Synthesis and fluid properties of acrylic emulsion thickeners (2)

2.2 The main factors affecting the performance of emulsions
2.2.1 effects of functional monosomes and dosages on thickening properties As can be seen from Figure 3, the viscosity of the system is low when pH 6. When the pH is raised to 7 to 8, the viscosity of the co-polymer emulsion containing 4 wt% functional monomer is significantly increased. Because with the polymer molecular chain of the carboxyl is gradually meliuminated, on the one hand, the electrostatic refractive refractive force between the root ions of the polymer causes the polymer chain to gradually stretch from the shrinking line group, the fluid mechanics volume of its solution increases, resulting in an increase in the viscosity of the solution; When pH is raised above 8, the molecular chain stretch is reduced due to the shielding of anti-ions, which causes the viscosity of the system to decrease slightly. The viscosity of acrylic co-polymers without functional monomers is much smaller.. The effect of functional monobody dosing on thickening performance is further studied (Figure 4). As can be known from Figure 4, the viscosity increases significantly as the amount of functional monosome increases. This is because, with the increase of the content of functional monomers in the copolymer, the structure of the synthetic physical crosslinking network of hydrophobic alkyl chains is becoming more and more complete, so the viscosity is getting bigger and bigger, and the effect of alkali thickening is becoming more and more obvious. However, when its content exceeds 10 wt%, the viscosity decreases due to the increased chance of connectivity within the polymer molecular chain.effects of 2.2.2.2 crosslinkers and dosages on viscosity
Figure 5 shows the effect of different crosslinkers on thickening properties. As can be known from Figure 5, the viscosity of the system added to the DAP increases rapidly with pH and maintains a high viscosity over a wide pH range compared to the addition of PETA as a crosslinker. This may be because DAP as a cross-linking agent of secondary function provides a more suitable cross-linking network structure, after alkali neutralization, the chain segment can be effectively stretched, thus having a more excellent thickening. By adding PETA of three-function energy, the cross-link density of the co-concentration is too large to dissolve effectively, and the thickening effect is slightly worse.. The effect of crosslinker DAP dosage on the viscosity of polymers with a solid content of 1% at pH=8 was further studied (Figure 6). As can be known from Figure 6, when daP usage is low, viscosity increases with crosslinking, and thickening at 0.4 wt% of DAP is best. Continue to increase the amount of DAP, emulsion thickening capacity decreased. Because crosslinker can make the polymer form a chemical cross-network structure, the dosage is small, the polymer molecule can fully dissolve, with the crosslinker dosage increased, the polymer particle rigidity increased, so the viscosity increased, thickening effect is significant. Crosslinking agent dosage is too large, network crosslinking structure is excessive, add alkali is not easy to be water-soluble expansion, so the viscosity is low, thickening effect is poor.. 2.2.3 Effect of MAA dosing onFigure 7 shows the effect of different MAA dosing on thickening performance. As can be known from Figure 7, the viscosity of the same pH system increases gradually with MAA in the range of pH-6 to 9, and the viscosity increases at 35 % of MAA, and then the viscosity begins to decrease. The pH corresponding to the maximum viscosity is reduced from 8.08 to 7.28, i.e. the desired moderate degree is reduced. This is because at low MAA content, sufficient -COOH must be mediumed to fully extend the polymer molecular chain in order to produce maximum electrostatic rebuke; On the one hand, with the increase of MAA, the electrostatic rebuke force between the meso-COO-s is also increased, the polymer molecular chain is also more stretched, the hydrophobic base group can form a greater degree of inter-chain connectivity, the density of physical cross-linking network nodes increases, the network strength increases, and the viscosity of the system increases. When the MAA content exceeds a certain value (35%), the corresponding viscosity decreases due to the increase of anti-ion shielding.. 2.3 Thickener's thickening fluid vulient behaviorThe effect of emulsion thickener on chlorpyrine emulsion was studied, and the results are shown in Figure 8. As can be seen from Figure 8, the viscosity of pure chlorpyrine emulsion is very low, and it hardly changes with the shear rate, which shows the properties of Newtonian fluid. With the increase of thickening lotion dosage, the viscosity of the system, especially the viscosity of zero-cut (approximate to the viscosity of ṙ-0.01), increases significantly, and the viscosity in the wider shear rate range decreases significantly with the increase of shear rate, i.e. shear thinning. 0.5 wt.% thickening emulsion can significantly improve the zero-cut viscosity of chlorpyrine emulsion system, giving the system a certain tactient performance. When the amount of thickening lotion is 2.0 wt.%, the system shows good tentacle performance in the whole shear rate range, and shows its good application prospects in water-based coatings, inks, adhesives and cosmetics.3 ConclusionIt is legal to use pre-emulsified seed semi-continuous emulsion, and the functional monomer of long-chain alkyl polyethylene ether methyl acrylates is copolymerized with methyl acrylic, ethyl acrylates, phthalates and propylene phthalates, resulting in an emulsion-type thickener with low initial viscosity and one particle size distribution. The results show that the introduction of functional monomer can significantly improve the thickening performance of emulsion, when the amount of phthalates propylene propylene crosslinker accounts for 0.4 wt of co-poly monomer mass, MAA dosage accounts for 35 wt% of co-poly monomer, emulsion has a better thickening performance. The thickener has obvious thickening effect on chlorpyridine emulsion, which can significantly improve its tentacle performance, and shows that the emulsion thickener has good application prospects in water-based coatings, inks, adhesives and cosmetics..