Sulfur-containing hyperbranched polymeric photoinitiator end-capped with benzophenone and tertiary amine moieties prepared via simultaneous double thiol-ene click reactions used for UV curing coatings

A series of sulfur-containing hyperbranched polymeric photoinitiators end-capped with benzophenone (BP) and tertiary amine moieties (B/A-HPIs) were synthesized via the simultaneous double thiol-ene click reactions of thiolated hyperbranched polymer with both dimethylaminoethyl acrylate and 3-(4-benzoylphenoxy)propyl acrylate. The molecular structures were characterized by ¹H NMR and FT-IR spectroscopy. From the UV-vis spectra, B/A-HPIs showed the stronger n-π* absorption at ∼340 nm with a higher molar extinction coefficients of 371 L mol⁻¹ cm⁻¹ than 148 L mol⁻¹ cm⁻¹ of BP, and an obvious red shift of π-π* absorption from ∼250 nm of BP to ∼280 nm. According to the photo-DSC study, the photopolymerization rate of 1,6-hexanediol diacrylate initiated by 5 wt% B/A-HPI was twice higher than that by BP. The DMTA results showed the good miscibility of B/A-HPIs with acrylate resins and high crosslinking density of cured films.     

A highly efficient photoinitiator for water-borne UV-curable systems

Water based UV-curable formulations comply with environmental and legislation constraints for volatile organic compounds. The photoinitiator is one of the critical components of the coating formulation. We developed a ready-to-use oil in water emulsion of the oligomeric, polyfunctional α-hydroxyketone photoinitiator Esacure KIP 150. The emulsion is stable and it is easily incorporated into water-borne formulations. It gives very good performances in curing experiments. The components of the emulsion do not adversely affect the performance of the photoinitiator itself. Moreover, the photoinitiator incorporated into the emulsion has a very low volatility, it does not release volatile photodecomposition products and has a very low tendency to migrate from the cured formulations.     

Investigation of the photoinitiation of methyl methacrylate polymerization by 2-morpholino acetonaphthone

2-Morpholino acetonaphthone (MPM) was synthesized as a cleavable photoinitiator and the structure of the photoinitiator was confirmed by spectral and elemental analysis. The photoinitiation capability of MPM was demonstrated by using methyl methacrylate and a formulation containing multifunctional monomers.     

光引发剂噻吨酮ITX的合成研究

以二硫代二苯甲酸(DTSA)经过酰氯化、氯代、然后与异丙苯在三氧化铝催化下缩合成为光引发剂。研究了反应时间、反应温度、配料比对反应的影响,得到了最佳反应条件。     

水性UV油墨各组分对体系固化速度的影响

采用甲苯二异氰酸酯、聚酯二元醇、二羟甲基丙酸(DMPA)和丙烯酸羟乙酯(HEA)合成水性阴离子型聚氨酯丙烯酸酯,用傅立叶红外光谱(FTIR)证实了该预聚物的结构,并最终制得成水性UV油墨。由紫外-可见分光光度计测得黄、品、青、黑等四种颜料的紫外吸收光谱,并且运用指干法研究了不同光引发剂、颜料含量及干燥工艺对油墨固化速度的影响。结果表明:黄、品、青、黑四色墨最佳的引发剂体系为819DW+MBF、819DW+500、819DW+MBF、819DW+MBF,最佳光引发剂含量为10%、10%、10%、11%;最佳颜料含量分别为6%、7%、6%、7%;该UV油墨不经过预先烘干直接进行固化时,光固化速度反而提高。     

