离子对高效液相色谱法分析注射用新灭菌

建立了离子对高效液相色谱法分离与测定复方制剂（新灭菌）中的羟氨苄青霉素及氟氯青霉素含量法。采用Ｃ８．１０μｍ，４．６×２００ｍｍ柱（大连化物所Ｓｐｈｅｒｉｓｏｒｂ），以含１．４％十六烷基三甲基溴化铵的ｐＨ６．５磷酸盐缓冲液－乙腈（６８＋３２）为流动相，在紫外检测器２５４ｎｍ波长处检测，线性范围为０．２５～２ｍｇ／ｍＬ，ｒ＝０．９９９９（ｎ＝５），羟氨苄青霉素及氟氯青霉素平均回收率分别为９９．５％及１００．７％（ｎ＝５）。精密度：羟氨苄青霉素及氟氯青霉素日内（４ｈ）平均ＲＳＤ（相对标准偏差）均为０．８％（ｎ＝１５），日间（２ｈ）平均ＲＳＤ分别为０．６％和０．７％（ｎ＝３）。     

烷基苯磺酸作用下环化聚异戊二烯-双叠氮型感光性高分子光交联产物的降解反应

<正> 环化聚异戊二烯-双叠氮型感光性高分子是一类应用广泛的负性光致抗蚀剂。关于它的光交联反应机理,许多人曾进行过研究,但是当这种具有三维网络结构的光交联聚合物完成其抗蚀使命后,怎样把它干净、彻底地从被涂表面去掉,是微细加工中急待解决的问题。常用的溶剂浸泡、高温加氧灼烧和等离子氧去胶法都存在着这样或那样的问题     

PMMA-PEO共混体系的辐射交联

<正> 聚甲基丙烯酸甲酯(PMMA)是典型的辐射裂解型聚合物。经辐照后,PMMA主链发生无规断裂。在聚合物共混体系中,PMMA是否能发生交联,这是辐射化学中一个非常重要的研究课题之一,也是一项探索性工作。 PMMA-PEO共混体系是可以分子水平共溶的体系。本文试图将共混体系的相容性与共混体系中的裂解型聚合物的辐射效应联系起来,讨论PMMA-PEO共混体系的辐射交联。     

Pt/TiO2光催化重整降解2-氯乙醇水溶液制氢

在无氧条件下,进行了Pt担载的TiO2光催化有毒的2-氯乙醇(下文简称氯乙醇)重整制氢反应的研究.详细讨论了动力学因素如催化剂表面Pt化学状态、Pt担载量、溶液pH值、氯乙醇浓度等对产氢速率的影响,并用XRD、HNMR、XPS等技术进行了表征,探讨了氯乙醇降解和产氢反应机理.研究表明,在光催化降解氯乙醇的同时产生氢是完全可行的.催化剂表面的Pt以Pt0的化学状态存在,有利于析氧;溶液pH值对产生速率影响也很大,而氯乙醇的浓度变化只是在开始略有影响,浓度的增加对产氢并没有明显的影响.研究得出Pt担载的TiO2光催化重整氯乙醇制氢反应的最佳条件是Pt的最佳担载量约为1.0%;氯乙醇溶液浓度范围为0.04～0.10 M;最佳溶液pH值范围为4～10.     

麦草碱木素及其热化学降解产物相对分子质量分布的测定

以pH=10的0．1mol/L NaNO3溶液为流动相，在Ultrahydrogel柱上测定麦草碱木素及其热化学降解产物的相对分子质量分布，测定碱木素降解产物所用洗脱液宜用pH10的0．1mol/LNaNO3水溶液，比较了由于样品结构特性和物理性质差异而造成的流动行为的差异，并确定两种样品各自的色谱条件。     

IR laser ablation of poly(vinyl chloride): Formation of monomer and deposition of nanofibres of chlorinated polyhydrocarbon

IR laser-induced ablation of poly(vinyl chloride) was examined under different irradiation conditions and its volatile and solid products were characterized by mass, infrared, UV and X-ray photoelectron spectroscopy, electron microscopy and thermogravimetry. It is demonstrated that the major component among the volatile products is monomeric vinyl chloride and that the process causes deposition of Cl-containing polymeric films. The proportion between the volatile and solid products as well as the nature of the deposited films at different laser fluences have been examined. We show that the deposited films incorporate less Cl atoms than poly(vinyl chloride) and that they initially contain conjugated CC bonds and incorporate nano-sized fibre and necklace features. The process represents the first example of thermal degradation of poly(vinyl chloride) into monomer and makes it possible to fabricate crosslinked Cl-containing intractable polymer films.     

