Characterization of a clear coating cured by UV/EB radiation

The quality and performance of the polymeric materials cured by ultraviolet (UV)/electron beam (EB) radiation depends on the components of coating formulation, as well as the type of radiation used in the curing process. The aim of this study was to establish the correlation between the cure degree of a clear coating irradiated with different radiation doses of UV or EB and the tensile properties of the polymeric films obtained. The cure degree was measured by DSC and FTIR.     

Photo-oxidative stability of electron beam and UV cured acrylated epoxy and urethane acrylate resin films

The post-cured photo-oxidative stability of urethane and bisphenol-A epoxyacrylate resins in mixed compositions with triacrylate and amine diacrylate resins are examined using UV and reflectance infra-red absorption spectroscopic techniques. Overall, by measuring the growth in hydroxyl absorption at 3400 cm⁻¹, electron-beam cured resin films are more photostable than UV curedfilms, indicating the high photo-activity of residual photoinitiator in the latter case. Regarding the UV cured systems benzophenone is found to be a more photo-active residual photoinitiator than the benzoyl ester photofragmenting types. Films containing the amine diacrylate resin are more photostable than those containing the triacrylate resin. This stabilising effect is associated with the oxygen and radical scavenging ability of the terminal amine groups. Photo-yellowing, as measured by the growth in an absorption band at 280 nm, is observed only in resin films containing the amine diacrylate resin and is associated with the formation of unsaturated carbonyl groups. The latter are, however, photobleached on prolonged irradiation whereas with resins containing the bisphenol-A epoxy acrylate resin, a longer term photo-yellowing is observed due to oxidation of the bisphenol-A to give stilbene-quinone products.     

UV cured transparent films including non‐aqueous conductive microgels

UV cured transparent films containing non‐aqueous conductive microgels coated with poly(aniline)/dodecyl benzenesulfonic acid(DBSA) were obtained. The conductive microgels were prepared by interface polymerization of aniline/DBSA in the presence of non‐aqueous polymeric microgels. The electrical conductivity and the particle size of the prepared conductive microgel were 0.5 S/cm and 58 nm, respectively. The prepared conductive microgels were easily blended with a UV curable coating formulation, and then were cured to make highly optically transparent films. For the UV cured film containing about 35 wt% of the conductive microgels, a surface resistance in the range of 10⁷ to 10⁸ Ω/square was obtained. In a polar cosolvent, such as NMP and m‐cresol, the critical volume was shifted to the lower range, with a value of 10 wt%. The UV cured films containing the conductive microgels exhibited good electrical stability against the thermal aging and humidity. Copyright © 2002 John Wiley & Sons, Ltd.     

UV‐cured polyester‐acrylate nanocomposite films with silane‐grafted silica nanoparticles

UV‐curing technique was employed in this study to prepare polyester‐acrylate nanocomposite films with silane‐grafted silica nanoparticles. Methacryloxypropyl trimethoxysilane was grafted to the surfaces of silica nanoparticles to improve dispersion of silica nanoparticles as well as interfacial adhesion between the resin matrix and silica nanoparticles. The silane‐grafting was confirmed by nuclear magnetic resonance and infrared spectroscopy. The effects of the silane‐grafting on the mechanical and optical properties as well as UV‐curing behavior of the nanocomposite films were investigated. The tensile strength, transmittance, UV‐curing rate, and final chemical conversion of the nanocomposite films were increased by use of the grafted silica nanoparticles as compared to the use of neat silica nanoparticles. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of silanized polyether urethane hybrid systems. Study of the curing process through hydrogen bonding interactions

Different types of silanized polyurethanes (SPUR) were prepared in two ways: the first type (a), by reacting a polyether diol with an isocyanatesilane and the second type (b) by reacting it with diisocyanate (IPDI) and afterwards with aminosilane. These systems are able to cure with atmospheric moisture and, as a consequence, a tridimensional hybrid structure is formed where the inorganic and organic phases are bonded with covalent bonds. The evolution of the curing process in both systems has been monitored by means of Fourier transform infrared spectroscopy, through the changes observed in the carbonyl stretching vibration region. The results obtained show that the SPURs of kind (b) present stronger hydrogen bonding interactions as a consequence of urea groups present in the final structure. Moreover, given the proximity of both urethane and urea groups to alkoxysilane end groups, during the alkoxysilane curing process these groups are forced to approximate themselves even further and therefore the reticulation process leads to an increase of the self association of urethane and urea groups.Finally, DSC has been used to measure T_g values of the systems studied before and after the curing process. The obtained results have confirmed the main conclusions obtained in FTIR analysis.     

