Insight and Comparison of Property Improvement in LTA and MFI Zeolite Reinforced Poly(methacrylic acid) Highly Concentrated Composite Hydrogels

The preparation of zeolite rich polymeric materials presents a challenge due to the zeolite settlingduring synthesis, poor miscibility, the phase separation and generally insufficient interactionsbetween polymers and zeolites. Combination of LTA, i.e. MFI, zeolite and poly(methacrylic acid) in theform of soft hydrogel network provided the stabilization of the zeolite particles and enabled synthesisof composite hydrogels with very high zeolite concentrations (26-52 mass%).The investigated morphological, mechanical and primary structural properties, water swelling abilityand thermal stability revealed high dependence on zeolite concentration and type. Zeolite particleswere uniformly dispersed in PMAA matrix as confirmed by SEM and there was no agglomeration orzeolite leaching despite very high concentrations. FTIR spectra disclosed the existence of functionalgroups of PMAA network and both zeolite types that interacted mutually and led to increasedcrosslinking density. The established interactions changed the PMAA chain dynamics around theparticles, especially of the LTA type, as showed by XRD. Having much more surface groups capable togenerate interaction with PMAA, LTA zeolite stronger affected all of the investigated properties.Composites’ mechanics was improved both in dry and swollen state compared to the PMAA hydrogel(up to 21.8 times for the sample with the highest LTA concentration). Thermal stability of thecomposites increased with increasing zeolite concentration.The composition-property correlations were determined making this work the base for furtherdevelopment of tailor-made zeolite-PMAA composite hydrogels aimed for specific application.Composites were tested as low-cost, regenerative, environmentally friendly sorbents and showedbetter removal of cationic dye compared to both components (PMAA and zeolite) alone.