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Steady melting of rectangular thermoplastic bars induced by hot contacting surfaces
Author(s) -
Poslinski A. J.,
Stokes V. K.
Publication year - 1992
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760321612
Subject(s) - materials science , composite material , melt flow index , thermal conduction , viscosity , thermoplastic , thermodynamics , mechanics , polymer , physics , copolymer
The steady melting of rectangular thermoplastic bars in contact with hot surfaces is analyzed by solving a simplified set of the momentum and energy balance equations, assuming a temperature and shear‐rate dependent melt viscosity. A numerical model is developed for predicting the flow field and the temperature distribution in the solid and molten regions of the bar and the location of the solid/melt interface. Computer simulations show that the steady melting rate of the thermoplastic solid is mainly affected by the temperature sensitivity of the melt viscosity, by the pressure applied on the end of the bar, and by a balance between heat conduction and the convection of colder material into the molten region. For the amorphous and semicrystalline polymers considered, heat convection in the outflow direction of the molten material, viscous dissipation, and shear‐thinning of the melt viscosity have a much smaller effect on the melting process. These results provide an insight into conduction‐induced melting with forced melt removal caused by pressure‐induced flow; they also provide a basis for developing a transient model for the hot‐tool welding process.