Process Characterization of Polyvinyl Acetate Emulsions Applying Inline Photon Density Wave Spectroscopy at High Solid Contents

The high solids semicontinuous emulsion polymerization of polyvinyl acetate using poly (vinyl alcohol-co-vinyl acetate) as protective colloid is investigated by optical spectroscopy. The suitability of Photon Density Wave (PDW) spectroscopy as inline Process Analytical Technology (PAT) for emulsion polymerization processes at high solid contents (>40% (w/w)) is studied and evaluated. Inline data on absorption and scattering in the dispersion is obtained in real-time. The radical polymerization of vinyl acetate to polyvinyl acetate using ascorbic acid and sodium persulfate as redox initiator system and poly (vinyl alcohol-co-vinyl acetate) as protective colloid is investigated. Starved–feed radical emulsion polymerization yielded particle sizes in the nanometer size regime. PDW spectroscopy is used to monitor the progress of polymerization by studying the absorption and scattering properties during the synthesis of dispersions with increasing monomer amount and correspondingly decreasing feed rate of protective colloid. Results are compared to particle sizes determined with offline dynamic light scattering (DLS) and static light scattering (SLS) during the synthesis.

THE INFLUENCE OF SURFACTANT AND PROTECTIVE COLLOID ON POLYVINYL ACETATE EMULSION SYNTHESIZED BY EMULSION POLYMERIZATION TECHNIQUE

A series of experiments have been carried out and reported. This report describes the stages of the polymerization reaction during emulsion Polyvinyl Acetate (PVAc) synthesis. PVAc was synthesized from the Vinyl Acetate Monomer (VAM) with Ammonium Peroxydisulphate (APS) as an inorganic thermal initiator in the aqueous media under reaction temperature was keep at 65 until 75oCs by agitation speed was 300 rpm respectively during 4 hours of reaction time. The protective colloid agents and several types of surfactants were added to improve the obtained emulsion PVAc performance. The polymerization reaction was carried out without the addition of a protective colloid agent. The surfactants were produced the emulsion PVAc with the properties of solid content 0.89%, density 1.02 g/ml, viscosity 0.0033 Poise, pH 2.8, conductivity 12 ms, respectively. While the polymerization reaction involved protective colloid agents by using Polyvinyl Alcohol (PVOH) was obtained properties of emulsion PVAc with Solid Content 4.36%, density 1.17 g/ml, viscosity 0.0216 Poise, pH 2.8, and conductivity 10 ms respectively. The same thing was shown when the surfactant was present in the polymerization reaction. The emulsion PVAc was synthesized with nonionic surfactant has solid content 8.20%, density 1.17 g/ml, viscosity 0.0099 Poise, pH 2.8, and conductivity 7 ms, the result is better rather than synthesized with anionic surfactant has solid content 2.65%, density 1.13 g/ml, viscosity 0.0068 Poise, pH 2.8, and conductivity 11 ms. According to the preliminary observations obtained, emulsion PVAc’s appearance is better when the protective colloid agents and the surfactant is present rather than without additional those substances. The physical properties of emulsion were depended on the addition of protective colloid agents and surfactants. In addition, the complete reaction indicated by solid content value was obtained from emulsion when the additional substances were present. All the testing parameters were observed using Viscometer Ostwald, Pycnometer, pH Meter, FTIR Spectrophotometer, Conductometer, and another supporting testing to explain the polymerization reaction stage of synthesis emulsion PVAc.

Study of SMA as Protective Colloid on the MF-Resin Micro-Encapsulation

The paper studied the effects of SMA as protective colloid on emulsification and micro-encapsulation process in the preparation of MF-resin microcapsules. The results indicated that pH value and the dosage of the SMA had important effects on zeta value and micro-encapsulation. The SMA dosage, emulsifying time and stirring rate influenced the capsule preparation, mean particle size and particle size distribution of microcapsules. The diameter became smaller with the increase of the amount of protective colloid. The applying amount of the SMA had an optimum value. The zeta potential just after emulsification was much larger than after reaction of MF in the preparation of microcapsules.

Effects of Protective Colloid on the MF-UF Double Wall Micro-Encapsulation Containing Essence Oil

Essence oil is difficult to microencapsulate and difficult to envelop into wall to prepare pressure sensitive microcapsules. With styrene maleic anhydride copolymer (SMA) as the protective colloid, the paper studied the effects of protective colloid and micro-encapsulation of pressure sensitive perfume microcapsules with melamine formaldehyde resin (MF) and urea formaldehyde resin (UF) as double wall first time by using the re-in situ polymerization method. The microcapsules and emusion process were characterized on morphologies, mean particle size and size distribution, zeta potebtial, wall thickness of microcapsules. It was found that the SMA seemed to be suitable for the emulsification and preparation of microcapsule with MF-UF resin as double wall containing essence oil. The results indicated the S/M mole ratio in MSA molecules affected the preparation and quality of microcapsules, pH value and the dosage of SMA had important impact on zeta value and encapsulation in the process of polymerization. The stirring time and stirring rate in emulsification process with MSA as protective colloid influenced the mean particle size and particle size distribution of microcapsules, SMA was one of the components of microcapsules, SMA amount used affected the mean particle size, size distribution and thickness of microcapsules.

Copolymerization of Organosilicone-Veova10-VAc Emulsion Modified with Protective Colloid of PAM-PEG

The purpose of this work is to modify the organosilicone-veova10-vinyl acetate (OSVVVA) copolymer emulsion with protective colloid in order to improve the viscosity of the original emulsion. The protective colloid was first prepared with polyacrylamide and polyethylene glycol as raw materials. The effects of use levels of protective colloid, vinyl triethoxyl silicane and potassium persulfate and reaction temperature on emulsion properties were investigated by orthogonal experiment and their optimum values were determined to be:50 g, 4 g, 0.5 g and 84 °C, respectively, under which the viscosity of the modified OSVVVA emulsion was greatly increased from 120 mPa•s to 430 mPa•s and the other properties of the modified OSVVVA were also satisfactory. The infrared spectra of the modified OSVVVA emulsion proved that the protective colloid was successfully grafted onto the OSVVVA copolymer emulsion.