JOURNAL OF POLYMER ENGINEERING

Vol. 22, No. 4, 2002, page 283

GEL POINT PREDICTION OF METAL-FILLED CASTOR OIL -BASED POLYURETHANES SYSTEM

Anil Srivastava¹ and Paramjit Singh²

¹Department of Chemical Technology

Sant Longowal Institute of Engineering and Technology, Longowal

SLIET, Longowal, Sangrur-148106, Punjab, India

²Department of Chemical Engineering and Technology

Panjab University, Chandigarh - 160 014, India

SYNOPSIS

      Prediction of gel point conversion and network formation is of great importance in polycondensation during synthesis as well as processing. It enables one to estimate the safe conversions for reactor operation without gelation, the cycle time during processing and plays an important role in controlling the moulding parameters used for reinforced reaction injection moulding (RRIM), reaction injection moulding (RIM) and compression moulding. Theories of gelation have been extensively published in literature and supported by experimental data for various polycondensation systems. However, most such studies are related to unfilled systems. In this work, metal filled polyurethanes have been synthesised in bulk by reacting toluene 2,4 di-isocyanate with castor oil and its polyols possessing different hydroxyl values. Aluminum metal powder in precalculated amounts in weight fractions of 0.09, 0.16, 0.23 and 0.285 of the reacting mixture containing [weight(polyol + TDI) + aluminium powder (10-40%){weight( polyol + TDI)}] is dispersed thoroughly in castor oil and its polyols in moisture free inert atmoshphere before reacting with toluene 2,4 di-isocyanate at different temperatures (30-60°C). The gel point conversions are measured experimentally and the experimental data have been used to predict the gelation behaviour through an empirical correlation named as the Srivastava and Singh (S.S) model.

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