羟乙基醚化淀粉在LWC涂布纸中的应用探讨

通过实验室在相同涂料中加入羟乙基醚化淀粉替代部分丁苯胶乳,探讨对LWc涂布纸的物理性能的影响以及对涂布纸成本进行分析。结果表明：在Lwc涂布纸涂料方案5中,4份羟乙基醚化淀粉可以替代5份丁苯胶乳,表现出较为理想的物理性能。涂料配方中还相应减少了羧甲基纤维素（CMC）的用量,明显降低了LWC涂布纸的生产成本。     

离子液体在生物大分子中的应用研究进展

离子液体作为一种可设计性的绿色溶剂和高效催化剂,以其热稳定性好,催化性强,电导率高,溶解能力强,零蒸汽压等特性,在诸多领域具有广泛的应用。本文总结了离子液体的历史、制备、应用,主要介绍了目前离子液体在纤维素、胶原蛋白、角蛋白等生物大分子中的应用研究。同时重点介绍了离子液体在制革固废物和废水处理中的应用,并指出离子液体在皮革应用领域具有巨大前景。     

表面活性剂对酶活性的影响研究进展

综述了不同类型表面活性剂对脂肪酶、蛋白酶与纤维素酶活性的影响。一般的结论是,非离子表面活性剂对酶活性影响较小,甚至有激活作用;阴离子表面活性剂对酶活性影响大,主要起抑制作用。同时,指出这些影响规律对皮革行业有效利用酶与表面活性剂的协同作用具有指导意义。     

Tencel与Model织物力学性能的比较

分别对天丝、莫代尔的平纹织物和斜纹织物进行力学性能测试,结果表明：天丝织物的拉伸断裂强度和撕裂强力优于莫代尔织物,但是耐磨性能不如莫代尔织物;对于同种纤维的织物．平纹织物的拉伸断裂性能、耐磨性能优于斜纹织物,而斜纹织物的撕裂强力却优于平纹织物。     

纳米结晶纤维素的常见制备方法及其改性应用

纳米结晶纤维素作为一种天然、可再生、无污染的高分子材料,其突出的理化性能和可生物降解性等在功能材料领域有着广阔的应用前景。对于纳米结晶纤维素的相关研究主要集中在制备、表面改性和应用方面,本文从上述三个方面综述了纳米结晶纤维素的研究现状,并对其进一步的研究趋势和发展方向进行了展望。     

4D printing of polyurethane paint-based composites

ABSTRACT

In recent studies, polyurethane has shown multiple properties that make it an excellent candidate material in 4D printing. In this study, we present a simple and inexpensive additive method to print waterborne polyurethane paint-based composites by adding carboxymethyl cellulose (CMC) and silicon oxide (SiO₂) nanoparticles to the paint. The first function of CMC and SiO₂ is to improve rheological properties of the polyurethane paint for making a printable precursor, which improves the printing resolution and enhances additive manufacturability. Second, the composite precursors improve the curing rate of the polyurethane paint without changing its inherited shape memory properties. Third, the printed composite parts shown enhanced mechanical strength compared with that of the parts printed with pure polyurethane. Finally, the 3D printed polyurethane-CMC and SiO₂ parts exhibit time-resolved shape transformation upon heat stimulation. To the best of our knowledge, this is the first study of using the polyurethane paint as the precursor for 4D printing, which would open new possibilities in future applications in biomedical engineering, soft robotics and so on.     

羧甲基纤维素钠复合纳滤膜的制备与性能表征

以羧甲基纤维素钠(CMC)为活性层铸膜液,聚砜(PSF)超滤膜为基膜,戊二醛(GA)水溶液为交联剂,采用涂敷和交联的方法制得一种新型荷负电复合纳滤(NF)膜。测定了复合膜的截留相对分子质量,并对其表面形貌进行了表征。在铸膜液中添加质量分数为3.5%的不同种类有机小分子,研究了其对复合膜截留性能的影响。CMC/PSF复合膜对几种无机盐的截留顺序为:Na2SO4>NaCl>MgSO4>MgCl2。     

Local solidosity of microcrystalline cellulose during dead-end filtration and sedimentation

Solid–liquid separation by filtration and sedimentation are important operations used in a wide range of industries. One important characteristic of both the filtration and sedimentation processes is the solidosity of the filter cake/sediment that is formed, affecting the efficiency and design of the separation. In this study local solidosity was investigated using a γ-attenuation method during both filtration and sedimentation experiments for microcrystalline cellulose, a highly crystalline cellulose with particles of about 2–80 μm in diameter. Constitutive relationships for the solidosity were investigated using both filtration (i.e. cake build-up and expression) and sedimentation data for experiments at different pH and suspension concentrations. The sedimentation behaviour under these different conditions was also investigated. It was found that a three parameter empirical model could be used to describe the constitutive relationship between local solidosity and local solid compressible pressure for the sediment formed and the filter cake after both cake build-up and expression. This correlation worked well for the material investigated even at low solid compressible pressures.     

Release of urea from cellulosic hydrogel coated urea granule: Modeling effect of crosslink density and pH triggering

ABSTRACT

Urea granules were coated with CMC-g-cl-PAA hydrogel by in situ spraying and polymerization technique with mean thickness of 0.24 mm. Water absorption capacity of hydrogel coated urea granules varied from 18.67 to 217.33 g/g depending on pH. Urea release was extended due to hydrogel coating and kinetic analysis at different pH (4.0, 7.0 and 9.2) revealed a sigmoid function as best fit model. The coated urea granules showed pH triggered release property with higher rate in alkaline medium and slower in acidic medium. The prepared hydrogel coated urea granules may find its application in integrated water and nutrient management strategies in agriculture.     

羟丙基甲基纤维素的体外自由基降解研究

通过Fenton-AH-H2O2体系模拟体内的活性氧簇自由基(ROS)条件对美容填充辅料羟丙基甲基纤维素(HPMC)进行降解,研究了降解过程中HPMC分子量与动力粘度的变化。结果发现,在降解过程中,E3-HPMC与E50-HPMC的分子量均下降了90%,E4M-HPMC的动力粘度下降了75%,E10M-HPMC的动力粘度下降了40%。表明ROS对HPMC具有显著的降解作用。