Polymeric Photoinitiators Containing Side-chain Ketoaromatic Moieties for Fast Ultraviolet Initiated Polymerisation of Acrylic Monomers

The synthesis of polymeric photoinitiators having side-chain cyclohexylphenylketone as well as benzophenone moieties at different distances from the backbone is described. Study of the activity of the former systems, in the ultraviolet initiated polymerisation of acrylic monomers, indicates that a remarkable increase in the polymerisation rate is observed when the cyclohexylphenylketone chromophore is attached to the main chain through an ethereal linkage rather than an ester group. In the case of the latter systems, considerable improvement is observed in the photoinitiating activity with respect to the corresponding low molecular weight model compounds in the polymerisation of acrylic monomers. Moreover, in general the copolymers of benzophenone-containing monomers show higher activity than the corresponding homopolymers. These results are discussed in terms of photoexcitation energy migration along the polymer chain, as well as of intramolecular hydrogen abstraction from both main and side chains. This last occurrence seems to be the main activation process, as suggested by a strict correlation between activity and hydrogen-donating properties of the co-units in the copolymers, Photophysical evidence supporting this point is also reported. Finally, the synthesis of polymeric photoinitiators, containing both benzophenone and tertiary amine groups in the same macromolecule, has been accomplished via copolymerisation of 4-acryloxybenzophenone with 4-(N,N-dimethylamino)styrene. Preliminary data concerning photoinitiating activity of these last copolymers indicate that conformational mobility affects the formation capability of exciplexes and then the activity itself.     

UV油墨光引发剂在食品包装材料中的残留分析

目的研究UV油墨光引发剂在食品包装材料中的残留行为。方法以2种常用的UV油墨光引发剂EDB和907为研究对象,分别以PET薄膜和铜版纸为承印材料,通过IGT印刷适性仪控制印刷膜层厚度,IGT UV干燥器控制紫外光固化时间,研究光照能量、墨层厚度和油墨浓度对光引发剂在食品包装材料中残留的影响。结果光引发剂残留量会随着光照能量的增加而减少,随着墨层厚度增加而增加。对于PET薄膜,油墨含量高时光引发剂的残留量比油墨含量低时大,而铜版纸结果相反,油墨含量高时光引发剂的残留量较小。结论在实际UV油墨印刷中,应提高光照能量,对于不同的承印材料应采用含量不同的油墨,以减少光引发剂的残留,降低其迁移风险,增加食品包装的安全性。     

Photoinitiated cationic oligomerization of terminal and internal epoxides

The iodonium salt‐catalyzed, photoinduced cationic oligomerization of terminal and internal monoepoxides from oleochemical as well as the petrochemical origin was studied. The ring‐opening of terminal epoxides (1,2‐octene oxide, phenyl glycidyl ether, 9,10‐epoxy decanoic acid methyl ester and 10,11‐epoxy undecanoic acid methyl ester) predominantly led to macrocyclic oligoethers (M_n = 650—1,100 g/mol) via backbiting in quantitative yields. Mixtures of cyclic and bishydroxy‐terminated oligoethers (M_n = 1,050—1,500 g/mol) were achieved by the conversion of internal epoxides (7,8‐tetradecene oxide and cis‐9,10‐epoxy octadecanoic acid methyl ester) in yields of 80—95%. Macrocyclization was completely suppressed by addition of 20 mol‐% water or ethylene glycol receiving diol‐oligoethers for potential application as soft segments for polyurethanes with molecular weights of approximately 1,300 g/mol.     

Organic sulfur compounds as initiators of polymerization. VII. Polymerization of methyl methacrylate by N-[(p-benzoyl)benzenesulfonyl]benzenesulfonamide

The photopolymerization of methyl methacrylate in bulk using N-[(p-benzoyl)benzenesulfonyl]benzenesulfonamide as a photoinitiator was studied. A kinetic study of the photopolymerization showed that the rate of polymerization is proportional to the square root of the photoinitiator concentration. The decomposition of a sulfur–nitrogen bond and the obtained radicals are suggested to be responsible for the initiation of polymerization. The influence of the photoinitiator on the molecular weight was also studied. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2083–2086, 1998     

Unsaturated polyester resins with different allyl ethers as crosslinking built-in monomers

The effect of the structure of allyl ethers used as built-in monomers of unsaturated polyester resins on the properties of the coatings obtained have been studied. It was found that high hardness of the coatings cured in air using photoinitiators was achieved for the resins with polyfunctional allyl ether monomers incorporated into polyester molecules as the end groups or as the pendant geminal groups. The influence of the presence of a cobalt organic salt on the hardness of the coating from unsaturated resins has also been studied. The extent of crosslinking for the copolymerization of fumaric esters with allyl ethers in air increases, and a smaller amount of photoinitiator may be used when cobalt (II) naphthenate is present in the resin. The results are discussed in terms of the oxidation of allyl ethers and redox cleavage of peroxides formed, leading to an increase in the rate of copolymerization of allyl ethers with fumarate esters. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2031–2039, 1998     

