# Eco-Friendly Filtrate Control in Drilling Fluids: Itaconic Acid-Grafted Corn Starch from Natural Organic Materials with Thermal and Salt/Calcium Resistance

## TL;DR

This study creates an eco-friendly drilling fluid additive from corn starch and itaconic acid that performs better than traditional chemicals and is safe for the environment.

## Contribution

A novel bio-based fluid loss reducer with superior thermal and salt resistance and low environmental impact is developed.

## Key findings

- IACS outperformed conventional additives like PAM, CMC, and PAC in filtration control.
- IACS effectively dispersed bentonite particles to the nanoscale at high temperatures.
- IACS showed moderate biodegradability and low toxicity, meeting green additive standards.

## Abstract

This study developed a bio-based fluid loss reducer based on itaconic acid-grafted corn starch (IACS) for water-based drilling fluid systems. The product was synthesized through free radical graft copolymerization and characterized by FTIR, TGA, and SEM. In bentonite-based mud systems, IACS demonstrated excellent filtration control performance significantly superior to that of conventional fluid loss reducers such as PAM, CMC, and PAC. IACS exhibited outstanding temperature resistance, salt tolerance, and calcium contamination resistance. Particle size analysis revealed that IACS effectively dispersed bentonite particles to the nanoscale at elevated temperatures, preventing thermal aggregation. Mechanistic studies indicated that carboxyl groups introduced by the grafting reaction endowed IACS with strong adsorption capacity and hydration ability, forming a dense polymer network layer on clay particle surfaces. Environmental evaluation confirmed that IACS possessed moderate biodegradability and extremely low toxicity, meeting green drilling fluid additive requirements. This study provides new insights for developing high-performance, environmentally friendly fluid loss reducers.