A Novel Tissue Adhesive Composed of Modified Gelatin and Polysaccharides

A two-component adhesive glue was prepared from gelatin and polysaccharides. Gelatin was modified with ethylenediamine (ED) in the presence of water soluble carbodiimine (WSC) to introduce more amino groups into the original gelatin, while dextran and hydroxyethyl-starch (HES) were oxidized by sodium periodate to convert neighbouring hydroxyl groups into dialdehyde groups. Upon mixing the two polymer components in aqueous solution, Schiff's base reaction occurred between the amino groups in the modified gelatin and the aldehyde groups in the modified polysaccharides to give intermolecular crosslinking and gel formation. This new glue showed a capability to stop bleeding and seal tissues when a cut liver of rat was used for hemostatic experiments. It could also form a gel much faster than fibrin glue in in-vitro experiments. The fastest gel formation took place within 2 sec and the bonding strength to porcine skin was about 225gf/cm2 when an amino-gelatin (55% amino) and an aldehyde-HES (>84% dialdehyde) was mixed. In contrast, the gelation time and bonding strength of fibrin gluewere 5 seconds and 120gf/cm2, respectively. The effective adhesive properties have also been identified by the animal experiments of rat.     

Evaluation of hydrogels for soft tissue adhesives <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis> analyses

In this study, natural materials (sodium alginate, dextran, gelatin and carboxymethyl chitosan) were modified to get aldehyde components and amino components. Upon mixing the two-component solutions together, four kinds of Schiff base hydrogels formed successfully within 5-300 s and could seal the wound tissue. The cytotoxicity tests of hydrogel extraction solution confirmed that the hydrogels are nontoxic materials. The adhesive ability was evaluated in vivo by measuring the adhesive strength after sealing the skin incisions on the back of rats. All the hydrogels showed higher adhesive strength than that of commercial fibrin glue and the blank control. The histological staining observation by hematoxylin and eosin staining (HE) and Masson’s trichrome staining (MTC) methods suggested that the hydrogels had good biocompatibility and biodegradation in vivo. They have only normal initial inflammation to skin tissue and could improve the formation of new collagen in the incision section. So, the prepared hydrogels were both safe and effective tissue adhesive, which had the great potentials to be used as skin tissue adhesive.     

基于Fluent的某卷烟机搭口胶枪喷嘴流体仿真分析

为解决高速卷烟机搭口胶喷涂过程中出现的涂胶不均匀等问题,利用Fluent模拟搭口胶的涂胶工艺,通过改变喷嘴的进口压力观察胶液出口黏度和出口流速的变化。首先利用Solid Works对搭口胶喷嘴进行建模,然后分析Fluent模拟搭口胶喷胶涂胶过程,最后通过实验测试详细分析在不同进口压力条件下胶液的黏结性能,包括初黏性和抗T型剥离强度。仿真结果表明,喷嘴的出口黏度随着进口压力的升高而逐渐降低,出口流速刚好相反,即随着出口压力的升高而增加。搭口胶的黏结性能随着进口压力的增加而降低的。利用搭口胶喷涂的流体仿真模拟对卷烟生产工艺进行优化具有一定的指导作用。     

骨胶粘合剂改性新工艺研究

研究了以环氧氯丙烷接枝共聚改性骨胶的制备工艺,通过对影响该合成工艺的各种因素如水胶比、加碱量、碱解时间等的分析,初步探讨出了一条与传统改性工艺不同的改性路线.所得到的改性骨胶粘合剂凝固点低,粘结强度高.     

木薯淀粉/壳聚糖可食共混膜的制备及在草莓保鲜中的应用

以木薯淀粉、壳聚糖为基材,制备用于草莓保鲜的可食共混膜,研究共混比、抗菌剂(柠檬酸)和表面活性剂(吐温60)对共混膜性能及保鲜效果的影响。结果表明:当壳聚糖和木薯淀粉质量比为1:1时,共混膜的拉伸强度为25 MPa,断裂伸长率为10.6%,水蒸气渗透率为160 g/(24 h·m2),其综合性能最佳。当添加质量分数为4%的柠檬酸时,共混膜综合性能较好;当同时添加质量分数为1%的吐温60与1%的柠檬酸时,60 h后的草莓失重率比单独添加质量分数为1%的柠檬酸和1%的吐温60分别降低约20%和15%,说明此时保鲜效果最佳。     

