Papers by Keyword: Emulsion Polymerization

Abstract: The self-assembly system driven by hydrogen bonding has been widely used in various fields. Two hydrogen-bonded cyclophosphazene derivatives with amino groups (AGHP) and carbonyl groups (CGHP) were synthesized by introducing hydrophobic groups and amino groups and hydrophilic groups and carbonyl groups into cyclophosphazene respectively through nucleophilic substitution. After they were dissolved in oil water two phases, stable emulsion, and self-loading membrane structures were obtained through self-loading behavior. The results indicate that strong hydrogen bonding can be formed between these two cyclic phosphazene derivatives with amino and carbonyl groups. This hydrogen bonding can significantly reduce the interfacial tension between water/oil phases (from around 33 mN/m to below 7 mN/m) and improve the interfacial coverage (which can reach over 80%). Meanwhile, under the hydrogen bonding between amino and carbonyl groups, an amphiphilic self-assembled film was obtained at the water oil interface. Through contact angle testing, it was found that the hydrophilic side of this self-assembled film had a contact angle of 77.5° and the hydrophobic side had a contact angle of 124.8°.

Abstract: The core structure of the emulsion was hydrolyzed and condensed by vinyltriethoxysilane and phenyltriethoxysilane, and the shell structure was synthesized by radical polymerization of butyl acrylate, methyl methacrylate, and vinyltriethoxysilane. The Zeta potential of the prepared silicone emulsion was maintained at-40 mV. The emulsion has good stability. Transmission electron microscopy can be used to study the core-shell structure of latex particles. The water contact angle of silicone-modified acrylate coating can reach 94°, and its mechanical durability, alkali resistance, and salt corrosion resistance are better than that of pure acrylate coating.

Abstract: Graphene oxide (GO) exhibits a wide range of outstanding mechanical, electrical, and physical characteristics, and it is of substantial interest to impart such qualities onto polymeric materials such as poly (methyl methacrylate) PMMA for wider specialized functionalization. The attention of this work is on the development of emulsion polymerization procedure to prepare PMMA-GO nanocomposite and the effect of sodium dodecyl sulphate (SDS) surfactant dosages incorporated during the polymerization, on the effect of PMMA surface interactions in oil. The grafting efficiency is quantified using the Fourier-transform infrared spectroscopy (FTIR), and the effect of surfactant concentration on PMMA-GO stability is examined using UV-Visible spectroscopy, zeta potential and particle size analyses using the Malvern Zetasizer. The surfactant free emulsion has a better stabilization in terms of zeta potential analysis compared to emulsion of PMMA-GO with 0.32, and 0.4 wt. % of SDS. The polymerized PMMA-GO can be used as a model system to alter wax crystallization at low temperatures in oil and gas industries.

Abstract: Synthesis of Polyvinyl Acetate (PVAc) through the conversion of Vinyl Acetate Monomer (VAM) was carried out by emulsion polymerization method assisted by thermal initiator Ammonium persulfate (APS) under reaction temperature was kept at 70 °C – 80 °C with 5 hours of reaction time and agitation speed at 300 rpm. The polymerization reaction was running used batch process technique where is all components were mixed all together simultaneously. A set of polymerization reactions was conducted when the absence of surfactant and cationic and amphoteric surfactant presence. The monomer chain's double bond was found at 1645 cm^-1 was measured by FTIR Spectrophotometer did not disappear after polymerization reaction was utterly done. The spectrum FTIR of Polyvinyl acetate did not explicitly found at 1644 cm^-1. During the reaction, characterization was conducted by measuring the solid content value where the maximum solid content was achieved was 6,1 % when using Amphoteric surfactant while the lowest solid content was obtained when the absence of surfactant. Other parameters were conducted to observe the acidity value by pH Meter.

Abstract: This experiment was conducted to investigate thermal and mechanical properties of the biodegradable composites based on Poly (lactic acid) (PLA) incorporated with cellulose-graft-polystyrene (cellulose-g-PS) at 1, 3, 5 and 10 wt%. The modification of cellulose filler was confirmed by the T_d shifting of thermogravimetric analysis (TGA) thermogram from 334 to 348 °C and characteristic peaks corresponding to the styrene benzylic ring obtained from fourier-transform infrared spectroscopy (FTIR) analysis. The slight improvement of PLA properties with addition of 1 wt% of cellulose-g-PS composite probably was due to the good interaction and compatibility between filler and the matrix of polymer.

