Organosilane compounds for tunable recycling of waste superabsorbent polymer fine particles

Dust and fine superabsorbent polymer particles (< 150 mu m) cause problems during absorbency through the gel blockage phenomenon. Hence, they are removed and considered as waste materials which can harshly raise economic and environmental issues for industries. The recycling of this class of material is of great importance. Herein, the fine acrylate-based SAP particles have been recycled using siliconebased coupling agents as reactant via IPN and crosslinking strategies to agglomerate the fine particles. The process has been conducted in three major steps: treatment solution preparation, agglomeration and moulding the SAP fines through the impregnation approach, and then pulverizing the moulded SAP. ATR-FTIR, SEM, oscillatory rheometer and compression strength analysis were employed for this study. The effect of acetone-to-water ratio, reactant type and extent on free swelling capacities in deionized water and saline solution, absorbency under load (AUL), recycling performance, elastic and loss moduli, and compression strength have been investigated. The fine SAP can be recycled up to 80% without any deteriorated properties, either swelling or mechanical; even recycling can raise the swollen gel strength under stress. The analytical investigation of recycled SAP particles reveals a well-attached porous structure that incredibly maintains its integrity in wet and dry states. The weld lines have been perfectly covered by siloxane-based IPN formation. The ability to design and tune the shape of the absorbent article with definite strength based on application makes this recycling process promising.

Automated summary

This study focuses on the recycling of fine acrylate-based Superabsorbent Polymer (SAP) particles using silicone-based coupling agents. The recycled SAP particles exhibit no deterioration in properties and even show increased gel strength under stress. The analysis reveals a well-attached porous structure of the recycled SAP particles, maintaining their integrity.