甲酸和草酸盐掺杂的AgBr乳剂对亲水型PTG材料感光性能的影响

研究了甲酸盐掺杂和草酸盐掺杂对AgBr乳剂和亲水型PTG材料感光性能的影响．实验结果表明，掺杂后的AgBr乳剂在PTG材料中作为光敏元显著提高了其相对感光度，而不引起灰雾的增加；掺杂增感与硫增感、金增感、硫加金增感在PTG材料中同样表现出协同增感效果，使PTG材料的感光度得到进一步的提高；掺杂后的AgBr乳剂在PTG材料中具有一个最佳使用量，即AgBr与硬脂酸银的摩尔比为1：4．     

苯亚磺酸钠在聚乙烯醇为粘合剂的光敏热成像材料中的化学增感

以水溶性聚乙烯醇(PVA)为粘合剂，以异位法制备的颗粒尺寸为100nm的AgBr乳剂作光敏元，考察了苯亚磺酸钠(SBS)的用量、增感时间和增感温度对光敏热成像(PTG)材料照相性能的影响．实验结果表明：分别增感硬脂酸银(AgSt)、AgBr或者两者混合物，PTG材料均可取得明显的增感效果；灰雾随着苯亚磺酸钠用量增加而增加；增感温度以及增感时间不同，PTG材料的感光度不同．     

苯并三氮唑在聚乙烯醇为粘合剂的光敏热成像材料中的化学增感

以水溶性聚乙烯醇（PvA）为粘合剂，硬脂酸银（AgSt）为银源，异位AgBr乳剂为光敏元，考察了苯并三氮唑（BZT）在光敏热成像（PTG）材料中的化学增感效应．实验结果表明：BZT首先增感AgBr乳剂，再与PTG材料的其它组分混合，可以明显提高PTG材料的感光度，而超过一定用量范围则导致影像和灰雾完全消失；在40℃增感温度下，增感70min可取得最佳感光度；另外，BZT首先与AgSt作用一段时间后，再与PTG材料的其它组分混合，其与AgSt的摩尔比为15％左右，可使得PTG材料取得感光度最佳值。     

甲酸盐在纳米AgBr／I粒子乳剂中的增感作用

分别以鱼明胶和骨明胶(惰胶)作为分散介质制备了两种不同形貌与粒径的纳米AgBr／I粒子乳剂．利用掺入作为正空穴捕获剂的甲酸盐，可以使本征感光度很低的纳米粒子乳剂的感光度有相当大的提高，显示甲酸盐具有很好的增感效果．对鱼明胶介质中制备的纳米AgBr／I粒子乳剂，甲酸盐掺杂方式不同其增感效果不一样．在乳剂颗粒中均匀掺杂增感效果最好，而趋向于近表面掺杂则增感效果降低，显示出甲酸盐掺杂的位置效应．籽晶掺杂后包壳的复合结构乳剂颗粒与均匀掺杂乳剂颗粒的增感效果近似．对鱼明胶介质中制备的掺杂甲酸盐的纳米AgBr／I粒子乳剂再进行硫增感或硫加金增感，乳剂感光度可进一步提高，表明甲酸盐掺杂与常规的硫增感或硫加金增感有很好的协同作用．     

AgBr的尺寸及含量对PVA为粘合剂的光敏热成像材料的光敏性的影响

本文以水溶性聚乙烯醇(PVA)为粘合剂，采用异位法合成不同尺寸的立方体AgBr乳剂为光敏元，考察了以硬脂酸银／溴化银为主体的光敏热成像材料体系在可见光区的光敏性与立方体AgBr颗粒尺寸以及含量之间的关系．实验结果表明：在体系中AgBr含银量确定的条件下，AgBr颗粒尺寸在100-200m范围内，体系的光敏性最大；AgBr与AgSt的银量比在40％左右，体系的光敏性出现最大值；而AgBr乳剂中本身存在的少量明胶对体系的光敏性影响很小．     

AgBr核壳乳剂的颗粒内部还原增感与表面化学增感的协同增感效应

采用对核颗粒进行还原掺杂和将其包壳的方法制备了一系列不同DMAB用量、内部有还原敏化中心(Ag2)的AgBr核壳乳剂．这些乳剂表现出明显的增感效应．当这些乳剂分别进行表面硫、金和硫加金增感后，一方面表现出明显的协同增感效应；另一方面又随DMAB用量的提高，灰雾明显增长，特别是在金增感和硫加金增感的情况下、此外实验结果还证明，提高核乳剂的包壳速率可以在一定程度上减少核壳乳剂的灰雾。     

不同光敏剂对光敏热成像材料感光性能的影响

本文考察了不同制备方法、不同种类的光敏剂对以苯并三氮唑银为银源的光敏热成像材料感光性能的影响。结果显示原位法中以AgI和AgBrI为光敏剂的PTG材料具有较高的感光度,分别为以AgBr为光敏剂的参比样片感光度的16倍和2.4倍;异位法制备的PTG材料中,以AgBrI乳剂为光敏剂的感光度比以AgBr为光敏剂的感光度高,是其3倍;此外,同是以AgBr为光敏剂、用异位法制备的PTG材料的感光度比原位法制备的PTG材料感光度高。文中初步分析讨论了出现以上实验结果的原因。     

