Superabsorbent resin of acrylic acid/ammonium acrylate copolymers synthesized by ultraviolet photopolymerization

A new method of synthesizing a superabsorbent resin (SAR) from an acrylic acid/ammonium acrylate copolymer by direct UV photopolymerization was studied. The effects of the degree of neutralization of acrylic acid, the photoinitiators, the crosslinking agents, and the UV‐light exposure time on the water absorbency (Q) were investigated. The results showed that Q of an SAR based on Irgacure 1700 or Irgacure 1800 and Irgacure 651 was high, reaching about 1200 mL/g, but under the same conditions, Q was low for an SAR based on other photoinitiators. The UV absorption spectrum proved that the photoinitiators matched the UV light source. Among the crosslinking agents, N,N′‐methylene bisacrylamide was more efficient than the others at a small concentration and a high value of Q. ¹³C‐NMR spectrometry was used to identify the mechanism of the crosslinking reaction through the esterification of hydroxyethyl acrylate (HEA) and 2‐hydroxypropyl acrylate with carboxylic acid group in acrylic acid/ammonium acrylate copolymerization, but the efficiency of the crosslinking reaction by esterification was lower than that of the copolymerization of vinyl groups in the crosslinking agent. Q of the acrylic acid/ammonium acrylate copolymer for the SAR reached 1255 mL/g under certain conditions (degree of neutralization of acrylic acid = 75%, Irgacure 651 concentration = 0.2 wt %, [HEA] = 0.2 wt %, exposure time = 10 min). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 546–555, 2005     

Synthesis of superabsorbent resin by ultraviolet photopolymerization

Synthesis of superabsorbent resin (SAR) was achieved by a new method, that of direct UV photopolymerization, and in particular the synthesis of a SAR of acrylic acid–potassium acrylate copolymer by UV photopolymerization was investigated. Influences of ratio (mol) of acrylate monomer to acrylic acid monomer, photoinitiators, crosslinking agents, and exposure time of UV light on the water‐absorbent properties were investigated. The results showed that the water absorbency (Q) of SAR based on Irgacure 1700 or Irgacure 1800 was 545–530 mL/g, but under the same conditions Q was 450 mL/g for the SAR based on Irgacure 651. N,N′‐Methylene bisacrylamide, hydroethyl acrylate, and glycerol were used as crosslinking agents, of which N,N′‐methylene bisacrylamide was the most effective. It crosslinked the molecular chains through attending the copolymerization with acrylic acid (AA) and potassium acrylate. When the exposure time was 5 min, the value of Q was 1368 mL/g (the content of N,N′‐methylene bisacrylamide was 100 ppm). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1618–1624, 2004     

pH‐response superabsorbant hydrogel synthesized by ultraviolet photopolymerization

A new synthesis method of pH‐response superabsorbent hydrogels (SHG) was achieved by direct ultraviolet (UV) photopolymerization, and in particular, the synthesis of SHGs of acrylic acid (AA), sodium acrylate (AANa), and methacrylcholine chloride (MACC) tricomponent copolymer by UV photopolymerization were investigated. The pH value responsive behavior of SHG with different monomer ratios of MACC and AA was researched, and SHG showed large swelling properties at pH value approximately 7. Influences of monomer ratio (mol) of AANa to AA, photoinitiators, crosslinking agents, and exposure time of UV light on the water absorbent properties were studied. The results showed that the water absorbent capacity of SHG based on photoinitiators: Esacure KTO46 or Irgacure 651 can reach comparatively high, N,N′‐Methylene bisacrylamide and diethylene glycol diacrylate (DEGDA) were high efficient crosslinking agents for its crosslinking the molecular chains through attending the copolymerization with monomers. When the exposure time was 10 min, the distilled water absorbency of SHG was 1503 mL/g under the condition: content of MACC, 14.3 wt %; monomer ratio (mol) of AANa to AA: 5.67; content of DEGDA and Irgacure 651, 0.0025 and 0.25 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1847–1852, 2007     

Design and synthesis of superabsorbent polymers

A series of novel copolymer superabsorbents based on the monomers acrylamide (AM), acrylic acid (AA), acrylonitrile, methacrylic acid, sodium acrylate (SA), and 2‐hydroxyethyl methacrylate (HEMA) were prepared by copolymerization using ammonium persulfate as an initiator and N,N‐methylenebisacrylamide as a crosslinking agent. The experimental results of superabsorbent polymers (SAPs) show that the absorbency in water and NaCl solutions is maximum for AM, SA, HEMA and AM, AA, SA combinations. The copolymers were characterized by IR spectroscopy. The water retention of soil was also enhanced using the above superabsorbents. Use of SAPs for the growth of the croton plant was also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2635–2639, 2001     

