난연성 LDPE 발포체의 전자선 가교 특성에 관한 연구

Abstract

The improvement of flame retardant behavior of low density polyethylene (LDPE) foams was conducted by formulating various, material i.e. LDPE, inorganic flame retardants, fly ash, surface material, cross-linking agent and activator. Here, the surface material is expected to be very useful for flame retardant because which consists of various materials such as PMMA, aluminium trihydroxide (ATH), alumina and silica etc. The ATH can be used for improving a flame retardancy of polymeric composites because which can absorbs the heat (470 kcal/kg) and resulting in decrease of a smoke emitted at a fire atmosphere. And an fly ash modified physically was used to improve a flame retardancy. As a cross-linking agent ratio (2∼4 phr) and an electron beam dose (30∼60 kGy) increased, gel contents increased. The same increasement was also observed with increasing content of the surface material. The expandability increased as the surface material increase but the fly ash decrease. High expandability was clearly observed for the LDPE foams cross-linked not only by the chemical agent for 2 phr (759∼1391 %) but also by the electron beam irradiations during 60 kGy (1080∼1536 %). In addition, closed-cell structures were observed for each LDPE foam. For TGA, all the LDPE foams did not show any apparent expected for the intial and maximum decomposition temperatures. In contrast, final residues decrease as the fly ash decreases (the surface material increases). The fire retardancy was indicated by the LOI values of 24∼25. As the expandability increases, LOI values decrease as well. Therefore, we showed that both the fly ash and the surface material could be used candidates for LDPE foams with an excellent expandability and a flame retardancy.