INTERPENETRATING POLYMER NETWORKS OF POLYURETHANE AND FURFURYL ALCOHOL .1. MORPHOLOGY AND MECHANICAL-PROPERTIES

Polyurethane/furfuryl alcohol (PU/FA) interpenetrating polymer network s (IPNs) were synthesized from furfuryl alcohol using p-toluene sulfon ic acid as a catalyst and blocked NCO-terminated PU prepolymer with m- xylylenediamine (MXDA) as a chain extender. From IR spectrum analysis it was found that the major reactions in the PU/MXDA/FA system are the polymerization of PU/MXDA and the self-polymerization of FA. The tens ile strengths of PU/FA IPNs that contain 5 p.h.r. PU are greater than those of the pure components. The flexural strength, flexural modulus, Shore D hardness and HDT decrease and the notched Izod impact strengt h increases with the polyurethane content. The compatibility of the co mpounds in these PU/FA IPNs was investigated by dynamic mechanical ana lysis and scanning electron microscopy. It was found that glass transi tion temperatures are shifted inwardly which indicated that the PU/FA IPNs were semicompatible. It was confirmed from scanning electron micr ography that the system was heterogeneous.