Soil conditioners based on anionic polymer and anionic micro-sized hydrogel: A comparative study

Abstract

In this article we describe the use of novel aqueous polymer formulations for stabilization of sand and soil against wind erosion and retention of water in polymer-treated sand/soil samples. Two series of formulations were prepared. The first consisted of polyacrylic acid (PAA) and two electrostatic complexes of PAA with cationic poly(diallyldimethylammonium chloride): negatively and positively charge; the second included PAA-based cross-linked copolymer (PAA#) which forms microgel particles upon swelling and two its electrostatic complexes with the polycation: negatively and positively charged. 1 mass% formulations showed the stability against aggregation for 3 months excepting the negative complex with PAA which aggregated within half an hour after preparation. The viscosity of 1 mass% formulations, which lies within a (1.6÷320)×10−6 m2/s interval, allowed their deposition over fine-grained sand and loamy sand soil using a conventional spray machine followed by formation of polymer-sand(soil) crusts. Both for sand and soil, the PAA#-based crusts demonstrated a higher resistance to mxechanical loads in comparison with the crusts formed by linear PAA: up to a 42.5 MPa mechanical strength for sand/PAA# crust against a 12.5 MPa strength for sand/PAA crust. Additionally, the PAA#-based crusts was not impacted by airstream, up to a 190 km per hour air speed, while PAA-based crust was destroyed within a minute. Finally, PAA# alone and its negative complex were characterized by a high swelling (degree of swelling up to 195) that allowed them to maintain a high water retention capacity, being bound to sand and soil. The results are promising for preparing anti-erosion and water-saving formulations, especially in areas with insufficient moisture content, and design of sand-based composite materials.