Physical properties and molecular behavior of chitosan films

Chitosan films, varying in molecular weight and degree of deacetylation, were prepared by a casting technique using acetic acid as a dissolving vehicle. The physicochemical properties of the films were characterized. Both molecular weight and degree of deacetylation affected the film properties. Powder X-ray diffraction patterns and differential scanning calorimetry thermograms of all chitosan films indicated their amorphous state to partially crystalline state with thermal degradation temperature lower than 280-300°C. The increase in molecular weight of chitosan would increase the tensile strength and elongation as well as moisture absorption of the films, whereas the increase in degree of deacetylation of chitosan would either increase or decrease the tensile strength of the films depending on its molecular weight. Moreover, the higher the degree of deacetylation of chitosan the more brittle and the less moisture absorption the films became. All chitosan films were soluble in HCl-KCl buffer (pH 1.2), normal saline, and distilled water. They swelled in phosphate buffer (pH 7.4), and cross-linking between chitosan and phosphate anions might occur. Finally, transmission infrared and ¹³C-NMR spectra supported that chitosan films prepared by using acetic acid as a dissolving were chitosonium acetate films.     

水性改性淀粉胶在包装用麻秆中密度纤维板中胶合机理的研究

利用农业加工剩余物麻秆,使用水性改性淀粉胶,生产固化后无毒的麻秆中密度纤维板.经过热压工艺探索,寻找出最佳工艺条件.利用傅立叶变换红外光谱仪(FTIR)和差示扫描量热仪(DSC)对水性改性淀粉胶在麻秆纤维板中的胶合机理进行了分析.结果表明: FTIR图谱证明了水性改性淀粉胶中的异氰酸酯基和麻秆材料中的分子发生了反应;改性淀粉胶和麻秆粉末混合后,固化反应所需要的热量远远低于单独淀粉胶固化所需要的热量;化学反应机理表明,改性淀粉胶的力学强度和耐水性主要是由异氰酸酯基起一定的作用.     

On the Level of Nucleic Acids in Bone Gelatins

It is shown that nucleic acids are present in bone and that these are largely removed in the acid de-mineralization step. Initial extraction of nucleic acid by mineral add is quite rapid and is probably followed by conversion to apurinic acid. When the bone is extracted without acid treatment, as in the preparation of bone glue, the product is very rich in nucleic acids of relatively low molecular weight. The acid treatment also extracts small amounts of a protein material which may be a restrainer     

涂布两种施胶剂对抄制纸板物理性能的影响

目的对涂布氧化淀粉胶纸板、聚乙烯醇胶纸板和未涂布纸板的耐破强度、戳穿强度、挺度、防水防潮性等物理性能进行研究。方法实验选用表面施胶的方法来增强纸板的物理性能。通过抄制不同定量的化学机械浆和化学浆纸板,在纸板表面涂布相同体积的氧化淀粉胶和聚乙烯醇胶,测试纸板的物理性能。结果在相同温度、相对湿度条件下涂布施胶剂的纸板,其耐破强度、戳穿强度、挺度和防水防潮性要优于未涂布纸板;涂布聚乙烯醇的纸板其耐破强度、戳穿强度和防水防潮性要优于涂布氧化淀粉胶的纸板,涂布氧化淀粉胶的纸板挺度要优于涂布聚乙烯醇胶的纸板。结论涂布施胶剂后纸板的物理性能均有所提高,涂布聚乙烯醇胶的纸板强度较强,涂布氧化淀粉胶的纸板韧性较好。     

Structure of dextran–magnetite complex: relation between conformation of dextran chains covering core and its molecular weight

A homologous series of dextran–magnetite complex (DM) was synthesized using alkali-treated dextrans with various molecular weights from 1800 to 27 000. The structure of DM particles in water, particularly effect on molecular weight of dextran, was studied. The number of dextran chains binding to a core is possibly determined by the steric hindrance between dextran chains covering core. The conformation of dextran chains may change from a fully extended state to a random-coiled state with an increase in molecular weight.     

基于TRIZ理论的文件袋密封涂胶装置设计

目的设计出一种文件袋密封涂胶装置,其涂胶机构能够适应不同尺寸的文件袋密封的涂胶,使机构更易于适应复杂的工况环境。方法基于TRIZ理论的动态化原理和机械系统的替代原理,创新设计一种文件袋密封涂胶机构。结果该文件袋密封涂胶装置能够对不同尺寸的文件袋进行精准涂胶,消除了人为涂胶可能产生的的泄密问题,极大地提高了生产效率和安全性。结论运用TRIZ理论,成功地解决了现有涂胶装置对不同尺寸文件袋施胶存在的成本高、生产效率低以及封口不准确等问题。     

助剂在骨胶粘合剂中的应用研究

以骨胶为基料,环氧氯丙烷为交联剂,制备新型环保粘合剂,调节pH值,研究脱色剂、表面活性剂、固化剂和无机填料等助剂对它的影响.通过电子显微镜、粘度计和热重分析对其性能进行检测.研究结果为骨胶粘合剂的工业生产提供一定的基础.     

