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Li Q, Yi Y, Wang YN, Li J, Shi B. Effect of cationic monomer structure on the aggregation behavior of amphoteric acrylic polymer around isoelectric point. JOURNAL OF LEATHER SCIENCE AND ENGINEERING 2022. [DOI: 10.1186/s42825-022-00078-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
AbstractAmphoteric 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.
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Chen Y, Li X, Zizeng W, Feng L, Xie J, Lin Z, Xu Z, Liu B, Li X, Zheng H. Research on a new cationic polyacrylamide (CPAM) with a cationic microblock structure and its enhanced effect on sludge condition and dewatering. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:51865-51878. [PMID: 33990923 DOI: 10.1007/s11356-021-14325-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 05/03/2021] [Indexed: 06/12/2023]
Abstract
Flocculation is one of the commonly used sludge conditioning methods in water supply plants, which can improve the sludge dewatering performance by reducing the specific resistance of sludge (SRF), decreasing the amount of sludge, and finally lowering the transportation cost and subsequent disposal cost of sludge. Therefore, it is particularly important to develop new and efficient flocculants. In this paper, the template copolymer of acryloxy trimethylammonium chloride (DAC) and acrylamide (AM) was successfully synthesized by microwave-template copolymerization (MV-TP) using sodium polyacrylate (NaPAA) as template. The template copolymer was analyzed by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), and scanning electron microscopy (SEM). It was found that this template copolymer had obvious cationic microblock structure. In addition, the test results of association constant (KM) and polymerization kinetics showed that the MW-TP was assigned to free radical initiated polymerization and the polymerization mechanism was I Zip-up (ZIP). It confirmed the formation of cation fragment structure again. Due to its dense positive charges in this new cationic microblock structure, it greatly improved the functions of electric neutralization, electrical patching, and adsorption bridging. The cationic fragment structure in the template copolymer could help to generate large and dense floc structure and form stable drainage channels. Under external pressure, these large and compact floc structures had greater compressive resistance, which avoided deformation and blockage of drainage channels and voids. It was beneficial to reduce SRF and evidently enhanced sludge dewatering performance.
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Affiliation(s)
- Yuning Chen
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Xuhao Li
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Wang Zizeng
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Li Feng
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China.
| | - Jiehong Xie
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Zeluan Lin
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Zhihong Xu
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Bingzhi Liu
- School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Xiang Li
- School of Civil Engineering and Architecture, Chongqing University of Science and Technology, Chongqing, 401331, China
- Chongqing Key Laboratory of Energy Engineering Mechanics & Disaster Prevention and Mitigation, Chongqing, 401331, China
| | - Huaili Zheng
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
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