反相悬浮聚合法合成可生物降解海藻酸钠高吸水性树脂

以丙烯酸(AA)和海藻酸钠(SA)为原料,用反相悬浮聚合法合成了聚丙烯酸钠/海藻酸钠高吸水性树脂。研究了海藻酸钠、引发剂(KPS)和交联剂(NMBA)用量、丙烯酸中和度、聚合反应温度等因素对树脂吸水率的影响以及树脂的生物降解性能。结果表明,当w(SA)=1.5%、w(KPS)=0.15%、w(NMBA)=0.1%、丙烯酸中和度为65%、聚合反应温度为75℃时,树脂对蒸馏水的吸水率为845 g/g,对生理盐水的吸水率为88 g/g,且能被土壤和微生物降解,w(SA)=10%的树脂在60 d内能够被芽苞杆菌降解52%,在土壤中能被降解36%,且降解速度随海藻酸钠质量分数的增加而加快。IR测定表明,树脂为丙烯酸盐与海藻酸钠的接枝共聚物。SEM测定表明,PAA/SA高吸水性树脂呈花瓣结构。     

Electro‐optic properties of CO2 fixed‐polymer/nematic LC composite films

Bis(cyclic carbonate) was obtained from the epoxide and CO₂ reaction with a quaternary ammonium halide salt catalyst. Cyclic carbonate derivatives were then reacted with amine to obtain quantitatively poly(hydroxy)urethanes that were reacted with isophorone diisocyanate (IPDI) and end capped with acrylate to form prepolymers. These prepolymers were mixed with reactive diluents and nematic LCs, and subjected to UV cure to form polymer/LC composite films in a transparent cell. Three types of diglycidyl ether [poly(propyleneglycol), cyclohexane, bisphenol A], three types of end‐capping acrylates [2‐hydroxyethyl acrylate (HEA), 2‐hydroxypropyl acrylate (HPA), and 2‐hydroxyethyl methacrylate (HEMA)], three types of multyfunctional diluents [tripropylene glycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA), dipentaerythritol hydroxy penta/hexa acrylate (DPHPA)], and three types of photoinitiators (Irgacure‐651, Irgacure‐184, Darocure‐1173) were incorporated to control the morphology, and hence, the electro‐optic properties of the polymer/nematic LC composite films. Poly(propylene glycol) diglycidyl ether segment of polyurethane acrylate (PUA) showed lower viscosity and gave larger domain size resulting in lower threshold (V₁₀) and driving (V₉₀) voltages, together with larger nematic–isotropic transition temperature depression. HEA end‐capped PUA gave larger polymer–LC phase separation and smaller V₁₀ as well as V₉₀. TPGDA‐based PUA showed the lowest V₁₀ and V₉₀ and the shortest response time. Among the three types of photoinitiators used Irgacure‐651 showed the larger LC domain, and smaller V₁₀ and V₉₀. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2744–2753, 2001     

Synthesis of polyacrylamide with pendant poly(n‐octyl acrylate) chains using macromer technique and studies on their properties

An amphiphilic graft copolymer of polyacrylamide (PAM) with uniform poly(n‐octyl acrylate) (POA) grafts was synthesized by copolymerization of AM with POA macromer in solution using azobisisobutyronitrile as the initiator. The macromer was synthesized by free radical polymerization of octyl acrylate in the presence of different amounts of thioglycolic acid as the chain transfer agent, followed by termination with glycidyl methacrylate. The reactivity ratio and effects of copolymerization conditions on the conversion of macromer or grafting efficiency were studied. The crude products were purified by extraction with toluene and water successively. The purified graft copolymer was characterized by IR, DSC, and TEM. PAM‐g‐POA can bring about microphase separation and exhibits good emulsifying properties and water absorbency. PAM‐g‐POA exhibits a very good compatibilizing effect on the acrylic rubber/poly(vinyl chloride) blends. About 2–3% of the graft copolymer is enough for enhancing the tensile strength of the blends. The tensile strength of the blends is more than twice that without the compatibilizer. DSC and SEM demonstrated the enhancement of compatibility in the presence of the graft copolymer. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Utilization of waste polystyrene and starch for superabsorbent composite preparation

