Bi/PVC柔性X射线屏蔽材料的制备及其性能研究

Preparation and Properties of Bi/PVC Flexible X-ray Shielding Material

为了研发高性能无铅柔性X射线屏蔽材料,以PVC为基材、Bi为射线屏蔽剂,设计并制备了不同梯度含量的Bi/PVC柔性无铅、高效X射线屏蔽面料。理论分析了其X射线屏蔽性能变化规律,研究了不同密度增加剂含量下屏蔽面料实际屏蔽性能及力学性能的变化规律。为考核屏蔽面料的耐辐照特性,对70%Bi含量的Bi/PVC柔性X射线屏蔽面料开展了累计剂量5KGy的γ辐照试验,并对其基体结构及力学性能变化进行了表征。结果表明:随着Bi的加入量由30%增加到70%,PVC基屏蔽面料的断裂强度及断裂伸长率由6.7 MPa和129%逐步降低到3.2 MPa和62%,而在引入0.3mm厚的基布后断裂强度提升至最低12MPa,并不随密度增加剂的变化而发生显著变化。面料的屏蔽性能由121KV下屏蔽率11.3%逐步增加至46.1%,130KV下屏蔽率10.3%逐步增加至37.5%,与理论计算结果较为接近且变化趋势保持一致。5KGy的γ辐照后,70%Bi含量的Bi/PVC屏蔽面料中PVC基体的C-H及=CH_(2)未发生键合断裂,但C-Cl发生了辐照断裂,屏蔽面料本身的断裂伸长率由辐照前的62%降至辐照后的45%,断裂强度由辐照前的3.29MPa降至辐照后的3.02MPa,较低的γ辐照剂量导致二者绝对值的变化较小。

In order to develop a type of flexible lead-free and high-efficiency X-ray shielding material,shielding fabrics based on PVC with different contents of Bi as the radiation shielding agent were designed and prepared.The X-ray shielding performance variation of the shielding fabrics was analyzed theoretically,and the actual shielding performance and variation of mechanical properties of the shielding fabrics with different contents of density increasing agent were studied.The Bi/PVC flexible X-ray shielding fabric with 70%Bi was irradiated with a cumulative dose of 5KGy gamma irradiation to evaluate the radiation resistance of shielding fabric,the ma-trix structure and mechanical properties were characterized.The results showed that with the increase of Bi content from 30%to 70%,the breaking strength and elongation at break of PVC-based shielding fabrics gradual-ly decreased from 6.7 MPa and 129%to 3.2 MPa and 62%respectively.After the introduction of 0.3mm thick substrate,the breaking strength decreased to a minimum of 12 MPa,which did not change significantly with the change of density increasing agent.The shielding rate of shielding materials gradually increased from 11.3%to 46.1%at 121KV and from 10.3%to 37.5%at 130KV,which was consistent with the theoretical calculation re-sults.After 5KGy gamma irradiation,the C-H and=CH_(2) of PVC matrix in Bi/PVC shielding material with 70%Bi content did not break,but the C-Cl broke.The elongation at break of the shielding fabric itself decreased from 62%before irradiation to 45%after irradiation,and the breaking strength decreased from 3.29 MPa before irradi-ation to 3.02 MPa after irradiation.No significant change appeared because of the low gamma irradiation dose.