Thermal Decomposition of Polymer/Montmorillonite Nanocomposites Synthesized<i>in situ</i>on a Clay Surface

Fecchio, Bruno D.; Valandro, Silvano R.; Neumann, Miguel G.; Cavalheiro, Carla Cristina Schmitt

doi:10.5935/0103-5053.20150216

Cited by 6 publications

(6 citation statements)

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“…Measurements were performed in a nitrogen atmosphere with a flow rate of 100 mL/min. The samples were put in open aluminum pans, and the analyses were performed with a heating rate of 10 °C/min from 25 to 450 °C …”

Section: Experimental Sectionmentioning

confidence: 99%

pH-Responsive Semi-Interpenetrated Polymer Networks of pHEMA/PAA for the Capture of Copper Ions and Corrosion Removal

Guaragnone

Rossi

Chelazzi

et al. 2022

ACS Appl. Mater. Interfaces

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Bronze artifacts constitute a fundamental portion of Cultural Heritage, but effective methodologies for the removal of corrosion layers, such as those produced by the “bronze disease”, are currently missing. We propose the formulation and application of novel poly(2-hydroxyethyl methacrylate) (pHEMA) networks semi-interpenetrated (SIPN) with poly(acrylic acid) (PAA) to achieve enhanced capture of copper ions and removal of corrosion products. The pHEMA/PAA SIPNs were designed to improve previous pHEMA/poly(vinylpyrrolidone) (PVP) networks, taking advantage of the chelating ability of pH-responsive carboxylic groups in PAA. Increasing the pH ionizes carboxyls, increases the porosity in pHEMA/PAA, and leads to the co-presence of enol and enolate forms of vinylpyrrolidone (VP), changing the macroporosity and decreasing the mesh size in pHEMA/PVP. The ion–matrix interaction is stronger in pHEMA/PAA, where the process occurs through an initial diffusion-limited step followed by diffusion in smaller pores or adsorption by less available sites. In pHEMA/PVP, the uptake is probably controlled by adsorption as expected, considering the porogen role of PVP in the network. Upon application of the SIPNs loaded with tetraethylenpentamine (TEPA) onto corroded bronze, copper oxychlorides dissolve and migrate inside the gels, where Cu(II) ions form ternary complexes with TEPA and carboxylates in PAA or carbonyls in PVP. The removal of oxychlorides is more effective and faster for pHEMA/PAA than its /PVP counterpart. The selective action of the gels preserved the cuprite layers that are needed to passivate bronze against corrosion, and the pH-responsive behavior of pHEMA/PAA allows full control of the uptake and release of the Cu(II)–TEPA complex, making these systems appealing in several fields even beyond Cultural Heritage conservation (e.g., drug delivery, wastewater treatment, agricultural industry, and food chemistry).

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Section: Experimental Sectionmentioning

confidence: 99%

pH-Responsive Semi-Interpenetrated Polymer Networks of pHEMA/PAA for the Capture of Copper Ions and Corrosion Removal

Guaragnone

Rossi

Chelazzi

et al. 2022

ACS Appl. Mater. Interfaces

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“…This behavior appeared in all clay types (C20 and B30). In the second region, the gradual change of weight at a temperature between 170 to 450 °C for C20 and 156 to 400 °C for B30 corresponded to the removal of organic clay residues, interlayer anions and further polymerization of the monomer network [42][43]. The third region showed the lowest weight loss at a temperature above 500 °C due to the strongly bound interlayer anions and removal of the OH group from the sample for both clay types (C20 and B30) as shown in Fig.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…3 and 4 show that, after an initial loss of 20% of the original weight, there is an almost total rapid degradation of the pure PVNCL and the nanocomposites in the range from 170 to 450 °C. For the decomposition of the nanocomposites around 15-30% is left, probably corresponding to the remaining clay and polymer ashes [42].…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Thermal and Structure Analysis Based on Exfoliation of Clay in Thermosensitive Polymer by <i>in-situ</i> Polymerization

2019

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Poly(N-vinylcaprolactam) (PNVCL) offers superior characteristics as a thermoresponsive polymer for various potential applications. An attractive procedure, namely in-situ polymerization, was used to prepare NVCL/clay nanocomposite in different clay ratios. Organo-modified clay as C20 and B30 were employed in a range between 1–5% based on weight. Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) were used to study thermal decomposition and to assess bond conversion during polymerization of the nanocomposite. This research was conducted to study PNVCL characteristics with the addition of clay as a nanocomposite. The stretch mode of the carboxylic group (C=O) and (C=C) was present in the band range about ~1635 cm–1 for the C20, but it was ranging between 1640 to 1664 cm–1 for the B30 of the nanocomposite. It was observed that the decomposition was different for each type of organoclay and the temperature peaked at 30 to 800 °C, to measure the degradation points at 5, 10, and 50%. Comparison results for FTIR and TGA showed that the best nanocomposite was found in the C20 (3%) case.

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“…Besides the conducted investigations for estimating mechanical properties of isolated nanoclay and also nanoclay reinforced polymers as the main objective of this article, the other topics of ongoing studies are focusing on either characterizing thermal properties of nanoclay/polymer nanocomposites or diffusional characteristics of them 118‐122]. The former provides insight into their application as fire retardant agent while the later can pave the road toward their application as a gas barrier.…”

Section: Discussionmentioning

confidence: 99%

Mechanical Properties of Nanoclay and Nanoclay Reinforced Polymers: A Review

Rafiee

Shahzadi

2018

Polymer Composites

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A literature review is conducted on performed investigations for characterizing Young's modulus of nanoclay platelet as the reinforcing agent of nanoclay/polymer nanocomposites from both experimental and theoretical aspects. The observed discrepancies in the reported results are discussed accordingly. All available investigations for predicting mechanical properties of nanoclay reinforced polymers are also reviewed. The employed methods in ongoing studies are categorized into three groups as atomistic, continuum and multiscale modeling techniques. Those challenging issues which are still in need of more accurate understanding and discussion are identified and outlined through a gap analysis on current investigations. The introduced shortcomings can be considered as prospective research areas for the future studies in the field of estimating mechanical properties of nanoclay based composites. POLYM. COMPOS., 40:431–445, 2019. © 2018 Society of Plastics Engineers

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Thermal Decomposition of Polymer/Montmorillonite Nanocomposites Synthesizedin situon a Clay Surface

Cited by 6 publications

References 0 publications

pH-Responsive Semi-Interpenetrated Polymer Networks of pHEMA/PAA for the Capture of Copper Ions and Corrosion Removal

pH-Responsive Semi-Interpenetrated Polymer Networks of pHEMA/PAA for the Capture of Copper Ions and Corrosion Removal

Thermal and Structure Analysis Based on Exfoliation of Clay in Thermosensitive Polymer by <i>in-situ</i> Polymerization

Mechanical Properties of Nanoclay and Nanoclay Reinforced Polymers: A Review

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