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Due to the deterioration of the environment, the environmental protection has received more and more attention from the world. Various countries have established regulations to strictly limit the emission of organic volatiles (VOC) in paints. Solvent-based paints contain a large amount of VOC components, which not only pollutes the environment and wastes resources but also endangers people's health. Waterborne polyester coatings as representative waterborne coatings have become the development direction of coatings. In this study, a novel waterborne unsaturated polyester was synthesized by melt polycondensation and its water solubility was regulated by changing the amount of sodium sulfonate group. Then, a series of UV curable polyester networks were obtained utilizing the waterborne unsaturated polyester and multifunctional thiols via thiol–ene click reaction. The water resistance, gel content and mechanical properties of the films were characterized. It was found that the UV-cured films exhibited excellent physical properties including adhesion (1), pencil hardness (5 H), water resistance and contact angle (105.36). This shows that it is feasible to prepare high-performance UV-cured films based on thiol-ene click chemistry.

Amphoteric polyacrylamide was prepared by dispersion polymerization with acrylamide, dimethylaminoethyl methacrylate methyl chloride, and acrylate acid as monomers, ammonium sulfate (AS) aqueous solution as a reaction medium, poly(dimethylaminoethyl methacrylate methyl chloride) (PDMC) as a stabilizer, and 2,2′-azobis(2-amidinopropane) dihydrochloride as an initiator. The influence of particle morphology on AmPAM dispersion and other factors and polymerization were investigated. Three crucial factors responsible for particle morphology are the dispersant concentration, sodium chloride concentration, and ionic degree of terpolymer. The ammonium sulfate concentration had relatively less of an effect on particle morphology, but a suitable concentration was necessary to obtain a stable dispersion system. A higher concentration of PDMC could yield more uniform and spherical particles during dispersion polymerization. A small amount of sodium chloride can decrease particle size and dispersion viscosity. These four factors heavily influenced the viscosity of polymer dispersion, and they had a large effect on the intrinsic viscosity of AmPAM except for the AS and NaCl concentration. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E212–E220, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21264

A cationic polyelectrolyte of P (CMTC-AM-DMC) was synthesized by dispersion polymerization in aqueous solution of ammonium chloride, with acrylamide and dimethylaminoethyl methacrylate methyl chloride as main raw materials. N-carboxymethylthioureidochitosan was used as both the reactant and the stabilizer, and 2,2′-azobis (2-amidinopropane) dihydrochloride (V-50) as the initiator. The effects of the major reaction variables such as the concentration of inorganic salt and initiator, temperature, reaction time, and pH on the polymerization were discussed in this article. The optimal conditions of the polymerization were determined by orthogonal tests. The results showed that an increase in salt concentration resulted in an increase of molecular weight and particle size and a decrease of apparent viscosity, while when salt concentration was up to 23.9%, apparent viscosity was slightly higher than others. Molecular weight, particle size, and apparent viscosity all decreased with the increase of initiator. The apparent viscosity, molecular weight, and particle size would decrease with pH, and the product would be coagulated when pH > 7. Temperature influenced the characteristic a lot. Overall conversion was less dependent on these factors except for the temperature. Molecular weight and overall conversion increased gradually with the time, and the monomers could react completely at about 5–7 h. Flocculation occurred with 13% of salt concentration, 0.005% of initiator, and pH > 7. The optimal reaction conditions for obtaining a stable aqueous dispersion were 22.3% for ammonium chloride, 0.007% for initiator, react under 55 °C for 5 h at pH = 4. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The terpolymer of acrylamide (AM), dimethylaminoethyl methacrylate methyl chloride (DMC), and acrylic acid (AA) was synthesized with their molar ratio of 70 : 15 : 15 through dispersion polymerization in aqueous solution of ammonium sulfate (AS), using poly(dimethylaminoethyl methacrylate methyl chloride) (PDMC) as stabilizer and 2,2′-azobis(2-amidinopropane) dihydrochloride (V-50) as initiator. The particle size of the terpolymer ranged from 5 to 8 μm and the intrinsic viscosity was from 5.5 to 11.6 dL g−1. The terpolymer had anti- polyelectrolyte effect under low AS concentration, but polyelectrolyte effect with the concentration beyond 10%. Polymerization dispersion with low apparent viscosity, uniform particles, good stability, and high molecular weight terpolymer was obtained in single stage. The effects of varying concentrations of salt, stabilizer, and monomers on particle morphology and intrinsic viscosity were investigated. With increasing concentration of AS and PDMC, the intrinsic viscosity of terpolymer increased, then decreased afterward. However, it increased gradually with increase in monomer concentration. The particle size was enlarged with increasing of AS and monomer concentration and decreasing of PDMC concentration. The optimum condition was the concentrations of salt, stabilizer, and monomers 28%, 3.0%, and 8% to 15%, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The copolymer of acrylamide (AM) and 2-acrylamide-2-methyl-propane sulfonate (AMPS) was synthesized through free radical dispersion polymerization in an aqueous solution of ammonium sulfate and poly(2-acrylamide-2-methyl-1-propane sulfonate) as a steric stabilizer. The average particle size of the copolymer ranged from 1.0 μm to 4.0 μm, and the molecular weight was 2.0 × 106 ~ 7.0 × 106 g mol−1. The swelling property of the dispersion copolymer was studied by characterizing the apparent viscosity and particle size distribution. When the dispersion was diluted with salt aqueous solution in which the ammonium sulfate concentration kept equal with that of the original dispersion, particle size and particle size distribution of the diluted dispersion changed little, compared with that of the original dispersion. While diluted with deionized water, particle size and particle size distribution could expand several times. The effects of the AMPS/AM molar ratios, the molecular weight of stabilizer, and the initiation temperature were investigated. It was found that with the increase of the AMPS/AM ratios, the molecular weight of copolymers increased, and then decreased. The particle size and conversion of monomers increased. The stability of the copolymer dispersion increased with increasing the molecular weight of stabilizer for a fixed stabilizer concentration. With the increase of the initiation temperature, the molecular weight of copolymer increased at first and then decreased gradually, but the particle size and conversion increased. The optimum conditions for the stable AMPS/AM dispersion were as follows: the AMPS/AM molecular ratio was 15/85, the molecular weight of the PAMPS stabilizer 3.0 × 105 ~ 4.0 × 105, and the initiation temperature 50 °С, respectively.

Swelling properties of amphoteric polyacrylamide (AmPAM) dispersions were investigated by measurements of apparent viscosity and particle morphology. AmPAM dispersion was prepared by dispersion polymerization in aqueous solution of ammonium sulphate. Changes of particles during dispersion polymerisation of AmPAM were simulated and compared with anionic and cationic polyacrylamide (APAM and CPAM, respectively). Sample viscosity and particle morphology were obtained using a rotational viscometer and optical microscope. It was found that small molecules or ions enter and swell particles in the AmPAM dispersion when (NH4)2SO4 concentration decreases. Similarly, monomers, including acrylamide, acrylic acid, and methacrylatoethyl trimethyl ammonium chloride, have the same effects on the AmPAM dispersion but the effect degree is different. Swelling properties of the AmPAM dispersion were different from those of the APAM and CPAM dispersions due to their different ionic nature, type of stabiliser, media, etc. Particles in the APAM or CPAM dispersions were swelled less than those in the AmPAM dispersion.