An Overview of Polymer–Clay Nanocomposites

Valapa, Ravi Babu; Loganathan, Sravanthi; Pugazhenthi, G.; Thomas, Sabu; Varghese, T.O.

doi:10.1016/b978-0-323-46153-5.00002-1

Cited by 84 publications

(52 citation statements)

References 114 publications

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“…51 The reduction in T m observed in the 12th, 16th, 20th, and 24th week of degradation might indicate the degradation of the smaller crystals in the composites. Similar change in bimodal melting peaks was reported by Luo et al 44 The lower T c of PLA/ASP-HNTs composites could be related to the reduction in molecular weight during the degradation process, because shorter chains would tend to crystallize at lower temperature, which has also reported by Valapa et al 43…”

Section: Discussionsupporting

confidence: 82%

“…The GPC results revealed that the molecular weight of PLA/ ASP-HNTs composites was reduced by 23.6% (M n ) and 30.6% (M w ) at the end of the 24th week of degradation. Valapa et al 43 also reported a similar reduction in molecular weight during degradation process, and they concluded that the nanofillers and elevated temperature can lead to high molecular weight reduction, due to enhanced chain mobility of PLA molecular chains. However, the molecular weight distribution was not significantly changed through the degradation process, which indicated that bulk degradation had not begun in this study.…”

Section: Discussionmentioning

confidence: 81%

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Surface‐modified halloysite nanotubes reinforced poly(lactic acid) for use in biodegradable coronary stents

Chen

Murphy

Scholz

et al. 2018

J of Applied Polymer Sci

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Poly(lactic acid) (PLA) was reinforced halloysite nanotubes (HNTs) in this study. To improve dispersion and interfacial adhesion of HNTs within the PLA matrix, HNTs were surface modified with 3‐aminopropyltriethoxysilane (ASP) prior to compounding with PLA. PLA/ASP‐HNTs nanocomposites were characterized by differential scanning calorimetry (DSC), Fourier transfer infrared spectroscopy (FTIR), surface wettability, thermogravimetric analysis, transmission electron microscopy (TEM), and tensile testing. The hemocompatibility and cytocompatibility of PLA and PLA composites were investigated and the in vitro degradation process of PLA/ASP‐HNTs composites was investigated for a period of 6 months by gel permeation chromatography, FTIR, weight loss measurement, DSC, and tensile testing. PLA and all PLA composites were blood compatibile and non‐cytotoxic. TEM analysis revealed that HNTs agglomeration in PLA matrix was reduced by surface treatment with ASP. ASP‐HNTs had better reinforcing effect than unmodified HNTs evidenced by tensile testing. ASP‐HNTs appeared to increase the hydrolytic degradation process as measured by weight measurement. PLA/ASP‐HNTs composites displayed 12.1% weight loss and 30.6% average molecular weight reduction while retaining 74% of Young's modulus by the 24th week of degradation. Based on this data, the reinforcement of PLA using ASP‐HNTs may prove beneficial for applications such as biodegradable stents. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46521.

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 81%

Surface‐modified halloysite nanotubes reinforced poly(lactic acid) for use in biodegradable coronary stents

Chen

Murphy

Scholz

et al. 2018

J of Applied Polymer Sci

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“…Both EVA/O/NB_pHs and EVA/O/CB_pHs nanocomposites show an amorphous halo throughout the evaluated 2 θ range. This could be due to either the loss of long‐range platelet registration (due to delamination of tactoids) or alternatively due to the increase of basal spacing beyond that detectable by the employed XRD machine . The results are in good agreement with the TEM analysis.…”

Section: Resultssupporting

confidence: 72%

“…Nanoclays are one of the best candidate fillers for reinforcing polymers. Bentonite is one of the most common nanoclay fillers used for polymers due to its availability, adjustable surface chemistry, and low cost . Bentonite is also a naturally occurring material with clay mineral smectite as its predominant composition.…”

Section: Introductionmentioning

confidence: 99%

Ethylene vinyl acetate nanocomposites with hybrid silicate nanofillers of destabilized natural and commercial bentonites and organomontmorillonites

