Reactive extrusion of poly(urethane‐isocyanurate)

Abstract

ABSTRACT:Reactive extrusion of poly(urethane-isocyanurate) (PUIR) was studied in an intermeshing corotating twin-screw extruder. Toluene diisocyanate (TDI) and polypropylene glycol (PPG) were used as initial materials with dibutyltin dilaurate (DBTDL) as catalyst. The reaction was first examined in a batch reactor as well as in an internal mixer in order to obtain the kinetics and temperature/torque evolution trends during the formation of PUIR, respectively. For the specified screw speed and temperature profile of the extruder, a working domain can be recommended for the reactive extrusion, in terms of NCO/OH ratio (r ) and catalyst concentration (C), to reach a sufficient extent of reaction. The effects of screw speed and temperature profile on the residence time parameters of the reaction mixture were investigated. It is found that the axial mixing and the RTD behavior of the reaction mixture in the extruder can be well represented by the axial dispersion model. For the reaction condition of r = 3, C = 2%, and barrel temperature profiles of 75-150• C or 90-165 • C, the optimum screw rotation speed for complete NCO conversion is 20 rpm. The structures, thermal stabilities,

Hydrogenated hydroxy-functionalized polyisoprene (H-HTPI) and isocyanurate of isophorone diisocyanates (I-IPDI): reaction kinetics study using FTIR spectroscopy

“…8). This result was also observed by Lomölder et al [23] on IPDI, and similar results were obtained on tolylene diisocyanate (TDI) for which orthoand para-NCO groups reactivities get closer in the presence of catalyst [39].…”

“…temperature enhancement of the primary NCO reactivity rather than the secondary one, was related by others when reacting IPDI with different alcohols in the temperature range 20-100 8C [23]. Similarly, the significant influence of temperature on selectivity was quoted for TDI molecule [39]. It was reported that at 25 8C the NCO group in the para position is 8 to 10 times as reactive as that in the ortho position, but at 100 8C both NCO have similar reactivities.…”

In Situ synthesis of multiblock copolymers of poly(ϵ‐caprolactone) with different poly(ether diols) based polyurethane by reactive extrusion

“…[7][8][9] It was reported that it was feasible to fabricate PU via reactive extrusion, but a further chain extension was followed. [10][11][12] PCL can also be obtained by a one-step reactive extrusion. 13 Thus, it is possible to simultaneously perform the ring-opening polymerization of ecaprolactone (CL) and the urethane reaction to form PCLU via one step in an in situ reactive extrusion with the proper initiator.…”

Rheokinetics and effect of shear rate on the kinetics of linear polyurethane formation

“…Although the exact reaction mechanism of polyurethane formation is more complex, the kinetics of reaction of diisocyanate with dihydroxyl compound is often expressed successfully by a second-order rate equation [1,2,7,24,25]:…”

“…The kinetics of formation of polyurethanes has been studied by several authors [7][8][9][10]. The most common methods for data acquisition are titration, Fourier transform infrared (FTIR), adiabatic temperature rise (ATR), and gel permeation chromatography (GPC).…”