甲壳素与甲壳胺纤维1.纤维的制备

甲壳素和甲壳胺是广泛存在于动物和植物中的天然高分子材料。近年来,这两个高分子的生物相容性、生物可降解性、对伤口愈合的促进性能和其它一些优异性能在科技和工商界引起了广泛的重视。作为一种天然再生资源,它们在许多领域内都有很广的应用和开发潜力。总结了甲壳素和甲壳胺纤维的生产条件。     

甲壳素与甲壳胺纤维 3.纤维的化学改性

作为天然高分子材料,甲壳素和甲壳胺有许多优良的物化和生物活性。通过化学改性,甲壳素和甲壳胺可以获得更多的性能。总结了甲壳素和甲壳胺的化学衍生物和各种复合材料。     

甲壳素与甲壳胺纤维2.纤维的性能

甲壳素和甲壳胺纤雏既具有纤维材料的强度、桀软性、高表面积和形成各种类型的织物的能力,又有这两种天然高分子所特有的生物相容性、生物可降解性、广谱抗菌性、凝血作用以及促进伤口复愈、调节血脂、降低胆固醇、增强免疫和抗肿瘤等多种生理活性作用。     

甲壳胺纤维的螯合性能

把甲壳胺纤维与CuSO4和ZnSO4的水溶液处理后,通过控制处理的时间可以使纤维吸附不同含量的金属离子。研究了纤维上的金属离子的含量对纤维的物理机械性能的影响。结果表明,吸附金属离子后,纤维的干强和湿强都有明显的增加。纤维上的金属离子可以被EDTA的水溶液洗去,从而可以使纤维重复地应用于废金属离子的回收利用。把甲壳胺纤维进行乙酰化处理后,纤维可以在固体状态下转化成甲壳素纤维。实验结果表明,乙酰化后的纤维失去了它们对金属离子的螯合性能,从而证明了甲壳胺纤维的螯合性能主要来自于纤维上的自由胺基团。     

甲壳胺纤维和含银甲壳胺纤维的抗菌性能比较

从定性、定量的角度探讨了甲壳胺纤维和含银甲壳胺纤维对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌三种常见的、具有代表性的细菌的抑制作用,并把这两种纤维和粘胶纤维的抗菌性能作了比较。实验结果表明:含银甲壳胺纤维比普通的甲壳胺纤维具有更好的抗菌性能。     

甲壳素与甲壳胺纤维4.纤维在生物医药领域中的应用

甲壳素和甲壳胺是广泛存在于动物和植物中的天然高分子材料。近年来,这两个高分子的生物相容性、生物可降解性、对伤口愈合的促进性能和其它一些优异性能在生物医药领域引起了重视。甲壳素和甲壳胺纤维既具有天然高分子的生物活性,又有纤维材料的特性,在手术缝合线、医用敷料、人工皮肤、硬组织修复材料、人工肾膜、抗菌材料、保健内衣面料、药物缓释等材料中得到了广泛的应用。     

甲壳素及其衍生物——甲壳胺的生产和应用

明胶在加工与应用中常常使用某些天然高分子材料以改进其性能,使明胶制品适应应用的要求,这些天然高分子材料大多数属于多糖类。本刊首先介绍甲壳素及其衍生物甲壳胺的生产和应用,今后还将陆续介绍其他多糖类天然高分子化合物,以支持读者们开发更多新型的明胶制品。     

间接法生产甲壳素纤维

由于天然甲壳素结晶度高,在湿法纺丝过程中溶解甲壳素时需要使用价格较高的有机溶剂。甲壳素脱乙酰基后得到的甲壳胺可以很方便地溶解在稀醋酸水溶液中,经喷丝孔挤出后用稀碱中和沉淀即可得到甲壳胺纤维。在甲壳胺纤维上加上乙酰基后可以得到再生甲壳素纤维。介绍了在用乙酸酐处理甲壳胺纤维制备再生甲壳素纤维过程中,反应时间、反应温度、乙酸酐用量对乙酰化的影响。     

直接染料对甲壳胺纤维的染色性能

探讨了中性盐、温度、染料用量对甲壳胺纤维直接染料染色性能的影响，比较了脱脂棉和甲壳胺纤维的染色性能。实验结果表明：中性盐对染料的影响与染料的磺酸基的数目有关，对4～6个磺酸基，中性盐起促染作用．对双磺酸基，起缓染作用：而在70℃时染色的上染速度明显快于40℃，染料浓度在2％时几乎尽染，当上升到8％时上染率仍在70％以上；甲壳胺纤维的上染速度和上染率明显高于棉，其可染性、染色速度、表观染色深度远高于棉易产生染色不匀现象。     

