微晶纤维素的微细结构研究

研究了各种纤维素材料及不同酸浓度水解制成的微晶纤维素的聚合度，并用X-射线衍射法研究结晶度、结晶形态、晶粒尺寸和颗粒大小；用透射电镜（TEM）观察颗粒形状和大小，发现不同纤维素材料达到平衡聚合度（LODP）的盐酸浓度略有不同；在酸水解过程中纤维素的结晶形态、晶粒尺寸和颗粒大小基本不变，而且用X-射线衍射及TEM测出的颗粒不是纤维素晶粒，而是微原纤。     

不同预处理条件下纤维素的结构变化及其在DMAc／LiCI中的溶解

介绍了乙二胺、氢氧化钠和高温等三种不同的纤维素预处理方法。研究预处理后纤维素的结构变化，讨论预处理过程中的转化机理，并通过X射线衍射对纤维素结晶度的变化进行表征，证明乙二胺预处理后纤维素的结晶度下降最大。纤维素经过预处理后可以溶解在DMAc／LiCI中，讨论其溶解机理，通过对比三种预处理纤维素的溶解性能，表明经过乙二胺预处理之后的纤维素在DMAc／LiCI中溶解性能最好，氢氧化钠预处理的纤维素次之，高温预处理的纤维素溶解性能相对较差。     

纤维素在丝光化处理过程中结构变化的研究

本文研究了纤维素在丝光化过程中其结构的变化，着重讨论不同再生条件对其晶型结构的影响。碱处理纤维素在水中再生，当碱含量＞12％时纤维素Ⅰ开始向纤维素Ⅱ转变；当碱含量＞18％时则完全转变为纤维素Ⅱ。在水中再生而晶型未发生变化的碱处理纤维素在不同醇中（如甲醇、乙醇和异丙醇等）再生时，则以分子体积大小不同发生部分或全部的晶型转变。在体积较大的异丙醇中再生时转变开始的碱含量降至3％。我们认为，上述现象源于醇的体积效应，以及相对于水较少形成氢键的能力，并从醇中再生这一角度初步探讨纤维素丝光化的机理。     

NMMO工艺纤维素包装膜透氧性能的研究

以纤维素棉浆和木浆为原料，N-甲基吗啉-N-氧化物（NMMO）为溶剂，采用沉浸凝胶法制备纤维素包装膜。研究了不同工艺条件对纤维素包装膜的透气性能的影响。结果表明：以纤维素棉浆为制膜原料，浆粕浓度为5％，凝固浴浓度为20％，温度为25℃时，可制得具有多孔结构的纤维素膜，有较好的气体通透性能。     

纤维素/聚乙二醇共混物相变行为及在DMSO/PF和DMAC/LiCl中相容性的研究

纤维素和聚乙二醇在二甲基亚砜／多聚甲醛（DMSO/PF）、二甲基乙酰胺／氯化锂（DMAC/LiCl）溶剂体系中表现出不同的相容性，同时再生共混物也表现出不同的相变行为。在DMSO体系下，聚乙二醇和纤维素在溶液状态下具有较好的相容性，再生共混物的相变焓较大，相变性质为固一固态相转变；而在DMAC／LiCl体系中，纤维素和聚乙二醇的相容性较差，再生后共混物的相变焓很小，相变性质为固一液相转变。纤维素在该两溶剂体系中的溶解机制及分子间的相互作用状态不同是导致它和聚乙二醇的共混相容性差异和再生共混物相变行为不同的原因。     

基于金属盐溶液的纤维素溶解及其应用研究进展

纤维素是自然界储量最丰富的可再生生物质资源，其绿色高值化利用在实现“双碳”和“循环经济”目标中起到重要作用。纤维素的绿色高效溶解是实现其高值化利用重要途径之一。众多纤维素溶剂体系存在价格昂贵、毒性和环境威胁、溶解工艺复杂、溶解效率低、溶剂回收困难和能耗高等问题。金属盐溶液体系具有稳定性高、价格便宜，同时溶解纤维素速度快、溶解工艺简单等特点，是更具应用前景的低成本绿色溶剂。该文综述了不同金属盐溶液溶解纤维素的溶解机理，总结了影响溶解性能的关键因素，并进一步介绍了基于不同金属盐溶液溶解纤维素在薄膜材料、凝胶材料以及复合材料等领域的应用研究进展，总结并展望了金属盐溶液在纤维素溶解及功能化应用方面的优势、不足及发展方向。     

微晶纤维素的FTIR研究

研究了两种不同晶型的微晶纤维素的傅立叶变换红外光谱及广角X-射线衍射谱。发现了纤维素Ⅰ型和纤维Ⅱ型的微晶纤维素的红外光谱在OH伸缩振动区均分裂为两个峰，并且它们的红外光谱的区别在于分子链堆砌的不同。     

纤维素在橡胶复合材料中的应用进展

纤维素经过处理后得到微米/纳米尺寸结构、高结晶度的纤维素，是可再生橡胶补强填料。本文系统介绍了微米、纳米纤维素晶体的制备方法，综述了微米、纳米纤维素晶体及不同改性材料改性后增强橡胶制备复合材料的进展，最后对纤维素增强橡胶复合材料研究的方向进行了展望。     