A superabsorbent composed of waste polystyrene, starch, and acrylic acid was prepared through emulsion polymerization. The effects of major factors such as starch, acrylic acid, initiator, crosslinker, and bentonite contents and the neutralization degree of acrylic acid on water absorbency were investigated to obtain optimum conditions with high swelling capacity. The superabsorbent hydrogel was characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The FTIR results confirmed that the grafting polymerization took place among the polystyrene, acrylic acid, starch, and bentonite. The introduction of bentonite particles into the polystyrene‐g‐poly (acrylic acid)‐co‐starch system could increase the water absorbency. The superabsorbent composite containing 3 wt % bentonite had the highest water absorbency (500 g/g in distilled water and 49 g/g in 0.9 wt % NaCl solution). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and properties of a salt‐resistant superabsorbent polymer

Crosslinked sodium polyacrylate was prepared by solution polymerization with N,N‐methylene‐bisacrylamide (bisAM) as crosslinking agent; it was subsequently surface‐crosslinked by ethylene glycol diglycidyl ether (EGDE) and then was modified with inorganic salt to obtain a superabsorbent with water absorbency in 0.9 wt % NaCl aqueous solution at atmosphere and applied pressure (P ≈ 2 × 10³ Pa) of 55 and 20 g.g^?1, respectively. Moreover, it also had excellent hydrogel strength. The effects of reaction temperature, reaction time, neutralization degree (ND) of acrylic acid, amount of initiator, crosslinking agent, and surface‐crosslinking agent, mass ratio of inorganic salt to initial superabsorbent, molar ratio of sodium aluminate (NaAlO₂) to potassium dihydrogen hyphosphate (KH₂PO₄) on water absorbency (WA) in 0.9 wt % NaCl aqueous, and the hydrogel modulus were investigated and optimized. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2532–2541, 2004     

Swelling properties of copolymers of styrene and divinylbenzene containing sulfonic and carboxylic acid groups

Copolymers of styrene, divinylbenzene, and acrylic acid that have undergone sulfonation exhibited good water absorbency properties. Removal of the lower molecular weight fraction in the surface region of the copolymer particles by toluene extraction before sulfonation has further increased the water swelling capacity of the sulfonated copolymers. The extent of swelling of the UV‐irradiated copolymer could be related to the ratio of divinylbenzene to styrene. The less crosslinked copolymers were shown to absorb more water. The incorporation of more carboxylate groups in the copolymer could further increase its swelling capacity. Without UV irradiation, the carboxylate containing copolymer was found to absorb more water than the sulfonated copolymer. UV irradiation has induced more effective crosslinking in the carboxylate containing copolymer, hence impairing its water absorbency. By replacing styrene and divinylbenzene partially with butyl acrylate, whereby the amount of crosslinking was reduced, the copolymer was able to absorb water 110 times of its dry weight. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and water absorbency of a novel poly(acrylate‐co‐acrylamide)/vermiculite superabsorbent composite

A novel poly(acrylate‐co‐acrylamide)/expanded vermiculite (EVMT) superabsorbent composite was synthesized by aqueous solution polymerization method. The water absorbency of the superabsorbent composite still reaches 850 g/g when 50 wt % EVMT is added, which is significant in decreasing the production cost of the superabsorbent composites. By controlling the molar ratio of acrylic acid monomer and acrylamide monomer, and neutralization degree of acrylic acid, the hydrophilic groups on the composite can be adjusted, and it is found that the collaborative absorbent effect of ? CONH₂, ? COOK, and ? COOH groups is superior to that of single ? CONH₂, ? COOK, or ? COOH group. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 735–739, 2007     

Preparation of superabsorbent based on the graft copolymerization of acrylic acid and acrylamide onto konjac glucomannan and its application in the water retention in soils

A new konjac glucomannan (KGM)-based superabsorbent polymer, KGM-g-poly(acrylic acid-co-acrylamide), was prepared by the free radical grafting solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers onto KGM in the presence of N,N′-methylenebisacrylamide as a crosslinker with potassium persulfate as an initiator. The effects of reaction parameters, including the amount of crosslinking agent and initiator, the weight ratio of both (AA + AM) to KGM and AM to (AA + AM), neutralization degree of AA, bath temperature, and reaction time, on the water absorbency of the superabsorbent were investigated. The Fourier transform infrared spectroscopy was used to characterize the structures of the copolymer. The maximum water absorbency of the optimized product was 650 g/g for distilled water and 70 g/g for a 0.9 wt % aqueous NaCl solution. Furthermore, the water retention of the copolymer in soils was studied. The effect of the copolymers on the aggregate distribution of soils was also evaluated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of a superabsorbent from an ultraviolet‐irradiated waste nameko mushroom substrate and poly(acrylic acid)

