Reactive microencapsulation of carbon allotropes in polyamide shell-core structures and their transformation in hybrid composites with tailored electrical properties

Oliveira, Filipa M.; Dencheva, Nadya Vasileva; Martins, P.; Lanceros‐Méndez, S.; Denchev, Z.

doi:10.3144/expresspolymlett.2016.15

Cited by 16 publications

(18 citation statements)

References 44 publications

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“…3 (images a, d, and g), complete enclosure of the metal particles in the PA6 matrix material is observed in the PA6-metal hybrids. On the contrary, the PA6/CNT or PA6/CB composites obtained earlier by microencapsulation [15] show a seven and eight order of magnitude improvement of the electrical conductivity, that is, from 10 −10 to 10 −2 S/m. These results were obtained with 5-8 wt% of CNT or CB meaning that these concentrations are above the percolation threshold and a conductive network was built with effective charge transfer.…”

Section: Electrical Conductivity and Dielectric Properties Of Molded mentioning

confidence: 69%

“…The determination of the real load content on the basis of the carbonized residue at 600 C is shown in Table 1. This method should account not only for the metal filler content but, as demonstrated in previous work [15], also for that of the C-allotropes.…”

Section: Tga Studiesmentioning

confidence: 94%

“…Thus, reactive microencapsulation of various organic and inorganic loads by AAROP of ε‐caprolactam (ECL) in suspension to produce loaded polyamide 6 (PA6)‐based microcapsules (PAMCs) with their subsequent compression molding to PA6 hybrids was recently communicated . This fabrication concept allowed the synthesis of a number of particulate and laminated PA6 composites comprising various single organic or inorganic fillers in wide concentration ranges and with controlled dispersion .…”

Section: Introductionmentioning

confidence: 99%

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Binary polyamide hybrid composites containing carbon allotropes and metal particles with radiofrequency shielding effect

et al. 2018

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Novel hybrid composites with polyamide 6 (PA6) matrices and binary metal/carbon allotrope reinforcements are synthesized using a two‐stage method. First, activated anionic ring‐opening polymerization (AAROP) of ε‐caprolactam is performed in suspension, in the presence of the desired amounts of different metal particles (Al, Cu, Fe, or Mg) and carbon allotropes (multi‐walled carbon nanotubes or carbon black). The AAROP produces dual core PA6 microcapsules (PAMCs) with controlled shape and size and a total metal/carbon load of up to 17 wt% in respect to the PA6 matrix. Second, these PAMC are compression molded to composite plates. The morphology and the crystalline structure of the different PAMC and their respective composites are studied by electron microscopy and thermal methods. The well‐dispersed binary metal–carbon allotrope fillers in the PA6 matrix increase its electrical conductivity by seven to nine orders of magnitude. Simultaneously, up to ca. 60% increase of the Young's modulus of the hybrids is registered. An almost total disappearance of the PA6 resonance lines in some of the binary hybrids is registered by solid state NMR spectroscopy. The tunable combination of enhanced electrical conductivity and screening of radiofrequencies can be potentially useful in electromagnetic interference shielding or radar absorbing materials. POLYM. COMPOS., 40:E1338–E1352, 2019. © 2018 Society of Plastics Engineers

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Section: Electrical Conductivity and Dielectric Properties Of Molded mentioning

confidence: 69%

Section: Tga Studiesmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Binary polyamide hybrid composites containing carbon allotropes and metal particles with radiofrequency shielding effect

et al. 2018

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“…The solution‐precipitation AAROP of ECL to MC was performed as described previously . The lactam was dissolved in a 1:1 v/v toluene/xylene mixture under nitrogen atmosphere refluxing the reaction mixture for 10 to 15 min.…”

Section: Methodsmentioning

confidence: 99%

“…Previous reports on polyamide powders preparation by AAROP in solution disclosed the synthesis of neat PA6 particles with various sizes and topographies. Recent communications on this subject showed the possibility to synthesize loaded PA6 microcapsules (MC) via AAROP in solution . The process was performed in the presence of high concentrations of various solid payloads.…”

Section: Introductionmentioning

confidence: 99%

Dually reinforced all-polyamide laminate composites via microencapsulation strategy

2016

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A new two‐stage strategy is disclosed for the preparation of all‐polyamide laminate composites based on polyamide 6 (PA6) matrices reinforced by high volume fractions of polyamide 66 (PA66) textile structures and three different types of nanoclays. In the first stage, PA6 microcapsules (MC) loaded with montmorillonite nanoclays (MMT) are synthesized by activated anionic ring‐opening polymerization of ε‐caprolactam in solution in the presence of three different organically treated MMT brands. In the second stage, the MMT‐loaded MC obtained with controlled molecular weight, composition and granulometry are compression molded in the presence of PA66 textile structures to produce the final dually reinforced laminate composites. Mechanical tests in tension, flexion, and impact for selected composites in this study showed up to 73% increase of the Young's modulus, up to 142% increase of the stress at break, and more than a fivefold increase of the notched impact resistance. The mechanical behavior of the dually reinforced composites was discussed in conjunction with the morphology of the samples studied by optical and electron microscopy, and the matrix crystalline structure as revealed by DSC and microfocus synchrotron X‐ray diffraction. POLYM. ENG. SCI., 57:806–820, 2017. © 2016 Society of Plastics Engineers

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Synthesis and properties of neat, hybrid, and copolymeric polyamide 12 microparticles and composites on their basis

Dencheva

Braz

Denchev

2021

J of Applied Polymer Sci

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Neat and hybrid polyamide 12 (PA12) based powders are important raw materials for additive manufacturing. This study describes a facile method for the synthesis of pure, hybrid and copolymeric microparticulate materials based on one‐pot activated anionic ring‐opening polymerization (AAROP) of laurolactam in solution. The results reveal the possibility to obtain in good yields, for reaction times of 2 h and temperatures of up to 110°C neat and hybrid PA12 microparticles (MP) carrying metal or carbon fillers. Copolymeric PA12/PA6 MP can also be successfully prepared. All MP materials are analyzed by spectral, microscopy, thermal, and synchrotron X‐ray scattering methods in order to clarify their morphology, chemical and crystalline structure, melting and degradation behavior. The melting temperature of the PA12 MP is lower than of the commercial PA12, the presence of metal particles or copolymerization with PA6 additionally decrease it well below 170°C. The composites prepared by compression molding of PA12 MP display elastic modulus of up to 1.49 GPa, the stresses at yield and break reaching 50 and 69 MPa, respectively. It is concluded that the neat, hybrid, and copolymeric pulverulent materials obtained via microencapsulation by AAROP in solution may be useful in additive manufacturing processing.

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Reactive microencapsulation of carbon allotropes in polyamide shell-core structures and their transformation in hybrid composites with tailored electrical properties

Cited by 16 publications

References 44 publications

Binary polyamide hybrid composites containing carbon allotropes and metal particles with radiofrequency shielding effect

Binary polyamide hybrid composites containing carbon allotropes and metal particles with radiofrequency shielding effect

Dually reinforced all-polyamide laminate composites via microencapsulation strategy

Synthesis and properties of neat, hybrid, and copolymeric polyamide 12 microparticles and composites on their basis

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