Mechanical Strengths of Molten and Solidified LLDPE/LDPE Blends and Wood/LDPE Composites Under Tensile Deformation

作者：Harnnarongchai Wanlop; Sitticharoen Watcharin; Intawong Naret; Sombatsompop Narongrit^*

来源：Journal of Vinyl & Additive Technology, 2011, 17(3): 164-176.

DOI：10.1002/vnl.20270

The mechanical strengths of neat low-density polyethylene (LDPE), a blend of LDPE with linear low-density polyethylene (LLDPE), and a composite of LDPE with wood flour (wood/LDPE) were investigated in molten and solidified states under tensile deformation. The results are discussed in terms of the effects of LLDPE and wood contents, roller speed, and volumetric flow rate. In LLDPE/LDPE blends, incorporating LLDPE from 0 to 30 wt% into LDPE caused a slight increase in drawdown force, a larger fluctuation in drawdown force, and a reduction of maximum roller speed to failure. The mechanical properties of the solidified LLDPE/LDPE corresponded to those of the molten LLDPE/LDPE with regard to the effect of LLDPE content. For wood/LDPE composites, increasing the wood flour content in molten LDPE caused considerable reductions in drawdown time and maximum roller speed to failure. The drawdown force increased with increasing wood flour up to 10 wt% before it decreased at the wood loading of 20 wt%. A number of voids and pores on the extrudate surfaces became obvious for the composites with 20 wt% of wood content. Increasing wood content enhanced the tensile modulus for the solidified LDPE but decreased its tensile strength. Unlike those of LLDPE/LDPE blends, the changes in tensile modulus and strength of solidified wood/LDPE composites with wood content did not correspond to those of the molten composites. In all cases, the drawdown force increased with increasing roller speed. The effect of volumetric flow rate from the extruder on the mechanical strengths of the solidified blends was more pronounced than on those of the molten ones. J. VINYL ADDIT. TECHNOL., 17: 164-176, 2011.

• 出版日期2011-9