Fauzi

Osman

Abdullah

et al. 2019

Vinyl Additive Technology

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In this research, the interlayer destabilization process of bentonite was applied to gain a loosely packed, swelled, and disorganized clay layered structure for better polymer intercalation and filler dispersion during the fabrication of ethylene vinyl acetate (EVA) nanocomposites. Three different destabilization methods were applied to natural and commercial bentonites and their effects on swelling and platelets’ ordering of the clays were observed. X‐ray diffraction results suggest that the destabilization process through a combination of pH control and salt addition is more efficient in swelling both types of bentonite clays. This was supported by field emission scanning electron microscopy analysis where smaller, more loosely packed, and uniform platelets were observed due to swelling of both natural and commercial bentonite clays. The “destabilized” bentonites were used as the co‐nanofiller with the organically modified montmorillonite (OMMT) to form hybrid silicate nanofillers for EVA matrix reinforcement. Results show that the “destabilized” natural bentonite (NB) prepared by the combination of pH control and salt addition is most efficient in reinforcing the EVA matrix when combined with the OMMT by achieving 124.9% increment in tensile strength and 190.8% in toughness values. This could be related to the improved dispersion of bentonites upon the destabilization process that allows greater matrix–filler interactions in the nanocomposite system. In summary, the destabilization process through the combination of pH control and salt addition is the promising and practical technique to improve the dispersion of bentonites throughout the EVA matrix. Without the use of expensive and toxic chemicals, it can be adopted as a new approach to swell bentonites for more environmentally friendly nanocomposite technology. J. VINYL ADDIT. TECHNOL., 25:396–411, 2019. © 2019 Society of Plastics Engineers

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“…The most improvement of Young's modulus compared with pristine PS was about 19% obtained from 3 wt% of the inorganic clay content using C10_P10 due to a partially exfoliated nanocomposite structure. Moreover, the improvement of the modulus intensively was related to the volume of the filled clay as well as the strong interaction between the nanoclay particles and polymer matrix . Focusing on the added 3 wt% nanoclay, the decrease of the modulus was shown by using C20_P20 and C30_P30, respectively.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of nanoclay gel composite: A novel nanoclay masterbatch approach to nanocomposite preparation via melt extrusion process

Luecha

Magaraphan

2018

Polymer Composites

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The objective of this research was to fabricate a novel nanoclay masterbatch containing polymer‐intercalated in nanoclay with comparable degree of interlayer expansion, flowability, and high thermal stability. It is ready to use for preparing polymer/clay nanocomposites by melt extrusion. The nanoclay masterbatch was efficiently prepared in one‐step via a new approach called nanoclay gel. The nanoclay gels were successfully prepared at different original nanoclay concentrations ranging from low to high clay loading (10%, 20%, and 30% w/v) in cooperation with polyethylene glycol (PEG) at various PEG loadings (weight ratios of nanoclay/PEG 1/1, ½, and 1/3) and kappa carrageenan (KC), a thermolytic hydrogel at a fixed minimum concentration. X‐ray diffraction (XRD) results revealed that the intercalation of PEG molecules expanded silicate basal spacing up to 17–18 A° even at high percentage of nanoclay (dry content about 24–49 wt%). Scanning electron microscope (SEM) revealed the denser packing of clay layers in accordance to an increase in density of the dry nanoclay gel with increment of original nanoclay loadings. An increase of PEG content exhibited better flow ability as seen by increasing melt flow index. Thermal decomposition of the nanoclay gels was up to 380°C; by using the dry nanoclay gels to prepare polystyrene (PS)/clay nanocomposites via melt extrusion. The morphological results showed that the exfoliated structures were achieved. The mechanical and thermal stability properties were significantly enhanced. The appearing color of PS/clay nanocomposites prepared from nanoclay gel was bright pale‐yellow without evidence of thermal degradation. POLYM. COMPOS., 40:2751–2767, 2019. © 2018 Society of Plastics Engineers

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An Overview of Polymer–Clay Nanocomposites

Cited by 84 publications

References 114 publications

Surface‐modified halloysite nanotubes reinforced poly(lactic acid) for use in biodegradable coronary stents

Surface‐modified halloysite nanotubes reinforced poly(lactic acid) for use in biodegradable coronary stents

Ethylene vinyl acetate nanocomposites with hybrid silicate nanofillers of destabilized natural and commercial bentonites and organomontmorillonites

Fabrication of nanoclay gel composite: A novel nanoclay masterbatch approach to nanocomposite preparation via melt extrusion process

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