国产棉浆粕的性能表征及制备二醋酸纤维素的研究

为了探索制造烟用二醋酸纤维素片的浆粕原料国产化,采用扫描电子显微镜、X-射线衍射、热重分析、红外光谱、半纤维素分析等方法表征了国产醋化级棉浆粕的物化特性,并评价了国产棉浆粕的醋化反应性能。结果表明,与进口木浆粕相比,国产棉浆粕具有α-纤维素含量高、结晶度高、半纤维素含量低的特点。国产棉浆粕的醋化反应活性低于木浆,采用国产棉浆粕制备的醋片白度和丙酮浊度优于以木浆为原料制备的醋片。     

石砚纸业将建10万吨醋化级木浆粕项目

正吉林石砚纸业集团确定建设10万吨醋化级木浆粕项目,总投资127000万元,其中固定资产投资107000万元。醋化级木浆粕是专用于生产醋酸纤维的高纯度溶解木浆。目前,醋酸纤维是再生纤维素纤维中仅次于粘胶纤维的第二大品种,是纤维素醋酸酯纤维的俗称。由于醋酸纤维以纤维素为基本骨架,因此具备纤维素纤维的基本特征,同时因其回潮率较低、有热塑性,而具有了合成纤维的某些特征。因此,醋酸纤维的应用非常广泛。     

技术贸易

南方速生材制醋化木浆粕成果介绍:本项研究根据我国桉树林混种情况较多的实际出发,直接以木片厂的混合木片为原料,加入添加剂预水解,经纤维均一化处理工艺,制备出适用于二醋片生产的醋化木浆粕。     

环氧浮油脂肪酸辛酯的合成及性能

以国产木浆浮油脂肪酸为原料,合成了环氧浮油脂肪酸辛酯.其环氧值为3.7％,碘值小于6。它是用于PVC的一种廉价而又有效的稳定增塑剂。     

25kt/a烟用醋酸丝醋化器制造技术

介绍了我国首台醋化器国产化制造技术 ,主要包括平底封头的冲压成型、釜体及搅拌器的机械加工 ,醋化器装配、调试等内容。     

再生纤维素颗粒的制备及其在水热条件下的结构变化

文章以醋化级木浆为纤维素原料,65%Zn Cl_2水溶液为溶剂,水为析出剂得到纤维素凝胶后,水热处理制备了颗粒状再生纤维素。考察了水热p H以及水热温度对再生纤维素颗粒性质的影响,并对孔结构、晶型、热稳定性和形貌等进行了表征。研究结果表明:水热p H为8时,水热后再生纤维素颗粒的孔容和比表面积均大于其他水热p H下的再生纤维素颗粒,且结晶度较高,含有少量纯度较高的Zn O。水热温度为170℃时,孔容大,孔径小,比表面积最大,达72.24 m~2/g。但是在水热温度为160℃时,再生纤维素颗粒的结晶度和热分解温度高于170℃和180℃得到的再生纤维素,且热稳定性较好,残余的Zn O的量较少。     

电线电缆涂料

9602209对苯二甲酸常压醋化生产聚醋漆包线漆新工艺:CN 1111668A〔中国发明专利申请公开〕/中国石化扬州石油化工公司(舒新华等)一1995.11.15一95103647.5(1995.4.6);IPC C09D167/03 一种由对苯二甲酸、乙二醇、丙三醇常压直接酷化制造聚酷漆包线漆的方法,其特征在于:常压醋化的工艺条件为:投料摩尔比为:对苯二甲酸/乙二醇/丙三醇1/0.8一LS/0·3一0.6;醋化温度为一80一230℃;醋化时间3一sh。醋化反应釜采用双功能分馏柱,该分馏柱即能迅速有效地脱除醋化反应中生成的水,又有迅速有效的实现反应物乙二醇的回流,经分馏柱分离馏出液中EG含…     

国产T800级碳纤维微观及理化性能研究

对不同厂家生产的国产T800级碳纤维及日本东丽T800H碳纤维先应用SEM(扫描电子显微镜)和AFM(原子力显微镜)进行表面物理形貌研究;测试不同碳纤维的线密度、体密度;应用Wilhelmy吊片法原理测试碳纤维的表面能,以表征其表面浸润性。结果表明,国产T800级碳纤维断面轮廓大多呈现“扁椭圆形”或“圆形”,少数呈现“腰状”;国产T800级碳纤维线密度均大于T800H碳纤维;国产T800级碳纤维体密度值均小于T800H碳纤维;而在表面能方面,不同厂家的国产T800级碳纤维存在一定差异,表面能较大的碳纤维,其表面能的极性分量均较高,极性参数达到0.80以上,而表面能较低的碳纤维,其表面能的极性分量也均较低,极性参数均在0.60以下。     

