Structure‐Property Relationships for Model Heterocyclic Polymer Networks: Effect of Network Density

J. Polym. Sci. Part A: Polym. Chem.

2013

A series of networked polymers bearing isocyanurate moiety was synthesized by cyclotrimerization of diisocyanates, with employing methylenediphenyl 4,4′‐diisocyanate and 1,6‐hexamethylenediisocyanate (HMDI) in several feed ratios. In spite of the large difference in intrinsic reactivity between these two diisocyanates, their coannulation proceeded efficiently by using sodium p‐toluenesulfinate (pTolSO2Na) and 1,3‐dimethyl‐2‐imidazolidinone as a catalyst and a solvent, respectively. The resulting networked polymers were transparent and exhibited excellent thermal stability. In addition, HMDI‐rich feed ratios allowed for the formation of networked polymers with increased flexibility. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2631–2637

Section: Introductionmentioning

confidence: 99%

Cyclotrimerization of diisocyanates toward high‐performance networked polymers with rigid isocyanurate structure: Combination of aromatic and aliphatic diisocyanates for tunable flexibility

J. Polym. Sci. Part A: Polym. Chem.

2013

“…So far, isocyanurate linkage has been frequently used in polyurethane chemistry to enhance heat resistance, flame retardation, and chemical resistance of polyurethanes 6. In addition, there have been a few reports on cyclotrimerization of diisocyanates that afforded the corresponding networked polymers bearing isocyanurate groups 7–14. We reinvestigated the cyclotrimerization conditions, leading to the achievement of rapid and quantitative formation of isocyanurate by using sodium p ‐toluenesulfinate ( p TolSO 2 Na) and 1,3‐dimethyl‐2‐imidazolidinone (DMI) as the optimized catalyst and solvent, respectively.…”

Section: Introductionmentioning

confidence: 99%

Development of high‐performance networked polymers based on cyclotrimerization of isocyanates: Control of properties by addition of monoisocyanates

J. Polym. Sci. A Polym. Chem.

2012

Highly heat‐resistant networked polymers consisting of isocyanurate moieties have been developed based on cyclotrimerization of isocyanates. To the polymerization system using methylene diphenyl 4,4′‐diisocyanate (MDI) as the main component, a series of aromatic monoisocyanates (p‐tolylisocyanate, p‐trifluoromethylphenylisocyanate, p‐tert‐butylphenylisocyanate, and p‐butylphenylisocyanate) were added with varying feed ratio [MDI]0:[monoisocyanate]0 to achieve successful control of flexibility of thecorresponding networked polymers without serious deterioration of the thermal stability.

“…In this case, formation of undesired structures involving urea, biuret, and uretidione was confirmed by a solid‐state NMR spectroscopy. Although there have been similar studies on the cyclotrimerizations of 1,6‐hexamthylenediisocyanate and 2,4‐tolylenediisocyanate as diisocyanate‐type monomers, the conversions of those monomers and selectivity of the reactions have not been satisfactory yet to achieve the potential of isocyanurate‐based materials 9–13…”

Section: Introductionmentioning

confidence: 99%

Development of high‐performance networked polymers consisting of isocyanurate structures based on selective cyclotrimerization of isocyanates

J. Polym. Sci. A Polym. Chem.

2011

Selective and quantitative cyclotrimerization of ptolylisocyanate proceeded by using sodium p-toluenesulfinate as a catalyst and 1,3-dimethylimidazolidinone as a solvent. Exploitation of this system to the cyclotrimerization of methylene diphenyl 4,4 0 -diisocyanate (MDI) permitted formation of the corresponding networked polymer, which was selectively consisted of isocyanurate moiety and thus exhibited excellent thermal stability. Utilization of phenyl isocyanate (PhNCO) as a comonomer with varying feed ratio [MDI] 0 /[PhNCO] 0 allowed successful control of flexibility of the networked polymers, while retaining its high thermal stability. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 5186-5191, 2011