To better use the waste nameko mushroom substrate (WNMS) and prevent its pollution into the environment, a novel superabsorbent polymer was synthesized via the UV irradiation copolymerization of acrylic acid and WNMS in the presence of an initiator (dimethoxy‐2‐phenylacetophenone and ammonium persulfate) and crosslinker N,N′‐methylenebisacrylamide. The factors that had an influence on the water absorbency of the superabsorbent polymer were investigated and optimized. Under the optimized conditions, WNMS–poly(acrylic acid) was obtained. Its swelling behaviors, which followed the pseudo‐second‐order swelling kinetic model, were investigated in distilled water (1701 g/g) and a 0.9 wt % NaCl solution (388 g/g). The water absorbency was 1011 g/g in a 0.1 wt % urea solution and 80% amount of urea diffused into the gels. The urea diffusion followed a Fickian diffusion mechanism. Moreover, the product showed excellent water retention capabilities under the condition of high temperature or high pressure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40471.     

Synthesis and characterization of super‐absorbent hydrogels based on hemicellulose

A kind of novel hemicellulose‐based hydrogel with excellent water absorbency was synthesized by the graft copolymerization of acrylic acid (AA), acrylic amide (AM) with hemicellulose. The various factors that influenced the water absorbency of the modified hemicellulose were studied, including AA content, hemicellulose content, neutralization degree of AA, and weight ratio (to monomer) of cross‐linker and initiator. The optimal conditions were found as follows: m(AA) : m(AM) : m(hemicellulose) = 15 : 3.5 : 1, the neutralization degree of AA was 75%, and weight ratio (to monomers) of the cross‐linker and the initiator was 0.03% and 1.0%, respectively. The maximum absorbencies toward distilled water and 0.9 wt % NaCl solution were 1128 g/g and 132 g/g, respectively. The characteristics of the hydrogels were also investigated by Fourier Transform InfraRed (FT‐IR), scanning electron microscope (SEM), and atomic force microscope (AFM). The results indicated that the undulant surface and broad network structure offer the hydrogels excellent water absorbency. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42441.     

Studies on poly(acrylic acid)/attapulgite superabsorbent composite. I. Synthesis and characterization

A novel poly(acrylic acid)/attapulgite superabsorbent composite was synthesized by graft copolymerization reaction of acrylic acid (AA) on attapulgite micropowder using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator in aqueous solution. The effects on water absorbency of such factors as reaction temperature, initial monomer concentration, degree of neutralization of AA, amount of crosslinker, initiator, and attapulgite were investigated. These crosslinked superabsorbent composites were characterized by thermogravimetetric analysis and scanning electron microscopy. The graft copolymerization reaction of AA on attapulgite micropowder was characterized by FTIR. The water absorbencies for these superabsorbent composites in water and saline solutions were investigated and water‐retention tests were carried out. Results obtained from this study show that the water absorbency of the superabsorbent composite synthesized under optimal synthesis conditions with an attapulgite content of 10% exhibited an absorption of 1017 g H₂O/g sample and 77 g H₂O/g sample in distilled water and in 0.9 wt % NaCl solution, respectively. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1596–1603, 2004     

Pervaporation separation of 1,1,2‐trichloroethane–water mixture through crosslinked acrylate copolymer composite membranes

The separation of a chlorinated hydrocarbon from a dilute aqueous solution through a crosslinked acrylate copolymer–porous substrate composite membrane by pervaporation was investigated. Poly(n‐butyl acrylate‐co‐acrylic acid) and poly(n‐butyl acrylate‐co‐2‐hydroxyethyl acrylate) were synthesized and composite membranes were prepared, which were made from the crosslinked polymer and a porous substrate. Pervaporation measurement was carried out for a dilute aqueous solution of 1,1,2‐trichloroethane at 25°C and under a vacuum on the permeate side (below 10 mmHg). The separation factor, overall flux, 1,1,2‐trichloroethane concentration in the membrane, and the degree of swelling decreased with increase in the acrylic acid or 2‐hydroxyethyl acrylate content of the acrylate copolymer. The influence of the crosslinking agent content on the pervaporation performance was small, and the separation factor and the overall flux showed a convex curve. The structure of the crosslinking agent had no effect on the separation. The influence of the pore size of the substrate and the thickness of the polymer layer on the separation of 1,1,2‐trichloroethane was observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 983–994, 1999     

Synthesis and Properties of Sepiolite/poly (acrylic acid-co-acrylamide) Nanocomposites