木浆纤维素/NMMO·H_2O溶液的流变性能研究

以含水率13.7%的N-甲基吗啉-N-氧化物(NMMO)为溶剂溶解木浆纤维素形成溶液,采用红外光谱分析仪对木浆纤维素的溶解过程进行表征,并采用黏度计研究了木浆纤维素/NMMO·H2O溶液的流变性能。结果表明:木浆纤维素在NMMO中先溶胀后溶解,且可完全溶解;木浆纤维素/NMMO·H2O溶液的流动呈现切力变稀的假塑性流体特征;木浆纤维素质量分数为6%时,溶液的非牛顿流动特征明显,溶液的表观黏度(ηa)随木浆纤维素浓度的增加明显增加,随剪切速率(γ)及温度的上升而下降,当γ高于一定值即logγ大于1.3时,溶液的ηa不受温度的影响,只随γ的上升而下降,且剪切应力不随γ变化而变化,为恒定值。     

酶水解pH值对酸性亚硫酸氨盐预处理杨木糖化效率的影响

改变酶水解p H值可以影响木质纤维生物质碳水化合物的酶水解糖化作用效果。以经酸性亚硫酸氢盐预处理的杨木浆为底物,探究了酶水解p H值对其碳水化合物转化率的影响。结果表明,预处理杨木浆的酶水解总糖得率随p H值增加呈现先升高后趋于平缓的规律,酶水解最佳p H值范围为4.8~5.4。当酶水解液p H值为4.8时,经6%亚硫酸氢钠预处理杨木浆在20 FPU/g酶用量下水解,葡聚糖和总糖转化率达到最高值,分别为91.3%和84.3%。     

A new approach for the production of cellulose acetate: Acetylation of mechanical pulp with subsequent isolation of cellulose acetate by differential solubility

A heretofore uninvestigated approach to the production of cellulose acetate, the acetylation of whole wood pulp with subsequent isolation of the cellulose derivative by differential solubility, is described. The mechanical pulp used was produced by refining aspen wood chips with a disc refiner. Two conventional acetylation techniques, the fibrous and solution process, were employed to acetylato all components of the pulp. The cellulose acetate was isolated from the acetylated lignin and hemicellulose by dissolving in dichloromethane/methanol (9:1, v/v). The advantage of this new approach is that the high cost involved in using an extensively purified dissolving pulp are avoided. Both acetylation techniques yielded a product that was about 84% cellulose acetate. The remaining acetylated components were lignin and hemicellulose. The yield of cellulose acetate, based on the cellulose content of the original pulp and the product, was 75–80%.     

棉浆和木浆掺混纺醋酸纤维素纤维结构与性能的分析

对棉浆和木浆三种掺混纺比例(棉浆与木浆的掺混纺比例为0∶100,50∶50,100∶0)的醋酸纤维素纤维的结构与性能进行了测试分析。采用光学显微镜观察、纤维图形分析软件计算、X射线衍射和强伸性能测试,对比分析了三种掺混纺比例纤维的截面形态、结晶度、取向度、断裂伸长率、断裂强度以及初始模量,为棉浆与木浆掺混纺醋酸纤维素纤维的广泛应用提供了理论依据。实验结果表明:三种掺混纺比例纤维的截面形态指标无显著差异,内部晶体基本结构相同,随着棉浆与木浆掺混纺比例的增加,结晶度、取向度以及强伸性能呈现出略微增大的趋势。     

Chemical reaction modeling of industrial scale nitrocellulose production for military applications

A model was developed to describe the nitration of cellulose in mixed acids used in the production of military grade nitrocellulose. Acid dissociation, swelling, diffusion, and chemical reaction were considered to model the nitration of industrially important cellulose materials for given reaction times and conditions. This model is supported by experimental work conducted to measure the dynamics of swelling and diffusion in wood pulp slivers, and the model was validated using the results of lab-scale nitration reactions. Microcomputed tomography was also used to perform a structural analysis of wood pulp slivers that were cut on industrial, rotary cutting machines to evaluate features that may influence the reactivity of these materials.     

从不同纤维素原料制得的粘胶在熟成过程中的行为

<正>在制造粘胶人造丝过程中需要将自碱纤维素黄酸化而得的纤维素黄酸盐溶于稀碱液中成为粘胶,然后在恒温下放置若干时间以进行熟成,达到一定程度后始可纺丝。在这熟成过程中,粘胶发生一系列的化学变化和胶体化学变化。 Klauditz曾指出在粘胶熟成过程中纤维素黄酸盐分子逐步分解,其酯化度逐渐降低,他认为这是由于纤维素黄酸盐的皂化作用:     

Chemistry and Pulping Feasibility of Compression Wood in Black Spruce

Abstract

This research was conducted to study the organic and inorganic constituents and pulping behaviour of compression wood (CW), in comparison to normal wood (NW) and opposite wood (OW). It was found that differences in the chemical properties of OW and NW were not significant, except in alpha-cellulose and hemicellulose content; whereas both differed significantly from CW which contained more lignin and calcium and less alpha-cellulose. These chemical characteristics of CW resulted in high residual lignin and poor pulp yields, in comparison with normal and opposite woods, when different cooking times and temperatures were applied. Bleachable grade pulp could be obtained from normal wood with H-factor 2300. Using CW, however, this was not practical even under severe cooking conditions.     

