New thermal study of polymerization and degradation kinetics of methylene diphenyl diisocyanate

Abstract

This work investigates the thermal polymerization process of a methylene diphenyl diisocyanate (MDI) monomer as well as its thermal degradation following the ICTAC recommendations. MDI monomer is widely used as a synthetic resin in the production of MDF panels, as it provides compaction of the eucalyptus fibers by polymerization. Thermogravimetry/ derivative thermogravimetric-differential thermal analysis (TG/DTG-DTA), differential scanning calorimetry, and midinfrared spectroscopy were used in this study. The polymerization process (An) and degradation (Fn) process exhibited activation energy equal to 149.70 and 80.22 kJ mol-1 , respectively. The combined the FTIR and kinetic information makes it possible to suggest the mechanism reaction, which is an inedited data in literature.

Aging behavior of nano-CaCO3-modified polypropylene nonwoven fabric composites

“…Compared with PP nonwoven fabric, the starting thermal decomposition temperature of modified PP nonwoven shifts toward high temperature, indicating that its thermal stability is enhanced. 14,15 In addition, the weight retention rate of PP nonwoven remains at 0% when the temperature exceeds 440°C, showing that PP nonwoven has been completely pyrolyzed. In comparison, the weight retention rate of modified PP nonwoven fabric remains at 40% when the temperature exceeds 460°C, demonstrating that there was still residue after pyrolysis; the residue was CaCO 3 component with the content of 40% (m/m).…”

Photo‐induced catalytic poly‐trimerization of polyisocyanurates

“…6 The resulting tight network with the isocyanurate core unit can theoretically be adjusted from hard/brittle to soft/flexible or mixtures thereof, depending on the selected residue (R). [7][8][9][10] Originally, PIRs were used in the field of thermal insulation as rigid foam boards. In combinations with polyols, isocyanates, mostly diphenylmethane diisocyanate (MDI) as a prepolymer, are processed in excess to a polyurethane/polyisocyanurate mixture to obtain dimensionally stable, rigid, and thermally stable foams.…”

“…These can be obtained directly from isocyanates or polyisocyanates by poly‐trimerization (Scheme 1). 6 The resulting tight network with the isocyanurate core unit can theoretically be adjusted from hard/brittle to soft/flexible or mixtures thereof, depending on the selected residue (R) 7–10 …”

The Effect of EDTA Functionalization on Fe3O4 Thermal Behavior

“…Functionalization is not expected to change the reaction sequence but only modify the mechanism and stabilize the crystalline phase. Non-isothermal kinetics could investigate the modification in the reaction mechanism, as data are obtained in situ, which is considered an advantage and, therefore, has been applied to several materials [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] . Thus, this study aims *e-mail: aroldo.magdalena@unesp.br to investigate the influence of EDTA functionalization on thermal behavior and the sequence of reactions observed when heating Fe 3 O 4 nanoparticles.…”