Surface modification of natural halloysite clay nanotubes with aminosilanes. Application as catalyst supports in the atom transfer radical polymerization of methyl methacrylate

Barrientos-Ramírez, S.; Oca-Ramírez, G. Montes de; Ramos‐Fernández, Enrique V.; Sepúlveda-Escribano, A.; Pastor-Blas, M. Mercedes; González-Montiel, A.

doi:10.1016/j.apcata.2011.08.003

Cited by 115 publications

(59 citation statements)

References 21 publications

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“…As evident from Figure 5 (approximately no intensity remains at the 7.27 Å peak), an almost complete expansion of the double layers has occurred as a result of urea intercalation. From Table 3, which shows the mechanical behavior of the nanocomposites containing 5 wt% HNT, it can be observed that the addition of untreated halloysite to the PP caused an insignificant influence on the mechanical properties, which has been found in similar studies using other HNT sources [14,15]. This can be explained by the low affinity between the filler particles and the polymer matrix, which was also confirmed by the presence of relatively rough HNT particles (Figures 6a-6c).…”

Section: 2supporting

confidence: 55%

“…However, in halloysite, nanocomposites with highly polar polymer contents [9][10][11][12], such as PVC [9,10], PA [11,12], or epoxy [13], require no modification/ treatment of the halloysite for the preparation of melt-mixed polymer nanocomposites with well distributed HNT. With non-polar polyolefins such as PP, due to the highly hydrophobic nature of PP, it is necessary to modify not only the halloysite [14][15][16][17], but also the polymer matrix to increase the polarity of PP [18][19][20][21]. Additionally, modification of halloysite by "-metacryloxypropyl-trimethoxysilane leads to enhanced thermal stability and decreases flammability [22].…”

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confidence: 99%

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The effect of halloysite modification combined with in situ matrix modifications on the structure and properties of polypropylene/halloysite nanocomposites

Khünová¹,

Kristóf²,

Kelnar³

et al. 2013

Express Polym. Lett.

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The effect of various modifications/intercalations of halloysite and the combination of these modifications with in situ PP matrix modification was investigated with respect to the structure and properties of the polypropylene/halloysite nanocomposites. Hexadecyl-tri-methyl-ammonium-bromide (HEDA), 3-aminopropyltrimethoxysilane and urea were used as the intercalators/modifiers. The best intercalation was found for urea, although an unexpected insignificant impact on the mechanical properties also resulted as a consequence of the urea polarity and the significant decrease in PP crystallinity. However, the simultaneous application of 4,4!-diphenylmethylene dimaleinimide (DBMI) brought about an increase in the mechanical behavior by increasing the halloysite/PP affinity as a result of in situ matrix modification. This effect was further supported by coupling between the PP and halloysite (HNT) in the system containing urea-intercalated HNT. This can be explained by the occurrence of a urea-supported reaction between the imide ring of DBMI and the OH groups of the HNT, which resulted in the best mechanical behaviors achieved in this study

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Section: 2supporting

confidence: 55%

mentioning

confidence: 99%

The effect of halloysite modification combined with in situ matrix modifications on the structure and properties of polypropylene/halloysite nanocomposites

Khünová¹,

Kristóf²,

Kelnar³

et al. 2013

Express Polym. Lett.

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“…The signals in both FTIR and 13C{H1}CPMAS were weak when compared to the spectra present in the literature [13]. However, when coupled with the FTIR data, our group concludes that the number of molecules capable of grafting to the surface of the HNTs is lower than that reported in other similar studies [42][43][44][45]. In previously reported studies, the solvents used for the reaction were used to wash the compounds after the synthesis [42][43][44][45].…”

Section: Fabrication and Analysis Of The Hnt-das-fa/fitc Complexcontrasting

confidence: 44%

“…Furthermore, the addition of fluorescein isothiocyanate (FITC) to the surface creates a method by which the effectiveness of the targeted system can be determined via in vivo imaging [16]. Additionally, this study describes a washing process for the HNTs, post modification, that is not reported in similar studies [24,33,37,[42][43][44][45]. The resulting modified HNTs were characterized via FTIR, 13C{H1}CPMAS NMR, and UV-Vis spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Bi-Functionalized Clay Nanotubes for Anti-Cancer Therapy

et al. 2018

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Systemic toxicity is an undesired consequence of the majority of chemotherapeutic drugs. Multifunctional nanoparticles with combined diagnostic and therapeutic functions show great promise towards personalized nanomedicine. Halloysite clay nanotubes (HNTs) have shown potential as a drug delivery vehicle, and its surface can be modified and tailored as a targeted drug delivery system. In this short report, we modified the HNT surface by covalently bonding folic acid (FA) and fluorescein isothiocyanate (FITC). The modification of HNTs with folic acid imparts the potential to target tumor cells selectively. The addition of FITC offers a method for quantifying the effectiveness of the FA tagged HNTs ability to target tumor cells. We documented cell uptake of our bi-functionalized HNT (bHNT) through phase contrast and epi-fluorescent microscopy. bHNTs showed no signs of cytotoxicity up to a concentration of 150 µg/mL. The increase in cell death with increased bHNT concentration may be due to induced cytotoxicity resulting from intracellular bHNT accumulation that disrupts cellular function leading to cell death. With HNTs recognized as having the ability to serve as both a nanocontainer and nanocarrier, we envision our construct as a potential modular platform for potential use in cancer therapeutics. The HNT interior can be loaded with a variety of anti-cancer drugs (or other chemotherapeutics) and serve as a "death cargo" designed to kill cancer cells while providing feedback imaging data on drug efficacy. The surface of the HNT can be modified with gold or silver nanoparticles and used in photothermal therapy by converting light to heat inside tumors. Our HNT-based drug delivery system has the potential to provide localized and targeted therapies that limit or reduce side effects, reduce patient costs and length of hospital stays, and improve quality of life. However, further research is needed to validate the potential of this new chemotherapeutic drug delivery system.

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“…With the development of the industry, catalyst has been widely used to change the reaction rate [49] in the industry. The modified HNTs were used as catalyst, due to their large special surface area, high-activity and luxuriant surface hydroxyl groups [50].…”

Section: As the Catalystsmentioning

confidence: 99%

Recent Advances on Surface Modification of Halloysite Nanotubes for Multifunctional Applications

Yang¹,

Chen²,

Fan³

et al. 2017

Preprint

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Halloysite nanotubes (HNTs) are natural occurring mineral clay nanotubes that have excellent application potential in different fields. However, HNTs are affected by size effect, surface electron effect and hydrogen bond formation on the surface which lead to weak affinity and prone to reunion at some extent. It is very significant to modify the HNTs' surface for expand its applications. In this review, the structural characteristics, performance and the related applications of surface modification HNTs are reviewed and summarized. we focus on the surface modified methods of HNTs, the effect of surface modification on materials and its related applications in various regions. In addition, future prospects and the meaning of surface modification have been discussed in HNTs studies. This review provided a reference for the application of HNTs modifications in new fields.

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Surface modification of natural halloysite clay nanotubes with aminosilanes. Application as catalyst supports in the atom transfer radical polymerization of methyl methacrylate

Cited by 115 publications

References 21 publications

The effect of halloysite modification combined with in situ matrix modifications on the structure and properties of polypropylene/halloysite nanocomposites

The effect of halloysite modification combined with in situ matrix modifications on the structure and properties of polypropylene/halloysite nanocomposites

Bi-Functionalized Clay Nanotubes for Anti-Cancer Therapy

Recent Advances on Surface Modification of Halloysite Nanotubes for Multifunctional Applications

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