Thermogravimetric analysis of some chemically modified celluloses

Thermal degradation of carboxymethylcellulose, cellulose acetate, grafted wood pulp, and viscose rayon have been studied using thermogravimetric analysis and differential thermal analysis. The values of rate constant K and the activation energy E were calculated from the kinetic of weight loss using the theory of the first-order reaction. The activation energy of grafted cellulose and viscose rayon was > cellulose acetate > carboxymethylcellulose.     

Graftability of beaten pulps and acetylated pulps

Ce(IV)-induced polymerization of acrylonitrile with acetylated bagasse and wood pulps, having different acetyl contents, has been investigated. The graft yield is dependent on the acetyl content as well as the origin of the pulp. Increasing the acetyl content of pulps caused a significant decrease in the polymer loading. However, the rate of polymerization of acetylated wood pulp is much higher than that of acetylated bagasse pulp. The ceric consumption during grafting decreases as the acetyl content of the pulp increases. The effect of beating of the pulps, to various degrees of freeness, on their reactivity toward grafting process has also been studied. Generally, the state of cellulose, as defined by its degree of beating, and the origin of the pulp strongly influenced the graft yield. In creasing the beating degree of bagasse pulp resulted in a decrease in graft yield, while beating of wood pulp, to a definite degree, inhibits the polymerization reaction. The consumption of Ce(IV) by the beaten pulps during oxidation is somewhat greater than that consumed by the unbeaten pulps, whereas the consumption during grafting of acrylonitrile onto beaten pulps depends on the initial concentration of ceric solution. Also, the effect of grafting of acrylonitrile onto acetylated wood and bagasse pulps on their strength properties as well as the effect of grafting onto beaten pulps on their properties has been investigated. Grafting of acrylonitrile onto acetylated bagasse pulp decreased its strength properties, but improved its beatability comparatively to those of original pulp (0 acetyl content). On the other hand, grafting of acrylonitrile onto acetylated wood pulp resulted in a great improvement in its strength properties compared to those of grafted unacetylated pulp. Grafted unbeaten pulps gave thinner and weaker paper than the original pulp (without grafting). Beating of bagasse pulp before grafting gave pulp which possessed a higher strength properties, at low °SR, than those of pulp beaten after grafting. Raising the °SR by rebeating the pulp after reaction up to the original value had an adverse effect on the strength. Beating of bagasse pulp before grafting did not accelerate the reaction rate, but it saved some power consumption, since the time required for beating of grafted pulp to a given °SR was lower than that of ungrafted pulp.     

Synthesis and Identification of Graft Copolymers of Wood Pulp and 4-Methyl-2-oxy-3-oxopent-4-ene

A set of graft copolymers of wood pulp and 4-methyl-2-oxy-3-oxopent-4-ene has been synthesized. The graft reaction is a free radical polymerization coinitiated by calcium chloride, hydrogen peroxide on wood pulp in dimethylsulfoxide at 30°C. The wood pulps used in this research are unbleached products produced by chemical, thermal and mechanical pulping. All of them contain 25 to 29 weight percent lignin. Separation of the grafted wood pulp from homopoly(1-methyl-1-(2-oxy-1-oxopropyl)ethylene) formed during the reaction was done by benzene extraction. The results show that after the reaction, virtually all the wood pulps have a weight increase and, for very high yield sodium bisulfite pulp, a weight increase of up to 92.7% of the original weight of pulp was obtained. The Fourier transform infrared spectra of the benzene unextr-actable fractions provide strong proof of grafting.

The grafted wood pulp is a surface-modified pulp. Grafting has changed the surface properties of the starting wood pulp from hydrophilic to hydrophobic. The importance of this change is that the grafted wood pulp has potential use as a reinforcing material without use of coupling agents in many hydrophobic polymer matrixes.

The reaction products contain homopoly(1-methyl-1-(2-oxy-1-oxopropyl)ethylene) and uniformly dispersed grafted wood pulp. Under ordinary thermal compression conditions, thermoplastic composite objects can be made directly from the reaction products which contain up to 56 weight percent wood pulp.     

THE EFFECT OF LIGNIN CONTENT OF WOOD FIBERS ON PULP SCREENING/SEPARATION

An experimental investigation of the effect of lignin content of wood fibers on pulp screening is conducted. A non-uniform lignin distribution may exist in wood pulp due to variations in wood chip characteristics, and/or cooking conditions in a digester. Pulp screening was conducted in a modified Williams Freeness tester at different fiber lignin contents and pulp consistencies. The study indicated a large drop in pulp accepts fraction, thus a substantial fiber loss, with an increase in lignin content. The fiber loss was more significant at higher consistencies of pulp. This study suggests that the fiber lignin content should be considered an important process variable affecting the efficiency of pulp screening processes.