N,N-disubstituted Phosphoryl Carbamates as Flame Retardants for Thermoplastics

Without polymer additives, polymers do not combine to form materials called plastics. Polymer additives are of key importance when it comes to safe and sustainable polymer and plastic applications.Flame retardants are used for decades to reduce the flammability of polymeric materials. However, it has become evident that the widely used halogenated flame retardants are persistent and bioaccumulative. Since they are also toxic, carcinogenic, and endocrine disruptors, several of these compounds have been banned. Organophosphorus flame retardants are extensively used as substitutes because they are not bioaccumulative. However, as more and more of these flame retardants are employed to meet flammability standards, the levels of these flame retardants in the environment have also increased as they are typically difficult to degrade and do not sequester in soil. Recent studies link high levels of organophosphorus flame retardants in dust and drinking water to behavioral and reproductive issues, which results in the likelihood of further bans. Here, we present phosphoryl carbamates as a new class of flame retardants. This class of substances offers flame-retardant properties in thermoplastics. Due to the phosphoryl- and the carbamate moiety in the chemical structure, it contains two attack points for biological degradation, which suggests a high level of biodegradability. These compounds are synthesized from CO2. Selected phosphoryl carbamates were fully characterized and their flame-retardant properties on different thermoplastics have been investigated.