Improvement of Eucalyptus Pulp Cellulose Reactivity by PFI Mill Pretreatment
After pretreatment of eucalyptus bleached chemical pulp by PFI mill,the esterification reaction was carried out using acryloyl chloride as the esterification reagent through ball mill.The morphology and structure of the fibers were analyzed by fiber mass analyzer,optical microscope,X-ray diffraction(XRD)and Fourier Transform Infrared Spectroscopy(FT-IR).The effect of esterification conditions on the reactivity of cellulose was further investigated.The results showed that with the increase of PFI beating revolutions,the fiber length and fiber width decreased,and the proportion of fine fiber increased significantly from 19.86%to 38.47%.After PFI mill pulping,obvious fibrillation was observed on the surface of pulp fibers.Moreover,part of the crystallization area was damaged and the crystalline decreased from 72.7%to 66.9%as well.XRD results showed that the crystal structure of the esterification products was changed during the reaction.FT-IR results showed that acryloyl cellullose was obtained by esterification of PFI milled fiber and acryloyl chloride by ball milling.The degree of substitution(DS)of esterified products increased as the increase of PFI grinding revolutions.Compared with untreated fiber,the DS of esterification of the reaction product increased up to 2.38.At this time,the reaction conditions were as follows:the PFI pretreatment was 24 000 r,the molar ratio of cellulose to acryloyl chloride was 1∶6,and the ball milling reaction time was 48 h.
PFI refiningpulp fiberfiber morphologycrystallinedegree of substitution
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