交联对聚乙烯醇/明胶生物复合材料溶胀性能的影响

采用溶液共混法制备了聚乙烯醇/明胶（PVA/gelatin）生物复合膜,研究了三种不同的物理和化学交联法（戊二醛（GTA）蒸汽、紫外（UV）照射和干燥脱水交联）对其溶胀性能的影响。结果表明,三种交联方式都能有效地降低其平衡溶胀度,改善其耐水性。戊二醛蒸汽交联对复合材料溶胀性能的影响最大,其中明胶组分的交联是影响PVA/...     

双醛淀粉交联明胶的制备及溶胀性能

以双醛淀粉为交联剂,采用溶液交联的方法对明胶进行交联改性.研究了反应条件对交联明胶吸水性能的影响.结果表明,交联明胶吸水能力随双醛淀粉/明胶增加而先增加后降低,随反应温度增加而减小,随反应混合物pH值增加而增加.当pH=2,温度为90℃,双醛淀粉/明胶=0.3,明胶溶液浓度为20%时,明胶的吸水倍率可降低至1.62.FTIR显示双醛淀粉对明胶的交联作用主要是形成希夫碱结构.     

PP-g-MAH/蒙脱土纳米复合材料的制备和性能

采用熔融插层法成功制备了接枝物(PP—g—MAH)／有机蒙脱土(Org—MMT)纳米复合材料，用X射线衍射法检测了复合材料的层间距、微晶尺寸和晶胞参数的变化，并考察了纳米复合材料的力学性能。结果发现，对于PP—g—MAH／Org—MMT=100：20的复合材料，接枝物大分子链难以插层进入有机蒙脱土片层间。增大PP—g—MAH／Org—MMT比例，接枝物大分子链能插层进入有机蒙脱土片层，形成插层型纳米复合材料。PP—g—MAH／Org—MMT=100：10时，PP—g—MAH／Org—MMT复合材料110、040、041等晶面垂直于反射方向的微晶尺寸出现最小值．且可获得较好的力学性能．说明选择适当的接枝物／有机蒙脱土比例可降低聚丙烯的微晶尺寸，改善力学性能．但对复合材料晶胞参数的影响较小。     

氧化海藻酸钠交联海藻酸钙/明胶(半)互穿网络的制备及性能

以自制的氧化海藻酸钠为交联剂,制备了海藻酸钙/明胶(半)互穿网络((semi)IPNs)。通过材料万能测试仪、扫描电镜、吸水保水率测试详细研究了氧化海藻酸钠的氧化度、海藻酸钠与明胶不同质量比对(semi)IPNs的力学性能、吸湿性能的影响。研究结果表明,随着氧化海藻酸钠氧化度的增加,(semi)IPNs的力学性能、吸水保水性能呈现先增加后降低的趋势,氧化度为80%的氧化海藻酸钠交联制备的(semi)IPNs的性能达到最佳;并且海藻酸钠与明胶质量比为2∶1时所制备的(semi)IPNs的拉伸强度、断裂伸长率达到最大值,此时海藻酸钠与明胶的相容性得到了改善。氧化海藻酸钠交联体系的性能优于或等同于戊二醛交联体系,说明可以采用氧化海藻酸钠代替毒性较大的戊二醛交联蛋白质(如明胶)制备(semi)IPNs。     

静电纺淀粉纳米纤维的交联改性研究

通过静电纺丝技术制备纯淀粉纳米纤维膜,并在密闭容器中和戊二醛蒸汽进行交联。利用环境扫描电子显微镜(ESEM)、傅里叶变换红外光谱(FT-IR)对纤维交联前后的表面形貌和结构进行观察和分析,通过电子万能材料拉伸试验机、接触角测试仪等考察了交联反应对纤维膜性能的影响。结果表明,戊二醛与淀粉分子之间发生了缩醛化交联反应,淀粉纳米纤维膜经戊二醛蒸汽交联后仍能较好的保留原纤维的形态,并且拉伸性能和耐水性能均得到一定程度的提高。     

羟基磷灰石／明胶复合材料的制备与表征

在湿法共沉积制备羟基磷灰石/明胶复合材料的基础上,采用质量分数为3%戊二醛对明胶进行交联,重点研究了戊二醛的加入量对材料力学性能和生物性能的影响.制备的复合材料两相分布均匀,结晶状态与自然骨相似,其拉伸强度和抗压强度分别达到71.6MPa和69.5MPa,在Tris缓冲液中浸泡降解50天后的质量损失率为4.83%.     

