Rheology of Wood–Plastics Composites

Li, Tieqi

doi:10.1002/9781118140611.ch6

Cited by 2 publications

(2 citation statements)

References 40 publications

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“…Sharkskin melt fracture has been attributed to a breakdown of the no slip boundary condition in the extrusion die, that is, to adhesive failure at the die walls, where the fluid moves with respect to the wall and this is called stick‐slip (see section 6.2.1 of Ref. ; [ ]).…”

Section: Introductionmentioning

confidence: 99%

Wall slip heating

Gilbert

Giacomin

2014

Polym Eng Sci

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When molten plastic is extruded, the upper limiting throughput is often dictated by fine irregular distortions of the extrudate surface. Called sharkskin melt fracture, plastics engineers spike plastics formulations with processing aids to suppress these distortions. Sharkskin melt fracture is not to be confused with gross melt fracture, a larger scale distortion arising at throughputs higher than the critical throughput for sharkskin melt fracture. Sharkskin melt fracture has been attributed to a breakdown of the no slip boundary condition in the extrusion die, that is, adhesive failure at the die walls, where the fluid moves with respect to the wall. In this article, we account for the frictional heating at the wall, which we call slip heating. We focus on slit flow, which is used in film casting, sheet extrusion, curtain coating, and when curvature can be neglected, slit flow is easily extended to pipe extrusion and film blowing. In slit flow, the magnitude of the heat flux from the slipping interface is the product of the shear stress and the slip speed. We present the solutions for the temperature rise in pressure-driven slit flow and simple shearing flow, each subject to constant heat generation at the adhesive slip interface, with and without viscous dissipation in the bulk fluid. We solve the energy equation in Cartesian coordinates for the temperature rise, for steady temperature profiles. For this simplest relevant nonisothermal model, we neglect convective heat transfer in the melt and use a constant viscosity. We arrive at a necessary dimensionless condition for the accurate use of our results: Pé(1. We find that slip heating can raise the melt temperature significantly, as can viscous dissipation in the bulk. We conclude with two worked examples showing the relevance of slip heating in determining wall temperature rise, and we show how to correct wall slip data for this temperature rise. POLYM. ENG.

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Section: Introductionmentioning

confidence: 99%

Wall slip heating

Gilbert

Giacomin

2014

Polym Eng Sci

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“…Thus, these monomers are unable to effectively reduce the moisture content within wood cell wall and correspondingly improve the durability of wood [7][8][9][10]. Consequently, various functional monomers have been explored to improve wood durability, including allyl 2,3 epoxy propyl ether, glycidyl methacrylate, and polyglycerol [11]. These monomers normally improved the decay resistance of wood.…”

Section: Introductionmentioning

confidence: 99%

Wood-Polymer Composite Fabricated by Polymerization of Monomers within Wood Porous Structure

Dong

Gong

Liu

et al. 2012

AMR

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A novel composite, wood-polymer composite, was fabricated by polymerization of functional monomers within wood porous structure. The wood was a fast-growing plant wood, Micheliamacclurel wood, which was rarely reported in previous studies, and two functional monomers, glycidyl methacrylate and ethylene glycol dimethacrylate, were novelly employed. The monomers, added with a few Azo-bis-isobutryonitrile as initiator, and maleic anhydride as catalyst, were first impregnated into wood pores under vacuum/pressure conditions, and then in-situ polymerized into polymers through a catalyst-thermal treatment. After the processes, wood-polymer composite was resulted. SEM and FTIR analysis for the composite indicated that the monomers polymerized into solid polymer, which fully filled up wood pores, and the resulted polymer grafted onto wood matrix, resulting in good interface combination between polymer and wood matrix. Such composite with satisfactory interface can be potentially applied as structural material in construction field.

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Rheology of Wood–Plastics Composites

Cited by 2 publications

References 40 publications

Wall slip heating

Wall slip heating

Wood-Polymer Composite Fabricated by Polymerization of Monomers within Wood Porous Structure

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