Study on Green Degradation Process of Polyurethane Foam Based on Integral Utilization and Performance of Recycled Polyurethane Oil-Absorbing Foam

Recycling of Polyurethane Foams via Glycolysis: A Review

Polyurethane foams constitute highly problematic waste due to their low density and consequently large volume. Among the most promising recycling approaches, the glycolysis of polyurethane waste stands out and was extensively discussed in this article. Existing literature reviews lack a detailed analysis of glycolysis processes and a clear presentation of the most important data. However, in this review, the scientific literature on glycolysis has been thoroughly examined and updated with the latest research in the field. The article provides an overview of glycolysis methods, categorized into rigid and flexible foams, along with a review of the catalysts and process conditions employed. Additionally, this study offers a comprehensive analysis of industrial methods protected by active patents, which has not been previously explored in the literature. This detailed examination of patent information adds significant value to the review and distinguishes it from others. Furthermore, this review also aims to introduce the main types of polyurethanes and their properties. It outlines the fundamentals of recycling strategies, thermomodernization trends, and environmental considerations, highlighting the critical role of recycling in the industry. The article serves as a complete foundation for exploring new alternative methods in this field.

Antimicrobial Nonisocyanate Polyurethane Foam Derived from Lignin for Wound Healing

Medical dressings, as a cover for wounds, can replace damaged skin in the wound healing process to play a temporary barrier role, avoid or control wound infection, and provide a favorable environment for wound healing. Therefore, there is an urgent need for medical antimicrobial dressings for the treatment of chronic wounds. Although traditional polyurethane foam has been widely used in medical dressings, conventional polyurethane foams are primarily prepared using nonbiocompatible isocyanate-based compounds, which are potentially hazardous for both operators and applications in the medical field. Here, we propose nonisocyanate polyurethane foams naturally derived from lignin by enzymatic lignin alkylation, cyclic carbonation modification, and polymerization with diamine and the addition of a blowing agent. Silver nanoparticle solution was added during foaming to confer antimicrobial properties. This lignin-based nonisocyanate polyurethane/silver composite foam (named NIPU foam-silver) using a green synthesis method has good mechanical properties, which can be used to manufacture polyurethane/silver foams, and thermal and antimicrobial properties. Notably, NIPU foam-Ag showed more than 95% bactericidal efficacy against both Escherichia coli and Staphylococcus aureus within 4 h. Evaluation of in vitro wounds in mice showed that this antimicrobial composite foam rapidly promotes wound healing and repairs damaged tissue. This suggests that this biobased biodegradable antimicrobial foam has significant scope for clinical applications in wound management.