We have seen studies mentioning that natural carboxylic acids like citric acid can also serve as compatibilizers. How do they compare with traditional maleic anhydride grafted types?

You are focusing on the cutting-edge direction of bio-based or sustainable compatibilizers. Research indicates that natural carboxylic acids such as citric acid and palmitic acid indeed exhibit certain compatibilization effects in bio-based composite materials like polypropylene/thermoplastic starch (PP/TPS). They can interact with the hydroxyl groups in starch, enhancing interfacial bonding. Their advantages lie in the renewability of raw materials and environmental friendliness.

However, compared with the mature maleic anhydride grafted compatibilizers, natural carboxylic acids generally still lag in terms of compatibilization efficiency, universality, and the extent of improvement in the final performance of composite materials (especially for high-strength and high-heat-resistance requirements). Currently, natural compatibilizers are more commonly applied in specific fields where mechanical performance requirements are relatively lenient and biodegradability is emphasized. Selection requires balancing performance, cost, and environmental considerations.