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CVD of nanocomposite coatings
Published in Kwang Leong Choy, Chemical Vapour Deposition (CVD), 2019
CVD together with polymerisation of methyl cyanoacrylate were introduced on silica aerogels (e.g., 650 mg) at approximately 7 mg/h at ambient temperature and pressure to create a silica-polycyanoacrylate nanocomposite as shown in Figure 7.37 [42]. Dry nitrogen gas (0.1 L/min) carrying methyl cyanoacrylate was delivered to silica aerogels and the polymerisation of methyl cyanoacrylate was initiated by the absorbed water. The resulting nanocomposites were stronger (>30-fold) than untreated aerogels, with rupture strength of unmodified and polycyanoacrylate coatings on the silica aerogel nanocomposites of 0.539N and 17.6N, respectively, while the density only increased (3×) to 0.235 g/cm3. The aerogels changed from transparent to opaque white as a result of the coarsening of silica nanoparticles comprising the aerogels as shown in Figure 7.38. The untreated aerogel immediately adsorbs liquid water and breaks into many pieces, whereas the CVD modified aerogels float intact on water without wetting or cracking as shown in Figure 7.39. The nanocomposites were inherently hydrophobic (water contact angle 129°), making them more likely to withstand degradation and weathering [42,43].
CVD of nanocomposite coatings
Published in Kwang Leong Choy, Chemical Vapour Deposition (CVD), 2019
CVD together with polymerisation of methyl cyanoacrylate were introduced on silica aerogels (e.g., 650 mg) at approximately 7 mg/h at ambient temperature and pressure to create a silica-polycyanoacrylate nanocomposite as shown in Figure 7.37 [42]. Dry nitrogen gas (0.1 L/min) carrying methyl cyanoacrylate was delivered to silica aerogels and the polymerisation of methyl cyanoacrylate was initiated by the absorbed water. The resulting nanocomposites were stronger (>30-fold) than untreated aerogels, with rupture strength of unmodified and polycyanoacrylate coatings on the silica aerogel nanocomposites of 0.539N and 17.6N, respectively, while the density only increased (3×) to 0.235 g/cm3. The aerogels changed from transparent to opaque white as a result of the coarsening of silica nanoparticles comprising the aerogels as shown in Figure 7.38. The untreated aerogel immediately adsorbs liquid water and breaks into many pieces, whereas the CVD modified aerogels float intact on water without wetting or cracking as shown in Figure 7.39. The nanocomposites were inherently hydrophobic (water contact angle 129°), making them more likely to withstand degradation and weathering [42,43].
Cyanoacrylate Adhesives
Published in Gerald L. Schneberger, Adhesives in Manufacturing, 2018
Several plastics—particularly the thermoplastic types like vinyl, butyrate, acrylic, polycarbonate, and polystyrene—usually give slightly stronger bonds with ethyl 2-cyanoacrylate than with methyl 2-cyanoacrylate although the methyl ester normally forms satisfactory bonds. The results of lap shear tests usually show that the bonds will hold, but that the plastics will break when either methyl or ethyl cyanoacrylate adhesives are used. When ethyl 2-cyanoacrylate is used, the plastics usually exhibit slightly higher tensile break values. When either adhesive is applied to the bonding surface or thermoplastics, it shows a solvent characteristic by attacking the plastic surface before polymerization occurs. Presumably, most thermoplastics are attacked more by methyl cyanoacrylate than by ethyl cyanoacrylate, which results in a slightly weaker substrate when the methyl ester is used.
Metal-free domino amination-Knoevenagel condensation approach to access new coumarins as potent nanomolar inhibitors of VEGFR-2 and EGFR
Published in Green Chemistry Letters and Reviews, 2021
Essam M. Eliwa, Marcel Frese, Ahmed H. Halawa, Maha M. Soltan, Larissa V. Ponomareva, Jon S. Thorson, Khaled A. Shaaban, Mohamed Shaaban, Ahmed M. El-Agrody, Norbert Sewald
As stated above in the biological evaluation and predicted docking modes of compounds 4e, 8e, and 9d, structure–activity relationship (SAR) study on the cyclic secondary amine fragment shows that 4-AMP and morpholine units are the optimal for cellular and enzymatic potencies. Compound 4e with 4-AMP and methyl cyanoacrylate cores has good anti-proliferative activity toward all the three tumor cell lines and more active against VEGFR-2 than EGFR. When methyl cyanoacrylate fragment is replaced by malononitrile and 4-AMP is retained, the generated compound 8e is selective toward KB-3-1 and a promising dual inhibitor VEGFR-2 and EGFR. Compound 9d with morpholine and nitro groups is effective against A549 and PC3 cell lines, but selective inhibitor of VEGFR-2 (IC50 =24.26 ± 1.1 nM) in comparison with EGFR (IC50 =165.00 ± 8.0 nM). When 3-NO2 group in 9d is changed by methylene malononitrile unit, the corresponding compound 8d is selective toward PC3 cell line (Table 2). It should be noted that, when methylene malononitrile unit in 8e is substituted by formyl group, the obtained small molecule 5e showed lower inhibitory activity against VEGFR-2 and EGFR kinases (Table 3).