External Heat Transfer in Moist Air and Superheated Steam for Softwood Drying

In kiln drying of softwood timber, external heat and moisture mass transfer coefficients are important in defining boundary temperature and moisture content at the wood surface. In addition, superheated steam drying of wood is a promising technology but this has not been widely accepted commercially, partially due to the lack of understanding of the drying phenomena occurred during drying. In this work, experimental investigation was performed to quantify the heat transfer between wood surface and surrounding moist air or superheated steam. In the experiment, saturated radiata pine sapwood samples were dried using dry-bulb/wet-bulb temperatures of 60℃/50℃, 90℃/60℃, 120℃/71℃, 140℃/90℃, 160℃/90℃, 140℃/100℃ and 160℃/100℃. The last two schedules were for superheated steam drying as the wet-bulb temperature was set at 100℃. The circulation velocity over the board surface was controlled at 4.2m·s-1. Two additional runs (90℃/60℃) using air velocities of 2.4m·s-1 and 4.8m·s-1 were performed t     

针叶木硫酸盐浆GIF仿酶漂白研究

采用Cu2 吡啶/H2O2构成的GIF有机仿酶降解体系进行了针叶木硫酸盐浆的漂白研究,并探讨了漂白过程中纸浆卡伯值、粘度和白度的变化规律.研究结果表明,GIF仿酶漂白在溶出木素大分子方面能力并不强,主要通过将木素氧化为含羰基的产物,使其在后续碱抽提和H2O2漂白中容易降解或溶出.GIF型仿酶体系对碳水化合物也有一定的氧化降解作用,纸浆粘度有明显降低,说明该反应体系中存在着自由基反应.     

烷基化改性针叶木纤维制备热塑性材料的研究

以针叶木纤维为原料,先通过机械分丝处理、再采用烷基化改性制备出具有低玻璃化转变温度的新型烷基化纤维功能材料.通过红外光谱(IR)、扫描电镜(SEM)、X射线衍射(XRD)、热重(TG)和差示量热扫描(DSC)等对烷基化纤维的结构和物理性能进行了表征.结果表明,针叶木纤维表面的大量羟基能够被环氧氯丙烷中的甲基环氧基取代,表面形貌呈现粘流态.XRD分析表明,改性纤维分子链间隙变大,结晶度下降至21.4%.热分析显示,改性纤维的热塑性提高,玻璃化转变温度为137℃.     

黑云杉枝扦插育苗技术的研究

采用全光自动喷雾扦插育苗设备进行了黑云杉半木质化嫩枝扦插育苗试验。3年研究结果表明，在辽宁省东部地区气候条件下，以ABT200mg/kg浸插穗30-50min，生根率达到78.3%。而且根系发育良好；嫩枝插穗生根率比带部分硬枝的插穗生根率高49%。两差异达显水平；河沙插壤比锯末插壤生根率提高11.2%。嫩枝插穗扦插后。25d形成愈伤组织，40d左右出现根状凸起，50d生根，秋季起苗，沙藏越冬，翌年移植成活率高达92.5%。当年新梢生长量6.6cm。     

ECF和TCF漂白硫酸盐针叶木浆表面特性的比较

主要目的是确定不同的漂白方法对硫酸盐针叶木浆纤维表面特性的影响,包括老化前和老化后。通过测量水中的动态接触角(DCA)和浆中纤维的电子光谱来检测。实验表明,漂白浆中纤维表面的不同是因为漂白方法不同。全无氯漂白(TCF)的纤维动态接触角(DCA)始终比较高一些。纤维的特性在贮藏六个月后发生了改变,TCF的DCA比ECF的更显著。贮藏后纤维的接触角变大说明可能是抽出物的迁移或木素从纤维壁中到了表面,也可能是纤维表面的组分发生了变化而变的更加疏水。     

细菌纤维素与针叶木浆配抄对纸张性质的影响

分别采用标准纤维解离器及PFI磨对细菌纤维素进行分散,并添加到针叶木浆中,比较这两种方法分散后的细菌纤维素纤维对纸张物理强度的影响。结果表明,当用标准纤维解离器高速疏解分散的细菌纤维素添加量达到3%左右时,纸张的强度指标综合评定较好,其中抗张指数增加了40.7%,撕裂指数增加了40.9%,耐破指数增加了38.3%,耐折度增加了23.2%;当添加经PFI磨12000转处理过的细菌纤维素时,纸张各项强度指标也都得到较明显的提高,其中,抗张指数增加了77.6%,撕裂指数增加了20.4%,耐破指数增加了38.2%,耐折度增加了25.3%。两种分散方法比较,后者较前者好。     

大型纸机使用复合打浆酶改善铜版纸折页爆裂

随着国内数台大型铜版纸机的投产,铜版纸市场日渐疲软,如何提高铜版纸的质量成为各大企业关注的焦点。铜版纸印刷后的折页爆裂问题是束缚铜版纸质量提高的一大障碍。太阳纸业大型铜版纸纸机通过使用提高成纸强度的打浆酶改善了铜版纸印刷后的折页爆裂问题,取得了较好的效果。     

CPAM在漂白针叶木浆和杨木APMP中的助留助滤性能

考察了W/O型和W/W型阳离子聚丙烯酰胺(CPAM)/膨润土体系对漂白针叶木浆和杨木APMP浆滤水和留着性能的影响。结果表明,在漂白针叶木浆中,W/W型CPAM单元体系助留助滤效果较好;在杨木APMP浆中,电荷密度较高的W/O型CPAM单元体系助留助滤效果较好;当W/O型CPAM用量为0.03%时,杨木APMP浆滤水速度和总留着率分别提高32.4%和20.2%。CPAM与膨润土组成的微粒体系可进一步提高漂白针叶木浆滤水和留着性能,但提高杨木APMP浆滤水和留着效果不明显。     

羧甲基纤维素改善纸张强度的研究

研究添加自制的造纸用羧甲基纤维素(CMC)作为助剂对针叶木化学浆、麦草化学浆所抄纸页强度的影响。结果表明：在打浆过程中加入CMC作为纤维润胀剂，可降低纤维内聚力，提高其柔软性，使成纸物理性质得到改善。     

Formation rate of benzyl cation intermediate from p-Hydroxyphenyl,guaiacyl, or syringyl nucleus in acidolysis of lignin

The benzyl cation intermediate is believed to be primarily formed in the acid-catalyzed reaction of lignin, and the reaction route of the intermediate determines which reaction products are afforded and whether lignin undergoes depolymerization or condensation. This study aimed to examine the formation rate of the benzyl cation intermediate from phenolic (P) or non-phenolic (N) lignin model compounds with different types of aromatic nuclei, namely p-hydroxyphenyl (H), guaiacyl (G), or syringyl (S). The rate was in the order of H > G > S for both P- and N-type model compounds and of P > N for all H-, G-, and S- type model compounds. The orders were successfully explained by the electron-donating or electron-withdrawing properties of the hydroxy and methoxy groups at the para- and meta- of the benzyl position, which is the reaction center in the formation of the benzyl cation intermediate.