3 lines
6.6 KiB
JSON
3 lines
6.6 KiB
JSON
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"protocol": "The synthesis of hydrophilic polymers involves the use of (meth)acrylate groups for photopolymerization. Proper selection of acrylic/methacrylic monomers and curing agents is essential to tailor the performance characteristics of the polymers. The process aims to improve the hydrophobicity of the materials for applications by combining these monomers with additives or modifications to achieve the desired properties.Minor amount of hydroxyethylmethacrylate were added to promote adherence property. Glycidyl methacrylate was used to introduce epoxy groups to react with methacrylate (MA) in the following reaction step. A series of organosiloxane modified polyacrylate (OSPAs) at different organosilicone concentration ratios were prepared by mixing PA with MATSi. In the presence of photoinitiator, OSPAs were crosslinked by the radical polymerization of the carbon-carbon double bonds in UV irradiation. The obtained polymers were characterized by gel permeation chromatography (GPC), fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR). Additionally, surface hydrophobic, optical, and thermal properties of the cross-linked coatings were investigated by gel content test, flexibility test, pencil hardness test, contact angle (CA) analysis, refraction index test, scanning electron microscope, energy dispersive spectrometer, differential scanning calorimetry thermograms, and thermogravimetric analyzer.Octaphenylpolyoxyethylene (OPE) was obtained from Quzhoumingfeng chemical company. Irgacure 1173 was obtained from Ciba Specialty Chemicals.Dodecylbenzene sulfonic acid (DBSA), glycidyl methacrylate (GMA), hydroxyethylmethacrylate (HEMA), 6-methylheptyl methacrylate (MHMA), methacrylic acid (MA), and methacryloxy propyl trimethoxylsilane (KH570) were utilized for the synthesis of hydrophilic polymers. The synthesis involves mixing these components without purification and can include other solvents and initiators such as methanol, triethanolamine, and azobisisobutyronitrile (AIBN) under specified reaction conditions to obtain the desired hydrophilic polymer with functional groups.The polyacrylate was prepared using a 1:1:8 weight ratio of GMA, HEMA, and MHMA in the presence of 4 wt% AIBN as initiator and butanone as solvent at a temperature of 80°C. The reaction was performed in a four-neck reaction kettle equipped with mechanical stirring, nitrogen inlet, water condenser, and thermometer for 8 hours. After the reaction, butanone was removed by reduced pressure distillation, and the product was labeled as GHM. This was then transferred to another four-neck kettle where a certain amount of MA was added in the presence of 0.8 wt% TBAB. The reaction continued at 102°C until 99.5% conversion was achieved, determined by standard acid value. Remaining butanone and unreacted MA were removed by reduced pressure distillation, and the final product was obtained and labeled as PA.MATSi was synthesized by emulsion polymerization. Distilled water, surfactants (DBSA and OPE), and monomers (D4) were added into a four-necked flask equipped with a thermometer, a reflux condenser, a mechanical stirrer, and a nitrogen inlet. Nitrogen was introduced to remove oxygen initially. The reaction was carried out for 8 hours at 80°C with stirring at about 500 rpm. After neutralizing with NaOH solution to stop the reaction, the final latex of PDMS was obtained. A specific quantity of KH570 was added into PDMS latex, and the condensation reaction of PDMS and KH570 was performed at 80°C for 3 hours. The copolymers were precipitated in ethanol and dried in a vacuum drying oven. The product was purified in ethanol and hexane several times to remove unreacted monomers and surfactants, resulting in the product designated as MATSi.Mix PA and MATSi in relative mass ratios ranging from 100:0 to 90:10. Add 5 wt% photoinitiator (Irgacure 1173/triethanolamine at a 2:3 w/w ratio) to each formulation while stirring for 10 minutes. Use triethanolamine to prevent oxygen inhibition during the UV-curing process. Cast the films onto a glass plate using 5% w/v solutions.Copolymers are synthesized in methanol using a wire-wound applicator. The coated films are allowed to sit at room temperature for at least 5 minutes until the solvent evaporates. After evaporation, the films are irradiated with a high-pressure mercury lamp (500W) for 30 seconds, maintaining a distance of 20 cm from the lamp to the surface of the samples in air atmosphere. The final thickness of the coating is approximately 100 micrometers.The molecular weight and distributions of PA and MATSi oligomer samples were measured at 25°C by gel permeation chromatography (GPC) on Waters 2410 instrument with THF as the solvent (1.0 ml/min) and polystyrene as the calibration standards. The FT-IR spectra were recorded with TENSOR27, Bruker, Germany spectrometer over the range 400 to 4000 cm^-1. 1H NMR and 29Si NMR were recorded with a 400MHz Bruker NMR spectrometer using CDCl3 as solvent and tetramethylsilane as the internal reference. The gel content method was performed on the cured films by measuring the weight loss after a 48-h extraction at 80°C, according to the standard test method ASTM D2665-84. Gel content was calculated as: Gel content = (W_t / W_0) × 100%, where W_0 is the initial weight of the film, and W_t is the final weight after extraction.Five UV-curable organosiloxane modified polyacrylates, OSPA1, OSPA2, OSPA3, OSPA4, OSPA5, were first prepared in this work in order to study the effects of silicon on the properties of UV-curable composite coatings.The synthesis of hydrophilic polymers involves the reaction of epoxide groups with methacrylic acid (MA) via a ring-opening addition reaction. Monitor the reaction by recording FT-IR spectra to confirm the disappearance of the characteristic absorption peak of the epoxide group at 910 cm^{-1}, which indicates the completion of the reaction. The formation of hydroxyl groups is indicated by the peaks at 1640 cm^{-1} (methacrylate double bond) and 700 cm^{-1} (C-O-H bending). Additionally, confirm the introduction of C=C groups and the presence of acrylate characteristics by observing carbonyl stretch at 1720 cm^{-1} and C-O stretches between 1140 cm^{-1} to 1280 cm^{-1}.The coating formulation was coated on a KBr window and then exposed to UV radiation for 30 s. The degree of conversion was determined using FT-IR spectroscopy by monitoring the absorption band at 1640 cm^{-1} due to C=C vibration. The degree of conversion was calculated using the equation Degree of conversion = (1 - (A_t / A_o)) x 100, where A_o is the absorption before UV exposure and A_t is the absorption after UV exposure."
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