马桑皮植鞣剂与铝盐结合鞣制性能及机理

以提取于马桑皮的植物鞣剂为原料，与铝盐进行绵羊酸皮结合鞣制，优化鞣制工艺并建立基于马桑皮鞣剂的植铝结合鞣制方法，对鞣制后皮革性能及鞣制机理进行研究。结果表明，当马桑皮鞣剂用量为酸皮质量的15%、Al3(SO4)2•18H2O用量为酸皮质量的20%、渗透pH为4.0、结合pH为4.5的条件下，皮革收缩温度可达110.5 ℃。皮革表观性能良好，增厚率为82.2%，抗张强度为10.0 MPa，撕裂强度为52.5 N/mm，断裂伸长率为76.8%，优于橡椀植物鞣剂结合鞣制的皮革。鞣制后皮革胶原纤维变粗，形成紧密的网状结构。马桑皮植物鞣剂能充分渗透至皮革胶原纤维中，并与其产生氢键交联。在结合鞣制时，铝盐与皮革胶原纤维中结合的单宁类成分产生络合，使交联作用增强，从而显著提高成革的热稳定性能和机械性能。     

马桑皮植物鞣剂与铝盐结合鞣制性能及机理

以提取于马桑皮的植物鞣剂为原料,与铝盐进行绵羊酸皮结合鞣制,优化鞣制工艺并建立基于马桑皮植物鞣剂植铝结合鞣制方法,对鞣制后皮革性能及鞣制机理进行研究.结果表明,当马桑皮植物鞣剂用量为酸皮质量的15％、Al3(SO4)2?18H2O用量为酸皮质量的20％、渗透pH为4.0、结合pH为4.5的条件下,皮革收缩温度可达110.5℃.皮革表观性能良好,增厚率为82.2％±2.7％、抗张强度为(10.0±1.1)MPa、撕裂强度为(52.5±1.9)N/mm、断裂伸长率为76.8％±3.3％,优于橡椀鞣剂结合鞣制的皮革.鞣制后皮革胶原纤维变粗,形成紧密的网状结构,马桑皮植物鞣剂能充分渗透至皮革胶原纤维中,并与其产生氢键交联.在结合鞣制时,铝盐与皮革胶原纤维中结合的单宁类成分产生络合,使交联作用增强,从而显著提高成革的热稳定性能和机械性能.     

胶原的热收缩性质(第二部分)

<正> 2.胶原的热收缩(续)2.3 收缩的热力学(包括热力学常数)Weir 指出:胶原在水系统中的收缩伴随有潜在体积增加.同样,Kuntzel 和Doehner 以及 Wohlisch 及其同事发现收缩反应是一种潜热反应.Flory 和Garett 采用合成高聚物的熔化行为比较了这些研究,且结论说:胶原的热收缩能认为是第一步为相转变,其特征根据已测定的熔点来确定.Flory 和 Garett 此后测定了不同胶原—稀释剂混合体系的熔点,采用的是精确的膨胀计测定潜在体积增加.甘油而不是水作为稀释剂用于大多数的测定,以避免由胶原的水解和明胶形成引起复杂的变化.腱胶原纯化和风干到恒重,再切成小样约0.01英寸厚,在甘油中蒸发到所需程     

蓝矾皮生产皮明胶

<正> 大型哺乳动物的皮(一般以牛皮、猪皮为主),在制皮过程中先经浸水、脱毛,脱脂后进行柔制加工成为蓝矾皮。这过程由于原料皮中胶原分子的官能团与铬盐结合、使原皮中的胶原蛋白质发生凝固和变性,其吸水性以及对酸、碱的破坏作用都比原皮稳定,同时也能抵抗微生物的腐蚀。因而含三氧化二铬百分之三以上的蓝矾皮难以处理制胶,过去绝大部分被废弃,造成环境污染。随着我国制革工业的发展,制革工艺的不断改进.使用一步法的制革新工艺夺去了     

Ⅱ型噁唑烷-儿茶素固化皮胶原的特性表征

选用儿茶素和Ⅱ型噁唑烷为基本交联剂交联动物皮胶原,通过对交联后胶原热变性温度的考察探索了双组分交联剂的加入顺序、样品湿含量及溶剂处理对其热稳定性的影响;根据扫描电镜图像对热变性前后交联胶原的组织形态进行了观察,进而推测了交联胶原的热变性机理.结果发现:先儿茶素后噁唑烷顺序交联的胶原热稳定性较高,其热变性温度可达113....     

