Cross-Linking And Grafting Technology

Cross-linking and grafting techniques are widely used in polymer materials. Alfa Chemistry can achieve flame retardancy of polymer materials through cross-linking grafting technology.

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What Can We Do?

• Combining the rich flame retardant design experience of material chemists of Alfa Chemistry, we can achieve flame retardant polymer materials through cross-linking and grafting techniques (such as chemical grafting, photosensitive grafting, etc.).
• Our materials chemists will design and develop the most suitable unique flame retardant formulation for your specific application needs.
• To ensure that flame retardants meet a wide range of flammability requirements, comprehensive and systematic performance characterization and analysis are also considered, especially for flame retardant properties.
• During the development of innovative flame retardants, our materials chemists will fully communicate with customers, understand your needs, and ensure a satisfactory flame retardant solution.
• Typical application examples of cross-linking and grafting technology include bromination and chlorination of polyethylene (PE), graft modification of PS by silane groups, and the like.

How does cross-linking and grafting technology achieve flame retardancy?

• Grafting and cross-linking is an effective method to functionalize polymer materials, and this technology has also been used for flame retardant polymer materials in recent years.
• Grafting is achieved through graft copolymerization to improve the thermal stability and flame retardancy of the polymer by means of multi-system condensed phase flame retardant mode, that is, by means of char formation.
• In addition, because the grafting monomer can form an adhesive insulating layer on the surface of the polymer, especially the inorganic insulating layer, it is particularly effective for improving the flame retardancy of the polymer.
• Crosslinking the polymer material itself, or crosslinking the thermal cracking product of the polymer material in the condensed phase, can reduce the generation of combustible products and improve the flame retardancy of the material, mostly radiation crosslinking.

Research Information

Photo-induced grafting PET fabric

The researchers functionally modified the PET fabric by photo-induced surface grafting technology, and then evaluated its fire resistance. The results show that the photo grafting treatment can improve the flame retardancy and drip resistance of PET fabrics. [1]

Microstructure of char residue from graft-treated (b-d) and untreated (a) PET fabrics [1]

Functionalized graphene by grafting

In addition to functionalizing polymer materials by grafting technology, the researchers also grafted 9,10-dihydro-9-oxa-phosphine-10-oxide (DOPO) on graphene by acylation-chlorination method, to prevent aggregation and obtain synergistic flame retardancy. In this study, a stable carbon layer and a uniform sheet-like structure graphene-DOPO form a protective layer, which can effectively protect the carbon fiber/epoxy composites from radiant heat and direct flame contact, thereby improving the flame retardancy of the composites. [2]

Proposed flame retardant mechanism [2]

References

1. Lihua Yu, et al. (2010). "Improving the flame retardancy of PET fabric by photo-induced grafting," Polymer Degradation and Stability 95(9), 1934-1942.
2. Fei Sun, et al. (2016). "Influence of functionalized graphene by grafted phosphorus containing flame retardant on the flammability of carbon fiber/epoxy resin (CF/ER) composite," Composites Science and Technology 136, 76-84.