共查询到19条相似文献，搜索用时 296 毫秒
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以非离子型聚合物改性得到阳离子化剂,通过转型法成功制得了阳离子型分散松香施胶剂(CDRS),并对其性质进行了表征。CDRS为白色均一乳液,其Zeta电位为 26mV,体积平均粒径为0.271μm,一致性为0.404,粒径分布较好。在pH值6.0、Al2(SO4)3用量1%的条件下,CDRS对再生纸浆的施胶度为40s,施胶效果接近对照样品,耐老化性能则优于对照样品Hi-phase35。浊度实验和扫描电子显微镜观察表明,由于游离松香的皂化作用,CDRS的施胶效果随着pH值的升高而迅速下降。由于成本低,制备方法简单,在近中性条件下施胶效果较好。 相似文献
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《林业科学》2021,57(8)
【目的】基于近红外光谱分析技术,判别纤维板生产过程中施胶量高低,为施胶工艺阶段提供技术支撑。【方法】以桉木纤维为研究对象,以脲醛树脂胶黏剂施胶量高低为判别指标,对同一批桉木纤维,控制含水率5%左右,建立施胶量为无(0%)、低(3%)、中(12%)、高(20%) 4种类别的近红外光谱偏最小二乘法回归模型(PLS),采用PLS-DA法判别施胶量高低,探究光谱采集方式(施胶纤维运动或静态状态)、施胶后纤维陈放时间对模型判别准确性的影响。【结果】1)随着施胶量增加,近红外光谱吸光度增大,PCA分析可区分无、低、中、高4种施胶量类别的桉木纤维; PLS-DA法能够建立相关性好、准确性高的近红外光谱模型,对未知样品的判别正确率达100%; 2)静态或动态光谱采集方式不会影响模型建立,对未知样品的判别正确率达100%;施胶后纤维陈放时间对近红外光谱影响很大,施胶后长时间陈放的纤维几乎不能正确判别施胶量高低。【结论】不同施胶量桉木纤维对近红外光谱的吸光度不同,PLS-DA法可准确判别桉木纤维施胶量高低;样品处于静止或运动状态均不影响模型建立和判别的准确性,可为在线识别纤维施胶量提供一定思路。 相似文献
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将生物乙醇木质素与自合成的聚酰胺多胺环氧氯丙烷(PAE)树脂进行接枝共聚改性大豆蛋白,制备环保型胶合板用胶黏剂,并通过单因素试验确定了木质素种类、木质素与PAE质量比、木质素与PAE树脂反应时间、大豆蛋白添加量等工艺条件对大豆蛋白胶黏剂胶合强度的影响。结果表明:当选用生物乙醇木质素与PAE进行接枝共聚、木质素与PAE质量配比为1∶4、反应时间为30 min、大豆蛋白添加量为50%(以木质素-PAE总质量而言)时,制得的三层胶合板湿胶合强度(1.03 MPa)可达到GB/T 9846—2015Ι类杨木胶合板的指标要求。 相似文献
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UF-MDI混合胶刨花板制造过程中施胶方式的探讨 总被引：3，自引：0，他引：3
利用 4 ,4′-二苯基甲烷二异氰酸酯 (MDI) -脲醛树脂 (UF)混合胶压制刨花板是一种能够显著降低游离甲醛含量的有效方法。本文借助差示扫描量热法 (DSC)和板的力学性能测试等手段 ,重点研究了酸对混合胶固化和施胶方式的影响。试验中所用混合胶的比例为UF∶MDI=6∶1(UF施胶量为 6 % ,可乳化MDI施胶量为 1% ) ,热压温度为 175℃ ,压力 3MPa ,热压时间 6min。按照是否添加固化剂、分别施胶和混合施胶等情况进行压板试验 ,并利用DSC分析固化剂对混合胶反应过程的影响。结果都证明 :酸性固化剂对MDI的固化是很不利的。在UF∶MDI=6∶1的条件下 ,添加氯化铵做固化剂时宜采取分别施胶方式 ,不加氯化铵时宜选择混合施胶方式。按刨花板性能优劣程度 ,施胶方式顺序为 :UF与MDI混合后施胶 ,不加氯化铵 >分别施加UF与MDI,UF里加氯化铵 >分别施加UF与MDI,UF里不加氯化铵 =UF与MDI混合后施胶 ,加氯化铵。混合胶刨花板的甲醛释放量可以降到 9mg·(10 0g) - 1 以下 ,符合E1 级人造板标准的要求 相似文献
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用苯乙烯、丙烯酸酯与甲基丙烯酸二甲胺乙酯或二甲基二烯丙基氯化铵的共聚物作乳化剂分别制备了叔胺型阳离子分散松香施胶剂(SYM-1)和季铵型阳离子分散松香施胶剂(JYM-1),并比较了它们的施胶性能。实验结果表明,叔胺型高分子表面活性剂(SYS-1)的电荷密度和SYM-1的施胶性能受pH值影响较大,SYM-1的施胶度在相同施胶条件下比JYM-1大10 s以上,但在含碳酸钙抄纸体系中失去其施胶性。季铵型高分子表面活性剂(JYS-1)的电荷密度不受pH值的影响,用硫酸铝和聚乙烯胺复合物作定着剂时JYM-1在含碳酸钙抄纸体系中的施胶度大于5 s。 相似文献
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以松香为原料,依次进行酰氯化和酯化反应合成松香基混合单体,并采用FT-IR、GC-MS、13C NMR对其结构进行表征;然后将该松香基混合单体、可逆加成-断裂链转移(RAFT)试剂二硫代苯甲酸异丙苯酯(CDB)和引发剂偶氮二异丁腈(AIBN)按物质的量比100∶1∶0.1进行RAFT聚合反应。为了进一步研究松香基单体的RAFT聚合过程,以高纯度的脱氢枞酸基单体进行了RAFT聚合反应。结果表明:脱氢枞酸基单体在松香基混合单体中GC含量为14.3%,在RAFT聚合中显示了很好的聚合结构可控性,聚合物的多分散系数(PDI)为1.28;而松香基混合单体基聚合物的PDI相对较高,PDI为1.85,但仍属于可控范围。所合成的松香基RAFT聚合物同时也是一种新型大分子RAFT试剂,可以作为下一步RAFT活性聚合的RAFT试剂。TGA分析表明:松香基RAFT聚合物显示了很好的热稳定性,质量损失为10%的温度和最大分解温度分别为250和350℃。 相似文献
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Retention behavior of size and aluminum components on handsheets in rosin-ester size/alum systems 总被引：1，自引：0，他引：1