硅烷交联聚乙烯/纳米蒙脱土复合材料的研究

以聚乙烯接枝马来酸酐为载体树脂制备纳米蒙脱土母料，在双螺杆挤出机中制备了硅烷交联聚乙烯／有机蒙脱土复合材料，研究了有机蒙脱土含量对硅烷交联聚乙烯接枝料力学性能、热性能以及交联料交联度的影响，并使用X射线衍射(XRD)、透射电子显微镜(TEM)研究了复合材料的微观结构。结果表明：硅烷交联聚乙烯接枝料的力学性能得到了提高，拉伸强度最大提高了近30％，断裂延伸率基本不变；维卡软化温度及热稳定性有一定提高；交联料的交联度有所下降，但可以通过延长交联时间弥补。XRD和TEM表明硅烷接枝聚乙烯大分子能够实现对有机蒙脱土的插层。     

甲醇、戊二醛交联剂对丝素蛋白/明胶多孔支架的性能影响

为了对比甲醇、戊二醛两种交联剂对丝素蛋白/明胶复合多孔支架的性能影响,采用冷冻干燥法等比例制备该支架,分两组分别用甲醇和戊二醛进行交联。通过观察支架的微观形貌,测量支架的孔隙率、吸水率、溶胀率,测试热稳定性及力学性能,比较经两种交联剂处理后支架结构和性能的变化。结果表明,经戊二醛交联后的支架孔隙分布更加规则、均匀,孔隙率、吸水率、溶胀率更高,力学性能更强。采用戊二醛交联丝素蛋白/明胶复合多孔支架,能够使支架性能更加优良。     

邻苯二甲酸二烯丙酯/蒙脱石纳米复合材料的微观结构及力学性能

利用几种不同表面活性剂(插层剂)改性蒙脱石制备邻苯二甲酸二烯丙酯/蒙脱石(DAP/MMT)复合材料,研究了插层剂的结构对复合材料微观形态及力学性能的影响。利用广角X射线衍射(WAXD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)及力学性能测试(弯曲和冲击测试)对复合材料进行了表征。WAXD及TEM结果表明,利用含长链的有机蒙脱石(O-MMT)制备复合材料时,尽管插层剂的结构不同,均只能制备有序插层型纳米复合材料。与纯DAP固化树脂相比,加入含长链的O-MMT可提高复合材料的力学性能,并且,含可聚合基团的O-MMT对复合材料力学性能的改善效果更为明显。     

甲壳素纳米纤维/蒙脱土复合材料的制备与性能

采用超声混溶-真空抽滤法制备了甲壳素纳米纤维(CNF)/蒙脱土(MMT)插层复合材料,通过FE-SEM和FTIR对复合材料的结构进行表征,并研究了MMT含量对复合材料力学性能、吸水性能、热膨胀系数(CTE)和热稳定性的影响。结果表明: 当MMT含量较少时,CNF与MMT的复合状态较好,CNF较均匀分散在片状MMT的片层间,形成了CNF/MMT插层复合材料;随着MMT含量的增加,复合材料的力学性能和吸水率降低;CNF的增多会抑制MMT的热膨胀,使复合材料的CTE降低;添加MMT可以减少材料的失重率,提高起始降解温度,有利于改善CNF/MMT复合材料的热稳定性。     

Thermal Transitions in Gelatin and Aqueous Gelatin Solutions

On the basis of the characteristic enthalpy changes associated with glass transformation, the glass transition (T_g) in gelatin can be detected readily, in addition to the helix-to-coiltransition, by difTerential scanning calorimetry, and the effects of water content on these transitions can be measured directly. The thermal behaviour of aqueous, deionized bone-gelatin systems with up to about 20 wt";' water is typical of amorphous or partially amorphous polymer-diluent systems depending upon the amount of gelatin structural order developed. Extrapolations of the T_g data to the T_g reported for water and of the helix-to-coiltransition data to that reported for aqueous gelatin solutions containing 90 wt% water are reasonable. Further, the T_g data suggest that the equilibrium water contents of aqueous gelatin systems containing gelatin structural order are higher than those of structureless systems at corresponding relative humidities.     

