可注射性骨修复材料不饱和聚磷酸酯的光引发交联聚合

通过凝胶含量的测定，研究了紫外光引发不饱和聚磷酸酯（UPPE）与N-乙烯基吡咯烷酮的共聚交联反应，结果表明：加入光引发剂能够显著增加凝胶含量，安息香乙醚（BE），安息香（BN），2，2-二乙氧基苯乙酮的引发活性较高,光引发剂浓度较低时，增加光引发剂的含量能够显著提高单位时间内的凝胶生成率，但含量过大反而降低凝胶生成率．BN、BE的适宜浓度分别为2．4E^-5（mol／gUPPE）及0．6E^-5（mol／gUPPE）,光照较短时间内，UPPE分子量为5960g／mol的体系具有最高的凝胶生成率，但由于粘度的影响，光照2min后其凝胶生成率低于UPPE分子量为4040 g／mol的体系,表层对紫外光的吸收降低了光能量，导致深层交联聚合反应速度降低，1.5mm厚试样通过延长曝光时间，凝胶含量可与1.0mm厚试样接近，6.0mm试样曝光24min后底层仍不能固化。     

可聚合型光引发剂4-丙烯酰氧基二苯甲酮的光聚合性能研究

以实时红外光谱（RT-IR）法研究了合成的4-丙烯酰氧基二苯甲酮（4-ABP）的光聚合动力学性质，考察了不同单体、不同引发剂和助引发剂浓度、不同光强对聚合性能的影响．以萃取法对比研究了4-ABP和二苯甲酮（BP）在固化膜中的的残留量．结果表明，4-ABP是一种非常有效的光引发剂．随着引发剂浓度和光强的增大，单体转化率、最大反应速率都增大，诱导期缩短．萃取实验表明4-ABP在固化膜中的残留量远低于BP．     

UV固化丙烯酸粉末涂料的制备

以环氧型聚丙烯酸酯一甲基丙烯酸酯树脂为光固化树脂，Irgacure2959、Irgacure651、Irgacure184等为光引发剂制得了UV固化丙烯酸粉末清漆，研究了单组分和双组分光引发剂种类及用量对固化程度和漆膜性能的影响，探讨了固化工艺。结果表明，采用3％的Irgacure2959单组分光引发剂或1．5％Irgaeure2959和1．5％Irgacure651复合光引发剂体系，130℃下流平10min，固化30s，所得涂膜具有较佳的综合性能。     

UV固化粉末涂料用光引发剂的选择

研究了白色体系UV固化粉末涂料用的光引发剂。讨论了单一引发剂体系、复合引发剂体系、引发剂用量和固化时间对固化性能的影响，由此确定了该粉末涂料体系的最佳引发剂配比、引发剂用量以及合理的固化工艺。     

1种新型紫外光固化水性涂料

华南理工大学,发明了1种复合型紫外光固化水性涂料。该发明公开了1种复合型紫外光固化水性涂料及其制备方法：取环氧-丙烯酸酯混合,搅拌0．5～4h,再加入水性光引发剂、有机硅消泡剂及水性防腐防霉剂搅拌0．5～2h,最后加入分散剂分散均匀;其中环氧-丙烯酸酯10～70份,聚氨酯-丙烯酸酯10～70份,水性光引发剂1．0～8．0份,有机硅消泡剂0．05～1．0份,水性防腐防霉剂0．3～2．0份,     

混杂光固化性能更优异

紫外光（UV）固化是一种免溶剂的环保型技术,具有固化速度快（0．1～10S）、能量消耗低、环境污染小、能自动化生产、适用于热敏材料等优点。UV固化按光固化机理分为自由基固化和阳离子固化。自由基固化是在光引发下产生的自由基,引发预聚物和单体上的双键产生聚合反应,具有固化速度快（〈10s）、性能易调节、引发剂种类多等优点,但存在的问题是不易表干、体积收缩大、粘附力差、无后固化作用等。阳离子固化是阳离子引发剂在光照射后产生质子酸或路易斯酸,形成正离子活性中心,引发阳离子开环聚合。     