AgBrⅠ核壳乳剂的还原敏化与硫加金敏化的协同增感效应

使用微机控制的双注仪和二次乳化方法制备了一系列在AgBrⅠ核内进行不同程度还原增感的溴碘化银／溴化银核壳乳剂．对这些乳剂感光性能的研究表明：1)颗粒内部经还原敏化或Ag2掺杂的乳剂表现出明显的增感效应，颗粒内碘离子的存在并不影响Ag2的增感作用；2)在对乳剂进行了颗粒表面的硫加金增感以后，在一定的DMAB用量下，观察到显著的颗粒内部还原增感和表面硫加金增感的协同增感效应，使乳剂的感光度有了成倍的增长．以上协同增感效应的结果再次说明，颗粒内部的还原敏化中心与颗粒表面的硫加金敏化中心具有两种不同的增感机理，前者捕获空穴，后者捕获电子，两者都有利于提高潜影的形成效率。     

光敏热成像材料的化学增感进展

本文综述了近年来光敏热成像（PTG）材料在化学增感方面取得的相关新进展．在分析文献结果以及结合作者相关实验数据的基础上提出了进行化学增感的有效方法，即提高卤化银外部潜影的形成效率，或者提高银离子供应源在显影过程中的热迁移能力．文章对PTG材料在化学增感方面的发展提出了一些见解和想法．     

溴化银乳剂中甲酸盐掺杂的位置效应研究

使用反馈式微机控制双注仪，在晶体生长过程的不同时刻，加入一定浓度的甲酸盐，制得了一系列甲酸根离子处于不同掺杂位置的立方溴化银微晶乳剂．对其感光性能的测试结果表明，(1)甲酸盐掺杂乳剂与未掺杂乳剂相比，感光度有显著提高；(2)甲酸根的掺杂位置越接近晶体表面，其感光度增益越大；(3)甲酸盐掺杂乳剂可同时与常规的硫加金化学增感和光谱增感进行协同增感；(4)光谱增感后的掺杂乳剂在延伸的光敏区内仍表现出明显的掺杂增感效应，但其增感倍率要低于乳剂在本征光敏区(蓝区)的增感倍率；(5)所有的掺杂乳剂，包括原始、硫加金和光谱增感的掺杂乳剂，它们的灰雾均保持在相当低的水平．     

光敏热显成像材料概述

本文综述了近十多年来国际感光界关注热点之一的光敏热显成像材料（Photothermographic materials,简称PTG）的研究情况.重点介绍了羧酸银、卤化银、调色剂、防灰雾剂与稳定剂、光谱增感剂以及粘合剂等PTG材料的主要组分,并对PTG材料成像机理的研究情况进行了评述.     

Ca^2＋、Ba^2＋对光敏热成像材料照相性能和稳定性的影响

以常用的硬脂酸银为银源，异位AgBr为光敏元以及亲水型PVA为粘合剂，分别考察了Ca^2＋和Ba^2＋对光敏热成像（PTG）材料照相性能以及老化稳定性的影响．实验结果表明：涂布前乳液中加入Ca^2＋或Ba^2＋后，PTG材料的感光度和灰雾均出现不同程度的降低，并且随着加入量的增加，感光度下降更快．另外，含有Ca^2＋或Ba^2＋的PTG材料随着老化时间的增加，其感光度和灰雾的变化趋势并不相同。     

4-羟基-6-甲基-1,3,3a,7-四氮茚对以苯并三氮唑银为银源的PTG材料感光性能的影响

本文以水性聚乙烯醇(PVA)为粘合剂,原位法合成的AgBr或AgBrI为光敏元,考察了4-羟基-6-甲基-1,3,3a,7-四氮茚钠盐(NaTAI)对以苯并三氮唑银为银源的PTG材料感光性能的影响.实验结果表明:NaTAI对PTG材料具有增感作用,其增感程度随着NaTAI用量的不同而改变,并且感光度升高的同时,灰雾没有明显升高.通过Dember光电压衰减测量,并结合对PTG材料乳液pH值和pAg值的测定以及紫外可见吸收光谱分析,引入NaTAI可以延长光电子寿命,有利于提高潜影形成效率,从而提高感光度.     

