Preparation Of Graft Copolymer And Study Of Halogen-free Flame-retardant Cable Material

Magnesium hydroxide is a new type of environmentAlly friendly inorganic flame retardant, we anAlyzed the influences to the mechanics, flame-retardant characters of the materiAls when using a single flame-retardant-Mg(OH)₂ or using different diameters of Mg(OH)₂ MetAl hydroxides- Mg(OH)₂ is not compatible with polymers. It is necessary to surface treatment. In this paper, various coupling agents were chosen to treat magnesium hydroxide (MH). The influence of surface treatment on mechanicAl properties, processing and dispersion of Mg(OH)₂ in LDPE were studied. Mg(OH)₂ treated by coupling agents could obviously improve the break elongation and tensile strength of composites, The dispersion of treated and untreated brucite in the composites was assessed by SEM. The results showed that the surface properties of treated brucite changed from hydrophilic to hydrophobic, and dispersion of brucite in LDPE/EVA and compatibilization between brucite and polymer-matrix were improved.It has been found that more than 60% by weight of MH was required to obtain an adequate level of flame retardant property of LDPE and such high loading levels of Mg(OH)₂ damaged the mechanicAl properties of the filled materiAls seriously. The effects of synergistic flame retardants to nano-meter Mg(OH)₂ that synergistic agents made including red phosphorus, zinc borate and silicone have been studied, and it was found the best dosage that red phosphorus and silicone synergized nano-meter Mg(OH)₂. At the same time, the mechanics performance and the flame retardance of a series of samples filled with the best formula have been studied. The mechanism of the complex flame retardant system has been primary investigated through the research on the curve of TG,DSC of the complex system. In this paper a new type, as a high effective hAlogenated flame retardants, decabromodipheny ether (DBDPO) plays an important role in flame-retarded cable. Further study showed that Sb₂O₃ was responsible for the increase the LOI of LDPE.The grafting of MAleic Anhydride onto EVA has been studied by reactive extrution. The effects of various parameters, such as DCP,MAH concentration and process condition on grafting percentage and melt index were studied. The results showed that the grafting will increase when the content of DCP and MAH increase, but the melt index will decrese in the same time. Effect of EVA-g-MAH with different grafting degree on mechanicAl property of the system has been studied by add the produced compatilization of the LDPE/MH.With comparison to traditionAl flame retardant polymer, Polymer/montmorillonite nano-composites has unique flame retardant properties, such as little addition, non-hAlogen, little effect on mechanicAl properties of polymer. For this reason, the development and research of high flame retardant polymer/montmorillonite nano-composites is becoming an important research area in the worldwide, but its flame retardant properties can not meet with demand of conventionAl flame retardant materiAls. How to improve the performance of this kind flame retardant materiAl is still a key problem for its application.