Benzophenone-1,3-dioxane as a free radial initiator for photopolymerization

Benzophenone-1,3-dioxane (BP-DO), a hydrogen abstraction type photoinitiator for free radical polymerization, is synthesized and characterized. Its capability for acting as an initiator for the polymerization of methyl methacrylate (MMA), styrene (St) and multifunctional monomers is examined. The relative photopolymerization efficiencies of BP-DO, benzophenone (BP), and BP/ethyl-4-dimethylaminobenzoate (EDAB) are compared. The amounts of leachable photoinitiator are determined through the extraction experiments. In contrast to BP-based photoinitiators, BP-DO does not require an additional hydrogen donor for the initiation; it could be a substitute for the conventional initiator systems of BP and BP/EDAB.     

Synthesis and photopolymerization kinetics of a photoinitiator containing in-chain benzophenone and amine structure

A photoinitiator HTD bearing in-chain benzophenone (BP) and coinitiator tertiary amine, based on 4-hydroxybenzophenone (HBP), toluene-2,4-diisocyanate (TDI) and N,N-dimethylethanolamine (DMEA), was synthesized and characterized by ¹H-NMR and UV-vis absorption spectroscopy. HTD had longer absorption wavelength in the UV-vis absorption spectra than the low molecular counterpart BP. The kinetics of photopolymerization was studied by real-time Fourier transformation infrared (FTIR) spectroscopy. It showed that HTD was a more effective photoinitiator than BP. When this photointiator was used to initiate polymerization of acrylates, both rate of polymerization and final conversion increased with increase of initiator concentration and light intensity. UV-vis extract analysis showed that the extractability of HTD was much lower than BP/DMEA on the same environment condition.     

Synthesis and photopolymerization kinetics of a photoinitiator containing in-chain benzophenone and amine structure

A photoinitiator HTD bearing in-chain benzophenone (BP) and coinitiator tertiary amine, based on 4-hydroxybenzophenone (HBP), toluene-2,4-diisocyanate (TDI) and N,N-dimethylethanolamine (DMEA), was synthesized and characterized by ¹H-NMR and UV-vis absorption spectroscopy. HTD had longer absorption wavelength in the UV-vis absorption spectra than the low molecular counterpart BP. The kinetics of photopolymerization was studied by real-time Fourier transformation infrared (FTIR) spectroscopy. It showed that HTD was a more effective photoinitiator than BP. When this photointiator was used to initiate polymerization of acrylates, both rate of polymerization and final conversion increased with increase of initiator concentration and light intensity. UV-vis extract analysis showed that the extractability of HTD was much lower than BP/DMEA on the same environment condition.     

光固化制备玻璃纤维(GF)增强不饱和聚酯树脂(UPR)复合筋材的研究

采用5种光引发剂体系,通过LED紫外光固化技术制备了玻璃纤维（GF）增强不饱和聚酯树脂（UPR）复合筋材（直径达1.5 cm）,进行了热重分析以及力学性能测试,讨论了光引发剂种类及浓度（0.1%~2.0%,质量分数）、紫外光波长（365 nm、395 nm）、光照强度（30~750 mW/cm²）和光照时间对固化及制品性能的影响。结果表明：波长为365 nm的光源具有更好的固化效果;对于给定的引发剂体系,随着光照强度的增加,表观固化时间缩短;巴氏硬度随光照强度的增强而增大,且趋于稳定。在相同的紫外光光照强度下,表观固化时间一般随光引发剂浓度的升高而降低,但对于PI1光引发剂体系,表观固化时间随光引发剂浓度的升高先降低而后又升高。采用PI0或PI5作为光引发剂,紫外固化40 s所得复合材料的拉伸强度达到1 000 MPa,弹性模量达到45 GPa,均优于经热固化所得复合材料,表明,通过LED紫外光固化技术,高效制备厘米级大直径筋材具有可行性。     

Utilizing the Sensitization Effect for Direct Laser Writing in a Novel Photoresist Based on the Chitin Monomer N-acetyl-D-glucosamine

The great flexibility of direct laser writing (DLW) arises from the possibility to fabricate precise three-dimensional structures on very small scales as well as the broad range of applicable materials. However, there is still a vast number of promising materials, which are currently inaccessible requiring the continuous development of novel photoresists. Herein, a new bio-sourced resist is reported that uses the monomeric unit of chitin, N-acetyl-D-glucosamine, paving the way from existing hydrogel resists based on animal carbohydrates to a new class of non-hydrogel ones. In addition, it is shown that the combined use of two photoinitiators is advantageous over the use of a single one. In this approach, the first photoinitiator is a good two-photon absorber at the applied wavelength, while the second photoinitiator exhibits poor two-photon absorbtion abilities, but is better suited for cross-linking of the monomer. The first photoinitiator absorbs the light acting as a sensitizer and transfers the energy to the second initiator, which subsequently forms a radical and initializes the polymerization. This sensitization effect enables a new route to utilize reactive photointiators with a small two-photon absorption cross section for DLW without changing their chemical structure.     

