铁－芳烃络合物光引发剂的吸收光谱研究

铁－芳烃络合物光引发剂的吸收光谱研究陈旭东，黄新华陈用烈，梁兆熙（西南师范大学化学系重庆，６３０７１５）（中山大学高分子研究所广州）关键词铁－芳烃络合物，光引发剂，吸收光谱，光解铁－芳烃络合物作为环氧化物阳离子聚合光引发剂已引起人们关注［１，２］．我...     

The New-generation of Green Surfactant （Alkylpolyglucoside） as an Inhibitor to the Corrosion of 907 Steel in Seawater

Weight-loss trials and potentiodynamic polarization curves have been used to study the inhibitive properties of alkylpolyglucoside (APG) towards the 907 steel in seawater. The inhibition was different, if the length of alkyl chain APG was different. As the result, calcium gluconate, zinc sulfate and APG can protect 907 steel from being corrupted in static seawater. The compound corrosion inhibitor was found to control both the anodic process and the cathodic process.     

聚硅烷高分子对烯类单体的光敏聚合作用

<正> 可溶性聚硅烷高分子(polysilane polymer)是80年代初期才发展起来的一种功能高分子,有关文献对于聚硅烷高分子的紫外光解及光刻作用有较详细的报道,然而有关它的光敏引发聚合作用则鲜有报道。我们研究了聚硅烷高分子对苯乙烯的光敏引发聚合作用及其特点,这对于开发一类新的高分子光敏剂有重要的意义。     

Bimolecular photoinitiating systems of polymerization: photochemical behavior and radical efficiency

A key component in light-induced radical polymerization is the photoinitiator which produces free radicals through a photochemical reaction. In the first part of this paper, a short analysis of the different steps that take place in the light-induced radical polymerization using bimolecular photoinitiating systems is made. In the second part, the obtained results in the polymerization of acrylic monomers using conjugated and nonconjugated aminobenzophenones as photoinitiators are shown. A summary of the photochemical behavior of these photoinitiators together with several aspects related to the polymerization kinetics are described. The nature and efficiency of the produced radicals are studied as well as the reactivity of the radicals generated from the substituted dimethylanilines-camphorquinone photoinitiation systems. Important mechanistic differences were found in the photochemical behavior and radical efficiency for the families of photoinitiators studied.     

光聚合引发剂研究进展

对最近几年光敏聚合引发体系的研究进展进行了评述，并就一些新型光敏引发体系及引发机理进行了介绍。     

Effect of cobalt carboxylates on the photo-oxidative degradation of low-density polyethylene. Part-I

The effect of three cobalt carboxylates of increasing chain length, namely cobalt laurate, cobalt palmitate and cobalt stearate on the photo-oxidative degradation of low-density polyethylene (LDPE) films has been investigated. LDPE films containing cobalt carboxylates were irradiated with UV-B light at 30 °C for extended time periods. FTIR spectroscopy, mechanical testing, morphological studies, molecular weight, density and MFI measurements were performed to monitor the degradation behaviour. The results of these studies were analysed to explain the structural and chemical modifications taking place in the polyethylene matrix due to UV-B exposure. FTIR studies indicate that the degradation is dominated by formation of carbonyl and vinyl species. The studies on mechanical properties reveal that samples containing cobalt carboxylates, become mechanically fragile after UV exposure for 400 h, while neat LDPE exhibits insignificant changes during this period. The degradation was found to increase proportionally with increasing chain length and follows the order CoSt₃ > CoPal₃ > CoLau₃. Migration studies were performed on food simulant systems to investigate the applicability of these films for food packaging.     

Accelerated aging of LDPE films containing cobalt complexes as prooxidants

This paper deals with the synthesis and characterization of two cobalt complexes, namely cobalt styrene maleate copolymer (CSMA) and cobalt stearate (CS) and studying the effect of these complexes on the degradation behavior of Low Density Polyethylene (LDPE) films. Seventy micron films containing these additives were prepared by sheeting process and were subsequently exposed to two different degradative environments, i.e. UV-B irradiation and heat. The degradation was monitored by measuring the changes in tensile strength, elongation at break, Carbonyl Index (CI), Melt Flow Index (MFI) and density. It was observed that although both the additives contained the same metal and similar type of bonding, CSMA was incapable of initiating thermal/photodegradation of LDPE while the analogous CS at the same concentration range significantly accelerated degradation. Films were also subjected to soil burial tests for a period of 1 year and the degradation was monitored by weight loss measurements. Multiple extrusions of LDPE were performed in the presence of the two additives to investigate their practicability for reprocessing. Overall migration of constituents from these films was determined in food simulants to evaluate the application of these films as food packaging material.     

薄层缓蚀剂液膜对907A钢防蚀效果的电化学测量技术

本文研究饱和海水湿气环境中对 90 7A钢施加缓蚀剂的防蚀作用 ,利用恒电量技术等电化学方法对同材质的三电极大气腐蚀监测探头 (ACM )进行腐蚀测量 .结果表明 :利用电化学方法监测薄层缓蚀剂液膜的防蚀效果可以更清楚地获知缓蚀剂成膜的过程 ,并对薄层缓蚀剂液膜防蚀效果作出快速评价     

基于光谱分析方法的光引发剂量子效率评估

基于光谱学和Beer-Lambert定律,提出了一种评估光引发剂量子效率的新模型和方法,并给出了有关的理论分析.研究通过增加曝光厚度的方法,测定了光引发剂1 173（HMPP）曝光过程中的吸收光谱,根据吸收光谱的特征峰值随曝光时间的变化速率与评估模型,获得相应的量子效率.研究结果表明：光引发剂1 173在247 nm和285 nm处存在两个吸收峰|主吸收峰（247 nm）的量子效率为0.278%|实验结果与理论分析一致.     

Excited state properties of a new photoinitiating system for laser imaging applications

The design of an efficient photosenzitizer/photoinitiator combination is partly governed by a better understanding of the excited state processes involved. In the present paper, the photochemistry of a thiopyrylium salt (TP) as photosensitizer and of a tetraperester of benzophenone, tetra t-butyl peroxycarbonylbenzophenone (BTTB) as initiator, used in laser imaging applications has been investigated. The reactivity of the triplet states of both compounds BTTB and TP was studied by time-resolved laser absorption spectroscopy. The laser excitation of TP leads to a long-lived triplet state (lifetime 20–25 μsec) and a second species arising from the triplet state which cannot yet be characterized. Under laser excitation, BTTB gives a longlived transient arising from the cleavage of the peroxy bond. The short-lived triplet state cannot be observed on the nanosecond timescale. The triplet state lifetime has been evaluated from quenching experiments and found to be about 1 ns in acetonitrile. The deactivation of the TP triplet state by BTTP was considered, the deactivation constant was found to be equal to 6.6 × 10⁷ m^?1/sec in acetonitrile. The initiation mechanism is discussed.