Facile construction of mono-component, halogen-free and Mn-doped compounds for silicone rubber with excellent balance among flame retardancy, mechanical properties and durability

Originated from the future trends and requirements for silicone rubber (SR) in harsh work condition of advanced cutting-edge fields (construction, aerospace, marine equipment and automobile, etc), the processing complexity, complex ingredients and unbalanced overall properties of traditional multi-component flame-retarding SR system are limited. The development of mono-component and halogen-free flame retardants with adequate efficiency, durability and strength have been urgently expected for settling the crucial bottleneck issue of SR materials, which can avoid the defects of performance contradictions for long-used multi-component system in previous published work. Under such background, this paper has fabricated a hydrophobic Mn-doped melamine phosphate (H-DTMA@Mn) via facile multi-stage construction strategy that has been confirmed by a series of characterizations. The results have indicated that SR/28 phr H-DTMA@Mn can achieve limiting oxygen index (LOI) of 32.4% and UL-94 V-0 rating. Along with the reduced peak heat release rate, the validity of as-prepared H-DTMA@Mn for raising the flame retardancy of SR has been straightway clarified. Different from the previous work, the prominent flame retardant durability of SR/H-DTMA@Mn in many extreme environment can be maintained via the protection action of hydrophobic structure. The detailed analysis on char residues of SR composites can explain the effective flame retardant mechanism in view of chemical composition and microscopic morphology. Moreover, the mechanical strength and thermal properties of SR composites are ideal and accommodated that are greatly required in the real-life application. To sum up, the desirable balance for comprehensive performance can be realized by introducing the mono-component flame retardants, which can innately open up the innovation for meeting the requirements of SR materials in more fields.