乙醇再生微晶纤维素的分级及其结构表征

在微晶纤维素（MCC）的Na OH/尿素溶液中加入不同质量的无水乙醇进行分级沉降，得到分级再生微晶纤维素。通过黏度法测定了再生微晶纤维素的聚合度，采用FTIR、XRD、XPS、TG和SEM对再生微晶纤维素的结构、结晶度、热稳定性和形貌进行了表征。结果表明，随着分级次数的增加，再生微晶纤维素的聚合度逐渐降低，3次分级后微晶纤维素的聚合度由MCC的203降至77；微晶纤维素形貌由表面光滑的棒状纤维结构变为粗糙多孔的结构；再生微晶纤维素的晶型由MCC的Ⅰ型转变为Ⅱ型，3次分级后微晶纤维素的结晶度由MCC的65.58%降至32.05%。分级再生微晶纤维素的自由羟基增加，参与成键的羟基减少；再生微晶纤维素的热稳定性随着分级次数的增加而降低，3次分级后初始分解温度由MCC的310℃降至257℃。     

粘胶纤维和Lyocell纤维生产中溶解机理的探讨

溶解技术是纤维素纤维制造过程中关键的技术，溶解的效果直接影响过滤、纺丝成形和最终产品的质量。纤维素溶解的详细机理非常复杂，但基本上都可以从分子间氢键的破坏方面得到解释，本文着重就粘胶纤维和Lyoeell纤维生产中纤维素不同的溶解过程和溶解机理作了初步探讨。     

Cyanoethylated cellulose prepared by homogeneous reaction in paraformaldehyde-DMSO system

A series of cyanoethylated celluloses with various degrees of substitution was prepared by homogeneous reaction of cellulose in PF/DMSO system. Their thermal deformation properties changed regularly with the degree of cyanoethylation. By comparing highly cyanoethylated cellulose in the series with that prepared by a traditional cyanoethylation method, it was seen that they were quite different in physical properties such as thermal deformation or tensile properties. Based on the results of dynamic mechanical measurements and infrared spectroscopy, cyanoethylated cellulose prepared in PF/DMSO system was found to be a new cellulose derivative, which includes oligo-oxymethylene groups at the position between the glucopyraneose ring and the cyanoethyl group in the side chain. The maximum DS value of this cyanoethylated cellulose was estimated to be ca. 2.5.     

纤维素直接溶解成膜及其分离特性研究进展

借鉴纺织行业Lyocell纤维制备过程中采用的溶解方法,以N-甲基吗啉-N-氧化物（NMMO）为溶剂物理溶解纤维素,制备出了新型纤维素膜,并对其性能进行了测试.结果表明通过溶剂法制备的新型纤维素膜,应用潜力主要表现在3个方面：在湿态条件下对酸性气体具有较好的渗透性能;经过改性加入亚砜基团的纤维素膜对SO₂表现出较高且稳定的渗透性;因为纤维素的强亲水性,该膜应用于油水分离,其耐污染能力较强.     

氨基聚硅氧烷接枝改性纤维素膜对其结构和性能的影响

采用氢氧化锂/尿素/水溶液作为溶剂,通过冷冻-解冻配置稳定的纤维素溶液并制备纤维素膜.利用高碘酸钠选择性氧化纤维素葡萄糖单元临近的两个羟基制备出二醛纤维素,然后用氨基聚硅氧烷对其进行改性制备出憎水性复合纤维素膜.通过傅立叶红外光谱仪、扫描电镜、热重分析、接触角测定和溶胀率测定等表征氧化纤维素和憎水性复合纤维素的结构和性能.研究了不同质量分数的高碘酸溶液对纤维素的氧化程度以及对纤维素膜的结构的影响,通过改变氨基聚硅氧烷的摩尔浓度来制备不同接枝度的憎水性复合纤维素.结果表明,二醛纤维素具有很强的反应活性,改性纤维素膜的憎水性得到明显提高.在纤维素改性及功能化材料制备的研究中,较强的反应活性使其可以应用在更多的领域.     

NMR study of water adsorbed on methyl methacrylate-grafted cellulose

Graft cellulose samples were prepared by three different initiation methods, and the widths of the NMR absorption spectra of samples were measured at various water contents. Samples prepared by both hydrogen peroxide and adsorbed ceric ion methods exhibited maximum widths of NMR absorption spectra at about 10% grafting, whereas the corresponding values for the sample prepared by the conventional ceric ion method were about 30%. Even a minimum value was found on the sample prepared by the latter method. The reason for such different water-binding behaviors of samples is discussed from the viewpoint of difference in the composition of graft celluloses.     

