The Preparation And Properties Of Silane Crosslinked LLDPE And Silane Self-crosslinked Lldpe

The silane crosslinked linear low density polyethylene (LLDPE) material was made with hot water process in this paper. And the influence of the silane, peroxide initiator, boiling process, the processing conditions etc on the gel content, crosslink density, mechanical properties, crystallization properties, thermal stability and aging resistance of the silane crosslinked LLDPE material was also systematically investigated. The silane self-crosslinked LLDPE material without boiling was made in this paper by introducing the water-carrying agent into the silane grafted LLDPE,which overcome the disadvantage including the time and energy consumption, lower production efficiency of the traditional boiled process. Two different types of were used in this paper, including aluminum potassium sulfate dodecahydrate (Alum) and the blends of stearic acid (St) and zinc oxide (ZnO).What’s more the Alum with crystal water which has the role of a nucleating agent was first used as the water-carrying agents in this paper, and the effects of different water-carrying agents on the gel content, crosslink density, mechanical properties, crystallization properties and thermal stability of silane self-crosslinked LLDPE material were investigated, too. In order to improve the self-retardant properties and thermal stability of the crosslinked LLDPE materials, the flame retardant composite was prepared by modifying silane self-crosslinked LLDPE with the flame retardant in this paper. And the flame retardant properties and thermal stability of the composite material was investigated with oxygen index (LOI), thermal gravimetric analysis (TGA).The gel content and the crosslink density results indicate that the the water-carrying agents can effectively promote the silane crosslinking reaction, improving the gel content and the crosslink density of the silane self-crosslinking LLDPE material; in compare with the silane boiled crosslinked LLDPE material which has a more loose crosslinked network structure, the silane self-crosslinked LLDPE material has a more close crosslinked network structure. X-ray diffraction (XRD) and differential scanning calorimeter (DSC) results showed that the water-carrying agent Alum can play the role of a nucleating agent, so as to promote the silane heterogeneous nucleation of silane self-crosslinked LLDPE material, improving the degree of the crystalline, meanwhile the St/ZnO blend has no obvious effects when acting as a nucleating agent. LOI and the TGA results showed that the flame-retardant properties and thermal stability properties of silane self-crosslinked LLDPE material can be significantly improved by adding POSS to the system.