Effect of the structural parameters of a series of fluoromonoacrylates on the surface properties of cured films

A series of fluorinated acrylates [F(CF₂)_q? (CH₂)_p? OCOCH?CH₂, where q = 8 and p = 2 ÷ 11) were synthesized and used as comonomers in the photopolymerization of acrylic systems. These fluoroacrylates were synthesized in a three‐step procedure through the radical addition of perfluoroalkyliodides to an unsaturated alcohol followed by their acrylation. The mixtures, containing up to 0.8% (w/w) of the comonomers, produced transparent films after UV curing; they showed changes in the surface properties as a function of the comonomer type and concentration. With contact‐angle and X‐ray photoelectron spectroscopy analyses, the relationship between the structure of the monomers and the surface properties of the UV‐cured films was investigated: the wettability decreased, depending on the length of the fluorinated group (q value) and the hydrogenated segment of the monomer (p value). © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4227–4235, 2001     

紫外光固化PDLC膜性能的温度效应

考察了紫外光固化PDLC膜的电光性能及其温度依赖性,阐述了其作为显示器件的工作稳定性。指出确定PDLC工作温度范围的方法,对PDLC膜中液晶相的N-I转变行为及其与膜的内部结构的关系进行了讨论。     

生物基UV固化预聚物制备及性能研究

近年来，随着制造业产能的严重过剩，我国政府对于环境保护越来越重视，传统油性涂料体系受到巨大的冲击，而光固化作为三大环保型涂料技术之一得到迅速发展。生物基原料是一种可再生资源，在不可再生资源越来越少的未来，生物基材料的发展和应用也就成为一种必然趋势。本文把生物基原料引入光固化预聚物体系，在类似结构条件下对比了含有和不含有生物基材料预聚物固化膜的基本物化性能，并对实验结果进行了总结。     

可紫外光固化的聚乙烯基硅氮烷合成与表征

采用带丙烯酸酯基团的烯丙基溴化合物(4-溴丁烯酸乙酯)和聚乙烯基硅氮烷发生取代反应,实现了丙烯酸酯基团在聚乙烯基硅氮烷主链上的链接.采用质子核磁共振谱(1H-NMR)和二维质子核磁共振谱(2D-1H-1H-NMR)对分子结构进行了表征,采用光学差热分析仪(Photo-DSC)和傅立叶转换红外光谱仪(FT-IR)测试了改性高分子的光敏性能,用热重分析仪(TGA)分析了产物在高纯氮气氛围下的陶瓷收率.结果表明,通过分子改性,交联固化时间从改性前的20min减少到1min之内,功能化的聚乙烯基硅氮烷可以在光刻蚀工艺中作为负性光刻胶使用.     

UV curing behaviors and hydrophilic characteristics of UV curable waterborne hyperbranched aliphatic polyesters

A series of waterborne hyperbranched polyesters (WBHPs) endcapped with methacrylic and salt-like groups in different ratios have been investigated as UV curable resins. The kinetic studies of the drying step and UV curing were carried out by FT-IR measurements. The drying of the film of 100 μm thickness was completed in less than 6 hr at 70°C or within 10 hr at 50°C in an oven. The influence of different photoinitiators and their concentrations, extent of unsaturation and acid content of WBHP on final unsaturation conversion was studied. The surface free energy is a critical character, which affects the surface properties of a cured film. So one method based on the measurement of contact angle of a pure liquid on a solid surface was applied to determine the polar and dispersive components of the surface energy of UV cured films. The investigations of surface energy of WBHPs illustrated that those with more acid content and thus higher polar component are more sensitive to water, while those containing less acid content and thus lower polar term are less water sensitive. Moreover, the UV cured films of WBHPs and their blends with commercial waterborne resins (trade name EB 210, EB 2002, EB 11 and IRR 160) have acceptable pendulum hardness varying from 55 to 180 sec. Copyright © 2003 John Wiley & Sons, Ltd.     