Acylation of iminochitosan: Its effect on blending with cellulose acetate

Chitosan has many similarities to cellulose, but there are few good direct solvents for codissolving them. Cellulose is cheaper than chitosan, and a blend film of the two would be expected to exhibit the desirable properties of both these polysaccharides. The formation of chitosanic and cellulosic acyl derivatives is an attractive route for the preparation of these fibers and films. They are soluble in common organic solvents, and in many cases it is not difficult to regenerate cellulose or chitosan from these derivatives. However, it may be desirable to protect the amino group from these reactions. Iminochitosan was used in the present study for that purpose. Chitosan at four molecular weights was prepared using an HCl/isopropanol binary system. The hydrolyzed chitosan was allowed to react with salicylaldehyde via Schiff base formation. Acylation of iminochitosan was carried out by its reaction with different acid halides containing a varied number of carbon atoms in the presence of a catalyst. The main factors that affected the dissolution of acylated iminochitosan in different organic solvents are described. Films from blends of n‐butyryl iminochitosan with cellulose acetate were prepared and are described. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 727–734, 2007     

小麦秸秆纤维素球的改性

对自制的环氧小麦秸秆纤维素球进行改性,制备了两种改性小麦秸秆纤维素球。用正交设计法设计实验方案,探讨了其制备的优化实验条件。实验结果表明:当三乙胺盐酸盐溶液体积为4 mL、无水碳酸钠的用量为0.6 g、溶剂为30%乙醇溶液、反应时间为6 h时,制得的三乙胺盐酸盐改性小麦秸秆纤维素球(WS-MB-TEAHC)对Cu2+的吸附容量最大;当乙二胺盐酸盐溶液体积为8 mL、无水碳酸钠的用量为0.6 g、溶剂为30%二氧六环、反应时间为6 h时,制得的乙二胺盐酸盐改性小麦秸秆纤维素球(WS-MB-EDADHC)对Cu2+的吸附容量最大。红外光谱表征显示:环氧小麦秸秆纤维素球的环氧基参与了反应,改性后引入了含N官能团。     

聚乙丙交酯和二乙酸纤维素化学共混物的制备和初步表征

以辛酸亚锡(SnOct2)为催化剂,将溶有二乙酸纤维素(CDA)的乙/丙交酯 (GA/LLA)熔体进行开环接枝反应,制得二乙酸纤维素和聚乙丙交酯的共混物,并提纯得到接枝共聚物CDA-g-Poly(LLA-co-GA)s.用IR和GPC对提纯所得接枝共聚物进行了初步表征,用TGA和DSC对共混物的玻璃化温度、熔点和热失重行为进行了测定,并与相应的机械共混物进行了比较.结果表明,接枝共聚物具有较短的聚L-丙交酯(PLLA)和聚乙交酯(PGA)侧链.共混物具有较好的热稳定性,玻璃化温度和熔点可通过改变投料比调节.通过化学接枝反应所得共混物的性能与机械共混物不同的原因可能是由于PLLA和PGA侧链的内增塑作用.     

不同溶解方法制备的纤维素/[BMIM]Cl纺丝液的性能比较

以离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl)为溶剂,分别采用直接溶解法和间接溶解法(即在含水[BMIM]Cl中溶胀后再减压蒸馏去除多余的水使之溶解)制备了纤维素/[BMIM]Cl纺丝液,系统地比较了这两种纺丝液的流变行为及可纺性。结果表明:相同条件下,直接溶解法制备的纤维素/[BMIM]Cl纺丝液的表观黏度最大,而间接溶解法制得的纺丝液的表观黏度随着溶胀时[BMIM]Cl的初始含水率的增加而下降。与直接溶解法相比,间接溶解法制得的纺丝液溶解均匀、流动性能好、纺丝过程中断头次数少、可纺性能提高,所得到的再生纤维素纤维具有更好的力学性能。     

Wet spinning of cellulose from ionic liquid solutions–viscometry and mechanical performance

A series of regenerated cellulose fibers was produced from dopes prepared by mixing and dissolving cellulose of two different degrees of polymerization in different ratios in the ionic liquid 1‐ethyl‐3‐methyl‐imidazolium acetate. Viscoelastic properties of the spin dopes were characterized by controlled stress rheometry. The cellulose solutions were solidified in pure water by the traditional wet spinning technique. The resulting fibers were characterized by means of wet and dry tensile testing and scanning electron microscopy. The characterization revealed a compact and homogeneous fiber. A nonlinear relationship between degree of polymerization and fiber properties was observed with a moderate difference in mechanical properties in a broad interval of fibers while fibers composed of polymers with the highest degree of polymerization stood out as stronger and stiffer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Model compounds of cellulose: Trityl ethers substituted exclusively at C-6 primary hydroxyls

Triphenylmethylcellulose (trityl cellulose) in which substitution of only the primary hydroxyls at C-6 on the cellulose chain occurs has been prepared using superdry cellulose derived from gel cellophane. The diacetate and dicarbanilate derivatives substituted exclusively at C-2 and C-3 secondary hydroxyls could then be prepared. Detritylation afforded the cellulose dicarbanilate or diacetate. Proof that no secondary substitution occurred was afforded by elemental analysis and by tosylation followed by replacement of the tosyl group with iodine. Because of the low D.P. of the cellulose and the ease with which the cellulose polymers can be cast into films, these cellulose model compounds might find utility for studying the effect of reactions at either the primary or the secondary hydroxyls of cellulose.