Anionic emulsion sizes consisting of rosin triglyceride esters and partly fortified rosin acids (i.e., rosin-ester sizes), have recently been used as internal sizes for alkaline papermaking. In this study, handsheets were prepared from pulp suspensions with alum and a rosin-ester size under various conditions, and sizing degree and size and aluminum contents of the handsheets were determined. Aluminum compounds originating from alum added to the pulp suspensions behave as retention aids of the rosin-ester size even in alkaline papermaking under limited conditions. Carboxyl groups in pulp are the primary retention sites of aluminum compounds in pulp suspensions. They form cationic sites on pulp fibers, and thus the anionic size emulsion particles are adsorbed on pulp fibers by electrostatic interactions. However, the cationic charges of aluminum compounds on pulp fibers decrease and finally disappear completely with the lapse of time after the alum addition by forming ionic bonds between the cationic sites and OH– ions. Thus, pH values of the pulp suspensions and timing of the size addition strongly influence the retention values of the rosin-ester size and the resultant sizing features.This research was presented in part at the 1995 autumn meetings of the Society of Fiber Science and Technology Japan in Hamamatsu, October 1995 相似文献
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DRS—1高分散松香胶分散剂的合成及应用研究 总被引：3，自引：1，他引：2
合成了碘基琥珀酸ＡＥＯ－９单酯二钠盐,表征了其结构和性质,并将其用作松香分散剂,在中、低转速搅拌和戒严用硬水转相,制备了固含量高「（４５±２）％」、粒度小（０．１－０．５μｍ≥９０％）、稳定性好的松香分散胶。 相似文献
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Application of cationic polymer prepared from sulfuric acid lignin as a retention aid for usual rosin sizes to neutral papermaking 总被引：3，自引：0，他引：3
Cationic polymers that acted as the retention aids for usual rosin sizes in neutral papermaking were prepared from sulfuric acid lignin (SAL), one type of acid lignin. To convert SAL to the cationic polymer (MP-SAL), SAL was phenolated and then treated by the Mannich reaction to introduce the amino groups. In the MP-SAL single system, MP-SAL exhibited high sizing effectiveness in neutral papermaking with the rosin emulsion size. However, MP-SAL showed no sizing effectiveness when soap rosin size was used. MP-SAL showed increased sizing effectiveness as the pK
a of the introduced amino group increased. From this and comparison of the sizing degrees of MP-SAL and polyethylenimine, which possesses a linear structure, it was suggested that the sizing effectiveness was not only affected by the charge density and molecular weight, but also by the basicity of the introduced amino groups and the molecular structure of the retention aid. In the alum–MP-SAL dual system, alum and MP-SAL synergistically enhanced the sizing effectiveness in the rosin emulsion sizing at neutral pH. In turn, this allowed a decrease in the MP-SAL dosage and resulted in a small decrease in brightness.Part of this report was presented at the 48th Lignin Symposium, October 2003, Fukui 相似文献