Lipoglycoprotein of Gelatin

Abstract

Solvent extracts were compared with the parent gelatins by means of TLC and HPLC. The photographic effects of the various protein fractions are discussed.     

Acid Ossein Gelatin

Abstract

The properties and manufacture of acid ossein gelatin are discussed with particular reference to the use of acid ossein gelatin in the photographic and allied industries.

The effect that the demineralizing process has on the properties of the gelatin extracted has been investigated with different demineralizing media. Loss of amide ammonia during the commercial demineralizing of bone has been confirmed and the rate of this toss has been studied using calcium and ammonia analyses. Different types of acid or lime processed gelatins can be distinguished also by analysis of their titration curves. From both experimental and calculated titration curve data, some correlations are found xvith gelatin amide content and isoelectric point.

A literature review is given, highlighting some of the applications found for acid ossein gelatin in the photographic industry.     

The Carbohydrate of Gelatin

It is shown that 5-hydroxymethylfurfural (HMF) readily reacts with Dreywood’s anthrone reagent at AO C. Gelatins do not give a positive result at this temperature and the normal reaction at 100 C. is therefore ascribed to the presence of a sugar which has first to be decomposed by HMF. The rate of colour formation given by gelatins is similar to that of glucose or dextran (a polyglucose). The sugar in gelatin is believed to be glucose (or possibly mannose or galactose) combined in the form of a polysaccharide.     

A High Viscosity Gelatin

Abstract

The viscosity of gelatin solutions may he increased by the addition of polysaccharides such as carrageenan. The rheology of such a high viscosity mixture is described.     

Dichromated Gelatin Reflection Gratings

Abstract

Reflection gratings were recorded in dichromated gelatin by using a non-symmetrical recording geometry. In addition to the primary grating, secondary gratings were also formed, as is generally known. It is found that the secondary gratings assist the structure stability during development in the exposure energy range (50–100) mJ cm^?2. The structure containing these secondary gratings is more rigid than those without and the reflection grating period is more stable during the development process in this exposure energy range, which is most suitable for the transmission grating formation. Secondary gratings also cause unwanted noise, but the noise level is low and the improved stability outweighs the extra noise.     

Carbodiimide Hardening of Gelatin

Carbodiimides con rapidly and effectively crosslink gelatin solutions and films. By proper choice of gelatin concentration and pH, these fast acting hardeners can be incorporated in gelatin solutions which have stable viscosity and can be cast into films which rapidly harden without after-hardening. Carbodiimides are attractive os hardeners for gelatin—silver halide photographic emulsions.     

Soft Gelatin Capsijle Update

The soft gelatin capsule is a relative unknown when compared to more traditional dosage forms. The technology and equipment. needed to prepare the gelatin mass and that. needed to encapsulate the fill material are highly specialized and not readily available. The acquisition of this equipment and technology is not usually economically feasible. The manufacture of soft gelatin capsules has. therefore, developed into primarily a contract manufacturing activity

Because of this. very little is known outside the encapsulation industry of the methods of production, advantages. Limitations, and other attributes of the soft elastic capsule This presentation explains the manufacturing process in order to give an understanding of current topics. Versatility of application. accuracy of dosage. content uniformity product. identification patient, compliance and other. attributes are discused. Consideration is also given to enhanced bioavailability, sustained release. and other innovations utilizing this unique dosage form     

明胶代用品特种树脂三元共聚物的合成与应用

介绍了特种树脂三元共聚物代替明胶的重要性以及三元共聚物的合成方法及应用。     

Soft Gelatin Capsijle Update

Abstract

The soft gelatin capsule is a relative unknown when compared to more traditional dosage forms. The technology and equipment. needed to prepare the gelatin mass and that. needed to encapsulate the fill material are highly specialized and not readily available. The acquisition of this equipment and technology is not usually economically feasible. The manufacture of soft gelatin capsules has. therefore, developed into primarily a contract manufacturing activity

Because of this. very little is known outside the encapsulation industry of the methods of production, advantages. Limitations, and other attributes of the soft elastic capsule This presentation explains the manufacturing process in order to give an understanding of current topics. Versatility of application. accuracy of dosage. content uniformity product. identification patient, compliance and other. attributes are discused. Consideration is also given to enhanced bioavailability, sustained release. and other innovations utilizing this unique dosage form