聚二甲基硅氧烷在过氧化氢溶液中的伽玛辐射效应

Gamma radiation effects on polydimethylsiloxane in hydrogen peroxide solution

研究了6%过氧化氢(H_2O_2)溶液中的聚二甲基硅氧烷(Polydimethylsiloxane,PDMS)橡胶材料的g辐射效应。首先利用拉伸实验测试了辐照前后PDMS橡胶材料力学性能的变化,然后利用甲苯平衡溶胀法,差示扫描量热分析和傅里叶变换衰减全反射红外光谱分析(Attenuated total reflection-Fourier transform infrared,ATR-FTIR)法对其辐照前后的化学结构变化进行了表征。结果表明,在H_2O_2溶液中辐照的PDMS仍发生以辐射交联为主的反应,且在相同的吸收剂量下,相较于空气中辐照的PDMS,在H_2O_2溶液中辐照的PDMS的断裂伸长率较高,弹性模量较小,交联密度较低。这可能是由于H_2O_2溶液在辐照过程中产生的氧化性活性物质能够捕获PDMS辐照生成的大分子活性自由基,从而降低了PDMS发生交联反应的概率。ATR-FTIR结果则进一步表明,随着吸收剂量的增加,PDMS表面出现一定程度的氧化,而相较于空气中辐照的样品,在H_2O_2溶液中辐照的样品表面氧化程度并未明显增强。

The effect of γ-radiation（^60Co γ-ray source） on polydimethylsiloxane（PDMS） rubber soaked in 6% hydrogen peroxide solution was investigated at room temperature. The mechanical properties of the virgin and irradiated PDMS were compared in terms of their tensile strength and the variations in their chemical structure. These properties were analyzed by differential scanning calorimetry（DSC）, attenuated total reflection-Fourier transform infrared（ATR-FTIR） spectroscopy, and solvent swelling experiments. It was found that when PDMS was irradiated in 6% H2O2 solution, cross-linking reactions were predominant. Compared with the samples irradiated in air, PDMS irradiated in 6% H2O2 solution had a higher elongation at break and a lower elastic modulus, which suggested a lower cross-linking density. This may be attributed to the hydroxyl radicals generated from H2O2 during irradiation process, which capture the free radicals generated from PDMS and reduce the probability of the cross-linking reaction. The ATR-FTIR results showed that slight oxidation reactions occurred upon irradiation and the degree of surface oxidation of PDMS irradiated in 6% H2O2 does not significantly enhanced compared with the samples irradiated in air.