# The Effect of the Conformation Process on the Physicochemical Properties of Carboxymethylcellulose–Starch Hydrogels

## TL;DR

This paper compares casting and extrusion methods for making hydrogels, showing that extrusion creates more porous materials with higher water absorption.

## Contribution

The study reveals that extrusion improves hydrogel swelling by creating porous structures, especially with higher starch content and effective crosslinking.

## Key findings

- Extrusion produces porous hydrogels with higher swelling capacity compared to casting.
- Hydrogels with higher starch content showed more effective crosslinking and water absorption.
- Porous surfaces from extrusion enhance water penetration and diffusion dynamics.

## Abstract

This study discusses the preparation of biopolymeric hydrogels (a biomaterial) via different techniques, such as casting and extrusion, to compare the effects of the process and the use of citric acid as a crosslinker on the morphology, physicochemical properties, and degree of swelling of the hydrogel. Casting is widely used for its low cost and space-saving nature, but upscaling is problematic. Extrusion offers a way to produce materials in large quantities; these materials can undergo mechanical and thermal energy, which can significantly alter their properties. The samples obtained by extrusion had porous surfaces, which are critical for the water penetration and swelling of superabsorbent hydrogels. In contrast, the hydrogels produced by casting did not form pores, resulting in a lower degree of swelling. Extrusion increased the degree of swelling threefold due to the formation of pores, influencing water absorption and diffusion dynamics, especially in samples with higher starch content, where crosslinking occurred more effectively.