Description of the research progress of modern flame-retardant foamed polypropylene materials

Polypropylene is a general-purpose plastic with excellent comprehensive properties and is widely used in automobiles, packaging, home appliances, electronic products, furniture and other fields. However, polypropylene itself is a flammable material. Once a fire occurs, it will seriously endanger the safety of human life and property. Therefore, the flame retardant modification of polypropylene is particularly important. At present, in the context of environmental protection, halogen-free, low-smoke, anti-drip intumescent flame retardants are still the main additives of flame-retardant polypropylene materials. However, due to the opposite polarity and poor compatibility between the intumescent flame retardant and the polypropylene matrix, the agglomeration of the intumescent flame retardant in the polypropylene matrix is u200bu200bsevere, which greatly damages the flame retardancy and mechanical properties of the material . Therefore, how to improve the dispersion of flame retardants in the polypropylene matrix has always been a difficult problem in the academic and industrial circles. In addition, how to design and prepare an ultra-light, ultra-strong, and highly flame-retardant polypropylene foam is of great significance. Based on the early preparation of polypropylene materials with high flame retardant properties (RSC adv., 2016, 6, 112184), polypropylene foams with ultra-light, super-strong and high flame-retardant properties were prepared by the following method. Supercritical carbon dioxide foaming technology combined with one-way ventilation method, the output can reach about 0.56ms-1. Polypropylene foam has a unique structure. Materials such as sugar cane and bones generally show an obvious anisotropic structure, which can be torn into 'foam flowers'. In addition, the density of the prepared polypropylene foam is only 0.08gcm-3, but its weight can be 30,000 times heavier than itself, and its specific strength (up to 1813MPa/(gcm-3)) is much higher than reported in the known literature Polymer foam. In addition, polypropylene foam also has excellent flame retardant properties under the condition of benefiting from the uniformly dispersed intumescent flame retardant. For example, in the horizontal combustion test, the flame can self-extinguish within 2s. In addition, on the basis of the above work, the influence of different biaxial stretching forces on the flame retardant substrate was further studied by supercritical carbon dioxide foaming technology. The results show that by combining the plasticization and mass transfer of supercritical carbon dioxide in the polymer melt and the biaxial stretching in the process, the refractory filler (/flame retardant) can be effectively improved in the polymer matrix (/poly Propylene). The bubble grows. At the same time, on the basis of the research results, the excellent flame retardant and mechanical properties of polypropylene materials were successfully prepared by using hot-pressing defoaming technology.