are restricted because of the emission of toxic gases and corrosive smoke during combustion. [7][8][9][10] For decades, halogen-free flame retardants, particularly phosphoruscontaining ones have received more attention due to the satisfactory flame-retardant effect in gaseous and condensed phases simultaneously.Phosphorus-containing compounds are the most common halogen-free flame retardants, [11,12] which produce less toxic gases and smoke than halogen-containing compounds. [13,14] They also could impart excellent flame retardancy to EP, as reactive or additive flame retardants. [5] Compared with additive flame retardants, reactive flame retardants impart long-lasting flame retardancy and environmental resistance to EP. [6] Hence, preparation of a novel phosphorus-containing reactive flame retardant has become a hot research spot in recent years. [15] Huo et al. successfully synthesized a novel reactive flame retardant (DPT) through the reaction among DOPO, 1,4-phthalaldehyde, and triacetonediamine. Particularly, EP/DDM/ DPT-4 with 1.0 weight percent (wt%) phosphorus achieves limited oxygen index (LOI) value of 38.3% and UL-94 V-0 rating, while the glass transition temperature decreased by 11 °C. [15] Unfortunately, the traditional phosphorus-containing flame retardant can improve the flame retardant performance of epoxy resin, but its thermal and mechanical properties often decrease. [16,17] Therefore, it is necessary to find an approach to simultaneously improve the thermal, flame-retardant, and mechanical properties.In fact, multi-element synergistic flame retardants, such as P/N/F, [18] P/N/S/Mo, [19] and P/N/Si [20] have been proved to be an effective approach to overcome this predicament. Liu et al. developed a multi-element synergistic flame retardant system through the classical Kabachnik-Fields reaction, which achieved a combination of DOPO, POM, and POSS. The LOI value was 34.5% and the flexural strength increased by 11.7% when the content of POSS-bisDOPO was 20 wt%. [21] Reactive flame retardants containing different elements give EP with excellent flame retardancy and maintain high glass transition temperature. [5] Among the phosphorus-containing reagents, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) with high flame retardancy, good thermal stability, and high reactivity has been widely used in flame retardant modification of EP., [22,23] However, it will cause the bioaccumula tion of phosphorus and deterioration Flame-Retardant Epoxy ResinTo obtain epoxy resins with satisfactory thermal, flame retardant, and mechanical properties, a novel multi-element synergistic flame retardant (PPVSZ) is synthesized through the reaction between PH of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and CC of polysilazane (PVSZ) and utilized as a multi-element synergistic flame retardant for epoxy resins. The flame retardant mechanism is explored by XPS and SEM, confirming that the excellent flame-retardance efficiency owes itself to an optimal flame retardant way which jointly exerts the f...

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Blend of ethylene-vinyl acetate copolymer (EVA), ethylene-propylene-diene terpolymer rubber (EPDM), and chlorinated polyethylene (CPE) filled with talc was cross-linked with dicumyl peroxide and blown simultaneously with azodicarbonamide for preparation of high elasticity material by injecting, cross-linking, and blowing process. It had excellent mechanical properties and elasticity. It was found that mechanical properties were a function of cross-linking and blowing temperature and time and formula. A good cross-linking and blowing temperature was in the range of 440-450 K and the optimum temperature and time were 448 K and 360 s, respectively. Kinetics of both cross-linking and blowing reactions were investigated by closed nonrotor torque rheometer. The results showed that both cross-linking and blowing reactions were first order. The activation energy of the cross-linking reaction was higher than that of the blowing reaction. With increasing of EDPM content, the activation energy of the crosslinking reaction reduced whereas it increased for the blowing reaction. The gas cell morphology was characterized by scanning electron microscopy (SEM). The results of SEM and mechanical property analyses showed that the morphology and mechanical properties were improved by incorporating CPE.