华南理工大学研究新型UV水性涂料获专利

一种复合型紫外光固化水性涂料及其制备方法,日前获得国家专利。该专利由华南理工大学发明。该发明公开了一种复合型紫外光固化水性涂料及其制备方法：取环氧-丙烯酸酯、聚氨酯-丙烯酸酯混合,搅拌0．5～4h,再加入水性光引发剂、有机硅消泡剂,及水性防腐防霉剂搅拌0．5～2h,最后加入分散剂分散均匀;其中环氧-丙烯酸酯10～70份,聚氨酯-丙烯酸酯10～70份,水性光引发剂1．0—8．0份,有机硅消泡剂0．05～1．0份,     

常用光引发剂在紫外光固化涂料中的应用研究

针对紫外光固化体系,研究了常用光引发剂在紫外光固化涂料中的应用。讨论了常用光引发剂的用量及其对亮光体系、亚光体系和色漆体系固化性能的影响。得出在紫外光固化涂料中选择引发剂的规律。     

常见光引发剂对水性UV光油固化的影响

光引发剂是水性UV光油体系的重要组成部分,对光油的的固化反应起着决定性作用。本文考察了光引发剂的种类及含量对光油固化效果的影响,选用不同的光引发剂设计水性UV光油的配方,测试比较其固化性能。不同的光引发剂及其在配方的的含量会影响水性UV光油的固化效果,测试结果表明907的固化速率较快,1173的固化速率较慢但是黄变影响最小。同时考察了光引发剂不同含量对水性UV光固化性能的影响。     

浅析水性光引发剂在紫外光固化涂料中的发展前景和应用

随着绿色发展理念深入人心,社会发展方式加快转变,紫外光固化技术做为一种绿色环保的技术,受到前所未有的关注。而水性光引发剂由于良好的引发光聚合反应的能力和优良的水溶性逐步成为紫外光固化涂料研究的热点。本文以水性光引发剂在紫外光固化涂料中的发展和应用研究为中心,首先分析水性光引发剂的应用优势以及对紫外光固化涂料的重要意义,其次研究水性光引发剂在紫外光固化涂料中的应用,最后明确紫外光固化涂料中水性光引发剂的发展与研究方向,为水性光引发剂的深入研究和拓展紫外光固化涂料应用领域奠定扎实理论基础。     

UV curable coatings for improved gas barrier properties of poly(ethylene terephthalate)

A new high-barrier coating based on methyl (α-hydroxymethyl)acrylate (MHMA) for poly(ethylene terephthalate) (PET) was developed along with the process for preform dipping and cure prior to blow molding into bottles. The UV curable coating gives excellent gas barrier improvement when coated onto PET biaxially oriented thin films. Blown bottle side walls from coated PET preforms also show 2–3 times improvement over uncoated side walls. The effect of photoinitiator concentration, initiator types, and temperature on photopolymerization kinetics of MHMA was investigated. Once the photoinitiator, Irgacure 819^®, concentration became larger than 1 mol%, a decrease in rate of propagation was observed. The conversion also decreased with higher initiator concentration. Irgacure 819^® reduced the auto-acceleration peak and reached maximum rates of polymerization much faster than Irgacure 651^®. It also gave a slightly higher conversion. Overall conversion for combinations of these photoinitiators was high, above 80%. Real-time FTIR (RT-FTIR) studies of copolymerization of MHMA and methyl methacrylate (MMA) showed that conversion was fairly high up to 25 mol% MMA. However, once MMA feed ratio exceeded 10 mol%, a decrease in barrier performance was observed.     

Photoinitiability of a water-borne polysiloxane-modified benzophenone macromolecular photoinitiator

This paper reported a water-borne polysiloxane-modified benzophenone macromolecular photoinitiator (WPSHBP), whose characteristics of the photopolymerization, the migration of photolysis fragments, the volatility, and reduction of oxygen inhibition were discussed in detail. WPSHBP has a maximum absorption peak at 286 nm, and the molar extinction coefficient (ε_286 nm) is 23200 M^?1 cm^?1. The photopolymerization rate and final double bond conversion of the system initiated by WPSHBP were enhanced with the increasing contents of triethanolamine (TEOA) and WPSHBP and irradiation intensity. WPSHBP exhibits a low migration of photolysis fragments and volatility compared with small-molecular photoinitiator benzophenone (BP). The cured films initiated by WPSHBP have good mechanical properties and thermostability compared with that by 2-hydroxy-4’-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959). More importantly, the water-borne polysiloxane-modified photoinitiator can mitigate the oxygen inhibition in radical photopolymerization due to its enrichment on the surface of the photopolymerization system.     