Summary Novel hydrogel nanocomposites, based on sepiolite, acrylic acid (AA), acrylamide (AM), and N,N’-methylenebisacrylamide (MBA), were synthesized by solution copolymerization. The structure, morphology and liquid absorbency of these composites were investigated through FTIR, SEM and the like. The influences of sepiolite, crosslinker content, initiator dosage, neutralization degree of AA and molar ratio of AA/AM on the distilled water absorbency (Q_w), physiological saline solution absorbency (Q_p) were discussed in detail. Results showed that needleshaped sepiolite dispersed in nanoscale, and the grafting of AA and/or AM on the sepiolite surface occurred. Compared with the sepiolite-free hydrogel, sepiolite contributed to liquid absorbency, and at its weight content of 15.0%, Q_w and Q_p were enhanced as high as 11.6% and 14.5%, respectively.     

Preparation and properties of UV-curable polyurethane acrylate ionomers

Ultraviolet (UV)-curable polyurethane acrylate ionomer (PUAI) prepolymers were synthesized from isophorone diisocyanate (IPDI), poly(methylene ether) glycol (PTMG), 2,2-bis(hydroxymethyl) propionic acid (DMPA), triethylamine (TEA), 2-hydroxy ethyl acrylate (HEA), and dibutyl tin dilaurate (DBT) as a catalyst. UV-curable polyurethane acrylate ionomer aqueous dispersion was formulated from the prepolymers, water (30 wt %), and 1-hydroxycyclohexylhenyl ketone (Irgacure 184) as a photoinitiator. The films of UV-cured polyurethane acrylate ionomer were formed by curing the dispersion using a medium-pressure mercury lamp (80 W/cm; λ max = 365 nm). Gel content decreased with increasing water content in the aqueous dispersion. Effects of DMPA content and molecular weight of PTMG and the degree of neutralization on the physical properties were investigated. It was found that the storage modulus increased with increasing DMPA content. Tensile modulus and strength decreased with increasing the molecular weight of PTMG from 650 to 2000. The glass transition temperature shifted to a higher temperature as the content of DMPA increased. As the degree of neutralization increased, the tensile strength and modulus decreased. However, the elongation at break increased. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2153–2162, 1998     

Synthesis of water‐reducible acrylic–alkyd resins based on modified palm oil

Water‐reducible acrylic–alkyd resins were synthesized from the reaction between monoglycerides prepared from modified palm oil and carboxy‐functional acrylic copolymer followed by neutralization of carboxyl groups with diethanolamine. Modified palm oil was produced by interesterification of palm oil with tung oil at a weight ratio of 1 : 1, using sodium hydroxide as a catalyst, whereas carboxy‐functional acrylic copolymer was prepared by radical copolymerization of n‐butyl methacrylate and maleic anhydride. The amount of acrylic copolymer used was from 15 to 40% by weight, and it was found that homogeneous resins was obtained when the copolymer content was 20–35 wt %. All of the prepared water‐reducible acrylic–alkyd resins were yellowish viscous liquids. Their films were dried by baking at 190°C and their properties were determined. These films showed excellent water and acid resistance and good alkali resistance. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1170–1175, 2005     

Synthesis and properties of poly(sodium acrylate‐co‐2‐acryloylamino‐2‐methyl‐1‐propanesulfonic acid)/attapulgite as a salt‐resistant superabsorbent composite

A novel salt‐resistant superabsorbent composite was prepared by copolymerization of partially neutralized acrylic acid, 2‐acryloylamino‐2‐methyl‐1‐propanesulfonic acid (AMPS) and attapulgite (APT). To enhance the swelling rate (SR) of the copolymer, sodium bicarbonate was used as a foaming agent in the course of copolymerization. Furthermore, for improving the properties of swollen hydrogel, such as strength, resilience and dispersion, the copolymer was surface‐crosslinked with glycerine and sodium silicate, and then the surface‐crosslinked copolymer was blended with aluminum sulfate and sodium carbonate in post treatment process. The influences of some reaction conditions, such as amount of AMPS, APT, and initiator, and neutralization degree of acrylic acid on water absorbency in 0.9 wt% NaCl aqueous solution both under atmospheric pressure (WA) and load (WA_P, P ≈ 2 × 10³ Pa) were investigated. In addition, the effect of them on SR was also studied. The WA and WA_P of the superabsorbent composite prepared under optimal conditions in 0.9 wt% NaCl aqueous solution were 52 g·g^?1 and 8 g·g^?1, respectively. Besides, the SR was fast, and it could reach 0.393 mL·(g·s)^?1. Moreover, the swollen hydrogel possessed excellent salt resistance, hydrogel resilience and dispersion. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers