The Analysis Of Willow’s Chemical Components And Pulping Properties

The lack of quality raw plant material has been a great problem to perplex the paper mill in recent years,the existing production demand was satisfied by imported material from abroad.Although poplar is widely planted in north of China as a pulp material,its weaker resistance limits the utilization,so it still could not meet the needs of actual production.About year of 2008,a new modified willow introduced to china,the willow（Salix matsudana cv.Zhuliu）has stronger resistibility to light,pests,drought,cold than other fast-growing wood.However willow has not been used as a pulp and paper material,just more used in production of sheet metal.So we should start a research on willow wood and pulping properties to probe weather is has the potential to be a pulp and paper material.In this thesis,firstly characteristic analysis of willow at different grades of wood-ages（one,two,three,five）,such as cold and hot water soluble material,alkali dissolution material,phenethyl alcohol extract material,lignin,cellulose,fiber quality.Compare these data with white poplar and huge end eucalyptus,the results showed that willow has good potential as a pulp material,because of willow’s cellulose content and fiber length were between white poplar and huge end eucalyptus.Then let willow chipped,screened and pulped using the kraft process to investigate physical properties of paper.Best conditions were: alkali charge（Na2O）16%,the max temperature 170 ℃.Then find that three years willow is more appropriateas pulp material.Next start a research on three years willow as raw material of P-RC APMP with twice pretreatment,which by changed the amount of NaOH and H₂O₂.The optimum addition amount conditions of pulping are Na OH 2.5%/4.0%,H₂O₂ 2.0%/5.0%,paper whiteness could reach 66.8 %ISO,opacity was 88.2%,optical absorption coefficient was 1.17 m²/kg,light scattering coefficient was 47.9 m²/kg,breaking length was 2.09 km,tearing index was 3.64 mN·m²/g.Lignin as a natural macromolecular substance,can be used for the production of high value-added platform compounds like phenolic resin,vanillin,dyes,etc.Thus,the black liquor lignin（AL）and enzymatic mild acidolysis lignin（EMAL）were prepared,and their molecular structure and molecular weight of the isolated lignin polymers were comprehensively investigated by Fourier transform infrared spectroscopy（FT-IR）,two-dimensional nuclear magnetic resonance（2D-NMR HSQC）,13 C nuclear magnetic resonance（13C-NMR）,thermo gravimetric analysis（TGA）and gel permeation chromatography（GPC）.Lignin after pulping,the quinoid structure was transformed to carbonyl functional groups,ether bonds in the β-O-4structure of syringyl and guaiacyl groups was broken,and carbon-carbon bonds also exhibited rupture.The HS-ion in cooking liquor was able to react with lignin with the removal of hydroxyl functions from the primary and secondary alcohol.In addition,methoxyl groups were also removal out of the lignin basic unit.Thereby the molecules weight of lignin broken into small and lignin structure became incomplete.Finally,lignin byproducts were dissolved into the black liquor from the wood.The two isolated lignin polymers,EMAL and AL showed low weight-average molecular weight: 4127 g/mol and 3522.5 g/mol,and in additionthey exhibited low polydispersity index（Mw/Mn < 2.0）.