In this work, we proposed a mild and fluorine-free strategy for fabricating robust superhydrophobic coatings with TiO
2
, 3-mercaptopropyltriethoxysilane (MPTS) and polyhedral oligomeric ...silsesquioxanes using dip-coating and thiol-ene click reaction. The modified cotton exhibited superb superhydrophobicity with a WCA of 157.6°, which showed anti-wetting property in both water and air. Moreover, the durability of the treated cotton against acid and alkaline solutions, different temperatures, abrasion and peeling tests was verified. The highlight is the dual self-cleaning afforded by superhydrophobicity and photocatalytic degradation. The oil red O was adopted as organic pollutant model and could be decomposed completely with the aid of resultant coating after UV irradiation for 3 h. In addition, the modified cotton could be used as filter material and has the potential in the application of oil–water separation. After seven separation cycles, the separation efficiency still maintained 99.0%, while the WCA of cotton kept as high as 154.6°. Therefore, the above-mentioned features demonstrated that this fluorine-free method could reduce the usage of long-chain fluorinated polymers and prepare superhydrophobic cotton which could be applied in self-cleaning as well as oil–water separation fields.
Graphic abstract
► Cycloaliphatic epoxy–silicone resins were prepared by a two-step reaction. ► The synthesized resins exhibited good compatibility and high transparent. ► Properties of cured resins with different ...epoxy values were studied. ► Excellent UV resistance and thermal stability of the cured resins. ► Potential application of the cured resins in LED packaging.
Cycloaliphatic epoxy–silicone resins were successfully synthesized through a two-step reaction route: (і) hydrosilylation of 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) and 1,2-epoxy-4-vinyl-cyclohexane (VCMX), (іі) blocking of unreacted SiH in (і) with n-butanol. The molecular structures of the cycloaliphatic epoxy–silicone resins were characterized by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H NMR and 29Si NMR). High grafting efficiencies of epoxy groups were confirmed by 1H NMR combined with weighting results, indicating over 90mol% of cycloaliphatic epoxy were grafted on the silicone resins. Subsequently, SiH groups from TMCTS were almost totally consumed after the blocking reactions. In comparison with commercial available cycloaliphatic epoxy resin 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ERL-4221) cured by MHHPA, the cured cycloaliphatic epoxy–silicone resins exhibited better thermal stability, lower water absorption and higher UV/thermal resistance. Moreover, the characteristics of transmittance (>90%, 800nm), 5wt.% mass loss temperature (>330°C) and no yellowing during thermal aging at 120°C or UV aging for 288h of the cured cycloaliphatic epoxy–silicone resins, made them possible for power light-emitting diode (LED) encapsulants, or other packaging materials, like optical lenses, and electronic sealings.
Robust superhydrophobic cotton textiles exhibiting photocatalytic self-cleaning ability under UV light were successfully achieved by surface functionalization with anatase TiO
2
sol and mercapto ...silanes, and hydrophobization with vinyl-terminated polydimethylsiloxane (V-PDMS) via thiol-ene click reaction. The modified cotton textiles not only showed outstanding water repellency with a water contact angle of 154.2°, but exhibited desirable photodegradation of oil red O by photocatalysis under UV irradiation. Moreover, the modified textiles exhibited excellent durability and stability after exposure to different severe conditions, such as acid and base solutions, organic solvents, laundering and UV exposure. The durably coated textiles manifested desirable separation performance in oil–water mixtures, and the separation efficiency was about 99.0% even after 20 times use. Cotton textiles with multi-functionality of superhydrophobicity, photocatalysis and oil-water separation are hopefully applied in a diverse range of practical applications in self-cleaning and oil-removal fields.
The purpose of this paper was to evaluate the feasibility of MXenes (Ti
3
C
2
T
x
) enforcing corrosion resistance performance and thermal stability of waterborne polyurethane (WPU). Firstly, the Ti
...3
C
2
T
x
was modified by hydrolysis of titanium butoxide (TBOT) and the 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane. Then, the modified Ti
3
C
2
T
x
(SiO
x
/TiO
2
@Ti
3
C
2
) was grafted into the WPU composite. The electrochemistry station and thermal analysis technique was used to detailly evaluate the effect of SiO
x
/TiO
2
@Ti
3
C
2
on the anticorrosion performance and thermal stability of all samples. The results revealed that the WPU with 0.15% SiO
x
/TiO
2
@Ti
3
C
2
showed the best thermal stability and anticorrosion performance. In detail, 0.15% SiO
x
/TiO
2
@Ti
3
C
2
/WPU improved the 31.71 °C T
max1
compared with that of WPU. In terms of electrochemistry results, after 28 days of immersion in 3.5 wt.% NaCl solution, the |Z|
f=0.01 Hz
of WPU was 3.65 × 10
6
Ω·cm
2
. However, the |Z|
f=0.01 Hz
of 0.15% SiO
x
/TiO
2
@Ti
3
C
2
/WPU was still at 1.15 × 10
7
Ω·cm
2
, after 64 days of immersion in 3.5 wt.% NaCl solution. In a word, this work opened up a novel strategy to enhance the performances of WPU polymer via introducing the SiO
x
/TiO
2
@Ti
3
C
2
.
