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The aging process of paper will be accelerated by acidification behavior during the storage process of paper archives, and the mechanical properties of paper archives will be weakened. By deacidizing and strengthening, the further aging of the acidified archives paper can be delayed or prevented, and the mechanical properties can be improved, so that the service life of paper archives is prolonged. To delay even to prevent the aging process, deacidizing and strengthening technology is employed. Herein, the "hybrid" system was reported by combining nano-calcium carbonate as deacidification agent, modified hydroxypropyl cellulose as reinforcement agent and ethanol as dispersant. The artificially acidified paper was brushed with it, and the pH value, mechanical properties and whiteness were measured to study the effect of deacidification and reinforcement. The results showed that oleic acid was successfully grafted onto hydroxypropyl cellulose by N,N′-carbonyl diimidazole mediated method to obtain oleic acid grafted hydroxypropyl cellulose with good dispersion in ethanol. After treating acidified paper with "hybrid" system, the pH value and the tensile strength index increase, the whiteness is almost unchanged, that is, the use of "hybrid" system plays a good deacidifying strengthening effect. The acidified paper samples before and after treatment with "hybrid" system were subjected to dry-heat aging treatment. Compared with acidified paper, the pH value, tensile strength index and whiteness of acidified paper treated with "hybrid" system are effectively inhibited, that is, the use of "hybrid" system can effectively delay the aging and acidification process of paper. [ABSTRACT FROM AUTHOR]

Aging behavior occurs in the storage process of paper archives, which accelerates the aging process of the paper. Therefore, it is important for paper archives management to explore the aging behavior of acidified paper (AP) and to delay or prevent its further aging. The aging behavior of the commonly used university archives paper with artificial acidification were studied by measuring pH value, electrical conductivity, mechanical properties and whiteness. The results show that the pH value, conductivity, mechanical properties and whiteness of AP change significantly compared with the non-acidified raw paper (P). After dry-heat aging treatment, the pH value of AP decreased more obviously than P, which shows more obvious aging degradation and further acidification of AP. During the aging process of AP, the molecular and structural degradation are promoted by the presence of acidic substances, which increase the electrical conductivity of the system. The microstructures of the paper are changed by acidification and aging treatment, and more fiber fracture, etching and microscopic holes are found in the surface SEM images. The reductions of the tensile index and whiteness of AP are also more significant because of the degradation acceleration of the acid. [ABSTRACT FROM AUTHOR]

The aging and acidification behavior of paper archives affect their long-term preservation. Therefore, delaying or preventing aging and acidification has become an important topic in the field of paper archives management. the aging and acidification behavior of commercial archival paper were studied by measuring pH value, electrical conductivity, mechanical properties and whiteness in this work. The results show that the aging and acidification phenomena are obvious after dry-heat aging treatment. The molecular degradation of cellulose, hemicellulose, lignin and other components results in the decrease of pH value of the system, which decrease with the increase of the treatment temperature and time. The electrical conductivity of the system increases because of the molecular degradation and structural degradation, and with the increase of the treatment temperature and time, the electrical conductivity increases more significantly. After aging treatment, the paper appears etching and increasing microcosmic pores. With the occurrence of molecular degradation and structural degradation, the tensile index and whiteness of the paper decrease, and with the increase of the treatment temperature and time, the tensile index and whiteness decrease more significantly. [ABSTRACT FROM AUTHOR]

In this paper, a multilayer diazo resin-graphene oxide/polyacrylonitrile composite membrane was prepared by layer-by-layer self-assembly and UV-induced modification of commercial polyacrylonitrile (PAN) hollow fiber membranes grafted with diazo resin (DR) and graphene oxide (GO). Scanning electron microscopy (SEM), infrared spectroscopy, contact angle, thermogravimetric analysis (TG), water flux and adsorption properties of heavy metals were studied. The results showed that diazo resin (DR) and graphene oxide (GO) were successfully grafted onto PAN membranes by layer-by-layer self-assembly. Carbonyl and carboxyl groups appeared on the surface of the modified PAN membranes; layer-by-layer self-assembly modification did not destroy the original morphology of PAN membranes, resulting in smaller pore size and higher surface roughness; hydrophilicity of the modified PAN-(DR-GO)3 membranes. The contact angle of pure water decreases from 87.8 degrees to 55.5 degrees, and the water flux increases from 733.30 g.m−1.h−1 to 1250.48 g.m−1.h−1. The thermo gravimetric curves of PAN films before and after modification did not change significantly, and the PAN films before and after modification had good thermal stability. The modified PAN membrane can achieve adsorption equilibrium in a relatively short time, and has good adsorption performance for heavy copper ions, with the adsorption rate as high as 92%. [ABSTRACT FROM AUTHOR]