Synthesis of enhanced urea–formaldehyde resin microcapsules doped with nanotitania

Niu, Xiaowei; Yangshan, Sun; Ding, Shou-Nian; Chen, Chaochao; Song, Bo; Xu, Hui; Qi, Zhengjian; Qi, Qi

doi:10.1002/app.34099

Cited by 13 publications

(7 citation statements)

References 29 publications

(36 reference statements)

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“…The results indicated that nano-SiO 2 can keep the structural integrity of the microcapsules. Similar results were found in the research of Niu et al [40]. The micrographs also showed that pores and cracks were not present on the surface of the microcapsules, which contributed to the protection of the core material by decreasing oxygen diffusion into the microcapsules [34].…”

Section: Resultssupporting

confidence: 89%

Preparation and Characterization of Double-Layered Microcapsules Containing Nano-SiO2

Xue

Zhang

et al. 2021

International Journal of Polymer Science

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The double-layered microencapsulation technology has been used in many fields. In this study, the double-layered microencapsulated anthocyanin of Passiflora edulis shells (APESs) was prepared via complex coacervation using gelatin and gum Arabic as the first wall materials (single-layered microcapsules (SMs)) and using gum Arabic containing nano-SiO2 as the second wall material (double-layered microcapsules (DMs)/nano-SiO2) to enhance the stability of the core material. Properties of microcapsules were analyzed on the basis of EE, morphology, scanning electron microscopy (SEM), droplet size, moisture content, and differential scanning calorimetry (DSC). The results showed that the EE values of SMs, DMs, and DMs/nano-SiO2 were 96.12%, 97.24%, and 97.85%, respectively. DMs/nano-SiO2 had the lowest moisture content (2.17%). The average droplet size of DMs/nano-SiO2 (34.93 μm) was higher than those of SMs and DMs. DSC indicated that the melting temperature of DMs/nano-SiO2 was 73.61°C and 45.33°C higher than those of SMs and DMs, respectively. SEM demonstrated that DMs/nano-SiO2 had the smoothest surface compared with the other two kinds of microcapsules. The storage stability of APESs and their microcapsules indicated that the stability of the microcapsules was improved by adding DMs/nano-SiO2 into the wall material of microcapsules. These results indicated double-layered microcapsules containing silica nanoparticles contribute to the stability of the core material.

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Section: Resultssupporting

confidence: 89%

Preparation and Characterization of Double-Layered Microcapsules Containing Nano-SiO2

Xue

Zhang

et al. 2021

International Journal of Polymer Science

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“…The DJ is an aromatic mixture containing The other procedures about emulsification and polymerization were similar to the fabrication of the pure MF shell microcapsules[35]. Eventually, most of the Al 2 O 3 nanoparticles were embedded into the MF shell[37,38].…”

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confidence: 99%

Thermo-mechanical analysis of microcapsules containing phase change materials for cold storage

Tchuenbou-Magaia

Al‐Duri

et al. 2018

Applied Energy

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Microencapsulated phase change material slurries (MEPCMSs) offer a potentially efficient and flexible solution for cryogenic-temperature cold storage. In this paper, the phase change material (PCM) microcapsules prepared to form MEPCMSs for cryogenictemperature cold storage consist of Dowtherm J (DJ) as core material and melamine formaldehyde (MF) as primary shell material. DJ is an aromatic mixture with diethylbenzene as the main component. Composite shell materials are adopted to avoid cracking by adding aluminium oxide (Al 2 O 3) nanoparticles or copper (Cu) coating into/on MF shell. In order to explore the heat transfer behaviour and mechanical stability of the microcapsules during the solidification process of PCM, a thermo-mechanical model is established by taking into account of energy conservation, pressure-dependent solid-liquid equilibria, Lamé's equations and buckling theory. Based on the proposed model, the effects of shell thickness, shell compositions and microcapsule size are therefore studied on the variations of pressure difference, freezing point, and latent heat. The cause of shell deformation is clearly explained and the shell buckling modes are predicted using the model, which agree well with the experimental observations. The critical core/shell size ratios of avoiding buckling are proposed for the microcapsules with different compositions. Simultaneously incorporation of Al 2 O 3 nanoparticles and Cu coating into/on MF shell can markedly enhance the resistant to buckling. In addition, special attention is paid to cold energy storage capacity of MEPCMSs, which has considerable superiority compared to packed pebble beds.

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“…Therefore, despite the high strength and low‐cost of UF, this drawback largely limits its usage. Many attempts have been made to improve the toughness of UF resins . One approach is reducing the mole ratio of formaldehyde/urea, however, this leads to a decrease of crosslinking degree and thus, inferior performance of the resin, regarding its mechanical strength and water resistance .…”

Section: Introductionmentioning

confidence: 99%

Reactive toughening of urea–formaldehyde resin with poly(vinyl alcohol) by formation of interpenetrating networks

Liu

Yuan

Zhao

et al. 2018

Polymer Engineering & Sci

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A series of urea–formaldehyde/poly(vinyl alcohol) (UF/PVA) blends were prepared via in situ polymerization. During the synthesis process, intra‐ and intermolecular acetalization of PVA occurred, along with the addition and condensation reactions between urea and formaldehyde, resulting in the formation of UF/PVA interpenetrating networks. With the increase of PVA content, the curing temperature shifted to higher temperatures and the activation energy (E) increased, suggesting that it was more difficult for the blends to cure. UF/PVA blends showed high storage modulus and only one broad tan δ peak, indicating that the stiffness was enhanced and the phase separation was limited at the chain segmental level. By the introduction of PVA, the elongation at break, impact strength, KIC value, and roughness of the fracture surface increased obviously, while the tensile strength can still maintain at a high level. Due to the forced compatibilization of the two components, homogeneous interpenetrating UF/PVA networks can form and thus the toughness of the blends was enhanced. POLYM. ENG. SCI., 58:2031–2038, 2018. © 2018 Society of Plastics Engineers

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Synthesis of enhanced urea–formaldehyde resin microcapsules doped with nanotitania

Cited by 13 publications

References 29 publications

Preparation and Characterization of Double-Layered Microcapsules Containing Nano-SiO2

Preparation and Characterization of Double-Layered Microcapsules Containing Nano-SiO2

Thermo-mechanical analysis of microcapsules containing phase change materials for cold storage

Reactive toughening of urea–formaldehyde resin with poly(vinyl alcohol) by formation of interpenetrating networks

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