The depletion of limited petroleum resources used for the fabrication of epoxy resins calls for the development of biomass-based epoxides as promising alternatives to petroleum-derived epoxides. ...However, it is challenging to obtain an epoxy resin with both high lignin content and excellent mechanical performance. Herein, a 4-dimethylaminopyridine (DMAP)-lignin epoxide with a certain epoxy value and a small molecular weight is obtained by the catalysis of DMAP for the macromolecular lignin. It was discovered that compared to the prepared composite resin of benzyltriethylammonium chloride (BTEAC)-lignin epoxide, there is a better low-temperature storage modulus for the DMAP-lignin epoxide resin and its composite resins with high-biomass contents, and higher tensile strength for its composite resins. In particular, the DMAP-lignin epoxide/ bisphenol A diglycidyl ether (BADGE) (DB) composite resin with DMAP-lignin epoxide replacement of 80 wt% BADGE, containing up to 58.0 wt% the lignin epoxide, exhibits the tensile strength of 76.3 ± 3.2 MPa. Its tensile strength is 110.2% of BTEAC-lignin epoxide/BADGE (BB) composite resins and is comparable to that of petroleum-based epoxy resins. There are good application prospects for the DB composite resin in the engineering plastics, functional composite, grouting, and other fields.
•A novel vinyl-terminated fluorosilicone graft copolymer was synthesized (Vi-PFSi).•High hydrophobic and oleophobic surface was obtained using small amount of Vi-PFSi.•Morphology analysis revealed ...that fluorosilicone groups migrated toward surface.•Fluorosilicone groups obviously improved the dielectric and electric properties.•Tribological property of cured film was enhanced because of fluorosilicone groups.
A novel functional fluorinated siloxane graft copolymer bearing with vinyl end-groups was synthesized from dihydroxypropyl-terminated poly(dimethylsiloxane) (PDMS), dicarboxyl terminated poly(2,2,3,4,4,4-hexafluorobutyl acrylate) oligomer (CTHFA), 2,4-toluene diissocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA). The chemical structure was characterized by FT-IR and GPC. The effect of concentration of the vinyl-capped fluorosilicone graft copolymer (Vi-PFSi) on the surface, thermal properties, dielectric and tribological properties of UV-cured films was investigated. Contact angles and surface energies showed that the high hydrophobic and oleophobic surfaces were obtained by incorporation of Vi-PFSi at very low amount (0.5wt%). X-ray photoelectron spectroscopy (XPS) evidenced that the fluorinated and siloxane moiety selectively migrated to the outermost surface of UV-cured film, thus reduced its surface energy from 45.42 to 15.40mN/m2 without affecting its bulk properties. The morphology of fracture surface of modified film exhibited rough fracture surface only at the outermost surface, revealing fluorinated and siloxane groups migrated toward air-side surface. The dielectric constants decreased from 5.32 (1MHz) for bisphenol-A epoxy methacrylate (EMA) to 2.82 (1MHz) for modified film when the Vi-PFSi copolymer concentration increased from 0 to 0.8wt%. Tribological results from abrasion tester suggested that the Vi-PFSi could obviously reduce the abrasion weight loss of modified films.
Fluorinated (meth) acrylate oligomer modified epoxy resin (PHFBMA-DGEBA) and polyether-modified epoxy resin (MPEG-DGEBA) were successfully synthesized and used as reactive modifier and emulsifier for ...epoxy resins, respectively. GPC, FTIR and
1
H NMR were employed to verify the synthesis. The influence of both the concentration and the molecular weight of PHFBMA-DGEBA on the properties of waterborne epoxy resin coatings was investigated. Surface energy and surface composition were probed by contact angle measurements and X-ray photoelectron spectroscopy (XPS), which strongly confirmed the enrichment of fluorinate atoms on the surface. The surface energy of waterborne epoxy coating was decreased from 44.46 mN/m to 23.20 mN/m by adding just 0.09 wt% PHFBMADGEBA-2, indicating its high effectiveness in improving the surface hydrophobicity. Moreover, the physical properties of waterborne epoxy coatings prepared with different concentration and molecular weight of fluorinated reactive modifier, such as water absorption, Shore D hardness, adhesion, thermal properties and optical transmittance, were also analyzed in detail. Taken together, the waterborne epoxy coatings prepared with low concentrations of reactive modifier are economical and have great potential in large scale industry applications.
In this paper, various fabrics with good self-cleaning performance were prepared via a facile dip-coating method. The fabrics composed with different fibers and woven techniques were firstly immersed ...in ZnO sol to increase the surface roughness, then dip-coated in fluoroalkylsilane (HFT) solution to reduce the surface energy. The coated fabric showed excellent superhydrophobicity with a water contact angle (WCA) of 157.8° and water shedding angle (WSA) of 5 °. The morphologies and chemical compositions of prepared fabrics were observed with SEM, XPS and EDS. The obtained fabric kept stable water-repelling property in acidic and alkaline solutions, solvents and UV irradiation. Benefited from its high antiwater ability and photocatalysis function of ZnO, the coated fabric demonstrated excellent self-cleaning performance. This versatile approach of constructing superhydrophobic fabrics is attractive and could be large-scaled employed in industrial production process.
Waterborne difunctional polyacrylate with long fluorinated side chains and epoxy groups (WALF) was successfully synthesized and used as emulsifier and reactive surface modifier for epoxy resin. The ...structure of WALF was characterized by FTIR and
1
H NMR. In order to investigate the effect of the length and the content of the fluorinated side chains on the properties of the epoxy thermosets, a waterborne difunctional polyacrylate with short fluorinated side chains and epoxy groups (WASF) was developed as a contrast modifier. The waterborne epoxy emulsion modified by WALF or WASF was prepared through phase inversion method. Transmission electron microscopy (TEM) signified that the waterborne epoxy emulsion has a particle size range of 201.4–590.2 nm, indicating excellent water dispersion property. In addition, the surface properties, thermal properties, and mechanical properties of the waterborne epoxy coating were also analyzed in detail. Compared with WASF, the epoxy coating modified by WALF had higher surface fluorine atomic concentration, lower surface energy, and higher thermal stability.
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