Studies On Design And Synthesis Of DOPO Derivative Flame Retardants

With the reinforcement of the health awareness and environmental protection consciousness, flame retardant materials have to meet more strict demands. Low-smoke, non-halogen and low-toxicity materials become more and more popular.Due to their special properties such as heat resistance, water resistance, migration resistance, good flame retardancy and good compatibility with polymer, DOPO and its derivatives are known to be versatile and environmentally friendly substances used to render a broad range of polymers flame retardant. So in this article we do some research around the application of DOPO, the specific content are as follows:1. In this paper category, characteristics, retarding mechanism and application of phosphorous flame retardants are summarized and the progresses in the research and application of DOPO is also reviewed.2. The reported method of synthesis of DOPO-ITA are tested and a new improved process of DOPO-ITA is put forward with high conversion rate and short reaction time,which is more suitable for large-scale production. The results showed that an exactly equimolar mixture of DOPO and itaconic acid are added to a ether solvent in a sealed tube or autoclave with nitrogen inlet, and heated to150-180℃. The reaction is completed for4-12h, The conversion rate can reach98%, when the crystallization mother liquor is reused, the yield is between95～108%and the purity can reach more than98%.3. Two kinds of novel phosphorus-nitrogen synergistic flame retardents DOPO-HAM and compound Ib are designed and synthesized from DOPO. The results of the thermal analysis indicate that DOPO-HAM has good thermal stability and good performance of carbonization. DOPO-HAM and Ib are respectively prepared from DOPO-AM with paraformaldehyde and glyoxal, while DOPO-AM is synthesized from DOPO and AM. When DOPO-HAM and Ib are used on cotton fabric, in the presence of1.02wt%and1.36wt%phosphorus content respectively, the flame retardant of cotton fabric can meet a flame retardancy standard, UL-94V-0.