纳米SiO_2的光敏改性及在光固化复合涂层中的应用

以六亚甲基二异氰酸酯(HDI)、4,4′-二羟基二苯甲酮(DHBP)、N-甲基二乙醇胺(MDEA)为原料,合成出主链含有夺氢型光引发剂以及共引发剂胺结构的NCO封端的聚氨酯预聚体,将预聚体接枝到纳米SiO_2表面,得到具有聚氨酯结构的光敏性纳米SiO_2(PU-photo-SiO_2),然后将其添加到聚氨酯丙烯酸酯树脂(PUA)中制备出光固化复合膜。红外光谱证实了PU-photo-SiO_2的成功合成;扫描电镜、热重分析、冲击强度等研究表明,PU-photo-SiO_2与光固化PUA树脂的相容性较好,利于提高光固化膜的热稳定性和力学性能。     

Migration of 17 Photoinitiators from Printing Inks and Cardboard into Packaged Food – Results of a Belgian Market Survey

Photoinitiators are widely used to cure ink on packaging materials used in food applications such as carton boards and can contaminate the food by migrating into the food. In this contribution, a fast and reliable confirmation method for the determination of photoinitiators in dry foodstuffs is described: benzophenone (BP), 4,4′‐bis(diethylamino)benzophenone (DEAB), 2‐chloro‐9H‐thioxanthen‐9‐one (CTX), 1‐chloro‐4‐ropoxy‐9H‐thioxanthen‐9‐one (CPTX), 2,2‐dimethoxy‐ 2‐phenyl acetophenone (DMPA), 4‐(dimethylamino)benzophenone (DMBP), 2‐ethylanthraquinone (EA), 2‐ethylhexyl‐4‐dimethylaminobenzoate (EDB), ethyl‐4‐dimethylaminobenzoate (EDMAB), 4‐hydroxybenzophenone (4‐HBP), 1‐hydroxycyclohexyl phenyl ketone (HCPK), 2‐hydroxy‐4‐methoxybenzophenone (HMBP), 2‐hydroxy‐4′‐(2‐hydroxyethoxy)‐2‐methylpropiophenone (HMMP), 2‐isopropyl‐9H‐thioxanthen‐9‐one (ITX), 4‐methylbenzophenone (MBP), 4,4′‐bis(dimethylamino)benzophenone (MK) and 4‐phenylbenzophenone (PBZ). Dry foodstuffs were extracted using acetonitrile, followed by the addition of inorganic salts to precipitate fatty residues. After filtration, the extract was analysed using ultra‐performance liquid chromatography in combination with tandem mass spectrometry (UPLC‐MS/MS). Quantification was carried out using benzophenone‐d₁₀ (BP‐d₁₀) as internal standard. The presented method was successfully validated in‐house. Afterwards, the procedure was applied in a marketing study, investigating 97 dry foodstuffs purchased on the Belgian market. In 89% of the samples, at least one photoinitiator was detected. The photoinitiators BP, EDMA and DMPA were most frequently found, while some photoinitiators (CPTX, DEAB, DMBP, HCPK, HMBP and MK) were never detected. Copyright © 2016 John Wiley & Sons, Ltd.     

一种新型紫外光固化涂料的性能研究

采用本体熔融聚合法制备了可紫外光固化的不饱和聚酯酰胺脲树脂,该类树脂可用作紫外光固化涂料,并对树脂进行了红外表征.研究了树脂反应的酸值与反应条件的关系,并研究了不同光引发剂体系对涂膜性能的影响.结果表明,该类树脂感光性好,用安息香双甲醚作为光引发剂,其用量为2%～3%时固化速度快、涂膜性能优异.     

