An Alcogel Based on Poly(2-acrylamido-2-methylpropane sulphonic acid) and the Effect of Neutralization Degree on its Swelling, Thermal and Mechanical Properties

Cross-linked polymeric organogels have attracted much attention in recent years. Most synthesized organogels are based on low molecular weight or denderitic materials. The study focuses on the preparation of an alcohol absorbent organogel based on 2-acrylamido-2-methylpropane sulphonic acid (AMPS) through cross-linking polymerization. Polyethylene glycol diacrylate-400 and ammonium persulphate were used as crosslinker and thermal initiator, respectively. Neutralization of acid groups increases swelling in superabsorbents. In this study, the effect of neutralization degree (N.D) on alcogel swelling was studied. The absorbency in alcohols and water are unexpectedly reduced with increased N.D. Also, the effect of N.D on thermal, mechanical and rheological properties was investigated, and found that increase in N.D leads to increased glass transition temperature, thermal stability and storage modulus

Crosslinkers of Different Types in Precipitation Polymerization of Acrylic Acid

Crosslinked poly(acrylic acid)s were prepared using two types of crosslinker by precipitation polymerization method in a binary organic solvent. N,N’-methylenebisacrylamide (MBA) and polyethylene glycol dimethacrylate (PEGDMA-330) were used as low-molecular weight and long-chain crosslinkers, respectively. The effect of various types of crosslinkers on polymer characteristics (i.e., gel content, equilibrium swelling, glass transition temperature, and rheological properties) was investigated. Maximum amount of viscosity was obtained by using long-chain crosslinker. The Flory-Rehner equation and rubber elasticity theory were used to discuss the network structure of polymer. It was observed that, the glass transition temperature (Tg) of the synthesized polymer containing PEGDMA-330 is higher than that of polymer containing MBA. Apparent and rotational viscosity were used to determine the optimal crosslinker type. In addition, the consistencycoefficient (m) and flow behavior index (n) parameter of Ostwald equation were investigated as well