Study of the dispersion of nanoclays in a LDPE matrix using microscopy and in-process ultrasonic monitoring

Villanueva, María Pilar; Cabedo, Luis; Giménez, Enrique; Lagarón, José M.; Coates, Phil; Kelly, Adrian L.

doi:10.1016/j.polymertesting.2008.12.009

Cited by 31 publications

(20 citation statements)

References 26 publications

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“…This is typical of an immiscible system and the size of the silicate agglomeration could lead to this being considered a microcomposite rather than a nanocomposite. Similar SEM images were shown by Villanueva et al when compatibilizers were added to HDPE nanoclay blends 40…”

Section: Resultssupporting

confidence: 85%

The effect of maleic anhydride grafting efficiency on the flexural properties of polyethylene composites

Gunning

Istrate

Geever

et al. 2011

J of Applied Polymer Sci

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Many authors have reported on the property enhancements possible by compounding high density polyethylene (HDPE) with fillers to produce composites. It is accepted that polyethylene combined with materials such as nanoclay or wood flour will not yield favorable properties unless a compatibilizing material is used to form a link. In this work, compatibilized HDPE was produced by grafting maleic anhydride (MA) to its backbone in a twin screw extruder using a peroxide initiated reactive process. Fourier transform infrared spectroscopy (FTIR) was used to examine the effects of varying peroxide and MA levels on the grafting percentage and it was found that a high percentage could be achieved. The gel content of each HDPE-g-MA batch was determined and twin bore rheometry analysis was carried out to examine the effects of crosslinking and MA grafting on the melt viscosity. These HDPE-g-MA compatibilizers were subsequently compounded with nanoclay and wood flour to produce composites. The composite materials were tested using a three point bending apparatus to determine the flexural modulus and strength and were shown to have favorable mechanical properties when compared with composites containing no compatibilizer. X-ray diffraction (XRD) was used to examine the effects of grafted MA content on the intercalation and exfoliation levels of nanoclay composites. The results from XRD scans showed that increased intercalation in polymer nanoclay composites was achieved by increasing the grafted MA content. This was confirmed using a scanning electron microscope, where images produced showed increased levels of dispersion and reductions in nanoclay agglomerates.

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Section: Resultssupporting

confidence: 85%

The effect of maleic anhydride grafting efficiency on the flexural properties of polyethylene composites

Gunning

Istrate

Geever

et al. 2011

J of Applied Polymer Sci

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“…As an indirect technique requiring calibration or artificial intelligence-based models instead of being properly a real-time monitoring technique, ultrasonic spectroscopy has been shown to be an efficient way to predict the dispersion of micro- and nano-fillers in the extruder as a function of process parameters [57,58,59], based on the monitoring of velocity and the attenuation of ultrasound in the flowing material. In the case of nanoclays in a low-density Polyethylene (LDPE) matrix, in-process ultrasonic measurements across melt flow in the extruder die were shown to provide a viable indication of dispersion levels, although the relationships between measured signals and morphology were complex and warranted further investigation [60]. The combination of NIR spectroscopy and ultrasonic measurements, which are in excellent agreement, was also reported as providing a highly reliable correspondence between the achieved process monitoring results and exfoliation level [54].…”

Section: Nanoparticles Dispersion Monitoringmentioning

confidence: 99%

Recent Prospects in the Inline Monitoring of Nanocomposites and Nanocoatings by Optical Technologies

et al. 2016

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Nanostructured materials have emerged as a key research field in order to confer materials with unique or enhanced properties. The performance of nanocomposites depends on a number of parameters, but the suitable dispersion of nanoparticles remains the key in order to obtain the full nanocomposites’ potential in terms of, e.g., flame retardance, mechanical, barrier, thermal properties, etc. Likewise, the performance of nanocoatings to obtain, for example, tailored surface affinity with selected liquids (e.g., for self-cleaning ability or anti-fog properties), protective effects against flame propagation, ultra violet (UV) radiation or gas permeation, is highly dependent on the nanocoating’s thickness and homogeneity. In terms of recent advances in the monitoring of nanocomposites and nanocoatings, this review discusses commonly-used offline characterization approaches, as well as promising inline systems. All in all, having good control over both the dispersion and thickness of these materials would help with reaching optimal and consistent properties to allow nanocomposites to extend their use.

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“…These mysterious particles being investigated only recently becoming a new subject in clay science [19][20][21] and have a lot of potential commercial applications. Nano-clay particles, because of their very small dimensions were overlooked in many previous studies but their impact on clay structure building behaviour is very important.…”

Section: Force Measurementsmentioning

confidence: 99%

Influence of smectite suspension structure on sheet orientation in dry sediments: XRD and AFM applications

Zbik

Frost

2010

Journal of Colloid and Interface Science

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The structure-building phenomena within clay aggregates are governed by forces acting between clay particles. Measurements of such forces are important to understand in order to manipulate the aggregate structure for applications such as dewatering of mineral processing tailings. A parallel particle orientation is required when conducting XRD investigation on the oriented samples and conduct force measurements acting between basal planes of clay mineral platelets using atomic force microscopy (AFM). To investigate how smectite clay platelets were oriented on silicon wafer substrate when dried from suspension range of methods like SEM, XRD and AFM were employed. From these investigations, we conclude that high clay concentrations and larger particle diameters (up to 5 microm) in suspension result in random orientation of platelets in the substrate. The best possible laminar orientation in the clay dry film, represented in the XRD 001/020 intensity ratio of 47 was obtained by drying thin layers from 0.02 wt.% clay suspensions of the natural pH. Conducted AFM investigations show that smectite studied in water based electrolytes show very long-range repulsive forces lower in strength than electrostatic forces from double-layer repulsion. It was suggested that these forces may have structural nature. Smectite surface layers rehydrate in water environment forms surface gel with spongy and cellular texture which cushion approaching AFM probe. This structural effect can be measured in distances larger than 1000 nm from substrate surface and when probe penetrate this gel layer, structural linkages are forming between substrate and clay covered probe. These linkages prevent subsequently smooth detachments of AFM probe on way back when retrieval. This effect of tearing new formed structure apart involves larger adhesion-like forces measured in retrieval. It is also suggested that these effect may be enhanced by the nano-clay particles interaction.

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Study of the dispersion of nanoclays in a LDPE matrix using microscopy and in-process ultrasonic monitoring

Cited by 31 publications

References 26 publications

The effect of maleic anhydride grafting efficiency on the flexural properties of polyethylene composites

The effect of maleic anhydride grafting efficiency on the flexural properties of polyethylene composites

Recent Prospects in the Inline Monitoring of Nanocomposites and Nanocoatings by Optical Technologies

Influence of smectite suspension structure on sheet orientation in dry sediments: XRD and AFM applications

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