- Preparation method of tetramethylolmethane-tri (3-aziridine) propionate
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A preparation method of tetramethylolmethane-tri (3-aziridine) propionate includes the steps: (1) mixing tetramethylolmethane with acrylic acid, adding methylbenzene and adding para-toluenesulfonic acid and hydroquinone while stirring the materials; (2) placing the materials in an oil bath, stirring and heating the materials and performing reflux reaction; (3) cooling the materials to reach room temperature, filtering reaction liquid, transferring the filtered reaction liquid into a separating funnel and neutralizing the reaction liquid by NaOH solution; (4) washing a separated oil layer after standing and layering; (5) performing reduced pressure distillation for the separated oil layer after standing and layering to obtain light yellow transparent liquid; (6) dripping aziridine into the light yellow transparent liquid kept being stirred, and transferring the liquid into a brown bottle; (7) placing the brown bottle in a dark place at the room temperature for 24 hours to obtain the tetramethylolmethane-tri (3-aziridine) propionate. An organic compound prepared by the preparation method is used for curing water-soluble polyurethane dispersoid to obtain a strippable protection film layer with the stripping strength of 300-500 newtons per meter.
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Paragraph 0006
(2017/06/02)
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- Piezoelectric pH sensors. AT-cut quartz resonators with amphoteric polymer films
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Piezoelectric AT-cut quartz resonators immersed in aqueous media, coated with cross-linked films of the random copolymer-{[CH2CH(CO2H)]a-[CH2C(CH3) (CO2CH3)]b-[CH2C(CH3) (CO2CH2CH3-NMe2)]c}n (1), exhibit large frequency changes when the pH is changed in the vicinity of the isoelectric point of the polymer film. The frequency changes are attributed to changes in the viscoelastic properties of the films that occur during phase transitions between the isoelectric form and the cationic polymer (1-NMe2H+) present at low pH or the anionic polymer (1-CO2-) present at high pH. These phase transitions are accompanied by dramatic changes in acoustic energy attenuation, film thickness changes, and film surface energy, as indicated by acoustic impedance analysis, phase measurement interferometric microscopy, and contact angle measurements. The results are consistent with pH-dependent segregation of the isolectric and ionic phases within the bulk and between the bulk and the surface. The unique pH-sensing capabilities of the coated resonators, combined with their robustness, ease of fabrication, and low cost, provide a convenient approach for the measurement of 'threshold' pH changes. Real-time measurements of enzymatic activity and microbe metabolism are demonstrated as examples of potential applications of these sensors.
- Wang,Ward,Ebersole,Foss
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p. 2553 - 2562
(2007/10/02)
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