紫外光固化聚氨酯自愈合涂层的合成和性能研究

Synthesis and Properties of UV Curable Polyurethane Self-healing Coating

目的制备一种紫外光(UV)固化聚氨酯自愈合涂层,并研究其自愈合性能。方法以2.4-甲苯二异氰酸酯(TDI)、聚丙二醇(PPG)、三羟基聚醚多元醇(HSH330)、甲基丙烯酸羟乙酯(HEMA)、1,4-丁二醇(BDO)为原料,采用两步法合成UV固化丙烯酸酯改性聚氨酯涂层(APU)。使用红外光谱对合成涂层的化学结构进行表征,使用激光共聚焦显微镜对涂层的表界面性能进行分析,并使用拉力试验机考察涂层的力学性能、自愈合性能及成膜性能。结果FTIR光谱结果表明,合成的涂层是丙烯酸酯改性聚氨酯涂层(APU),810cm^-1处存在来自HEMA的—C=C—双键弯曲振动峰,同时涂层仍呈现出明显的聚氨酯化学结构特性。随着HEMA的引入,涂层硬段质量分数从20%增加至40%的过程中,吸水率从36.8%降至3.1%,弹性模量从0.29MPa增加至8.69MPa。自愈合性能测试结果表明,随着HEMA的引入,涂层的自愈合率降低,当APU涂层硬段质量分数超过45%后,涂层失去自愈合能力。结论制备的APU涂层具有优异的耐水性和致密性,由于HEMA含量的增加限制了软段结构的分子链运动和氢键作用,从而削弱了涂层的自愈合性能。

The work aims to prepare a UV curable polyurethane self-healing coating and study its self-healing properties. The UV curable acrylate modified polyurethane (APU) coatings were synthesized by two-stage method with 2,4-toluene diisocyanate (TDI),poly-propylene glycol (PPG),trihydroxy polyether polyol (HSH330),hydroxyethyl methacrylate (HEMA) and 1,4-butanediol (BDO) as raw materials.The chemical structure of the coating was characterized by Fourier Transform Infrared Spectrometer,the surface-interface property was analyzed by Laser Confocal Microscopy and the mechanical properties,self-healing properties and film forming properties were tested by Tension Testing.The FTIR curve results indicated that APU coating was synthesized with the bending vibration peak of -C=C- at 810 cm^-1 from HEMA,while the coating still exhibited the obvious chemical structure characteristic of polyurethane.With the addition of HEMA,the hard segment content increased from 20% to 40%,the water-absorption rate of APU coating decreased from 36.8% to 3.1%,and the elastic modulus increased from 0.29 MPa to 8.69 MPa.The self-healing rates of APU coatings decreased due to the incorporation of HEMA.When the hard segment content of APU coating exceeded 45%,the coating lost self-healing property.The synthetic APU coatings have the good water-resistance and compactness.The addition of HEMA limits the molecular chain motion and the hydrogen bonding of soft segment,thus weakening the self-healing property of APU coating.