光引发剂对UV丝印光致变色油墨固化性能的影响

UV丝印光致变色油墨体系中主要包括了预聚物、单体、光致变色材料、光引发剂等成分,而此油墨的固化是在UV光源的照射下,引发具有化学反应活性的液态物质快速转变为固态的过程,光引发剂在此化学反应中的作用就是引发这种反应进行,因此,它是油墨体系中直接影响着油墨固化性能的主要成分之一。通过改变光引发剂的含量和种类,分别制备油墨,并测试油墨的固化速度,从而研究光引发剂对油墨的固化性能的影响。实验表明当光引发剂的含量为10%的时候,油墨的光固化性能最好。另外选出三种固化性能最好的光引发剂184、907和BP进行配方实验,结果表明由光引发剂907所制备的油墨具有最好的固化性能,并且,最佳的固化速度为68m/min(固化功率:100W/cm)。     

Benzophenone-di-1,3-dioxane as a novel initiator for free radical photopolymerization

Benzophenone-di-1,3-dioxane (BP-DDO), a novel photoinitiator for free radical polymerization, was synthesized and characterized. The photopolymerization kinetics of BP-DDO was studied by real-time infrared spectroscopy (FT-IR). When this photointiator was used to efficiently initiate polymerization of acrylates and methacrylates, there was an optimum cure rate with the increase in BP-DDO concentration. Both the polymerization rate and final conversion increased with the increase in light intensity. The kinetics study of photopolymerization of TMPTA showed that BP-DDO was a more effective photoinitiator than benzophenone and benzophenone/ethyl-4-dimethylaminobenzoate (EDAB).     

Percolation of glassy regions during photopolymerization of epoxy acrylate in DMF

The gelation of epoxy acrylate (EA) 80% and tripropyleneglycol diacrylate (TPGDA) 20% was studied through the use of photo-differential scanning calorimetric (photo-DSC) technique in the presence of a thioxanthone based initiator. Photo-induced polymerization reactions were performed under identical conditions of temperature, initiator concentration and UV light intensity in various N,N-dimethylformamide (DMF) contents. Photo-DSC technique allowed us to monitor the gelation without disturbing the system mechanically, and to test the universality of the gelation as a function of DMF content. During gelation, it was observed that all conversion curves presented useful sigmoidal behavior which was predicted by employing a percolation model. Observations around the glass transition point, t_g, revealed that gel fraction exponent β obeyed the percolation picture. A significant solvent effect on the photopolymerization kinetics of EA/TPGDA was observed with changes in DMF content. DMF is used as solvent, which acts as a diluent and proton donor during photogelation.     

Study of methoxyphenylquinoxalines (MOPQs) as photoinitiators in the negative photo-resist

To develop photoinitiator systems of high performance for the negative photo-resist, we synthesized six methoxyphenylquinoxalines (MOPQs) and investigated the photopolymerization of 2,2-bis(4-(acryloxypolyethoxy)phenyl)propane (A-BPE-10) initiated by these MOPQs in the negative photo-resist. MOPQs possess suitable UV–vis maximum absorption wavelengths in the range of 349–402 nm, along with high extinction coefficients ?. Except for T3MOP-DQ and T4MOP-DQ, the other four MOPQs, D3MOP-Q, D4MOP-Q, D3MOP-BenQ and D4MOP-BenQ, could initiate photopolymerization of A-BPE-10 in the negative photo-resist very efficiently. In particular, D3MOP-BenQ was the most efficient, with almost 100% final conversion in the presence of 2-mercaptobenzothiazole (MBO) as a coinitiator. Among the four coinitiators LCV, MBO, NPG and MDEA, MBO was the best coinitiator for MOPQs. The negative photo-resist containing MOPQs as a photoinitiator can also form good patterns on copper through photolithography. These characteristics make MOPQs potential photoinitiators in the negative photo-resist.     

The effect of the amine structure on photoinitiated free radical polymerization of methyl methacrylate using bisketocoumarin dye

Photoinitiation of the polymerization of methyl methacrylate by the bis-diethylaminocoumarin dye (BKC) in the presence of various amines was studied in order to determine the efficient amine that leads to the formation of the initiating radicals. RT-FTIR studies were also performed for multifunctional methacrylate. According to photoinduced polymerization and RT-FIR studies, N-methyldiethanol amine was the more efficient H-donor compared with the others.