γ射线辐照对聚砜结构与性能的影响

Effect of gamma irradiation on structure and properties of polysulfone

应用力学性能测试、傅立叶变换红外光谱分析、扫描电镜断口形貌分析、差示扫描量热分析、凝胶渗透色谱分析、X射线光电子能谱分析等多种手段从多个角度研究了聚砜材料在γ射线辐照下的老化行为,并研究了吸收剂量对材料结构和性能的影响。结果表明,聚砜材料的拉伸强度、弯曲强度、冲击强度、玻璃化温度、数均分子量、峰值分子量和数均聚合度等均随吸收剂量的增加而下降;化学结构在辐照过程中基本上没有变化;其断口表面的光滑程度随辐射剂量的增加而增大;弯曲强度、冲击强度和重均分子量随吸收剂量变化曲线的上升段表明,在低吸收剂量下聚砜材料内部交联反应占优势;这些曲线的下降段表明,在中高吸收剂量下聚砜内部降解反应占优势。动力学分析表明,聚砜在化学上的降解属于无规降解类型,间接证明了聚砜在低吸收剂量下交联反应占优势,在中高吸收剂量下降解反应占优势。

The structure and properties of polysulfone under irradiation by gamma rays were investigated by mechanical testing, fourier transform infrared spectroscopy, scanning electronic micrograph, differential scanning calorimeter, gel permeation chromatography and X-ray photoelectron spectroscopy respectively. The results show that tensile strength, flexural strength, impact strength, number averaged molecular weight, peak molecular weight, glass transition temperatures and number averaged polymerization degree of polysulfone decrease with the absorbed dose. The chemical structure of polysoJfone keeps unchanged. The emhrittlement of material and the smoothness of the fracture surface increase with the absorbed dose. The ascending part of the aging curves of flexural strength, impact strength and weight averaged molecular weight of polysulfone reveale that the cross-linking mechanism dominates at lower absorbed doses, and descending part of the curves shows that degradation mechanism dominates at higher doses. Radiation degradation kinetics of polysulfone under gamma irradiation can be described as random event. It may be indirectly proved that cross-linklng mechanism dominates at low absorbed doses, and degradation mechanism dominates at higher absorbed doses.