甲壳素及壳聚糖的应用

介绍了甲壳素及壳聚糖的性质,概述了近年来甲壳素及壳聚糖在生物工程、化工环保、生物医学、食品工业等领域的应用进展。     

Improvements in the drying process for wet-spun chitosan fibers

Chitosan fibers were wet spun from a 6% by weight chitosan in 3% by volume acetic acid solution. The fibers were collected as a 20 filament yarn intended for use as a chaff substrate. The yarn had to be sufficiently dry following spinning to allow for winding and subsequent separation of the filaments. Drying of the yarn was attempted using various techniques including direct and radiant heat, forced air, and chemical drying agents. Product yarns were analyzed for ease of separation of the filaments, as well as comparison of mechanical properties. Individual fibers were evaluated on the basis of moisture content, surface morphology and fiber diameter. Results indicate that the particular drying method or agent used has a considerable impact upon all of the characteristics listed above. A methanol dry bath was found to provide optimum drying of the chitosan yarn, producing filaments with low moisture content that separated easily from one another. Methanol drying yielded chitosan fibers with smaller diameter, superior surface smoothness and superior mechanical properties to fibers dried using forced air, heat, or other tested drying agents such as acetone and isopropanol. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1435–1444, 1998     

甲壳素/壳聚糖在废水处理中的应用

综述了甲壳素和壳聚糖在含重金属离子废水、有色废水、食品加工废水和生活污水强化生物处理中的应用现状，认为甲壳素和壳聚糖是高效的生物吸附剂和絮凝剂，有颦在水处理领域获得更加广泛的应用。     

Production of high‐quality chitin and chitosan from preconditioned shrimp shells

Chitin and chitosan with improved characteristics were produced from shrimp shell waste preconditioned by limited decay or by treatment with 0.016 mol L^?1 benzoic acid. Preconditioned shrimp shells were transparent, had a clean surface and were susceptible to demineralization and deproteinization using 0.68 mol L^?1 HCl and 0.62 mol L^?1 NaOH, respectively. The ash and protein residues in the final chitosan were about 0.2% and 0.4%, respectively, the viscosity was up to 7000 cps, and the solubility and transparency nearly 100%. In comparison with treatment at ambient temperature (30 °C) without preconditioning, the chemical consumption, the duration of the treatment, ash and protein residues was reduced to 75–25%, whereas viscosity and absence of insolubles improved by a factor of 2–3. Copyright © 2006 Society of Chemical Industry     

Current state of chitin purification and chitosan production from insects

Chitin, and especially its deacetylated variant chitosan, has many applications, e.g. as carrier material for pharmaceutical drugs or as a flocculant in wastewater treatment. Despite its versatility and accessibility, chitin, the second most abundant polysaccharide on Earth, has so far been commercially extracted only from crustaceans and to a minor extent from fungi. Insects are a viable alternative source of chitin, but they have not been exploited in the past due to limited availability. Today however, for the sustainable production of animal feed, insect farming is being developed substantially. The availability of large quantities of insect biomass and chitin-rich side products such as exuviae and exoskeletons has been increasing. This review provides an overview of recently published studies of chitin extraction from insects, its subsequent conversion into chitosan and the primary analytical methods used to characterize insect-based chitin and chitosan. We have discovered a large number of research articles published over the past 20 years, confirming the increased attention being received by chitin and chitosan production from insects. Despite numerous publications, we identified several knowledge gaps, such as a lack of data concerning chitin purification degree and chitosan yield. Furthermore, analytical methods used to obtain physicochemical characteristics, structural information and chemical composition meet basic qualitative requirements but do not satisfy the need for a more quantitative evaluation. Despite the current shortcomings that need to be overcome, this review presents encouraging data on the use of insects as an alternative source of chitin and chitosan in the future. © 2020 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).     