LC-MS/MS法测定纸质包装材料中15种光引发剂向改性聚苯醚模拟物的迁移量

为了考察光引发剂的迁移特性,评估安全风险,建立了一种基于液相色谱 串联质谱（LC-MS/MS）分析纸质包装材料中15种光引发剂向改性聚苯醚（MPPO）模拟物迁移量的方法。纸质包装材料中迁移出的被分析物被MPPO吸附后用乙腈萃取,萃取液经有机滤膜过滤后,采用乙腈和0.1%甲酸水溶液作为流动相进行梯度洗脱,Luna PFP(2)色谱柱（150 mm×4.6 mm×3 μm）分离,串联质谱法分析,外标法定量。通过对色谱条件优化,15种光引发剂在12 min内可实现有效分离,且目标分析物在0.01~0.2 mg/kg范围内线性关系良好,线性相关系数R²>0.993。3个加标水平（0.01、0.05和0.2 mg/kg）的回收率在70.2％～122.5%之间,相对标准偏差（RSD）小于7.5％,检出限（LOD）为0.001～0.021 mg/kg。实际样品的分析结果表明,该方法的检出限低、测定结果准确,可用于纸质包装材料中15种光引发剂向改性聚苯醚模拟物迁移量的检测。     

水性光引发剂(4-苯酰基)苯甲基铵-N-十二烷基-N,N-二甲基溴化物的合成

以4-甲基二苯甲酮为原料,经溴化合成4-溴甲基二苯甲酮,再与二甲基十二胺反应合成新型的光引发剂(4-苯酰基)苯甲基铵-N-十二烷基-N,N-二甲基溴化物,对新化合物结构进行了IR,MS,1HNMR表征。产品纯度大于98%,收率大于81%(以4-溴甲基二苯甲酮计)。对产品的光引发性能进行了初步研究。     

Photocrosslinking of solvent-based acrylic pressure-sensitive adhesives (PSA) by the use of selected photoinitiators type I

This study investigated the photocrosslinking of solvent-based acrylic pressure-sensitive adhesives (PSA) containing selected photoinitiators type I, known as α-cleavage photoinitiators. Photocrosslinking of PSA, especially of acrylic PSA, is well established crosslinking process using the UV radiation technology. UV-initiated crosslinking of acrylic PSA allows the synthesis of the wide range of UV-crosslinkable PSA with the interesting features. Especially, the important balances of properties such as adhesive and cohesive strength which are typically critical for the application performance can be achieved by this technology. The selection of suitable photoinitiator plays an important role to obtain the optimum properties of acrylic PSA including tack, peel adhesion, and shear strength. In this study, the investigations on different saturated conventional photoinitiators of type I for solvent-based PSA were carried out. The effects of photoinitiator concentration, UV crosslinking time and UV dose on the tack, peel strength, and shear strength were explored in detail for guiding the choice of photoinitiators to fabricate advanced PSA for industrial usage.     

Photopolymerization of N,N‐dimethylaminoethylmethacrylate studied by photocalorimetry

Photopolymerization of dimethylaminoethylmethacrylate (DMAEMA) is studied in bulk and in solutions in the presence of different photoinitiators using differential photocalorimetry (DPC). The rate of DMAEMA photopolymerization is slow compared to that of alkylmethacrylates. Bimodal DPC curves of DMAEMA photopolymerization in bulk are obtained. The type I photoinitiators (IRGACURE® 651 and IRGACURE® 1700), which produce free radicals by homolytic fragmentation of photoexcited molecules, are more effective in promoting photopolymerization of DMAEMA. The type II photoinitiators (benzophenone and IRGACURE® 500), which initiate DMAEMA photopolymerization through an H‐abstraction mechanism involving an amino group from the monomer (polymer), are less efficient and favor the formation of partly crosslinked products. The effects of the photoinitiator concentration, temperature, and solvent on the kinetic data are evaluated and discussed. A scheme of photopolymerization of DMAEMA, including the formation of intermediate DMAEMA based macromonomers, is proposed. The main point of the suggested scheme is a high chain transfer to the DMAEMA monomer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 579–588, 2002     

Photochemistry and photophysics of poly(organophosphazenes) and related compounds: A review. III. Applicative aspects

In the third part of this review we report some applicative aspects of poly(organophosphazenes) in photochemical fields. In particular, the possible application of phosphazene polymers that contain azobenzene or spiropyran residues as photochromic macromolecules is outlined; the light-induced grafting of organic, carbon-backboned polymers onto polyphosphazene matrices, as a method of modifying both surface and bulk properties of these materials, is highlighted; and the potential application of cyclophosphazenes as photo-stabilizers for commercial organic polymers or as photoinitiators for radical polymerization of vinyl monomers is described.Parts I and II in this series appeared in this journal, Volume 4, Numbers 1 and 2, 1994, respectively.