纸质文献保存的合适pH值范围研究

Study on the Proper pH Range for Paper Documents Preservation

关键词:  pH值范围  纸质文献  保存

Key Words:range of pH value  paper documents  preservation

摘要:本研究利用超声雾化法改变纸张的初始pH值，对预处理后的纸张进行湿热老化，通过评估其色差、机械性能、热稳定性及纤维素聚合度、结晶度和官能团变化来探究保存纸张的合适pH值范围。结果表明，适合纸张长时间保存的pH值范围在8.0~8.5之间，对于已酸化的纸质文献应使脱酸终点保持在此范围内。纸张pH值碱性过高或酸性，都会导致纤维素发生水解，纸张机械性能下降、热稳定性变差、纤维素结晶度和聚合度降低，并加速纸张返黄。纸质文献脱酸时，为避免碱性过高pH值条件下的纤维素碱性水解，纸质文献脱酸保护中选用的脱酸剂pH值也不宜过高。

Abstract:The initial pH value of the paper was changed by the ultrasonic atomization method， and the pretreated paper was subjected to damp and heat aging， and the appropriate pH range for the preservation of the paper was explored by evaluating its color difference， mecha-nical properties， thermal stability， degree of polymerization， crystallinity and functional group changes. The results showed that the range of pH value suitable for long-term storage of paper was 8.0~8.5， and the end point of deacidification should be kept within this range for acidified paper documents. If the pH value of the paper was too high or too low， the cellulose would be hydrolyzed， the mechanical properties of the paper would decrease， the thermal stability would deteriorate， the crystallinity and degree of polymerization would decrease， and the yellowing of the paper would be accelerated. During deacidification， in order to avoid alkaline hydrolysis of cellulose under high pH conditions， the pH value of the deacidification agent selected in the deacidification protection of paper documents should not be too high.