溴化银乳剂中Ag2掺杂的位置效应研究

使用微机控制的双注仪，在晶体生长过程的不同时刻，加入一定浓度的二甲基胺硼烷（DMAB），制得了一系列Ag2处于不同掺杂位置的立方体溴化银微晶乳剂．对这些乳剂感光性能的研究表明：1）他掺杂乳剂与未掺杂乳剂相比，感光度有显著提高；2）心掺杂乳剂可同时与常规的硫加金化学增感和光谱增感进行协同增感；3）心掺杂接近微晶表面时乳剂感光度的增幅最大；4）在本实验条件下，掺杂乳剂的灰雾均保持在较低的水平。     

Preparation and antibacterial effects of PVA‐PVP hydrogels containing silver nanoparticles

The poly(vinyl alcohol)/poly(N‐vinyl pyrrolidone) (PVA–PVP) hydrogels containing silver nanoparticles were prepared by repeated freezing–thawing treatment. The silver content in the solid composition was in the range of 0.1–1.0 wt %, the silver particle size was from 20 to 100 nm, and the weight ratio of PVA to PVP was 70 : 30. The influence of silver nanoparticles on the properties of PVA–PVP matrix was investigated by differential scanning calorimeter, infrared spectroscopy and UV–vis spectroscopy, using PVA–PVP films containing silver particles as a model. The morphology of freeze‐dried PVA–PVP hydrogel matrix and dispersion of the silver nanoparticles in the matrix was examined by scanning electron microscopy. It was found that a three‐dimensional structure was formed during the process of freezing–thawing treatment and no serious aggregation of the silver nanoparticles occurred. Water absorption properties, release of silver ions from the hydrogels and the antibacterial effects of the hydrogels against Escherichia coli and Staphylococcus aureus were examined too. It was proved that the nanosilver‐containing hydrogels had an excellent antibacterial ability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 125–133, 2007     

Characterization of poly(vinyl alcohol)/poly(ethylene glycol) hydrogels and PVA-derived hybrids by small-angle X-ray scattering and FTIR spectroscopy

The purpose of this study is to develop novel poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogel blends and PVA-derived organic-inorganic hybrid materials and perform nanostructural characterizations. PVA and PEG hydrogels were prepared by dissolving the polymer in aqueous solution, followed by addition of glutaraldehyde (GA) chemical crosslinker. Hybrids were synthesized by reacting PVA in aqueous solution with tetraethoxysilane (TEOS). PVA/TEOS were also modified in the nanometer-scale by crosslinking with GA during the synthesis reaction. Hydrogels and hybrids were characterized by using small-angle X-ray scattering synchrotron radiation (SAXS) and Fourier transform infrared spectroscopy (FTIR). Thin film samples were prepared for SAXS experiments. SAXS results have indicated different nano-ordered disperse phases for hydrogels made of PVA, PEG, PVA/GA, PVA/PEG. Also, PVA/TEOS and PVA/TEOS/GA hybrids have indicated different X-ray scattering patterns. FTIR spectra have showed major vibration bands associated with organic-inorganic chemical groups present in the hybrid nanocomposites PVA/TEOS and PVA/TEOS/GA. PVA/PEG hydrogels and PVA-derived hybrid materials were successfully produced with GA crosslinking in nanometer-scale network.     

Synthesis of ion‐imprinting chitosan/PVA crosslinked membrane for selective removal of Ag(I)

A novel ion‐imprinted membranes were synthesized for selective removal and preconentration for Ag(I) ions from aqueous solutions. The membranes were obtained via crosslinking of chitosan (CS), PVA, and blend chitosan/PVA using glutaraldehyde (GA) as crosslinker. The FTIR spectra were used to confirm the membrane formation. Comparing with the nonimprinted membranes, Ag(I)‐imprinted CS and CS/PVA has higher removal capacity and selectivity for Ag⁺ ions. An enhancement in the Ag⁺ removal capacity by ～ 20% (from 77.8 to 94.4 mg g^–1) and ～ 50% (from 83.9 to 125 mg g^–1) was found in the Ag(I)‐imprinted CS and Ag(I)‐imprinted CS/PVA membranes, respectively, when compared with the nonimprinted membranes. Removal equilibra was achieved in about 40 min for the non‐ and ion‐imprinted CS/PVA. The pH and temperature significantly affected the removal capacity of ion‐imprinted membrane. The relative selectivity coefficient values of Ag⁺/Cu²⁺ and Ag⁺/Ni²⁺ are 9 and 10.7 for ion‐imprinted CS membrane and 11.1 and 15 for ion‐imprinted CS/PVA membrane when compared with nonimprinted membranes. The imprinted membranes can be easily regenerated by 0.01M EDTA and therefore can be reused at least five times with only 15% loss of removal capacity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Enhancement of the optical properties of poly vinyl alcohol by doping with silver nanoparticles

Poly vinyl alcohol (PVA) incorporated with different weight percent of Silver nanoparticles (Ag NPs) were prepared. The enhancement factors for each band in the Raman spectra were calculated and the degree of enhancement were found to be increased as the percent of Ag NPs increases up to 0.3%, and thereafter it decreases. Some bands were red shifted while others were blue shifted. The overtones FTIR bands and photoacoustic spectra were recorded and show the same behavior as those bands. The X‐ray diffraction pattern and Raman and photoacoustic spectra showed that PVA has a high degree of crystallinity. The UV–vis spectra of the same samples were red shifted and increase in their intensities up to 0.3% Ag NPs, thereafter the band intensities of the peak corresponding to Ag NPs were diminished. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3608–3614, 2006