低粘度紫外光固化竹木基涂料的研制

用一缩二乙二醇与E-44环氧树脂反应,得到的改性环氧树脂再与丙烯酸反应,制备了适于配制竹木基涂饰的紫外光固化的改性环氧丙烯酸酯预聚物。讨论了催化剂种类对环氧树脂转化率及产物粘度的影响,催化剂用量对改性环氧树脂丙烯酸酯化的影响,及光引发剂种类对固化速度的影响。最终制得的改性环氧丙烯酸酯光固化涂料比改性前的性能良好。     

光引发淀粉-AM/AA反相乳液接枝聚合--光引发剂的影响

采用多种光引发剂引发淀粉-丙烯酰胺/丙烯酸反相乳液接枝聚合,IR光谱分析表明了淀粉接枝共聚物的生成,考察了光引发剂的种类和浓度对接枝聚合的影响并初步探讨了引发接枝的机理。     

层间引发聚合法制备EA/α-ZrP光固化纳米复合材料及其结构表征

以4-溴甲基二苯甲酮与二甲基正十二胺反应合成的新型长链季铵盐光引发剂苯甲酰苄基二甲氨基十二烷基溴化铵(BDDB),进行插层修饰α-ZrP,通过层间引发聚合的方法光固化制备EA/α-ZrP纳米复合材料.XRD和TEM分析结果表明,α-ZrP片层在光固化复合材料中已得到插层和部分剥离;力学性能测试结果表明,EA/α-ZrP光固化纳米材料的拉伸强度、弹性模量及断裂伸长率得到了显著提高.     

UV-LED喷墨油墨用单体和光引发剂性能的评估

目的 为了建立评估方法,优选出适用于UV-LED固化喷墨油墨的光引发剂和低粘度单体种类。方法 用紫外-可见光分光光度计表征TPO, ITX, DETX, 819, 784, TPO-L等常见的6种光引发剂的紫外-可见吸收光谱。采用TPO为引发剂,分别用HDDA, ACMO, DPGDA, EOEOEA, DMAA等5种常用的低粘度单体,配制UV-LED喷墨油墨用连接料和油墨,用红外光谱和可见光透过光谱表征连接料的固化速度和固化膜的颜色,并通过指压法判定表干程度。结果 DMAA, EOEOEA组成的喷墨油墨连接料成膜性不好;含有ACMO连接料的透明度较好。结论 满足食品、药品包装安全要求,可以用于UV-LED固化的光引发剂为TPO, TPO-L及819;以粘度和固化程度为标准,用于制作喷墨油墨的5种单体的适用性从高到低排序为DPGDA, HDDA, ACMO, EOEOEA, DMAA。建立的评估方法合理有效。     

UV固化喷墨中光引发体系的研究

本文选择了6种光引发剂和5种颜料，测试了光引发剂和颜料的吸收谱图。研究了不同颜料体系的光引发剂与UV喷墨固化时间的关系，其中涉及单引发体系与复合引发体系对固化时间的影响。     

UV油墨光引发剂与颜料匹配的研究

UV油墨固化体系的关键组分是光引发剂,确定颜料的透光窗口是选择光引发剂的主要依据.阐述了影响油墨固化的相关因素,提出了确定UV油墨透光窗口的方法,并以此为基础讨论了UV油墨光引发剂与颜料匹配和印刷工艺色序的问题.     

Effects of the O2 flow rate and post-deposition thermal annealing on the optical absorption spectra of Ga-doped ZnO films

The optical absorption spectra of polycrystalline Ga-doped ZnO (GZO) thin films deposited by ion plating with direct current arc discharge have been studied. The GZO films that were deficient in oxygen showed absorption in the visible wavelength range. The intensity of the absorption band decreased with increasing O₂ flow rate during the deposition. Post-deposition thermal annealing in air and in a N₂ gas atmosphere also decreased the intensity of the absorption band. The intensity of the absorption band showed a slight correlation with carrier concentrations in the GZO films. The absorption intensity decreased with the decrease of the carrier concentration and diminished at a carrier concentration of around 7 × 10²⁰ cm^− 3. The contribution of carriers from native donors to transport in GZO films is discussed.     

Sensitive Detection of Carcinoembryonic Antigen Using Stability‐Limited Few‐Layer Black Phosphorus as an Electron Donor and a Reservoir

