混合异氰酸酯型聚氨酯的制备与耐黄变性能

Preparation and yellowing resistance of mixed isocyanate based polyurethane

摘要:

以脂肪族异氟尔酮二异氰酸酯（IPDI）和芳香族二苯基甲烷二异氰酸酯（MDI）为原料，将其与聚四氢呋喃醚二醇2000（PTMG-2000）进行反应，以二月桂酸二丁基锡（DBTDL）为催化剂，合成了聚氨酯预聚体，将预聚体用1,4-丁二醇（BDO）扩链，最后用无水乙醇封端，制得一系列n(IPDI)/n(MDI)不同的混合异氰酸酯型聚氨酯（IMP-1~IMP-11），并对其固含量进行了测定。对所合成的聚氨酯进行稀释进而成膜，制得聚氨酯膜IMPU-1~IMPU-11，对聚氨酯膜的力学性能及紫外老化前后的色差值、黄变等级和紫外透过率进行了测定。采用傅里叶红外光谱仪（FTIR）、X射线衍射（XRD）、热分析（TG）对聚氨酯膜的结构与性能进行了测定。结果表明：随着n(IPDI)/n(MDI)的减少，聚氨酯膜耐黄变性能逐渐降低，但其断裂强度由IMPU-6的18.73N增加到IMPU-11的42.85N，而断裂伸长率则由IMPU-1的763.44%减小到IMPU-11的463.85%。紫外老化前后的色差值由IMPU-1的0.72增加到IMPU-11的22.92，黄变等级由IMPU-1的5级降低到IMPU-11的1级；同时，波长为400 nm时的紫外透过率由IMPU-1的89.74%降低到IMPU-11的35.04%，结晶度由IMPU-1的2.02%增加到IMPU-11的11.27%，450℃时残留量由IMPU-1的1.07%增加到IMPU-11的18.11%，温度为285℃的残留量由IMPU-1的97.01%降低到IMPU-11的91.84%。

Abstract:

A series of different mole ratio of hybrid isocyanate based polyurethane was successfully synthesized via step-by-step polymerization, with isophorone disocyanate (IPDI)/two phenyl methane diisocyanate (MDI) and polytetramethylene ether glycol (PTMG-2000) used as raw materials, dibutyltin dilaurate (DBTDL) as the catalyst, 1,4-butanediol (BDO) as the chain extender and anhydrous ethanol (EtOH) as the blocking agent. The prepared polyurethane was diluted and dispersed with a dispersing machine, and then prepared the polyurethane film. The solid content of the prepared polyurethane was measured; the mechanical properties and the yellowing resistance and UV transmittance before and after ultraviolet aging of the polyurethane film were measured too. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermal analysis (TG) were used to characterize the structure and properties of the polyurethane film. The results showed that with the decrease of n(IPDI)/n(MDI), the yellowing resistance of polyurethane film decreased, but its breaking strength increased from 18.73N of IMPU-6 to 42.85N of IMPU-11, as well as the elongation at break was reduced from 763.44% of IMPU-1 to 463.85% of IMPU-11. The color difference before and after UV aging increased from 0.72 in IMPU-1 to 22.92 in IMPU-11, and the yellowing grade decreased from grade 5 of IMPU-1 to grade 1 of IMPU-11. Meantime, the UV transmittance decreased from 89.74% of IMPU-1 to 35.04% of IMPU-11, the crystallinity increased from 2.02% of IMPU-1 to 11.27% of IMPU-11, the residue at 450℃ increased from 1.07% of IMPU-1 to 18.11% of IMPU-11 and the residue at 285℃ was reduced from 97.01% of IMPU-1 to 91.84% of IMPU-11.