《明胶科学与技术》第13-14卷总目录

题目卷(期)页题目卷(期)页 综述评论胶原的热收缩性质(一)13(l”胶原的热收缩性质(二)13(2)57NMR技术在明胶研究中的应用13(2)80氧化明胶的研究进展一3(3)一13改革开放以来中国明胶事业的发展 13(4)169从胶原到明胶(一)一4。)-从胶原到明胶(二)一4(2)57明胶分子量分布测定和表征的研究 进展(一)一4(3)一3明胶分子是分布测定和表征的研究 进展(二)一4(4)169俄罗斯的照相明胶科学与技术14(4)184鹿角与鹿角胶14(4)195 研究报告用自动电位滴定仪测定明胶中 的氯离子一3(l)9用聚丙烯酞胺薄层平板等电聚焦测定 明胶等电点分布的研究13(2)64人造…     

辐射交联低烟无卤阻燃低温收缩聚烯烃热收缩材料

由中国科学院上海原子核研究所申请的专利(专利号　 0 0 1 1 5 3 5 3 ,公布日期　 2 0 0 0 0 9 2 0 )“辐射交联低烟无卤阻燃低温收缩聚烯烃热收缩材料”是一种低烟、无卤、阻燃且在较低温度 (≤ 90℃ )下可收缩的辐射交联聚烯烃热收缩材料。该材料制品由乙烯 乙酸乙烯酯共聚物和ＥＰＤＭ及抗氧剂、无卤阻燃剂、消烟剂、润滑剂、交联助剂经混合挤出造粒、挤出成型、辐射交联工艺制成。用该材料制备热收缩器件不仅原材料易得 ,而且加工方法简单、生产成本低、产品性能好 ,适合工业化生产辐射交联低烟无卤阻燃低温收缩聚烯烃热收缩材料$杭州…     

高交联多相聚合物热收缩材料的研究

研究了高交联多相聚合物热收缩材料的配方及性能,讨论了配方及辐照剂量对材料的收缩性能和物理性能的影响,得出了高交联多相聚合物不仅有良好的物理性能,而且有理想的热收缩性能,可用作电缆附套材料。     

新型热收缩管连续扩张定径装置的研制

<正> 本文介绍了一种制造热收缩管用的新型连续扩张定径装置,对泄压口、喉部结构、双层冷却水套的作用以及影响热收缩管质量的诸因素进行了分析,通过对内径小于8mm交联后的聚乙烯管进行扩张实验,表明工艺过程非常稳定,热收缩管的轴向收缩率不大于3％。     

共混胶的硫化--交联键分布及其对共混胶性能的影响

综述了共混胶硫化过程中不同橡胶相间交联键的分布,交联键分布的分析,控制方法以及交联键分布对共混胶性能的影响.共混胶分为3类--橡胶的极性不同;橡胶的饱和度不同;橡胶的极性及饱和度差别不大.经测试后发现,为了获得最佳性能的共混胶,控制交联键的分布是很重要的.当共混胶中交联键分布极不均匀时,通过改善交联键的分布可以提高共混胶的物理性能.     