The instability of few‐layer black phosphorus (FL‐BP) hampers its further applications. Here, it can be demonstrated that the instability of FL‐BP can also be the advantage for application in biosensor. First, gold nanoparticle/FL‐BP (BP‐Au) hybrid is facilely synthesized by mixing Au precursor with FL‐BP. BP‐Au shows outstanding catalytic activity (K = 1120 s^?1 g^?1) and low activation energy (17.53 kJ mol^?1) for reducing 4‐nitrophenol, which is attributed to the electron‐reservoir and electron‐donor properties of FL‐BP, and synergistic interaction of Au nanoparticles and FL‐BP. Oxidation of FL‐BP after catalytic reaction is further confirmed by transmission electron microscope, X‐ray photoelectron spectroscopy, and zeta potentials. Second, the catalytic activity of BP‐Au can be reversibly switched from “inactive” to “active” upon treatment with antibody and antigen in solution, thus providing a versatile platform for label‐free colorimetric detection of biomarkers. The sensor shows a wide detection range (1 pg mL^?1 to –10 µg mL^?1), high sensitivity (0.20 pg mL^?1), and selectivity for detecting carcinoembryonic antigen (CEA). Finally, the biosensor has been used to detect CEA in colon and breast cancer clinical samples with satisfactory results. Therefore, the instability of BP can also be the advantage for application in detecting cancer biomarker in clinic.     

3D Hierarchical Nanorod@Nanobowl Array Photoanode with a Tunable Light‐Trapping Cutoff and Bottom‐Selective Field Enhancement for Efficient Solar Water Splitting

Constructing 3D nanophotonic structures is regarded as an effective means to realize both efficient light absorption and efficient charge separation. However, most of the 3D structures reported so far enhance light trapping beyond the absorption onset wavelength, and thus greatly attentuate or even completely block the long‐wavelength light, which could otherwise be efficiently absorbed by narrow‐bandgap materials in a Z‐scheme or tandem device. In addition, constructing a 3D conductive substrate often involves complex processes causing increased cost and upscaling problems. To overcome these shortcomings, a novel 3D hematite nanorod@nanobowl array nanophotonic structure is designed and fabricated by a low‐cost method. This unique structure can enhance light absorption with tunable cutoffs and rationally concentrate photons right above the bowl bottom, enabling efficient charge separation. By loading NiFeO_x as a cocatalyst, a high photocurrent density of 3.41 ± 0.2 mA cm^?2 at 1.23 V versus reversible hydrogen electrode (RHE) can be obtained, which is 2.35 times that with a planar structure in otherwise the same system.     

光固化EA体系中Eu(TTA)(AA)2Phen配合物的原位法合成及荧光性能

利用“原住法”合成技术，在EA(双酚A环氧丙烯酸酯树脂)中，合成了稀土荧光配合物Eu(TTA)(AA)2Phen(TTA：噻吩甲酰基三氟丙酮；AA：丙烯酸；Phen：邻菲咯啉)，利用红外光谱、紫外一可见光谱和荧光光谱对体系进行了表征。红外光谱的研究表明，配合物在EA体系中的特征吸收峰被基质树脂所掩盖，主要表现为基质树脂的特征吸收；紫外一可见光谱的研究表明，该体系在350nm附近出现配体TTA的强特征吸收，在低于300nm时，吸收峰被基质树脂掩盖；荧光光谱的研究表明，配合物在EA体系中能发出强的铕离子的特征荧光．并且低于铕质量分数为0．4％的范围内，荧光强度与稀土离子含量接近线性关系。     

Ultrafast synthesis of bentonite-acrylate nanocomposite materials by UV-radiation curing

Nanocomposite materials made of silicate platelets randomly dispersed in a crosslinked polyurethane-acrylate have been readily produced by photoinitiated polymerization. The mineral filler (bentonite) was treated by an ammonium salt or an acrylated amine to make it organophilic and allow the acrylic resin containing a photoinitiator (aromatic ketone) to penetrate into the expanded organoclay galleries. The photoinitiated crosslinking polymerization reaction was followed in real time by infrared spectroscopy and shown to proceed extensively (>95% conversion) within a few seconds of UV-irradiation. The flat X-ray diffraction spectra recorded with the UV-cured material shows that the layered silicate has been completely exfoliated, thus demonstrating that a nanocomposite material has well been produced. This method of synthesis presents the distinct advantages associated with the UV-curing technology, namely, a solvent-free formulation undergoing ultrafast polymerization at ambient temperature in the presence of air.     

聚硅氧烷的紫外光固化特性及热解机理研究

通过调聚法合成了不同乙烯基含量的聚硅氧烷,利用红外光谱和凝胶渗透色谱对聚合物进行了表征.研究了光引发剂、固化氛围、乙烯基团含量对所制备聚硅氧烷紫外光固化行为的影响;并利用热失重分析仪对固化物的热解机理进行了探讨.实验表明在氮气气氛下,以IHT-PI-185为光引发剂,随着聚合物中乙烯基团含量增加,固化速率加快,且固化后聚合物的耐热性能提高.