Solvent-free hexamethylene diisocyanate (HDI)-based polyisocyanates were prepared by cyclotrimerization of HDI monomer using tri-n-butylphosphine (TBP) as a catalyst, and characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and mass spectrometry (MS). The GPC results revealed the effects of reaction time, temperature and concentration of TBP on the molecular weight distribution of the polyisocyanates. The structures of the polyisocyanates were identified and confirmed by the combined analysis of MS, FTIR and NMR. There are dimer, pentamer, heptamer and higher-molecular-weight oligomers presented in the product, beyond the main product of trimer oligomers.

无溶剂的六亚甲基二异氰酸酯（HDI）类使用三-由HDI单体的环三聚，制备多异氰酸酯Ñ丁基膦（TBP）作为催化剂，并且其特征在于通过凝胶渗透色谱（GPC），核磁共振（NMR），傅里叶变换红外光谱（FTIR）和质谱（MS）。GPC结果揭示了反应时间，TBP温度和浓度对多异氰酸酯分子量分布的影响。通过MS，FTIR和NMR的组合分析鉴定并确认了多异氰酸酯的结构。产品中存在二聚体，五聚体，七聚体和更高分子量的低聚物，这超出了三聚体低聚物的主要产品。