CT条盒包装机条盒纸自动喷胶控制系统的研发

目的 由于乳胶长时间暴露在空气中,使得乳胶的品质降低,影响乳胶涂抹在条盒上的效果,为解决在条包生产工序中条包产品的质量缺陷,以及清洗胶缸所产生的乳胶浪费和对环境污染等问题。方法 设计一种新型条盒包装喷胶自动控制装置,通过对喷胶控制技术的研究,综合喷胶装置、压力胶桶、PLC控制器、控制程序,通过光电检测、PLC移位控制、胶枪高压涂胶和压力泵供胶等技术,实现条盒包装机条盒的自动同步喷胶、精准涂胶、乳胶余量检测及报警。结果 安装条盒喷胶自动控制装置后,能实现乳胶的密封无污染储藏与输送,新增条盒定位检测,胶枪准确涂胶,压力供胶与胶量余量检测等功能,条盒喷胶的质量得到了提升,保证了产品合格率,提高了乳胶的品质,并降低了乳胶消耗。结论 该条盒喷胶自动控制装置能提升条盒的喷胶质量,降低乳胶消耗,减少乳胶对环境的污染,提高设备作业率,降低有缺陷的条盒进入下道工序的风险,可推广应用于烟草行业内所有条盒包装机组设备上。     

Chitosan tailor‐made films: the effects of additives on barrier and mechanical properties

With the aim of achieving ‘tailor‐made’ chitosan films, the effects of several variables on the properties of chitosan films were studied. These variables were chitosan concentration and molecular weight of thermally depolymerized chitosan, addition of lipids (palmitic acid, beeswax or carnauba wax) and plasticizer (glycerol). The water vapour transmission rate (WVTR) and mechanical properties of these films were measured. The innovative feature of this study is that it provides specific information to support the design of tailor‐made films. These can only be formulated when the effects of the important variables are well understood. It was found that WVTR was reduced by 57% in film made from chitosan that had been thermally treated for 7 h at 100°C (molecular mass 13.7 kDa), while in the emulsion films, the WVTR was increased by incorporation of palmitic acid, beeswax or carnauba wax incorporation. The mechanical properties (tensile strength and elongation at break) were improved when glycerol was used as plasticizer, resulting in more elastic films (increasing the elongation at break by 62%). Copyright © 2008 John Wiley & Sons, Ltd.     

Dextran-magnetite complex: conformation of dextran chains and stability of solution

Three kinds of dextran-magnetite (DM) complexes were prepared using alkali-treated dextrans with molecular weights of 1900, 4200 and 9600, respectively. The number of dextrans binding to a magnetite core was determined. The number was proportional to the area of core surface and the area occupied by a dextran was 2.5 nm² for molecular weight of 1900, 2.8 for 4200 and 3.8 for 9600. The binding of dextrans to core may be conditioned by the conformation of dextran chains in water (possibly by the steric hindrance between dextrans covering core). Stability of the DM solution was examined at 80 °C. Aggregation and/or precipitation of DM particles were observed within two weeks. The stability of DM solution was found to increase with increasing molecular weight of dextran. The dissociation of dextran from the core may cause the aggregation and subsequent precipitation of DM particles (the dissociation constant at 20 °C, 3.7 x 10 ^-6 for a molecular weight of 1900 and 5.4 x 10⁷ for 9600).     