Effects of the structures of polymerizable monomers on the electro‐optical properties of UV cured polymer dispersed liquid crystal films

Polymer dispersed liquid crystal (PDLC) films were prepared by photopolymerization of liquid crystal (LC)/polymerizable monomers/photoinitiator composites. The effects of the structures of the polymerizable monomers on the electro‐optical properties of PDLC films were investigated. It was found that the length of the molecular chain and the rigidity and flexibility of molecules influenced the structure of the polymer network in the PDLC films somewhat, and then affected the electro‐optical properties of the composites accordingly. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1369–1375, 2008     

Synthesis and properties of UV curable polyvinylsilazane as a precursor for micro‐structuring

Photosensitive acrylated polyvinylsilazanes were prepared by reacting a diacrylate containing compound, 1,1‐bis (acryloyloxyethyl) ethyl isocyanate (BAEI), with polyvinylsilazane (PVSZ) and utilized as an inorganic photoresist for generating SiCN‐based ceramic microstructures. The acrylate‐modified polymers (m‐PVSZ) were characterized by ¹H‐NMR, ¹³C‐NMR and FT‐IR methods to determine the chemical reaction mechanism. Differential photo‐calorimeter and FT‐IR analysis were employed to examine its photosensitive properties. Line patterns were fabricated by a UV nano‐imprinting method; multi‐layered octagon structures were fabricated by a two‐photon absorption stereolithography process. The results indicate that m‐PVSZ is quite a novel inorganic photoresist for the fabrication of micro ceramic structures. Copyright © 2015 John Wiley & Sons, Ltd.     

POP-290阻燃剂对丙烯酸酯光固化涂料的影响

制备了双酚A环氧丙烯酸酯(EA)/阻燃剂(POP-290,聚合物聚醚多元醇)/活性单体阻燃UV涂料,主要考察了不同用量的阻燃剂对丙烯酸酯UV涂料的阻燃性能和光固化的影响.研究结果表明,阻燃剂的使用提高了UV涂料体系的固化速度、凝胶含量及玻璃化转变温度(T_g).当m(EA):m(活性单体)=4:1,POP-290含量为7%(质量分数)时,水平燃烧等级达到FH-1,LOI从原来的21提高到26.     

UV curing kinetics and mechanism of a highly branched polycarbosilane

The UV curing process in both air and nitrogen atmosphere for the highly branched polycarbosilane system was investigated by differential scanning photo calorimeter. The UV cured products were characterized by Fourier‐transform infrared spectrometry (FTIR). By comparison with the FTIR results of the uncured liquid mixture and the cured samples, the possible cross‐linking reactions were determined. The kinetics of the curing systems was studied. The rate constant k was calculated based on the experimental results. The activation energies in different curing conditions were obtained. According to these results, it was learned that the mechanism for the UV curing in nitrogen was controlled by the photolysis of photoinitiator. Comparably, the UV curing process in air was complicated. It was affected by not only the photolysis of photoinitiator, but also oxygen and tripropane glycol diacrylate. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and properties of oxetane‐based polysiloxanes used for cationic UV curing coatings

The polysiloxanes end‐capped with oxetane group (PSiO‐H and PSiO‐L) were synthesized via hydrosilylation reaction based on α,ω‐dihydrogen‐terminated polydimethylsiloxanes with a higher (0.23%, PDSi‐H) and lower (0.12%, PDSi‐L) hydrogen amount. The molecular structures were characterized by FT‐IR and ¹H NMR spectroscopy. The polysiloxanes were added into a commercial oxetane‐based resin, 3,3′‐(oxydi(methylene)) bis(3‐ethyloxetane) (DOX), as an additive to prepare a series of cationic UV curable formulations. The photo‐DSC results showed that the maximum photopolymerization rate decreased while the oxetane conversion increased with the polysiloxane content increasing. The surface hydrophobic property of cured films was improved having the water contact angles of 97° and 99° compared with 82° of the cured DOX film with only 1 wt% PSiOs, respectively. The dynamic mechanical thermal analysis results showed that both the storage modulus on the rubbery plateau region and the glass transition temperature decreased with increasing PSiO‐H loading. Moreover, the decrease became more obvious as PSiO‐L was added instead of PSiO‐H due to its lower concentration of oxetane group. The thermal stability of cured films was enhanced by the addition of PSiOs from the thermogravimetric analysis. And the DOX/PSiO‐H film possessed higher thermal degradation temperatures than DOX/PSiO‐L film. Copyright © 2011 John Wiley & Sons, Ltd.     

