Organically-modified silica based microspheres for self-curing polyurethane one component foams

Loureiro, Mónica V.; Ciriminna, Rosaria; Lourenço, Maria José; Santos, Luı́s F.; Schrijver, Aster De; Bordado, João; Pagliaro, Mario; Marques, Ana C.

doi:10.1016/j.micromeso.2016.10.039

Cited by 12 publications

(5 citation statements)

References 9 publications

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“…The work reported in this paper was performed within the framework of a Technology Platform on Microencapsulation and Immobilization led by A. C. Marques, which deals with the synthesis of MCs, microscaffolds, and microspheres with tailored morphology, organic functionality, and a wide porosity range for different applications. − ,− …”

Section: Introductionmentioning

confidence: 99%

Microencapsulation of Isocyanate in Biodegradable Poly(ε-caprolactone) Capsules and Application in Monocomponent Green Adhesives

Loureiro

Vale

Santos

et al. 2020

ACS Appl. Polym. Mater.

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We report on the encapsulation of high loadings of liquid isophorone diisocyanate (IPDI) in biodegradable, temperature-responsive poly(ε-caprolactone) (PCL) microcapsules (MCs), aimed to be applied as cross-linking agents for the development of a generation of safer and eco-innovative adhesives, which are one-component and self-reactive. The biodegradable PCL MCs were formed via the solvent evaporation method in combination with an oil-in-oil-in-water (O/O/W) doubleemulsion system. Two PCL grades with different molecular weights (MW), of 45000 and 80000 Da, were tested as the MCs' outer surface (shell) material. The use of a higher MW PCL, for the encapsulation of IPDI, resulted in core−shell MCs of smoother surface and a slightly smaller average shell thickness leading to remarkably high isocyanate loadings, up to 60 wt %. Also, a higher resistance of the MC's shell to air moisture diffusion was revealed by the longer shelf life exhibited by these MCs. The successful IPDI encapsulation and MCs' shell composition were revealed by Fourier transform infrared spectroscopy (FTIR) in combination with thermogravimetric analysis (TGA) and gel permeation chromatography (GPC), while the MCs' morphology and size distribution were assessed by scanning electron microscopy (SEM) and optical microscopy. Differential scanning calorimetry (DSC) in combination with adhesion proof-of-concept studies showed that the developed PCL MCs were able to respond to the external stimuli of temperature and pressure, typically employed during the adhesive application, revealing an effective IPDI release in the adhesive joint. The results obtained confirm the viability of the sustainably engineered MCs to be used as cross-linking agents and therefore enablers of eco-innovative high-performance adhesives. Finally, it should be stressed that the obtained MCs are potentially useful to provide self-healing capability to materials and that the developed technology may be used in the encapsulation of other reactive species by means of a purely physical process using biodegradable polymers.

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Section: Introductionmentioning

confidence: 99%

Microencapsulation of Isocyanate in Biodegradable Poly(ε-caprolactone) Capsules and Application in Monocomponent Green Adhesives

Loureiro

Vale

Santos

et al. 2020

ACS Appl. Polym. Mater.

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“…Figure exhibits the FTIR spectra of cationic–nonionic PU obtained from PUD50 and the corresponding cationic–nonionic PU‐SiO 2 particles. In FTIR spectra of PU, absorption peaks at 3337, 1541, and 1178 cm −1 are attributed to NH stretching vibration, NH flexural vibration, and CN stretching vibration, respectively . And the peak at 1734 cm −1 corresponds to CO stretching vibration, all of them indicate that NCO has reacted with OH and NH 2 .…”

Section: Resultsmentioning

confidence: 96%

Preparation of antireflection coatings with novel cationic–nonionic PU‐SiO₂ core–shell particle dispersions

Jin

Sun

2017

J of Applied Polymer Sci

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A novel polyurethane (PU)-SiO 2 core-shell particle dispersion was prepared by an acid-catalyzed sol-gel process using cationic-nonionic PU particle as template. Results of average sizes, polydispersity index, and transmission electron microscope indicated that tetramethylorthosilicate were first diffused to the surface of PU particles, then occurring hydrolysis-condensation reaction to form core-shell particles. Antireflection coating formulation was prepared by as-prepared core-shell particle dispersion and SiO 2 sol binder. After dip-coating in the formulation, antireflection coating was formed on glass surface by calcination. Scanning electron microscopy images showed that pores had been formed inside coating after removing PU template particles, and the coating surface could be almost fully closed. In addition, ultraviolet-visible spectrophotometer analysis showed that the maximum transmittance of antireflection glasses can be as high as 98.6% at 548 nm.

