γ-射線照射應用於紙質文物滅菌之探討

The Application of Gamma Radiation to the Disinfection of Paper-based Materials

本試驗探討鈷-60γ-射線照射對紙質文物滅菌及紙質劣化之影響。由試驗結果得知，對試驗菌株有效滅菌劑量為3～5 KGy。在此劑量之照射下，對紙張白度及紙力影響不明顯，然而對紙張之聚合度已呈現10～20%之下降現象。照射劑量提升至30 KGy時，紙張白度及引張強度雖仍無明顯下降，但紙張之聚合度及耐摺力均約降低50%。500 KGy以上之劑量導致變色、紙力下降、粘度損失及化學組成變化（羧酸基、羰基類降解產物增加）極為顯著。γ-射線照射前施以50°C加熱處理，有助於降低照射時之有效滅菌劑量。在低劑量照射下（30 KGy）之紙張白度雖無明顯下降，但經加熱促進劣化後，白度則有明顯降低，由此可見，以γ-射線照射紙質文物有潛在的劣化作用。在25 KGy劑量下照射裱裝塑膠膜時，PVC、PE及PP膜之變色甚少，而壓克力板則是呈現較多的變黃現象。在20 KGy劑量下照射國畫用顏料，其變色程度不明顯。 The aim of this study is to investigate the feasibility of gamma radiation for the disinfection of paper-based artifacts. The gamma radiation load at 3～5 KGy gave the sufficient biocidal dosage to the fungi strains. There were not apparent brightness and tensile strength loss for the papers irradiated at the load of 3～5 KGy, whereas the decrease in fold occurred concomitantly. An irradiation less than 3 KGy resulted in 10～20% decrease in degree of polymerization (DP) of papers. Severe damage to fold and DP of papers are caused by 30 KGy irradiation (ca. 50% falling). Over 500 KGy irradiation decreased the paper strength, viscosity and changed color and chemical compositions such as carboxylic group, carbonyl group to a certain extents. Preheating the papers at 50°C prior to gamma irradiation reduced the amount of lethal dosage in disinfection. Accelerating tests results have shown that, even at a low dosage of gamma radiation in which may lead to the deterioration of paper-based artifacts. Except acrylic board, slightly yellowing in PVC, PE, PP films can be found under 25 KGy irradiation. The color change in colored pigments of Chinese painting can be ignored by 20 KGy or gamma radiation.

The aim of this study is to investigate the feasibility of gamma radiation for the disinfection of paper-based artifacts. The gamma radiation load at 3～5 KGy gave the sufficient biocidal dosage to the fungi strains. There were not apparent brightness and tensile strength loss for the papers irradiated at the load of 3～5 KGy, whereas the decrease in fold occurred concomitantly. An irradiation less than 3 KGy resulted in 10～20% decrease in degree of polymerization (DP) of papers. Severe damage to fold and DP of papers are caused by 30 KGy irradiation (ca. 50% falling). Over 500 KGy irradiation decreased the paper strength, viscosity and changed color and chemical compositions such as carboxylic group, carbonyl group to a certain extents. Preheating the papers at 50°C prior to gamma irradiation reduced the amount of lethal dosage in disinfection. Accelerating tests results have shown that, even at a low dosage of gamma radiation in which may lead to the deterioration of paper-based artifacts. Except acrylic board, slightly yellowing in PVC, PE, PP films can be found under 25 KGy irradiation. The color change in colored pigments of Chinese painting can be ignored by 20 KGy or gamma radiation.