Identification of formation stages in a polymeric foam customised by sonication via electrical resistivity measurements

Torres-Sánchez, Carmen; Corney, Jonathan

doi:10.1007/s10965-008-9249-4

Cited by 25 publications

(19 citation statements)

References 34 publications

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“…Such techniques could enable on-line damage identification as well as production qualification and become part of novel more advanced monitoring systems [42]. As a matter of fact, similar techniques have demonstrated their suitability to offer prompt information particularly on the production progress of the 'packing' and 'gelation' stages of polymeric foams, otherwise not so easily possible [27].…”

Section: Discussionmentioning

confidence: 99%

“…The use of the electric field has been proposed and demonstrated to perform very well in defining various other properties. For example, electrical measurements have been used to monitor the foaming process and polymerization of polymeric foams [27] while dielectric measurements have been used for measuring the density of polymer foams [28]. Brady et al [29] developed electrically conductive poly-pyrrole coated PUR foam.…”

mentioning

confidence: 99%

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Sensing strain and damage in polyurethane/MWCNT nano-composite foams using electrical measurements

Baltopoulos¹,

Αθανασόπουλος²,

Fotiou³

et al. 2013

Express Polym. Lett.

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The addition of carbon nano-fillers (nanofibers (CNF), nanotubes (CNT) etc.) into plastics has been shown to affect the various properties of the resulting material and effectively increase the electrical conductivity of the system by several orders of magnitude [1]. This is attributed to the formation of a conductive network of the conductive nanofillers, which can be described as a percolated network. The increased electrical conductivity of the nano-reinforced materials has given rise to their use in various applications [2]. Polymeric foams (e.g. Rigid PolyUrethane (PUR)) represent a very interesting and useful sub-group, finding vast range of applications due to their versatility. In structural applications, they are commonly used due to the weight saving capabilities they can offer in the design (e.g. as sandwich cores). Combining nano-fillers with foam materials, nanoreinforcement of foams has been developed and studied the past decade, but mainly focused on the mechanical and thermal properties. Electrical conductivity of nano-composite foams is much less studied. Works on the electrical properties of nanoreinforced polymeric foams are rather sporadic [3][4][5][6][7][8][9][10]. The relationship between the resulting electrical conductivity and the density of the rigid foams for given CNT concentrations was reported in [6] but only recently described further [10]. 40Sensing strain and damage in polyurethane-MWCNT nano-composite foams using electrical measurements A. Baltopoulos, N. Athanasopoulos, I. Fotiou, A. Vavouliotis Abstract. This work deals with the damage identification in polymeric foams through the monitoring of the electrical resistance of the system. To assess this idea electrically conductive rigid Poly-Urethane (PUR) foams at various densities were prepared. Multi-Wall Carbon Nanotubes (MWCNT) were dispersed in the host polymer at various concentrations through high shear mixing to provide electrical conductivity to the system. The PUR/MWCNT foams exhibited varying electrical conductivity on a wide range of densities and nano-filler contents. The prepared foams were subject to compression tests. Electrical resistance was recorded online during the tests to monitor the change of the bulk property of the materials. A structural-electrical cross-property relation was exhibited. The distinctive phases of foam compression were successfully identified from the electrical resistance profile recorded during the tests. A characteristic master curve of the change of electrical resistivity with respect to load and damage is proposed and analyzed. It was shown that the found electrical resistance profile is a characteristic of all the MWCNT contents and depends on density and conductivity. MWCNT content contributes mainly to the sensitivity of electrical sensing in the initial stage of compression. Later compression stages are dominated by foam microstructural damage which mask any effect of CNT dispersion. Micro-structural observations were employed to verify the experimental findings and curves.Keywo...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Sensing strain and damage in polyurethane/MWCNT nano-composite foams using electrical measurements

Baltopoulos¹,

Αθανασόπουλος²,

Fotiou³

et al. 2013

Express Polym. Lett.

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“…5. Good linear relationship between the concentration of CO 2 and the square root of the desorption time for pure PS, [VBTMA][BF 4 ]-St and [VBTMA][PF6 ]-St is observed, indicating that the diffusion of CO 2 obeys Fick's law. Through fitting and extrapolation of the curves, the initial solubility in both pure PS and the IL copolymers can be obtained (as shown inFig.…”

mentioning

confidence: 87%

“…For example, their impact strength is 5 times higher than the non-foamed polymer, the specific stiffness has 3~5 times higher than the non-foamed polymer, and the fatigue life is over 5 times than the non-foamed polymer. Furthermore, microcellular structure offers polymer foams with low thermal conductivity and dielectric constant [4][5][6]. Due to the aforementioned advantages, polymer microcellular foams have be widely used in a variety of applications ranging from packaging, aircraft and automobile parts to sports equipment, insulation materials and bio-medical materials.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of ionic liquids copolymerize styrene and their nucleation, carbon dioxide sorption effect on supercritical carbon dioxide microcellular foaming

Zhong

Yang

2015

J Polym Res

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Aiming to prepare polystyrene microcellular foam with improved foam morphology and high thermal stability, ionic liquids which have been well demonstrated to possess high carbon dioxide (CO 2 ) absorption capacity were introduced into polystyrene by copolymerization of styrene and polymerizable ionic liquids, i.e., vinylbenzyl trimethyl ammonium fluoroborate ([VBTMA][BF 4 ]) and vinylbenzyl trimethyl ammonium hexafluorophosphate ([VBTMA][PF 6 ]), Abbr. ILs). These copolymers showed higher glass transition temperature (T g ) and high supercritical carbon dioxide (scCO 2 ) solubility, based on which foams with smaller cell size, higher cell density, and higher thermal stability were prepared by the microcellular foaming using scCO 2 as blowing agent. The morphology of the resultant foams highly depended on the foaming temperature, ionic liquid type and content. Compared to [VBTMA] [BF 4 ]-St foam, [VBTMA][PF 6 ]-St have higher CO 2 absorption and glasstransition temperature, making it exhibit superior cell morphology. This work demonstrates that the introduction of ionic liquids can benefit the morphology control and thermal stability of polymeric foams and hopefully provides a promising method for the design and preparation of polymeric foams with high performance.

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“…Figure 2 shows a schematic of the experimental rig. Further details on the experimental process for the sonication of the samples and details on the detection of the different polymerization stages can be found elsewhere [25][26][27].…”

Section: Manufacture Of Density Tailored Polymeric Foams In This Studymentioning

confidence: 99%

Morphological and biological characterization of density engineered foams fabricated by ultrasonic sonication

Torres-Sánchez

Corney

2010

J Mater Sci

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Identification of formation stages in a polymeric foam customised by sonication via electrical resistivity measurements

Cited by 25 publications

References 34 publications

Sensing strain and damage in polyurethane/MWCNT nano-composite foams using electrical measurements

Sensing strain and damage in polyurethane/MWCNT nano-composite foams using electrical measurements

Synthesis of ionic liquids copolymerize styrene and their nucleation, carbon dioxide sorption effect on supercritical carbon dioxide microcellular foaming

Morphological and biological characterization of density engineered foams fabricated by ultrasonic sonication

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