| In order to increase the new application of Tetra Pak waste recycling and enlarge the usingrange of wood-plastic composite materials, this paper is based on Tetra Pak waste as theprinciple raw material, adding intumescent flame retardant and basalt fiber, to manufactureflame-retarded wood-plastic composite materials in different ways. Investigating the content ofTetra Pak powder, the ratio and content of flame retardant and the content of basalt fiber, whichis made influence on the properties of composite materials; comparing different processingpreparation technology, to determine the optimum process conditions of hot-press approach onmanufacturing composite material; analyzing the dynamics of thermal degradation offlame-retarded wood-plastic composite materials, and the flame-retardant mechanism ofwood-plastic composite materials is discussed. The chief research results of this paper are asfollows:1). It is feasible to use the Tetra Pak packaged waste as raw material of wood-plasticcomposites. Within the scope of the given Tetra Pak powder, the bending strength ofwood-plastic composites first increases then decreases, with the increase of the Tetra Pakpowder’s content. It reaches the maximum38.07MPa when the adding quantity of Lile powderis60%, and its tensile strength, bending fracture strain and the elongation at break is reducedwith the increase of Tetra Pak powder.2). APP and MEL have good synergistic flame retardant effects, when the proportion ofAPP and MEL is3:1, the effective of flame retardant is the best. Within the scope of the test,when the content of flame retardant is increased, the expansion of the material surface is greaterafter burning, carbon layer and dilatation tend to be coMPacted and stable, so that the flameretardant effect is stronger, and the oxygen index value is higher. Along with the flame retardantcontent increase, the bending strength of wood-plastic composites first increases then decreases.When the flame retardants content is20phr, the oxygen index is25.1, and burningbehavior-vertical reaches FV-level2, and the bending strength reaches the maximum48.75MPa; when the flame retardants content is50phr, the tensile strength decrease gradually, and itreaches the minimum17.38MPa, the oxygen index is29.2, and burning behavior-verticalreaches FV-level0.3). The flame-retarded properties and mechanical properties of wood-plastic compositescan be improved when basalt fiber is added. Within the scope of the test, the oxygen index ofthe flame-retarded wood-plastic composites can reach more than30with added basalt fiber, thebending strength reaches the maximum59.21MPa when the adding quantity of basalt fiber is 2%, and the tensile strength reaches the maximum26.5MPa when the adding quantity of basaltfiber is0.5%.4). By orthogonal tests, the optimum technology condition of hot-press approach onmanufacturing Tetra Pak powder/HDPE flame-retarded wood-plastic composites was obtained:the clamping time is15min, the temperature is160℃, and the pressure is10MPa.Through theoptimum technology condition, the oxygen index of the sample was28.31, bending strengthwas44.17MPa, and tensile strength was16.98MPa. Contrast hot-press approach with injectionmolding, the flame-retarded wood-plastic composites has more excellent mechanical propertiesand flame-retarded properties when manufacturing by injection molding, and the carbon layerand expansion of the burned composites material remainder is more coMPacted and stable afterinjection molding.5). The activation energy of wood-plastic composite materials in APP/MEL/basalt fiberflame retardant systems is higher than that in APP/MEL flame retardant systems. In APP/MEL/basalt fiber flame retardant systems, pyrolysis of wood-plastic composite materials is roughlydivided into two stages. The Coats-Redfern method was used to solve kinetic parameters andequations of pyrolysis at various stages, therefore, the reaction mechanism in each stage wasobtained. The model of pyrolysis reaction in the first stage （da）/（dt）=（1-α）~2×2.87×exp（-4.24×10~3/T）, and the apparent activation energy is35.26KJ/mol; the apparentactivation energy becomes171.16KJ/mol in the second stage, while the model of pyrolysisreaction is （da）/（dt）=（1-α）×27.77×exp（-20.64×10~3/T）. |
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