Effects of initiator type in rigid polyurethane foams

Abstract

Rigid polyurethane foams (RPUFs) have been synthesized from high‐functional polymeric 4,4′‐diphenylmethane diisocyanate (PMDI) and polypropylene glycols (PPG), which were prepared from sorbitol and its combinations with toluene diamine (TDA, T), ethylene diamine (EDA, E), and sucrose/glycerin (G) using environmentally friendly blowing agent, i.e., HFC 365mfc and/or distilled water. Effects of initiator type and blowing agent content have been analyzed in terms of cell morphology, thermal conductivity, and mechanical and dynamic mechanical properties. It was found that TDA‐based initiators gave smallest cell, highest value of rubbery plateau modulus, and greatest thermal insulation, whereas EDA gave the greatest dimensional stability. It was also found that the foam properties were largely governed by the blowing agent, whereas initiator gave fine controls of the properties. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Ultra Low Density Shape Memory Polymer Foams With Tunable Physicochemical Properties for Treatment of intracranial Aneurysms

“…However, we did not elaborate on the complexity of this method: it is a dynamic process where several factors such as raw materials [165,166], polyol functionality [167,168], isocyanate index [169], solution viscosity, blowing agent [170,171], type and concentration of catalysts and surfactants [172][173][174][175][176], temperature of foaming [166,177] and curing and mold size [132,178], can play a significant role in the final physical properties of the foams. This chapter reports a broad range of formulative and process changes in foam fabrication, to achieve a new paradigm in low density SMP foams ( ρ porous < 0.015-0.020 g•cm -3 ), and discusses the mechanism of action of these improvements.…”

Thermal and fire behavior of isophorone diisocyanate based polyurethane foams containing conventional flame retardants

“…This work reports the study of the morphology, density, and thermal and fire behavior of a PUR foam based on IPDI when combined with M, APP, ATH, EG, and combinations of them. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and optical microscopy were used to characterize the morphology of the foams and the density was determined according to ASTM D 1622 standard. Thermogravimetric analysis (TGA) was utilized to investigate the thermal stability and the cone calorimeter was employed to evaluate the influence of the FRs on the fire behavior.…”