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“…The FTIR spectra of the MICROSCAFS ® after drying at 45 °C (Supplementary Figure S7a,b ) contain multiple bands characteristic of the oxides’ network, as well as of other organic compounds from the reactional mixture, including some residues of precursors (alkoxides), surfactant and decalin. The band at 1267 cm −1 is characteristic of the epoxy group of the GPTMS [ 30 , 31 ]; however, the peaks at 906 and 850 cm −1 , ascribed to C–O and C–O–C stretching of the GPTMS’ epoxy (oxirane), are hard to detect because they might be hidden by the intense band at 915 cm −1 (Si-OH, or Si-O − from Si-O-Ti units). After the heat treatment at 900 °C (Supplementary Figure S7c,d ), the organic groups completely disappeared.…”

Section: Resultsmentioning

confidence: 99%

Robust Photocatalytic MICROSCAFS® with Interconnected Macropores for Sustainable Solar-Driven Water Purification

Vale,

Barrocas,

Serôdio

et al. 2024

IJMS

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Advanced oxidation processes, including photocatalysis, have been proven effective at organic dye degradation. Tailored porous materials with regulated pore size, shape, and morphology offer a sustainable solution to the water pollution problem by acting as support materials to grafted photocatalytic nanoparticles (NPs). This research investigated the influence of pore and particle sizes of photocatalytic MICROSCAFS® on the degradation of methyl orange (MO) in aqueous solution (10 mg/L). Photocatalytic MICROSCAFS® are made of binder-less supported P25 TiO2 NPs within MICROSCAFS®, which are silica–titania microspheres with a controlled size and interconnected macroporosity, synthesized by an adapted sol–gel method that involves a polymerization-induced phase separation process. Photocatalytic experiments were performed both in batch and flow reactors, with this latter one targeting a proof of concept for continuous transformation processes and real-life conditions. Photocatalytic degradation of 87% in 2 h (batch) was achieved, using a calibrated solar light simulator (1 sun) and a photocatalyst/pollutant mass ratio of 23. This study introduces a novel flow kinetic model which provides the modeling and simulation of the photocatalytic MICROSCAFS® performance. A scavenger study was performed, enabling an in-depth mechanistic understanding. Finally, the transformation products resulting from the MO photocatalytic degradation were elucidated by high-resolution mass spectrometry experiments and subjected to an in silico toxicity assessment.

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Organically-modified silica based microspheres for self-curing polyurethane one component foams

Cited by 12 publications

References 9 publications

Microencapsulation of Isocyanate in Biodegradable Poly(ε-caprolactone) Capsules and Application in Monocomponent Green Adhesives

Microencapsulation of Isocyanate in Biodegradable Poly(ε-caprolactone) Capsules and Application in Monocomponent Green Adhesives

Preparation of antireflection coatings with novel cationic–nonionic PU‐SiO₂ core–shell particle dispersions

Robust Photocatalytic MICROSCAFS® with Interconnected Macropores for Sustainable Solar-Driven Water Purification

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Organically-modified silica based microspheres for self-curing polyurethane one component foams

Cited by 12 publications

References 9 publications

Microencapsulation of Isocyanate in Biodegradable Poly(ε-caprolactone) Capsules and Application in Monocomponent Green Adhesives

Microencapsulation of Isocyanate in Biodegradable Poly(ε-caprolactone) Capsules and Application in Monocomponent Green Adhesives

Preparation of antireflection coatings with novel cationic–nonionic PU‐SiO2 core–shell particle dispersions

Robust Photocatalytic MICROSCAFS® with Interconnected Macropores for Sustainable Solar-Driven Water Purification

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Product

Resources

About

Preparation of antireflection coatings with novel cationic–nonionic PU‐SiO₂ core–shell particle dispersions