针叶木化学浆高温液态水处理制浆粕工艺研究

以针叶木化学浆为原料,采用高温液态水工艺进行降解、次氯酸钠氧化调整聚合度和碱精制,制备化纤用浆粕,并研究主要影响因素,如有效氯用量、温度、时间及浆浓等对浆料甲纤含量及聚合度的影响。结果表明:在浆浓9%、温度180℃、时间40min的条件下对针叶木浆进行高温液态水处理,纸浆甲纤含量为88.47%,聚合度降低到768;在有效氯用量2.0%、温度50℃、时间1h的条件下对高温液态水预处理后的纸浆进行次氯酸钠氧化,纸浆甲纤含量达到91.54%,聚合度降低到528;在用碱量13%、20℃的条件下精制纸浆1h,浆粕的甲纤含量达到95.85%,聚合度达到536,浆粕的总得率为73.46%,甲纤含量和聚合度均可以满足黏胶纤维用浆粕的要求。     

活性木炭研制初报

提出“活性木炭”概念,叙述了用杉木、柳木、扁柏和绿竹等软木、竹材原料,在炭化终了提高煅烧温度至８００～９００℃制取活性木炭的初步研究结果     

阳离子聚丙烯酰胺的制备及其增强效果

分析了引发剂、单体浓度和温度对阳离子聚丙烯酰胺(CPAM)制备的分子质量的影响，并比较了它们对针叶木浆和漂白麦草浆手抄片物理性能的增强效果。结果表明：聚丙烯酰胺的分子质量随引发剂用量的增加而降低，随单体浓度的提高而增加；温度对聚丙烯酰胺的分子质量影响不大，较低温度下制备的CPAM具有较均一的分子质量，对手抄片增强效果较好；对于麦草浆，CPAM的增强效果略优于两性淀粉或阳离子淀粉。     

热磨机械浆水中溶解物和胶体物对成纸质量的影响及酶处理的效果

本文介绍了针叶木 TMP浆水中 DCS对成纸质量如强度、白度、吸水性和空气阻力(透气度 )等方面的影响,同时介绍了酶处理对降解 TMP浆中 DCS的效果.结果认为:浆水中的溶解物是降低纸页强度的主要成分,浆水中的胶体物则对纸页的吸水性和透气度有重要影响.漆酶处理能降解浆水中大部分的抽出物,而脂肪酶处理主要是水解胶体物中的酯键抽出物.     

Treatment of Caribbean pine by in situ polymerization of styrene and furfuryl alcohol

Caribbean pine impregnated by the full cell treatment schedule with styrene, furfuryl alcohol (FFA), and styrene–FFA monomers was cured for 48 h at 100°C. Styrene did not penetrate inside the wood cell wall; instead, it adhered on the cell wall surfaces and fill cell lumens. The volume contraction during the formation of polystyrene causes the volume contraction of the wood sample. The permanent volumetric swelling is attained only for samples treated with FFA, which is caused by cell wall impregnation. The dimensional stability of the treated wood samples is evaluated with the antiswell efficiency coefficient (ASE). The water repellency is expressed as the water‐repellent effectiveness (WRE). Treatment with styrene improves the water repellence, whereas a double treatment increases the dimensional stability. Lixiviation slightly affects the ASE and WRE coefficients. The treatments improve the Shore D hardness in comparison to untreated wood. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1763–1769, 2004     

Near-Infrared Spectroscopy and Chemometric Analysis for Determining Oxygen Delignification Yield

Abstract

Oxygen delignification studies were carried out using a softwood kraft pulp under varying reaction temperatures (80–140°C) and alkaline charges (1–12%). Near-infrared (NIR) spectroscopy combined with chemometric methods was employed to analyze oxygen delignification pulp yields, which were compared to gravimetric analysis. Principal component analysis (PCA) of the NIR spectra data was performed and a partial least-square (PLS) regression model was developed to predict the pulp yield of oxygen delignified pulps based on the NIR spectra data. PCA analysis indicated that 99.1% of total variances of NIR spectra data in the range of 1100–2266 nm could be expressed by three principle components. A PLS1 model based on the NIR spectra data had good predictive ability and appeared to be an effective tool for pulp yield prediction for the oxygen delignification process.     

MODELLING OF STRESS DEVELOPMENT DURING DRYING AND RELIEF DURING STEAMING IN PINUS RADIATA LUMBER

ABSTRACT

A one-dimensional stress model was proposed for drying of radiata pine lumber, which has considered wood moisture shrinkage, instantaneous stress-strain relationships, mechano-sorptive creep, time-induced creep and temperature effects. In addition, wood hardening behaviour in the plastic region and differences between stress increase and decrease have been taken into account. The proposed Stress model can predict stress development and relief in a drying cycle once the required wood mechanical and Theological properties have been quantified.

Drying experiments were performed to dry Pinus radiata sap wood boards of 100×40×590 mm in a tunnel dryer. In the experiment, wood temperature, moisture content gradient and residual stress through board thickness were measured. The drying cycle included HT drying, cooling and final steam conditioning. The measured stress patterns were in agreement with the model predictions. However, more accurate calculations will be made once the detailed experimental data for radiata pine wood mechanical and rheological properties are available.     

Analysis of Lignin Aromatic Structure in Wood Based on the IR Spectrum

Abstract

A total of 17 softwoods and 48 hardwoods were analyzed by IR spectroscopy to examine if syringyl ratio (syringyl/(syringyl+guaiacyl)) calculated from nitrobenzene oxidation products can be precisely expressed by area ratios of characteristic peaks of lignin in IR spectrum. Area ratio of two peaks is referred to as that of two wavenumber domains, represented by “wavenumber 1/ wavenumber 2.” Examined peak area ratios were 1595/1509, 1509/1460, 1275/1220, 1130/1032, and 835/(855+815). Among these ratios, log(1595/1509) and log(1275/1220) showed significant linear relationship with the syringyl ratios with a correlation coefficient of 0.98 for all 65 woods. These two ratios could also be used to distinguish all the hardwoods from the softwoods.     

Tailoring the Wet Strength of Linerboard Via Dielectric Barrier Discharge

Abstract

Atmospheric dielectric‐barrier discharge treatments were shown to be a facile and direct means of enhancing the wet‐strength tensile properties of softwood kraft linerboard furnish. The improvements in wet‐tensile strength were shown to vary between 10–190% depending on the charge of cold plasma applied. These benefits were accompanied with a minor increase in dry tensile strength and slight decrease dry tear strength and negligible changes in creep properties. AFM analysis of the treated sheets demonstrated that this treatment results in surface smoothing of the fibers.     

An Anomalous Effect in the Drift Spectra of Woods and Papers

Diffuse Reflectance Fourier Transform Infrared (DRIFT) Spectroscopy is a very useful and convenient means of obtaining the infrared spectra of woods and papers. However, distortions can occur in the intensities of bands in the region 950–1200 cm^?1 when the spectra are obtained by reflection directly from wood and paper surfaces due to interference from specularly reflected radiation. Such distortions are reduced in spectra obtained from very thin sheets of paper of from fibres diluted in potassium bromide.