Study On The Performance Of Polyurethane And Its Modification For The Protection Of Handwriting On Paper Relics

Paper cultural relics have vital historical deposits and artistic flavor,and the writing bearing them is the soul of paper cultural relics so that researchers can glimpse the truth of history.The quality of the writing determines the value of the paper.However,in the process of preservation,the report is influenced by humidity,illumination,pests,and other factors,often appearing as fading,diffusion,Yin,and other damage.At present,there is abundant research on the protection of paper cultural relics in the reinforcement and deacidification of paper carriers,but there are few kinds of research on the protection of paper cultural relics.Therefore,this paper focuses on the study of the chemical reinforcement method of handwriting protection,polyurethane material Hmethylene diisocyanate(HDI)trimer and its modification on the writing protection effect as the research content,through the experimental comparison of the change of the handwriting before and after reinforcement,durability,and microstructure,to study its protection effect,to provide experimental data and technical support for the related applications in the field of cultural relics protection.Using HDI trimer solution as a reinforcement agent,ink,carbon ink,blue and black ink,pure blue ink,red ink,and pencil writing materials commonly used in paper cultural relics were selected to compare the color changes and diffusion phenomena of the writing before and after reinforcement.Compared with the reinforcement effect of chitosan,carboxymethyl cellulose,and gelatine-glycerin solution,the safety of HDI trimer reinforcement of paper cultural relics writing was evaluated.The durability of the reinforcement effect is analyzed comprehensively by testing the acid resistance,alkali resistance,oxidation resistance,and dry heat aging resistance of the samples after reinforcement.The results show that,compared with traditional reinforcement materials,the HDI trimer has less influence on paper and writing and has higher safety.The suitable reinforcement concentration of ink and blue and black ink writing is 5%-10%,the appropriate reinforcement concentration of pure blue ink writing is 10%-15%,the optimal reinforcement concentration of carbon ink writing is 5%,and the optimal reinforcement concentration of red ink and pencil writing is 5%,but the reinforcement effect is worse than that of other writing.In conclusion,the HDI trimer has a specific protective impact on writing.With the HDI trimer solution as the base solution,the acrylic polyurethane solution was modified by hydroxyl acrylic resin as the modified material,and the properties of the modified solution were detected by the infrared spectrum.The color change,diffusion phenomenon,and durability test of the handwriting before and after reinforcement were compared.The results show that the optimal reinforcement concentration of ink writing is 15%,carbon ink writing is 10%,blue and black ink writing is 20%,pure blue ink writing is 15% to 20%,and red ink and pencil writing is 3%.In conclusion,the prepared solution fully meets the experimental expectations,and the experimental data shows that the acrylic polyurethane material has a protective effect on the handwriting material,and the optimal reinforcement concentration for different handwriting materials is determined.To further investigate the reinforcement effect of HDI trimer and acrylic polyurethane on different handwriting materials,experimental data of these two reinforcement materials were compared.Use scanning electron microscopy and laser confocal microscopy to analyze the microstructure of paper samples with better reinforcement effects,and explore the reinforcement mechanism.The results showed that the acrylic polyurethane reinforcement material was superior to the HDI trimer reinforcement material in both the comparison of handwriting change data after reinforcement and durability experimental data.Acrylic polyurethane reinforcement material forms a thin film on the surface of the fibers,thereby strengthening handwriting.It also forms cross-linking and resin particles between the fibers,thereby enhancing the strength of the paper.