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The addition of a bulking agent achieves the bulking of paper and increases the pore volume. In this study, the effect of adding bulking agents with various alkyl chain lengths (C14, C18, and C22) on the bulk of paper, the sizing performance, and sheet wettability was evaluated. The bulking effect of a bulking agent with a short alkyl chain length (C14) was large, and reduction in the sheet tensile strength was confirmed to be suppressed. Good sheet sizing performance was achieved when a bulking agent was used with an alkyl ketene dimer (AKD). When 0.1% or more of AKD was added, using a bulking agent with a shorter alkyl chain length increased the improvement in the sizing degree. Pyrolysis gas chromatography measurements of the amount of reacted AKD revealed that the addition of a bulking agent increased the AKD content of the sheet. The sheet contact angle measured by the two-liquid method tended to increase with increasing alkyl chain length. However, the sheet contact angle was not directly correlated with the Stöckigt sizing degree. By using 1% ferric chloride (FeCl3) and 2% ammonium thiocyanate (NH4SCN) aqueous solution, which are used for measuring the Stöckigt sizing degree, the time-dependent change in the contact angle on the paper sheet surface was measured to evaluate wettability. The Stöckigt sizing degree of paper sheets was found to be greatly influenced by the sheet wettability by NH4SCN solution. In the case of 2% NH4SCN aqueous solution, different samples exhibited large wettability differences. When 0.2% or less of AKD was added, the effect of the concentration on the contact angle was confirmed to be large at all NH4SCN concentrations. 相似文献
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Preparation and sizing mechanisms of neutral rosin size II: functions of rosin derivatives on sizing efficiency 总被引：1，自引：0，他引：1
Four rosin derivatives, including rosin esters and rosinamides, were synthesized and used to prepare neutral rosin sizes. Their effects during sizing are discussed in detail. Compared to natural rosin, the rosin derivatives had nearly no effect on sizing even at high retention levels in paper. However, the rosin derivatives in the rosin sizes improved the stability of the emulsion size particles, and there was good correlation between the sizing effect and the stability of the emulsion sizes under neutral to alkaline conditions. On the other hand, the structure of the rosin derivatives significantly influenced the stability and sizing effect of the neutral rosin sizes. In particular, for glycerin rosin ester-rosin sizes, the emulsion stability and sizing effect increased with an increasing proportion of dirosinate, among the glycerin rosin esters. Consequently, it was suggested that the rosin derivatives hardly contribute to the sizing performance of paper but predominantly function to stabilize the neutral rosin size particles, thereby improving the efficiency of the size under neutral to alkaline sizing conditions. Also it was supposed that glycerol dirosinate in the neutral rosin size would probably enable formation of a more stable particle structure to prevent the destructive action of the OH– ion.This research was presented in part at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998 相似文献