalescence phenomenon between identical grains. The novelty of the present work consists in the extension of the coalescence model to wider describe the coalescence phenomenon between grains of different polymers. In addition, probabilistic analysis was performed in order to investigate the effect of the parameters governing the coalescence model, namely the viscosity, the surface tension and the relaxation time. The results have shown a good compromise between the experimental results and the predictive generalized Bellehumeur model.

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Predictive coalescence modeling of particles from different polymers: application to PVDF and PMMA pair

1 PIMM Laboratory, CNRS UMR 8006, Arts et Métiers ParisTech 151 bd de l'Hôpital, 75013 Paris, France. sara.aid@ensam.eu; anissa.eddhahak@ensam.eu; abbas.tcharkhtchi@ensam.eu 2 Calle Juan de Quesada, 35001 Las Palmas de Gran Canaria, Las Palmas, Spain zaida.ortega@ulpgc.es 3 Institut de Chambéry, Arts et Métiers ParisTech Savoie Technolac, rue du Lac Majeur F-73375 LE BOURGET DU LAC Cedex-Chambéry, France daniel.froelich@ensam.eu

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Sara Aid

Papers

On the miscibility of PVDF/PMMA polymer blends: Thermodynamics, experimental and numerical investigations

Experimental study of the miscibility of ABS/PC polymer blends and investigation of the processing effect

Predictive coalescence modeling of particles from different polymers: application to PVDF and PMMA pair

Modelling and simulation of the coalescence of two different polymer grains