Abstract: Hybrid nanoparticles were prepared by direct polymerization of methyl methacrylate, vinyl acetate, and styrene monomers onto the unmodified hydrophilic surfaces of 33 nm silica nanoparticles in a semi-continuous soap-free emulsion polymerization at a monomer starved condition. The polymerization was initiated by potassium persulfate with constant monomer feed at 0.01, 0.02, or 0.04 mL/min. The growth of the core-shell nanoparticles were measured by a laser particle size analyzer. FT-IR spectra analysis confirmed the hybrid structures of the synthesized nanoparticles. SEM images and size exclusion chromatography (SEC) results indicated regular core-shell microsphere structures. The hybrid nanoparticles increased in monodispersity and size over 100 nm with the reaction. However, SiO₂/polystyrene (PS) nanoparticles grew much faster compared with SiO₂/polymethyl methacrylate (PMMA) and SiO₂/polyvinyl acetate (PVAC). There was particle coagulation, about 12 SiO₂/PS particles aggregating to one, in the early stage of the seeded process. In addition, PS secondary particles were formed before the particle coagulation, and then merged with the SiO₂/PS nanoparticles in the particle coagulation. The formation of SiO₂/polymer hybrid nanoparticles depended on the hydrophilic characteristics of the polymer, and the size of silica seeds.

Abstract: Submicron hybrid particles were prepared by direct polymerization of three monomers of styrene, methyl methacrylate (MMA), and vinyl acetate (VAC) onto the hydrophilic surface of 230 nm silica submicron particles without any coupling agent in a semi-continuous emulsifier-free emulsion polymerization at a monomer starved condition. The polymerization was initiated by potassium persulfate with constant monomer feed at 0.01, 0.02, or 0.04 mL/min, after adding 230 nm silica seed particles. The particle growth was investigated with a laser particle size analyzer and SEM, and the particle surfaces by Fourier transform infrared spectroscopy (FT-IR). It was founded that the growth of the hybrid particles depended on the hydrophobic characteristics of the polymers. When monomer was the most hydrophobic styrene, polystyrene (PS) shells split off from the hydrophilic surface of the unmodified silica particle whenever the shells reached a limit of ~20 nm. However, both polymethyl methacrylate (PMMA) and polyvinyl acetate (PVAC) shells grew constantly on the hydrophilic surface of silica particles. In the process of the whole reaction, the SiO₂/PMMA and SiO₂/PVAC hybrid particles kept almost monodisperse.

Abstract: In this contribution, hard/soft latex blends were prepared by mixing proportionable non-crosslinkable hard and self-crosslinkable soft latices. The stability and mechanical properties of latex blends were comparatively studied with the neat latex with high glass transition temperature (T_g). It was found that the calcium ion stability of the latex blends is better than neat hard latex. In addition, the stress at break decreased with the increasing of φ_s (mass fraction of soft particle in latex blends) and the break elongation increased when φ_s below 0.8. Meanwhile, the value of tensile stress and break elongation of the hard latex film with coalescing agent, DPnB, additive is between that of the latex blends film with 60% and 70% soft particle. The study on viscoelasticity of the latex films demonstrated that this composite latex can be considered as phase separation blend involving a soft phase filled with hard spheres. The results indicate that the soft latex can serve as the substitution of coalescing agents in water-based ink industry to obtain low or zero VOC ink, without compromise on properties.

Abstract: Core-Shell structure Poly(vinyl acetate-butyl acrylate) emulsion is prepared by the semi-continuous emulsion polymerization. And the emulsion particles are modified by ethyleneglycol dimethacrylate crosslinker (EGDMA) to improve the properties of films in the different reaction stages. Then the emulsion particles structure is characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The particle size and distribution are characterized by Zata Potential- Particle analyzer, as well as analysis of the film mechanical properties and thermal performance. The results show that the emulsion particles possess a clear core-shell structure. The performance of the emulsion film show better when 1% and 0.5% EGDMA are added in the second reaction and the third reaction stage respectively under the emulsion preparation process.

Abstract: Soap-free Cationic polystyrene microspheres were prepared by emulsion polymerization using a water soluble monomer Methacrylatoethyl trimethyl ammonium chloride (MADAC). Experimental studies were performed in detail to check the effect of the synthesis process of the microspheres, the MADAC dosage, and initiator dosage on the particle size and distribution. The chemical structure of latex particles was characterized by Fourier transform infrared spectroscopy. The micro-morphology of latex particles were observed by Transmission electron microscope. The results show that different particle sizes of polystyrene microspheres with good monodispersity were finally obtained by seeded semi-continuous emulsion polymerization.