驴皮中胶原蛋白的提取及其特性研究

分别采用酸法和酶法提取驴皮胶原蛋白,并测定了所提取胶原蛋白的性质。结果表明,两种方法提取的胶原蛋白紫外最大吸收峰都在234 nm处,在280 nm处吸收较小;两者红外吸收光谱相似,并且都具有三股螺旋结构;电泳图谱分析所得胶原蛋白的亚基组成形式为(α1)2α2,推测所提取的是Ⅰ型胶原蛋白;DSC(示差量热扫描法)测定发现,酶溶性胶原蛋白的热收缩温度(65.33℃)高于酸溶性胶原蛋白(50.90℃);羟脯氨酸测定发现,酶法提取驴皮胶原蛋白的纯度高于酸法提取驴皮胶原蛋白的纯度。     

Marine Spongia collagens: Protein characterization and evaluation of hydrogel films

Fibrous proteins such as collagens are important raw materials for the production of new bio-based or biomimetic materials. A rich source of collagen is found in the extracellular skeletal matrix of marine or sea sponges, an anatomically simple animal species. This abundant source of collagens was explored for its potential to create a hydrogel suitable as a biomaterial for drug delivery and tissue engineering. Collagen proteins were extracted from the skeletons of hard and soft species of sponges from the Spongia genus. The protein profile, amino acid composition, and partial sequences of the extracted proteins were determined, and the protein extracts were fabricated with chitosan and organic cross-linkers to create hydrogel films. The amino acid compositions and sequences of Spongia collagens are similar to collagens obtained from other species. Spongia collagens are hydrophilic and mechanically fragile. Blending these with chitosan and the organic crosslinkers, genipin and glyceraldehyde, formed blended films with improved mechanical performance and structural integrity and improved stress–strain and water swelling characteristics. These material properties show the potential of the films to be used as hydrogel biomaterials in medical applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47996.     

Main and Minor Types of Collagens in the Articular Cartilage: The Role of Collagens in Repair Tissue Evaluation in Chondral Defects

Several collagen subtypes have been identified in hyaline articular cartilage. The main and most abundant collagens are type II, IX and XI collagens. The minor and less abundant collagens are type III, IV, V, VI, X, XII, XIV, XVI, XXII, and XXVII collagens. All these collagens have been found to play a key role in healthy cartilage, regardless of whether they are more or less abundant. Additionally, an exhaustive evaluation of collagen fibrils in a repaired cartilage tissue after a chondral lesion is necessary to determine the quality of the repaired tissue and even whether or not this repaired tissue is considered hyaline cartilage. Therefore, this review aims to describe in depth all the collagen types found in the normal articular cartilage structure, and based on this, establish the parameters that allow one to consider a repaired cartilage tissue as a hyaline cartilage.     

Characterization and implantation of a novel foamy type of collagen into SD rats to regenerate tissue by slowing down the collagen degradation rate

Collagen has high biocompatibility and biodegradability and therefore is an ideal natural polymer biomaterial for tissue regeneration, such as gel-like and porous collagens. However, the limitation of gel-like collagen is unsuitability for cell/tissue ingrowth and the limitation of porous collagen is quick degradation rate. Here, the authors propose a novel type of foamy collagen to address the previous limitations. Foamy collagen with a closed/nonconnective porous structure was formed using foaming technology and not using toxic crosslinking reagents. This research aimed to investigate the macro-/microstructure, the in vitro/vivo degradation rate, and the tissue regeneration feasibility of foamy collagen. For in vitro degradation rate, porous collagen was completely degraded by enzyme, whereas 91.5% and 72.1% of gel-like and foamy collagens, respectively, remained intact. In vivo degradation rate had a similar trend as in vitro data. After implantation of the collagens in Sprague Dawley rats, immune cells were observed at the periphery of the three types of collagen at day 3. Fibroblast ingrowth was observed in foamy and porous collagen groups at day 7. Neocapillary formation and tissue regeneration were observed in foamy and porous collagen groups at day 14, but nearly none in gel-like collagen group. In conclusion, the authors believe that foamy collagen is promising for application of soft-tissue regeneration.     

