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慈竹薄壁组织的部分去除对化机浆制浆、漂白性能的影响

Effect of Partial Removal of Parenchyma Tissues of Neosinocalamus affinis on Pulping and Bleaching Properties of Chemimechanical Pulp

  • 摘要: 采用螺旋挤压法破坏竹片组织结构,并筛除分离部分薄壁组织,选用不同的化学预浸渍方法进行浸渍软化,对制得的不同化学机械浆(CMP)进行过氧化氢漂白对比试验。结果表明:螺旋挤压法去除11.4%薄壁组织后,竹丝化学组成与原竹片相比差异十分明显,其灰分质量分数降低了38.6%,纤维素质量分数增加了4.71%,但螺旋挤压对竹纤维没有造成明显的损伤;碱性过氧化氢(AP)预浸渍可以显著降低磨浆电耗,在加拿大游离度300 mL时,该方法比烧碱(AA)法节电18.0%,并且其化机浆的结合强度较高;AA法浆料的松厚度最高、强度较差;碱性亚硫酸钠(AS)法化机浆的松厚度和强度性能介于AP和AA之间;在H2O2用量为8%的漂白条件下,AP、AS和AA预浸渍法的最佳碱用量分别为4.5%、4.5%和3.5%,同时AP预浸渍可以改善漂白效率,漂后浆白度可达56.8%(ISO),而AA预浸渍化机浆漂白浆白度仅为49.9%(ISO)。

     

    Abstract: The microstructure of bamboo chips was destoried by screw extrusion and part of parenchyma tissues were removed by screening. The obtained bamboo chips were impregnated individually by using different chemical impregnation, i.e. alkaline peroxide(AP), caustic soda(AA) and alkaline sodium sulfite(AS) and followed with atmospheric high consistency refining operation, those different chemimechanical pulps(CMP) were bleached with multiple-stage alkaline peroxide bleaching sequence and the bleached chemimechanical pulps(BCMP) were compared their bleach abilities. Results showed that, the chemical compositions of bamboo chips by removing 11.4% parenchyma tissues were significant different from these of initial bamboo chips, for instance, ash content decreased by 38.6%, cellulose content increased by 4.71%. But screw extrusion didn't cause obvious damage to bamboo fiber. AP impregnation could significantly reduce the refining energyconsumption, which was 18% less than that of AA impregnation as the Canadian standard freeness was 300 mL, and improve the bonding strength of CMP. AA impregnation produced pulps with better bulk properties but poor strength, these properties of AS pulps located among AP and AA pulps; by suing the same H2O2 dosage of 8.0%, the optimal alkali dosages of AP, AS and AA impregnation 4.5%, 4.5% and 3.5%, the bleached pulp brightness of 56.8%(ISO) was achieved from AP impregnation process, but only 49.9%(ISO) obtained from AA process.

     

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