Effects of Surface Pretreatment on the Mechanical and Dielectric Properties of Photocuring Jute Fibers

Jute fabrics were treated with ethylene glycol dimethylacrylate (EGDMA) + MeOH solutions at different proportions along with photoinitiator Irgacure 907 and cured under UV-radiation. Monomer concentration, soaking time, and radiation dose were optimized in terms of polymer loading and mechanical properties. Twenty-five percent EGDMA, 30-minute soaking time, and tenth-pass of radiation produced higher tensile strength (75%) and tensile modulus (88%) than those of the untreated sample, as well as the highest polymer loading value (70%). Among different additives used, urea showed the best performance. SEM, water uptake, and dielectric properties of the samples were studied.     

UV光固化有机硅的制备及其光固化条件

以聚甲基三乙氧基硅烷(PTS)、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)、二甲基二乙氧基硅烷(DDS)为原料,以盐酸为催化剂通过溶胶凝胶法制备了可UV光固化的有机硅材料,利用FTIR和29SiNMR对材料进行了表征,研究了可UV光固化有机硅材料的缩聚程度和光引发剂种类对可UV光固化的有机硅材料固化速率的影响。结果表明,光引发剂中,Irgacure 369的固化速率最快,在相同的光照时间和引发剂质量分数下,使用Irgacure 369作为光引发剂的有机硅双键转化率达到了95.89%,同时通过改变光照时间和引发剂质量分数确定了最佳的光照时间和最佳引发剂质量分数分别为15 s和2%。     

Controllable properties and microstructure of hydrogels based on crosslinked poly(ethylene glycol) diacrylates with different molecular weights

This work describes a comprehensive study of hydrogels based on polyethylene glycol diacrylates (PEGDAs) with the molecular weight (MW) range of 400–2000. The blends of low‐ and high‐molecular weight PEGDA macromers with different ratios were photopolymerized under visible light irradiation, using a blue light sensitive photoinitiator Irgacure819, at the total polymer concentration of 60 wt %. Swelling ratios, wetting property, elastic moduli, transparency, and the microstructure of the resulting hydrogels were investigated. Among them, equilibrium water contents, hydrophilicity, and mesh size of the hydrogels increased while the elastic moduli decreased when increased the PEGDA MW or the content of higher MW PEGDA in the blends. Most of the hydrogels possessed excellent transparency in visible region. The viability of L929 cells on the surface of hydrogel was also estimated. All the selected hydrogels exhibited a relatively high proliferation rate, which demonstrated this hydrogel system with photoinitiator Irgacure819 had good biocompatibility. These results show the properties of PEGDA hydrogel could be easily adjusted by varying PEGDA MW or the ratios of low‐ and high‐MW macromers in the composites. It could be helpful for the design of proper PEGDA hydrogels in the applications as tissue engineering or drug delivery system. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Investigation of influence factors in electron beam curing of epoxy resins using a calorimetry technique

Because of the complexity of the electron beam (EB) curing process, current understanding of EB curing of polymer resins and composites is limited. This article describes an investigation of different factors affecting EB curing of epoxy resin such as dose rate, time interval between irradiation doses, moisture, and photoinitiator concentration using a calorimetry technique. Results show that higher dose rate resulted in a higher and faster temperature increment in the uncured resin samples, and thus a higher degree of cure. In the multiple‐step EB irradiation, a shorter time interval between irradiation doses resulted in higher temperature in the resin samples and therefore higher degree of cure. Results indicate that moisture could delay crosslinking reaction in the early stages of the cure reaction, but accelerates it later in the curing process. Given a reasonable percentage of photoinitiator, experiments confirmed that samples with higher photoinitiator concentration reach higher degree of cure under same EB irradiation conditions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A simple Raman technique to measure the degree of cure in UV curable coatings

The curing behavior of four UV curable clearcoats was examined using spectra from a confocal Raman microscope. The disappearance of the C=C line near 1636 cm⁻¹ provides the signature for the curing of the samples, but quantification of the degree of cure by standard peak-fitting and baseline subtraction methods does not work well because of sample fluorescence, baseline shifts and overlapping peaks. A smoothed second-derivative processing approach overcomes all of these difficulties and provides a simple, fast and objective quantification procedure. Steep cure gradients through the thickness of the clearcoat, due to screening of the bottom of the clearcoat by both the UVA and photoinitiator, were observed. Cure gradients at the top of the clearcoat due to oxygen inhibition were also observed. The most complete cure throughout the film thickness was obtained with a mixture of standard and red-shifted photoinitiators.     

