Effect of cationic monomer structure on the aggregation behavior of amphoteric acrylic polymer around isoelectric point

Amphoteric polymer can be used as retanning agent in leather manufacture.It is particularly useful in chrome-free tanning systems since it can regulate the charge properties of chrome-free leather and enhance the fixation of anionic post-tanning chemicals in leather.However,the aggregation and precipitation of amphoteric polymer retanning agents around the isoelectric point(pl)hinder their wide application.Herein,we synthesized five amphoteric acrylic polymers(AAPs)by free radical copolymerization with acrylic acid and five different cationic acrylic monomers.The effect of cationic monomer structure on the aggregation behavior of AAPs was investigated.The aggregation of AAPs in aqueous solution showed pH and concentration dependence.Light scattering analysis showed that Poly(AAA-co-MAPTAC)and Poly(AA-co-DMAPMA)were in the shape of coiled linear flexible chains with small particle size(R_(g)7.6 nm and 14.8 nm,respectively)near the pl.However,Poly(AA-co-DAC),Poly(AA-co-DMC)and Poly(AA-co-DMAEMA)were in the shape of hollow spheres and exhibited serious aggregation.Quantum chemical calculations suggested that the amide groups in the cationic monomers MAPTAC and DMAPMA enhanced the nucleophilicity of AAPs.Thus the corresponding AAPs could carry a large number of cationic charges to slow their aggregation when the pH just climbed over the pl.The results are expected to provide theoretical reference for the synthesis and wide-spread application of AAPs.

Effect of cationic monomer on properties of fluorinated acrylate latex

Cationic fluorinated acrylate latex was prepared via semi-continuous emulsion copolymerization of cationic monomer and other monomers. The resultant latex and its film were characterized with dynamic light scattering detector and contact angle meter. Influences of amount of DMDAAC on the properties of resultant latex and its film were investigated in detail. Results show that the particle size of the latex has the minimum value knd the zeta potential of the latex is increased when the amount of DMDAAC is increased. In addition, the particle size of the latex is unimodal distribution when the amount of DMDAAC is not more than 2.5%. However, the particle size of the latex is bimodal distribution when the amount of DMDAAC is more than 2.5%. The contact angle is varied slightly with the increase of amount of DMDAAC when it is not more than 2.5%. Nevertheless, the contact angle is decreased with the increase of the amount of DMDAAC when it is more than 2.5%.

Effect of cationic monomer structure on the aggregation behavior of amphoteric acrylic polymer around isoelectric point

Amphoteric polymer can be used as retanning agent in leather manufacture. It is particularly useful in chrome-free tanning systems since it can regulate the charge properties of chrome-free leather and enhance the fixation of anionic post-tanning chemicals in leather. However, the aggregation and precipitation of amphoteric polymer retanning agents around the isoelectric point (pI) hinder their wide application. Herein, we synthesized five amphoteric acrylic polymers (AAPs) by free radical copolymerization with acrylic acid and five different cationic acrylic monomers. The effect of cationic monomer structure on the aggregation behavior of AAPs was investigated. The aggregation of AAPs in aqueous solution showed pH and concentration dependence. Light scattering analysis showed that Poly (AA-co-MAPTAC) and Poly (AA-co-DMAPMA) were in the shape of coiled linear flexible chains with small particle size (Rg 7.6 nm and 14.8 nm, respectively) near the pI. However, Poly (AA-co-DAC), Poly (AA-co-DMC) and Poly (AA-co- DMAEMA) were in the shape of hollow spheres and exhibited serious aggregation. Quantum chemical calculations suggested that the amide groups in the cationic monomers MAPTAC and DMAPMA enhanced the nucleophilicity of AAPs. Thus the corresponding AAPs could carry a large number of cationic charges to slow their aggregation when the pH just climbed over the pI. The results are expected to provide theoretical reference for the synthesis and widespread application of AAPs.

Studies on a Cationically Modified Quaternary Ammonium Salt of Lignin

A new quaternary ammonium salt monomer was synthesized and a quaternary amination of lignin（ noted as QL）, with the monomer was carried out by grafting copolymerization. The products were characterized by Fourier Transform Infrared spectroscopy（ FTIR）. The experimental results indicate that the yield of the monomer was 99.06%, and the conversion of the monomer and the grafting yield of QL were 93.69% and 185.78%, respectively. The feasibility of QL as the flocculant to be applied in color removal of five artificial dyes, erioehrome black T（dye A）, gongo red（dye B ）, direct fast black G （dye C ）, cuprofix blue green B （dye D ）, and acid black ATT （dye E ） was examined. Results show that OL exhihits the favorable flocculation nerformance and high stability.

Preparation and properties of a double quaternary ammonium copolymer used in acid fracturing

Triethylamine(TEA),1,4-dibromobutane(C4H8Br2)and N,N-dimethylaminopropyl acrylamide(DMAPAA)were selected to synthesize a double quaternary ammonium cationic monomer(TDD).TDD,acrylamide(AM),2-acrylamido-2-methylpropane sulfonic acid(AMPS)and acrylic acid(AA)were used to create a quadripolymer(PAAT)that was characterized by FT-IR and ^(1)H NMR.Following that,the basic performance of thickened acid was assessed.The results revealed that PAAT outperformed PAA(copolymerized by AM,AMPS and AA)in terms of acid solubility,thickening performance,temperature resistance and shear resistance.Furthermore,this crosslinked acid containing PAAT was subjected to a series of performance evaluations.The viscosity of the crosslinked acid could be kept at 67 mPa$s at 160C after 90 min and the weight loss rate of crosslinked acid in acid-rock reaction at 60 min was 23%,indicating the temperature resistance and retarder performance of the crosslinked acid solution was significantly better than that of the thickening acid and the blank acid.A scanning electron microscopy experiment revealed that crosslinked acid has good corrosion ability and low damage to the reservoir.The above experimental results indicated that the thickener PAAT has a promising future application in acid fracturing of high-temperature and high-mineralization carbonate reservoirs.