Electrospun poly(l-lactide)-grafted hydroxyapatite/poly(l-lactide) nanocomposite fibers

Composite fibers composed of poly(l-lactide)-grafted hydroxyapatite (PLA-g-HAP) nanoparticles and polylactide (PLA) matrix were prepared by electro-spinning. Environmental scanning electron microscope (ESEM) and transmission electron microscopy (TEM) were employed to investigate the morphology of the composite fibers and the distribution of PLA-g-HAP nanoparticles in the fibers, respectively. At a low content (∼4 wt%) of PLA-g-HAP, the nanoparticles dispersed uniformly in the fibers and the composite fibrous mats exhibited higher strength properties, compared with the pristine PLA fiber mats and the simple hydroxyapatite/PLA blend fiber mats. But when the content of PLA-g-HAP further increased, the nanoparticles began to aggregate, which resulted in the deterioration of the mechanical properties of the composite fiber mats. The degradation behaviors of the composite fiber mats were closely related to the content of PLA-g-HAP. At a low PLA-g-HAP content, degradation may be delayed due to the reduction of autocatalytic degradation of PLA. When PLA-g-HAP content was high, degradation rate increased because of the enhanced wettability of the composite fibers and the escape of the nanoparticles from fiber surfaces during incubation.     

TiO2/polyaniline composites： An efficient photocatalyst for the degradation of methylene blue under natural light

Polyaniline (PAn) sensitized nanocrystalline TiO_2 composites (TiO_2/PAn) were successfully prepared and used as an efficient photocatalyst for the degradation of dye methylene blue (MB).The results showed that PAn was able to sensitize TiO_2 efficiently and the composite photocatalyst could be activated by absorbing both the ultraviolet and visible light (λ:190～800nm),whereas pure TiO_2 absorbed ultraviolet light only (λ<380nm).Under the irradiation of natural light,MB could be degraded more efficiently on the TiO_2/PAn composites than on the TiO_2.Furthermore,it could be easily separated from the solution by simple sedimentation.     

Monitoring of paintings under exposure to UV light by ATR-FT-IR spectroscopy and multivariate control charts

This paper concerns the improvement of a method, already applied for the conservation state monitoring of wooden and painted surfaces, to a system closely simulating a real artwork, namely a canvas painted with mixtures of three organic pigments (Alizarin, Permanent Red, Phtalocyanine Green). Ten mixtures of these pigments, according to an augmented simplex-centroid design, were prepared, mixed with linseed oil and spread on 10 cotton canvas strips. Drying ended, all the samples were analysed by ATR-FT-IR spectroscopy to describe the superficial variability in normal conditions of conservation, i.e. when no degradation is present. Successively, the samples were exposed to artificial UV light simulating the action of an aggressive portion of sunlight. The IR spectra of the surfaces were regularly acquired to monitor the superficial changes due to the UV aggression. Treatment ended, a chemometric study based on the Principal Component Analysis of the spectroscopic data collected both in normal conditions of conservation and during the artificial accelerated ageing, was performed and the multivariate Shewhart and Cusum control charts were built with the scores of the significant PCs (principal components). PCA based control charts showed to be able to identify the presence of significant changes of the painted surfaces, to identify the starting of the degradations and to provide insights about the chemical alterations induced by the UV exposure.     

Analytical strategies for the quality assessment of recycled high-impact polystyrene: a combination of thermal analysis, vibrational spectroscopy, and chromatography

Various analytical techniques (thermal analysis, vibrational spectroscopy, and chromatographic analysis) were used in order to monitor the changes in polymeric properties of recycled high-impact polystyrene (HIPS) throughout mechanical recycling processes. Three key quality properties were defined and analysed; these were the degree of mixing (composition), the degree of degradation, and the presence of low molecular weight compounds. Polymeric contaminations of polyethylene (PE) and polypropylene (PP) were detected in some samples using differential scanning calorimetry (DSC). Vibrational spectroscopy showed the presence of oxidised parts of the polymeric chain and gave also an assessment of the microstructure of the polybutadiene phase in HIPS. The presence of low molecular weight compounds in the HIPS samples was demonstrated using microwave-assisted extraction followed by gas chromatography-mass spectrometry (GC-MS). Several volatile organic compounds (VOCs), residues from the polymerisation, additives, and contaminations were detected in the polymeric materials. Styrene was identified already in virgin HIPS; in addition, benzaldehyde, α-methylbenzenaldehyde, and acetophenone were detected in recycled HIPS. The presence of oxygenated derivates of styrene may be attributed to the oxidation of polystyrene (PS). Several styrene dimers were found in virgin and recycled HIPS; these are produced during polymerisation of styrene and retained in the polymeric matrix as polymerisation residues. The amount of these dimers was highest in virgin HIPS, which indicated that emission of these compounds may have occurred during the first life-time of the products. This paper demonstrates that a combination of different analytical strategies is necessary to obtain a detailed understanding of the quality of recycled HIPS.