A water-soluble Irgacure 2959-based diallylammonium salt system for antibacterial coatings

A water-soluble mixture of a novel diallylammonium salt photoinitiator based on 2-hydroxy-1-[4-(2-hydroxyethoxy) phenyl]-2-methyl-1-propanone (Irgacure 2959 or I2959) and diallylammonium tosylate has been prepared. It shows excellent water-solubility of 6.8 wt% in water, much greater than the solubility of I2959 (<2 wt%). It has a strong absorbance at 269 nm (ε ~ 15731) in methanol. It exhibits 15.6 times higher migration stability than I2959 due to its monomeric nature. Its photoinitiating efficiency of 2-hydroxyethylmethacrylate (HEMA) and poly(ethylene glycol) diacrylate (PEGDA, M_n = 575 D) was found to be similar to I2959. PEGDA hydrogels prepared using the synthesized photoinitiator (PI) were found to have highly porous structures (15.44 μm) compared with those using I2959. PEGDA film prepared using this PI has demonstrated antibacterial properties against gram-negative Pseudomonas aeruginosa (ATCC 15442) and gram-positive Staphylococcus aureus (ATCC 23235) bacterial species.     

Impact of radiation attenuation and temperature evolution on monomer conversion of dimethacrylate‐based resins with a photobleaching photoinitiator

The photopolymerization process of a dimethacrylate copolymer system activated by the camphorquinone (CQ)/amine photoinitiator system (1 wt%), was experimentally studied under nonisothermal conditions in 1‐ and 2‐mm thick samples by measuring double bond conversion, temperature rise and radiation attenuation through the sample during polymerization. The peak temperature in 1‐ or 2‐mm thick samples irradiated at 5 mW/cm² was 29 and 38°C, respectively. The temperature evolution during polymerization was also predicted by solving the energy balance coupled with the kinetic expressions for the reaction rate. Radiation attenuation as a function of depth by the photobleachable CQ results in spatial and temporal variation in the local rates of the kinetic steps involved. General relationships for spatiotemporal variations in concentration of a photobleaching initiator, in systems where attenuation and initiator consumption are taken into account, were used to compute local polymerization rates. The effects of radiation attenuation, photobleaching of the photoinitiator and variation of cure temperature at different depths into the resin, all compete to determine the double bond consumption. The increased radiation attenuation in the 2‐mm thick sample was accompanied by a higher cure temperature compared with the 1‐mm thick sample, and as a result, the monomer conversion averaged over the sample thickness in the 1‐ and 2‐mm thick samples was the same. Results obtained in this research highlight the inherent interlinking of thermal and radiation attenuation effects in bulk photopolymerizing systems. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Novel pyridinium derivatives as very efficient photoinitiators for UV-activated synthesis of acrylic pressure-sensitive adhesives

During the development of synthesis of acrylic pressure-sensitive adhesives, newly synthesized pyridinium derivatives were used by the UV-initiated polymerization quarantines of new polymer design for the synthesized self-adhesive acrylics with excellent performance, for which tack, peel adhesion, shear strength and shrinkage were measured. For example, the best tack and peel adhesion performances were achieved after 30 and 60 s UV radiation for 3.0 wt% pyridinium photoinitiator PPP, after 60 and 90 s UV exposure for 4.0 wt% pyridinium photoinitiator HPP and after 90 s UV-crosslinking in the case of 5.0 wt% pyridinium photoinitiator OPP. An increase of novel pyridinium photoinitiators concentration causes in an increase of the monomers conversion. For high photoinitiator content, characterized for each investigated photoinitiator, ranging from about 3.0 (PPP) to 5.0 wt% (OPP), the degree of monomer conversion reaches a maximum value of about 99.6 wt%.Preliminary results are reported illustrating the effectiveness of the acrylic PSA development.