不同分子质量的聚氨酯-不饱和树脂IPN的合成与性能

Synthesis and properties of polyurethane- unsaturated polyester IPNs of different molecular weights

控制二元醇的过量比例,合成了一系列不同分子质量的线性端羟基不饱和树脂(UP),通过自由基引发聚合以及UP树脂羟基与聚氨酯(PU)预聚体的反应,形成PU改性UP互穿网络材料(PUUP-IPN,简称IPN)。采用红外光谱表征了UP树脂及IPN材料的分子结构。通过凝胶渗透色谱和羟基滴定法研究了二元醇过量比例对不饱和树脂分子质量的影响,得到较为一致的结果。研究了UP树脂分子质量对于IPN材料力学和热稳定性的影响。结果表明,经过PU增强改性后,IPN材料的热稳定性有所提升,低分子质量的IPN材料具有较高的弯曲强度和模量,弯曲应变较小,而高分子质量UP及其IPN试样韧性有较大提升。

A series of different molecular weight linear hydroxyl - terminated unsaturated polyester resins （UP） were synthesized by controlling the excess diol ratio. The polyurethane（PU） modified UP interpenetrating network materials（ PUUP - IPN, referred to IPN） were formed by free - radical polymerization and reaction of hydroxyl groups of UP resins and PU prepolymer. The molecular structures of UP resins and IPN materials were characterized by infrared spectroscopy. The effect of glycol excessive proportion on the unsaturated resin molecular weight were investigated by the gel permeation chromatography and hydroxyl titration. The results were consistent. The effect of UP molecular weight on the mechanical properties and thermal stability of IPN materials was studied. The results showed that the thermal stability of IPN was improved after reinforcing modification by PU. The flexural strength and modulus of low molecular weight IPN material were higher and flexural strain was smaller. The toughness of high molecular weight UPs and their IPN specimens were significantly improved.