The influence of thermoplastic polyurethane (TPU) elastomer on the rigidity of polyacetal (polyoxymethylene, POM) was studied by determining heat deflection temperature (HDT). The higher the content of TPU in the POM/TPU blend, the lower the HDT of the blend, as would be expected. A comparative study of the recycle capability of POM and the blends was carried out by measuring melt flow index (MFI) on each successive extrusion. Stress‐strain behaviour of the virgin material and that obtained after fourth‐time extrusion was analysed for POM and the blends. The effect of γ‐radiation on the mechanical behaviour of the blends was investigated. The kinetics of thermal degradation of POM, TPU and their blends was studied. The kinetic parameters, viz. activation energy and the order of reaction, were established. The values of the activation energy of the blends were found to be higher than those of the POM and TPU, indicating improved stability of the resultant blends. Copyright © 1993 Society of Chemical Industry

N. R. Neelakantan

N. Bala Subramanian

Elastomers

Mechanical properties

Polyurethanes

stability

Thermodynamic properties

Thermoplastics

Activation energy

HEAT DEFLECTION TEMPERATURE

ORDER OF REACTION

POLYACETAL

POLYOXYMETHYLENE

RECYCLE CAPABILITY

Rigidity

thermal stability

Yield stress

Polymer blends

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Polymer International

The burning behavior of polyoxymethylene in the counterflow of oxidizing air has been studied experimentally and numerically. Measurements have been performed using a specially designed burner. The temperature profiles were measured in gas phases by a microthermocouple technique. The burning surface temperature and the mass burning rates of solid fuel were determined. The chemical structure of counterflow flame was investigated using the mass spectrometric sampling by microprobe. The composition of the gas sample was analyzed on-line with a mass spectrometric complex (Hiden HPR 60), based on a quadrupole mass spectrometer. The species CH2O, CO, CO2, H2O, O2, N2 were identified and their concentration profiles were measured. The composition of products and kinetic parameters of POM thermal degradation have been determined by mass spectrometry and thermogravimetric analysis. Quasi one-dimensionality of considered diffusion flame has been established experimentally, which allows analysis of flame parameters in relation to the only coordinate normal to the solid fuel's burning surface and substantially simplifies the theoretical description. Predictions have been performed by a coupled model describing feedback heat and mass transfer between gas-phase flame and polymeric solid fuel. A two-dimensional elliptic equation in axisymmetric formulation has been employed to simulate heat transfer in solid fuel, and a set of one-dimensional hyperbolic equations has been used to determine the solid-to-gas conversion degree of the pyrolysis reaction. Gas-phase formulation is presented by one-dimensional conservation equations for multi-component flow with a detailed kinetic mechanism of combustion. Numerical results showed good agreement with the measurements for temperature and species concentration profiles, as well as for the mass burning rate and the surface temperature of solid fuel. © 2019 The Combustion Institute

Combustion and Flame

Experimental and numerical study of polyoxymethylene (Aldrich) combustion in counterflow

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Yang Jie-Chang

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Studies on thermal stability and behaviour of polyacetal and thermoplastic polyurethane elastomer blends

Journal	Polymer International
ISSN	09598103
Open Access	No