皮肤组织工程支架材料的研究进展

综述了近年来国内外关于皮肤支架材料的研究现状,重点介绍天然皮肤支架材料中的胶原、壳聚糖和明胶类皮肤支架以及人工合成皮肤支架材料的研究进展。     

Collagen heterogeneity and its functional significance

The proportion of various collagen types in calf skin, placenta and aorta are compared. It has been found that calf skin provides a good source for type I collagen; while placenta and aorta are the best sources for type III collagen. Type IV and V collagens are found mainly in placenta and aorta. Appreciable amounts of the new cysteinerich high molecular weight collagen was found mainly in placenta. The various collagen types were characeterized by SDS-Gel electrophoresis, amino acid analysis, cyanogen bromide peptides and electron microscopy. Localization of type IV and V collagens in placental membranes were achieved by immunological methods. Further, the functional significance of various collagen types together with the diseases of the collagen molecule are discussed.     

Computer model of a bovine type I collagen microfibril

Collagens are a family of structural proteins of the extracellularmatrix. The fibril-forming collagens are the major structuralproteins of skin, cartilage, bone, blood vessel walls and internalorgans. In addition to biological function, the collagens providenatural structural frameworks that are utilized in the medical,food and leather industries. Many schemes for the organizationof type I collagen into triple helices, microfibrils and fibrilshave been proposed during the past 30 years. Here, the developmentof a molecular model of a bovine type I collagen ‘Smith’microfibril is described. In cross-section, this model exhibitsa symmetrical, pentagonal grouping of five triple helices. Themodel comprises 15 polypeptide chains having 315 residues each.This model is large enough to allow a comparison of its grossstructural features with images of stained collagen obtainedby electron microscopy, yet small enough to be manipulated ona minicomputer or work-station. The model is useful for (amongothers) studies of structure-function relationships in collagen,exploring folding pathways, predicting the efficacy of potentialcrosslinking agents or chemical modifications, and designingsynthetic collagen-like materials or modifications for specificapplications.     

重组生产胶原蛋白的研究进展

近几年来对人源胶原蛋白的重组表达系统的研究有很大进展.哺乳动物细胞和昆虫细胞是最开始被应用的,但其生产成本昂贵.酵母已经可以较高水平的表达Ⅰ型、Ⅱ型和Ⅲ型胶原蛋白,共表达胶原蛋白基因和脯氨酰羟化酶亚基cDNAs的酵母已经能够产生完全羟基化和热稳定的胶原蛋白.人源Ⅰ型和Ⅲ型胶原蛋白同型三聚体可以在转基因烟草中得到表达.转基因小鼠可以表达全长的Ⅰ型原胶原同型三聚体.最近,转基因蚕用来表达包含胶原蛋白序列的融合蛋白.每一个重组系统都有可能应用于大规模的商业化生产.     

Evaluation of Polymeric Matrix Loaded with Melatonin for Wound Dressing

The development of scaffolds mimicking the extracellular matrix containing bioactive substances has great potential in tissue engineering and wound healing applications. This study investigates melatonin—a methoxyindole present in almost all biological systems. Melatonin is a bioregulator in terms of its potential clinical importance for future therapies of cutaneous diseases. Mammalian skin is not only a prominent melatonin target, but also produces and rapidly metabolizes the multifunctional methoxyindole to biologically active metabolites. In our methodology, chitosan/collagen (CTS/Coll)-contained biomaterials are blended with melatonin at different doses to fabricate biomimetic hybrid scaffolds. We use rat tail tendon- and Salmo salar fish skin-derived collagens to assess biophysical and cellular properties by (i) Fourier transform infrared spectroscopy—attenuated total reflectance (FTIR–ATR), (ii) thermogravimetric analysis (TG), (iii) scanning electron microscope (SEM), and (iv) proliferation ratio of cutaneous cells in vitro. Our results indicate that melatonin itself does not negatively affect biophysical properties of melatonin-immobilized hybrid scaffolds, but it induces a pronounced elevation of cell viability within human epidermal keratinocytes (NHEK), dermal fibroblasts (NHDF), and reference melanoma cells. These results demonstrate that this indoleamine accelerates re-epithelialization. This delivery is a promising technique for additional explorations in future dermatotherapy and protective skin medicine.