Preparation of partially neutralized poly(acrylic acid) microspheres via inverse pickering suspension polymerization

Abstract

Partially neutralized poly(acrylic acid) (PAA) microspheres have been prepared by Inverse Pickering Suspension Polymerization (IPSP) using 1,2‐dichlorobenzene (DCB) and hydrophobic fumed silica nanoparticles (HFSi‐NPs) as organic dispersing media and dispersing agent respectively. As crosslinker N,N'‐methylene bisacrylamide (MBAc), as initiator potassium persulfate (KPS) and sodium metabisulfite (SMBS) redox couple were used. Neutralization degrees were adjusted using 8N NaOH solution and polymerizations were initiated at 34°C. Water/oil phase ratio was set to 1/7 for all polymerizations. Morphology of prepared dry poly(acrylic acid) beads was examined by two microscopic methods, scanning electron microscopy (SEM) and optical microscopy. Prepared microsized polymer beads were observed as smooth and spherical in shape. Effect of neutralization degree (α) varied from 70% to 90% on absorptions in both distilled water and saline solutions, absorption under load (AUL) and crosslink density (CD) results were also investigated. POLYM. ENG. SCI., 59:162–169, 2019. © 2018 Society of Plastics Engineers

Microwave-Assisted Hydrothermal Decomposition of Super Absorbent Polymers

“…Samples treated with microwave heating were observed to be 53% decarboxylated as compared to stock SAP as monitored by the band ratios of 1710 cm −1 /1460 and 1580 cm −1 /1460 cm −1 . 30,31 Samples treated via autoclave heating exhibited a decarboxylation degree of 60%. This result is consistent with previous literature comparing microwave and conventional heating in organic synthesis and polymer processing.…”

Synthesis of copolymer nanocomposite by in situ intercalative polymerization for batch and fixed bed adsorption

“…AA monomer was partially neutralized by drop-wise addition of 20% NaOH (w/v) in an ice bath (to eliminate the exothermic heat of neutralization) with a degree of neutralization (α = n b /n a ,n a and n b are mole of AA and NaOH, respectively) of 40%. 19 The weighed amount of partially neutralized AA (AA/NaAA) monomer, MA, and MBA crosslinker-comonomer were then added to the thee-neck reactor followed by addition of KPS/SMBS redox initiator pair and NaMMT clay. The reaction was carried out at 30 C for around 3 h until the gel was obtained.…”

Preparation of Cross-Linked Monodisperse Poly(acrylic acid) Particles by Precipitation Polymerization

“…Water-soluble polymers are widely applied in dispersants, thickeners, flocculants, and superabsorbent polymers. − Poly­(acrylic acid) (PAA) is a well-known water-soluble polymer commonly produced by aqueous solution polymerization − or heterogeneous polymerization. − Commercially available PAA for the applications of thickeners, flocculants, and superabsorbents is mostly in a powder form, which makes handling easier.…”

“…To obtain the powder form of PAA, various heterogeneous polymerizations are utilized. Inverse suspension polymerization could be used for the preparation of the PAA particles in hexane, and (more recently) inverse Pickering suspension polymerization was also reported in which hydrophobic silica nanoparticles were used as a particulate stabilizer . A common problem in these processes is the use of surfactants or stabilizers.…”

“…Inverse suspension polymerization could be used for the preparation of the PAA particles in hexane, 23 and (more recently) inverse Pickering suspension polymerization was also reported in which hydrophobic silica nanoparticles were used as a particulate stabilizer. 21 A common problem in these processes is the use of surfactants or stabilizers. The surfactant for inverse suspension polymerization is rather hydrophobic; thus, the residual surfactant sometimes gives rise to a turbid aqueous solution of PAA.…”