Structure and properties of dynamically cured EPDM and ionomer blends

The structure and properties of dynamically cured ethylene-propylene-diene terpolymer (EPDM) and ionomer blends have been studied. The blends were prepared in a laboratory internal mixer, where EPDM was cured under shear in the presence of ionomer with dicumyl peroxide (DCP) under different shear conditions. The effects of EPDM/ionomer compositions, DCP concentration and the intensity of shear mixing were investigated using capillary rheometer, differential scanning calorimeter (DSC) and scanning electron microscopy (SEM) techniques. Two kinds of poly(ethylene-co-methacrylic acid) ionomers containing different metal ions(Na⁺ and Zn⁺⁺) were compared and the effect of the metal ion type for neutralization was considered. The Zn-neutralized ionomer showed better miscibility with EPDM than the Na-neutralized ionomer. It is concluded from the rheological properties, crystallization behavior and morphology that the dynamically cured EPDM and Zn-ion ionomer blends show the behavior of a thermoplastic interpenetrating polymer network (IPN).     

Kinetic model of diepoxides with reactive diluents cured with amines

The systems of diepoxides cured with primary amine in presence of an monoepoxide, monofunctional reactive, under equal stoichiometric ratio has been analyzed by a generating function method. The average degree of polymerization, which changed with time or conversion, and gel point were calculated. The profiles of the degree of polymerization and critical conversion are dependent on the content of and relative reactivities of epoxy groups. For a system with the same ratio, the critical epoxy conversion increases with increasing reactivity. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2339–2348, 1998     

Multimaterial hydrogel with widely tunable elasticity by selective photopolymerization of PEG diacrylate and epoxy monomers

We present a method to make continuous multi‐material structures from a monomer solution that becomes a soft hydrogel when exposed to blue light and a hard solid when exposed to UV light. We show that the material can be varied between a hard epoxy material to a several hundred times softer poly(ethylene glycol)‐diacrylate material. Moreover, the elastic properties of the material depend on both the wavelength of and exposure time of the light, which is used to produce a material with an elasticity gradient. We expect our material to find use in a range of fields, with immediate applications as 2D sheets with tunable mechanical properties for cell durotaxis studies, and 3D stereolithographically printed tissue mimicks, for example, for disease models and tissue engineering. Spatially resolved photo‐polymerization of a mixture of epoxy and acrylate monomers can be used to make multi‐material structure, with unique freedom to polymerize each monomer individually. The elastic compressive properties of the material are shown to be fully tunable from <100 kPa to >20 MPa depending on the light exposure time. This is used to make a functionally graded continuous material with a large variation in elastic properties. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1195–1201     

甲基丙烯酸二甲胺乙酯对光固化阴极电泳漆性能的影响

通过自由基共聚合得到丙烯酸树脂,然后用甲基丙烯酸异氰酸乙酯(MOI)对其改性,合成了既带有N,N-二甲胺基,又带有乙烯基的紫外光固化阴极电泳漆基体树脂。研究了甲基丙烯酸二甲胺乙酯(DMAE-MA)用量对改性丙烯酸树脂水分散体和漆膜性能的影响规律。结果表明,树脂分子链上引入DMAEMA后,其水分散性有较大改善,随DMAEMA用量增加,水分散体的粒径减小、粘度略有增加、稳定性增强,电泳沉积量和漆膜厚度增加,电泳沉积漆膜的初期含水率增加。综合考虑水分散体和漆膜的性能,丙烯酸树脂中DMAEMA质量分数以0．144左右为宜。     

固化条件对聚合物分散液晶膜电光性能的影响

选用聚乙二醇二缩水甘油醚(EGDE)/季戊四醇缩水甘油醚(PERTGE)/1,8-二氨基-3,6-二氧杂辛烷(EDBEA)/向列相液晶(SLC1717)复合体系,在不同的固化条件下,通过热聚合诱导相分离方法制备了一系列电光性能不同的聚合物分散液晶(polymer dispersed liquid crystal,简称PDLC)膜.研究了固化温度和固化时间对制备的PDLC膜中聚合物网络的微观形貌和电光性能的影响.结果表明,随着固化温度的升高以及固化时间的缩短,PDLC膜的对比度、驱动电压和开态响应时间逐渐增大,而关态响应时间逐渐减小.在固化温度为363.2 K,固化时间为7 h时,所制备的PDLC膜具有较佳的电光性能.