聚四氢呋喃醚二醇相对分子质量对聚氨酯耐辐照性能的影响

Influence of Polytetrahydrofuran Ether Diol Molecular Weight on Radiation Resistance of Polyurethane

文中针对聚氨酯(PU)软段耐辐照性能差制约其在高能辐照领域的应用,采用不同相对分子质量的聚四氢呋喃醚二醇合成了一系列PU材料,研究了其辐照前后的结构和性能。结果表明,当多元醇相对分子质量为650时,软段排列紧密,可有效抵抗电子辐照对材料的损伤,因而辐照后PU的力学性能保持完好。随着多元醇相对分子质量增加至1000,软段尺寸变大,辐照后PU易发生氧化降解,PU的力学性能显著下降。当多元醇的相对分子质量进一步增加,软段内分子链超过其临界缠结长度,分子链相互缠结,可在一定程度上抑制软段对辐射的阻抗作用,辐照后样品的力学性能可保持原始样品的70%。

The poor radiation resistance of polyurethane(PU)soft segments restrained its applications in the field of high-energy radiation.Aimed at this issue,a series of PU materials were synthesized by polytetrahydrofuran ether diols with different molecular weight.Then the structures and properties before and after radiation were studied.When the molecular weight of polyol is 650,the soft segments are closely arranged to effectively resist the material damage by electron radiation,so the mechanical properties of PU remain intact after radiation.As the molecular weight of polyol increases to 1000,the soft segment size becomes larger which is susceptible to oxidative degradation by radiation,leading to significantly reduced mechanical properties of the prepared PU.With further increasing the molecular weight of the polyols,the molecular chains of soft segment exceed the critical entanglement length and the molecular chains become entangled with each other.The entangled molecular chains are able to inhibit the radiation resistance of soft segment to a certain extent.Accordingly,the mechanical properties of the samples after irradiation maintain 70%of the original one.