水溶性壳低聚糖快速制备的方法及其性能表征

针对天然壳聚糖不溶于水的特点,采用微波辅助下的H_2O_2/UV体系快速氧化降解壳聚糖,制备得到不同低分子质量的水溶性壳低聚糖,并对壳低聚糖的相对分子质量、分子结构和水溶性进行表征。实验结果表明,天然壳聚糖在微波辅助下的H_2O_2/UV体系中5 min内发生快速降解,制备得到的壳低聚糖在较宽的p H值范围内都具有良好的水溶性。FTIR结果表明,水溶性壳低聚糖的化学结构和功能基团与壳聚糖原料一致;XRD结果表明H_2O_2会对壳聚糖的结晶结构造成破坏,从而使壳低聚糖的水溶性得到提升;TG结果表明水溶性的壳低聚糖结晶区被破坏后,热稳定性变差。     

Histological study of surface modified three dimensional poly (<Emphasis Type="SmallCaps">d</Emphasis>,<Emphasis Type="SmallCaps"> l</Emphasis>-lactic acid) scaffolds with chitosan in vivo

Biocompatibility and tissue regenerating capacity are essential for biomaterials that used in tissue engineering. The aim of this study was to histologically assess the tissue reactions and bone conductivities of surface modified three dimensional (3-D) poly (d, l-lactic acid) (PDLLA) scaffolds, which were coated with chitosan via a physical entrapment method. The native PDLLA scaffold was prepared via thermally induced phrase separation technique and was characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Osteocalcin assay, a method to evaluate the bone formation potential, has shown that the osteocalcin production in chitosan-modified 3-D PDLLA scaffold group was significantly higher (p < 0.05) than that of in control. The tissue reactions and bone conductivities between surface modified PDLLA and native PDLLA scaffolds were evaluated using a rabbit radialis defect model in vivo and compared at different implantation intervals (2, 4, 8 and 12 weeks). The histological results have shown a higher bone formation potential and better biocompatibility of chitosan-modified 3-D PDLLA scaffolds as compared with the control group scaffolds.     

氧化淀粉胶黏剂的交联改性及其性能研究

用玉米淀粉与过硫酸铵反应制备了氧化淀粉胶黏剂,再与二羟甲基双氰胺(DMDCD)进行交联反应,制备了一种交联改性氧化淀粉胶黏剂。采用红外光谱对样品进行了表征,并讨论了交联改性对氧化淀粉胶黏剂耐水性和贮存稳定性的影响。实验结果表明:DMDCD改性提高了淀粉胶黏剂的耐水性与贮存稳定性;当过硫酸铵质量分数为淀粉质量的1.5%,DMDCD质量分数为淀粉质量的3%时,交联改性氧化淀粉胶黏剂的贮存稳定性在45 d以上,其耐水时间、黏度分别为102 h和1680 mPa.s;红外分析证实了DMDCD与氧化淀粉发生了交联反应。     

Physical Properties and Molecular Behavior of Chitosan Films

Chitosan films, varying in molecular weight and degree of deacetylation, were prepared by a casting technique using acetic acid as a dissolving vehicle. The physicochemical properties of the films were characterized. Both molecular weight and degree of deacetylation affected the film properties. Powder X-ray diffraction patterns and differential scanning calorimetry thermograms of all chitosan films indicated their amorphous state to partially crystalline state with thermal degradation temperature lower than 280–300°C. The increase in molecular weight of chitosan would increase the tensile strength and elongation as well as moisture absorption of the films, whereas the increase in degree of deacetylation of chitosan would either increase or decrease the tensile strength of the films depending on its molecular weight. Moreover, the higher the degree of deacetylation of chitosan the more brittle and the less moisture absorption the films became. All chitosan films were soluble in HCl–KCl buffer (pH 1.2), normal saline, and distilled water. They swelled in phosphate buffer (pH 7.4), and cross-linking between chitosan and phosphate anions might occur. Finally, transmission infrared and ¹³C-NMR spectra supported that chitosan films prepared by using acetic acid as a dissolving were chitosonium acetate films.     

锯材指接自动涂胶设备的研制与应用

针对锯材指接涂胶过程中存在的涂胶不均、效率低、涂胶辊易磨损等问题，提出一种锯材指接自动涂胶的方法。基于PLC(programmable logic controller，可编程逻辑控制器)，采用自动化检测技术，经过模块化设计，设计了一种新型自动涂胶设备，并进行了锯材指接自动涂胶试验。工厂化试验结果表明：自动涂料设备以200根/30 min的速度工作时，自动1次循环涂胶的合格率可达到97%及以上，且随时间逐渐提高，整个过程中设备无故障；自动2次循环涂胶时，在60—90 min、90—120 min内设备各出现1次故障，合格率均达95%及以上，无故障工作时间内自动2次循环涂胶的合格率可达到98%及以上，而人工涂胶合格率在90%以下。试验表明该自动涂胶设备能够实现快速自动涂胶，保证锯材指接涂胶质量，提高锯材指接涂胶的自动化程度，适合应用于锯材指接的工业化生产。