Industry Gelatin-based Papermaking Retention And Drainage Aid:Synthesis Performance Investigation

Papermaking retention and drainage aid is an important process additive,main function is to enhance filler retention rate and improve drainage performance of pulp,which has great significance for the quality of paper and paper machine operating performance.Along with the people environmental protection consciousness enhancement,the development and application of biomass based retention and drainage aid become a research hotspot.In this paper,the gelatin based retention and drainage aid was prepared by using industrial gelatin extracted from leather waste as raw material,and investigation its retention and drainage performance.Firstly,G-Gel was prepared by using glutaraldehyde as crosslinking agent and Gel as raw material.The results showed that the optimum conditions for the synthesis of G-Gel,the dosage of glutaraldehyde was 10% of the quality of Gel,the reaction temperature was 40oC,pH value was 7,and the reaction time was 3h.By Ninhydrin colorimetric method determination of Gel and G-Gel primary amine content was26mmol/100 g,9.5mmol/100 g,respectively.Showed that the crosslinking reaction of glutaraldehyde and Gel has been successfully carried out,and G-Gel crosslinking degree was 63%.The structure of G-Gel and the reaction mechanism were analyzed by fourier infrared spectrum(FT-IR),ultraviolet spectrum(UV-Vis)and thermo gravimetric analysis(TGA).IR and UV spectra showed that the formation of Schiff base structure between the primary amino group of Gel and the aldehyde group of glutaraldehyde.Thermogravimetric analysis showed that the crosslinking reaction effective increased thermal stability of G-Gel.Due to the function mechanism of the flocculants is similar to the function mechanism of retention and drainage aid,so the flocculation performance of G-Gel is studied by using the kaolin suspension simple model.The results showed that flocculation performance of G-Gel was good when lowdosage(0.3% of the dry weight of kaolin)of G-Gel and in a short flocculation time(30s).Next,studying the retention and drainage performance of G-Gel and G-Gel/polyaluminium chloride(PAC)binary retention and drainage system,respectively.The result showed that the retention and drainage performance of G-Gel compared with commercial grade retention agent gap is lager,the filler retention rate was 73%(the blank retention rate was 39%)and beating degree was 33o(the blank beating degree of adding filler pulp was 35o)when the dosage of G-Gel was 1%.After Introducing the PAC,the G-Gel/PAC binary retention and drainage system had excellent retention and drainage performance.The result showed that filler retention rate reached86% and beating degree was 31o when the dosage of PAC was 0.5%,the dosage of G-Gel was 0.8%.In addition,determination of Zeta potential of pulp showed that the bridging flocculation was main function mechanism of Gel retention and drainage aid,and function mechanism of G-Gel/PAC binary system include charge neutralization,positive charge patch and bridging flocculation.Experiments showed that G-Gel/PAC binary retention and drainage system is a kind of excellent performance of biomass based retention and drainage aid.Therefore,development and application of crosslinked gelatin-based retention and drainage aid,not only was of important significance for the sustainable development of papermaking industry,also provided a new way for the utilization of tannery waste.