Fine tuning of SAP properties via epoxy-silane surface modification

Abstract

Using 3-[(2,3-epoxypropoxy)-propyl]-trimethoxysilane as a surface modifier, superabsorbent polymers with improved gel strength in their swollen state and saline absorbency under load are synthesized. The products are characterized using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), rheometry, scanning electron microscopy-energy dispersive X-ray analysis, contact angle, thermogravimetric analysis, water absorbency and gel content. The temperature and the duration effect of the surface-treatment process on residual monomer content are also investigated by high performance liquid chromatography. The gel strength (as shown by storage modulus) and absorbency under load are improved up to 3500-4000 Pa, and 30-40 g/g, respectively. It is suggested that the surface of the superabsorbent polymer particles has been modified by two mechanisms: i.e. interpenetrating polymer network and cross-linking. Moreover, the surface modification has enhanced thermo-stability and prohibited undesirable gel blockage. Depending on the post-treatment method used, the wetting behavior of particles is also altered. Water absorption capacityFree swelling capacity values were measured using the sieve method. [2] The powdered samples (0.10 g) were permitted to Scheme 1. A snapshot of the present research.

Topological Insight into Superabsorbent Hydrogel Network Structures: a 1H Double‐Quantum NMR Study

“…A slightly crosslinked reference polymer hydrogel (DC = 0.3 mol%) was synthesized without surface crosslinking. Surface crosslinking was achieved by applying a crosslinking solution to the gel particles followed by a curing procedure . Both the reference SAP hydrogel (SAP75|20|0.3|R) and the gels with surface crosslinking (SAP75|20|0.3|RSXL) were investigated by 1 H DQ‐NMR ( Figure ).…”

Synthesis of bio‐based internal and external cross‐linkers based on tannic acid for preparation of antibacterial superabsorbents

“…The cross-linking type and the amount of cross-linker are the significant factors that can affect on the SAP swelling. The TG was synthesized as an internal cross-linker with different numbers of functionality (5,10,15,28) and used in SAP synthesis at different amounts. Generally, increasing the amount of cross-linker decreased the final swelling value and water uptake.…”

“…Another necessity in SAP would be the presence of acceptable strength of the swollen gel, which is obtained from external (surface) cross‐linking. However, data of swollen gel strengths measured by absorbency under load (AUL) are rare in nonpatented studies . There have been only few reports on SAPs that surface cross‐linked via bio‐based materials as a replacement of petroleum‐based raw materials.…”

“…However, data of swollen gel strengths measured by absorbency under load (AUL) are rare in nonpatented studies. 8,10,11 There have been only few reports on SAPs that surface cross-linked via bio-based materials as a replacement of petroleum-based raw materials. Ghasri et al reported the synthesis of a star-shaped 3-arm polylactic acid as an external cross-linker and enhanced the AUL value.…”

Composites of poly(L‐lactide‐trimethylene carbonate‐glycolide) and surface modified SBA‐15 as bone repair material

“…Several methods have been developed to improve the adhesion and interactions between them. Due to the presence of abundant silanol groups on the surface of mesoporous material, silane coupling agents such as 3‐[(2,3‐epoxy propoxy)‐propyl]‐trimethoxysilane and 3‐aminopropyltrimethoxy silane (APTES) have been used to attach polymers such as chitosan and polylactide onto the internal and external surfaces of mesoporous silica.…”