Optimum parameters for production of chitin and chitosan from squilla (S. empusa)

Chitin and chitosan of high quality were produced from squilla, a by‐catch of Indian Ocean fisheries, by demineralization, deproteination, and deacetylation. Optimum conditions for the production of chitin and chitosan were determined. The quality of chitin was assessed from its ash and protein content. Ash content was below 1% after treatment with 4% HCl for 12 h at 50°C. A protein content of less than 1% could be achieved by treatment with 4% NaOH in 12 h but only at a temperature of 70°C or higher. Production of chitin was also tested by a three‐stage treatment with altering sequence of sodium hydroxide and hydrochloric acid (HCl–NaOH–HCl or NaOH–HCl–NaOH). This three‐step treatment appeared to be successful to achieve a mineral content and protein content below 1% within 30 h and at a temperature not exceeding 50°C. The chitin obtained under optimum conditions was tested for deacetylation using NaOH concentrations of 40 and 50% for 12–44 h at 30, 50 and 70°C. The chitosan obtained had a degree of deacetylation of 77–86%, a viscosity of 8.2–16.2 × 10² cps, solubility of 98%, and molecular weight of ? 1 × 10⁶ dalton. The data show that processing of squilla waste can lead to a high quality chitosan, useful for a broad range of applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 103: 3694–3700, 2007     

Entanglement network of chitin and chitosan in ionic liquid solutions

Concentrated solutions of a chitin from squid pens and of two commercial samples of chitosan were successfully prepared by using an ionic liquid 1‐butyl‐3‐methylimidazolium acetate as a solvent. The dynamic viscoelasticity data for the solutions exhibited rubbery plateaus, indicating the existence of entanglement network of chitin and chitosan in the solutions. To characterize the network, the values of the molecular weight between entanglements (M_e) for chitin and chitosan in the solutions were determined from the plateau moduli. Then the values of M_e in the molten state (M_e,melt), a material constant reflecting the inherent nature of polymer species, for chitin and chitosan were estimated to be 1.7 × 10³ and 3.0 × 10³, respectively. It was found that there was a significant difference in M_e,melt between chitin and chitosan. Compared with other polysaccharides such as cellulose and agarose in terms of the number of monosaccharide units between entanglements (N_unit), chitin had significantly smaller N_unit of 8, while chitosan had equivalent N_unit of 19. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2439–2443, 2013     

Chemical structure and compatibility of polyamide–chitin and chitosan blends

This work presents a comparative study of the compatibilization of four binary blends with slight differences in their chemical structures. The natural polymers chitin (QA) and chitosan (QN) are blended with polyamide 6 (PA6) and polyamide 66 (PA66). The results, obtained using differential scanning calorimetry, infrared spectroscopy, and light and scanning electron microscopy, gave the following compatibilization sequence: PA6/QN ≈ PA66/QN > PA6/QA > PA66/QA. This behavior could be related to the ability of QN to form hydrogen bonds and also to the capability of the packing of PA66. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 850–857, 2000     

Preparation of acetylated chitosan sponges (chitin sponges)

Acetylated chitosan sponges (chitin sponges) were prepared according to acetylation time (25, 50, 75, and 100 h). As the acetylation time increased, the degree of acetylation increased, and a 75‐h acetylation time produced the highest degree of acetylation (DA). The surface morphologies of samples were examined by scanning electron microscopy. Sponge samples were shown by a water uptake ability test to have higher water absorption abilities. An in vitro biodegradation test showed that sponges with a higher DA were more susceptible to lysozyme hydrolysis. Acetylated chitosan sponges were further shown by an in vitro fibroblast proliferation test to have a higher degree of cell viability on increasing the DA, with 75 h exhibiting the maximum effect. The results showed that the wound healing effect of chitosan sponges can be controlled by the DA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

甲壳素铁卟啉和壳聚糖铁卟啉催化性能差异研究

用紫外和红外光谱技术考察了含氮生物高分子甲壳素和壳聚糖对四苯基铁卟啉的固载差异性,并研究了这种差异对四苯基铁卟啉催化空气氧化环己烷反应的影响。实验结果表明,壳聚糖比甲壳素通过分子间力对四苯基铁卟啉有更强的吸附固载能力,它们对四苯基铁卟啉的吸附平衡常数分别为9.68×104和6.80×104L/mol。这种吸附能力差异引起所固载的铁卟啉催化空气氧化环己烷的性能差别。在相同的催化反应条件下,载体对铁卟啉吸附能力越强的催化剂催化环己烷氧化生成酮和醇的速率越快,获得越高的产物选择性和催化剂转化数。