China
Africa
Explore chapters and articles related to this topic
Copolymerization of Nonconjugated Dienes with Conventional Vinyl Monomers
Published in George B. Butler, Cyclopolymerization and Cyclocopolymerization, 2020
The preparation of acrylamide-dimethyldiallylammonium chloride-diethyldiallylammonium chloride terpolymer has been reported by terpolymerizing the corresponding monomers in the presence of ethylenediamine tetraacetic acid (EDTA), Na salicylate, (NH4)2S2O4, NaHSO3, and CuSO4.23 The partially hydrolyzed polymer was useful as a retention aid in paper making.
Stability of fatty acid-containing AKD emulsions and sizing performance on handsheets
Published in Journal of Dispersion Science and Technology, 2020
Lili Melani, Jung-Yoon Park, Hyoung-Jin Kim
Paper is composed of cellulosic fiber containing hydroxyl groups that give hydrophilic properties. Most paper or board grades need to be resistant to liquids such as water, aqueous solutions, and suspensions. Therefore, for improving the hydrophobicity of paper in the papermaking process, chemical additives were introduced as internal sizing or surface sizing.[1] Internal sizing adds a sizing agent into the wet end of paper machines. The liquid penetrating the paper or board is limited by the inner structure modification of the paper. The main purpose of internal sizing is establishing a barrier against the penetration and spreading of liquids through the pore systems of paper and board. In surface sizing, the sizing agents are applied to dry paper web in the dry end of the papermaking process.[2] Surface sizing modifies the liquid absorption properties of paper and board surfaces. Common sizing additives added to paper machine include rosin, alkyl ketene dimer (AKD), and alkenyl succinic anhydrides (ASA). In addition, to improve the hydrophobicity of paper, sizing also improves paper printability by controlling ink spreading and absorption. In order to apply a sizing system, the wet-end chemistry and chemicals need to be considered due to the individual chemistry of paper. In the case of internal sizing, additives chemical such as filler, retention aid, starches, alums, biocides, and surfactants, should be considered.[3]
Effect of different ions present in fresh water on performance of polyvinylamine based ASA emulsion
Published in Journal of Dispersion Science and Technology, 2020
Ashish Kumar, Nishi K. Bhardwaj, Surendra P. Singh
The density of light amber color ASA oil was 0.963 g/cm3 at ambient temperature. Cationic fatty acid condensation product was used as cationc fixing agent (CFA), poly aluminum chloride (PAC) to maintain the pH/charge, tapioca based cationic starch having 0.025 degree of substitution as dry strength additive and a cationic polyacrylamide (i.e. CPAM) having medium to high molecular weight as retention aid were used at wet end during the stock preparation. Fresh water basically the ground water collected from a borewell was used in ASA emulsification. Various chemicals of laboratory grades viz. calcium chloride, sodium chloride, magnesium sulfate, sodium sulfate and sodium bicarbonate were procured from Loba Chemie Pvt. Ltd.
Investigation into the Ozone Reactivity during the O3/O2 Flotation of Recovered Cellulosic Fiber: Does Ozone Affect the Papermaking Properties of Fibers?
Published in Ozone: Science & Engineering, 2021
A. Ghorbel, N. Marlin, M. Aurousseau, A. Boyer
To characterize the whole fiber suspension, pads of “entire pulp” were produced. The fibrous suspension containing an equivalent of 4 g oven-dry pulp material is filtrated after the addition of (1) a retention aid solution (cationic polyacrylamide at 2 g/L in water) to retain all the remaining soluble contaminants, in particular detached ink particles still present in the fiber suspension and (2) an aluminum sulfate solution at 2 g/L till to reach neutral pH (INGEDE Method 1, 2014). No two-sidedness effect has been observed.