A novel epoxy methacrylate resin containing phthalazinone moiety for UV coatings

A novel phthalazinone modified epoxy acrylate resin for the high temperature resistant ultravioet (UV) curable coating was synthesized. The methacrylated epoxy resins obtained were utilized to UV radiation curing by taking 2.5% (wt%) of photoinitiator in combination with 20% (wt%) of diluent, and generated the interpenetraring polymer networks. The cured film had good thermal and chemical stability.     

木质素基环氧丙烯酸酯的合成及紫外光固化

正木质素是地球上一种储量十分丰富的可再生资源,可生物降解[1,2].木质素结构中含有大量羟基,主要以酚羟基和醇羟基形式存在,可与许多化合物发生化学反应制得木质素基环保材料,是最有前途的生物质资源之一[3].但工业木质素纯度较低,对其利用多为直接混合,如水泥减水剂等低端领域.环氧丙烯酸酯(EA)作为紫外光固化的预聚体,在紫外光照射下可快速固化,其黏接性高,耐化学药品性能优异,应用广泛[4,5].因此降低EA的成本,对其进行改性是近年来该领域的研究热点[6].本文以工     

Synthesis of an epoxy functionalized spiroorthocarbonate used as low shrinkage additive in cationic UV curing of an epoxy resin

The synthesis of an epoxy functionalized spiroorthocarbonate (SOC) is reported. The obtained monomer has been used a slow shrinkable additive in cationic UV curing of a commercially available dicycloepoxy resin. A polymer network flexibilization was evidenced by increasing the SOC content in the photocurable formulation. It has been demonstrated that SOC acts as shrinkage reduction additive reaching expansion on volume after polymerization in the presence of 10 wt% of the functionalized spiroorthocarbonate.     

UV‐curable acrylate‐based nanocomposites: effect of polyaniline additives on the curing performance

Composites of nanostructured polyaniline (PANI) conducting polymer in a polyester acrylate (PEA) formulation were made to provide conductive organic coatings. The effect of the presence and amount of PANI on the photocuring performance of the ultraviolet (UV)‐curable acrylate system has been investigated employing real‐time Fourier transform infrared spectroscopy as the main technique. Longer initial retardation of the radical polymerization and lower rates of cross‐linking reactions were observed for dispersions containing PANI of higher than 3wt.%. The PEA/PANI samples were more affected than the neat PEA resin by the changes in UV light intensity and oxygen accessibility during UV curing. Samples with higher PANI content, of up to 10wt.%, were tested and could be partially cured even at UV light intensities as low as 2 mW cm^?2 when the oxygen replenishment into the system was inhibited. Thermal analysis revealed that the presence of PANI did not induce any significant change in Tg of the cured system, meaning that early decrease in mobility and vitrification is not the reason for lower ultimate conversion of the dispersions with higher PANI content compared with the neat PEA resin. Curing under strong UV lamps, of 1.5 W cm^?2 intensity, made it possible to reach high degrees of conversion on films with similar mechanical properties independent of the PANI content. Copyright © 2013 John Wiley & Sons, Ltd.     

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.     

Effect of monoacrylate type in UV curable PU acrylate based bicontinuous polymer/liquid crystal networks

Polymer network liquid crystals (PNLC) have been prepared from ultraviolet-curable polyurethane acrylate (PUA) and a nematic liquid crystal mixture (BL002). Effects of monoacrylate type on film morphology, temperature-dependent off-state transmittance, and electro-optic performance of the film have been studied. Among three types of monoacrylates incorporated (EHA(2-ethyl hexyl acrylate), MMA (methylmethacryalte), NVP (N-vinylpyrrolidone)), EHA-based PUAs gave the greatest polymer–LC phase separation, lowest threshold (V₁₀), and operating (V₉₀) voltages, and the effect was more pronounced in monoacrylate/triacrylate systems than in monoacrylate/diacrylate systems. Contact angle measurement offers a clue to the observed morphology and electro-optic behavior. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1393–1399, 1998     

Surfactant assisted dispersion of MWCNT's in epoxy nanocomposites and adhesion with aluminum

This article presents an experimental investigation into the adhesion between aluminum and epoxy nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT's). The nanotubes are dispersed in epoxy chemically with the aid of a surfactant, rather than mechanically via high shear mixing or ultrasonication. Four MWCNT weight fractions are considered viz. 0%, 0.1%, 0.5% and 1%. The adhesion with aluminum is tested via end-notched flexure tests conducted on specimens consisting of Aluminum strips adhered together with various epoxy nanocomposite glues. The best results are obtained for 1% MWCNT, where the tests show a notable increase in adhesion, evidenced by an intact bond despite considerable plastic deformation of Aluminum. However, the peak load capacity is seen to be not enhanced. The higher adhesion with 1% MWCNT addition is seen to successfully suppress the brittle debonding failures even at very high levels of adherend plasticity. For this weight fraction the overall response is highly ductile involving shearing of the glue and is desirable for engineering applications. Despite promising results, the surfactant itself is seen to be not very effective as a dispersing agent for the epoxy resin considered here.     

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.     

UV assisted photo reactive polyether-polyesteramide resin for future applications in 3D printing

Among additive manufacturing, photocuring 3D printing technologies are very relevant because of its high printing speed and high precision. However, the limited performance of photosensitive thermoset polymers is the bottleneck for the application of photocuring 3D printing in some fields, particularly in the biomedical sector. Thus, the development of biodegradable and biocompatible materials is highly desirable and of utmost importance. In this work, a biodegradable and non-cytotoxic thermoset polymer for photocuring 3D printing is reported. It consists of an unsaturated polyesteramide bearing phenylalanine, 2-butene-1,4-diol and fumarate building blocks, which is photocured under UV irradiation using a low molecular weight poly(ethylene glycol) diacrylate as crosslinker. The main characteristics of the new thermoset are: (1) very high volumetric and mechanical integrity stabilities, comparable to that of photocured epoxides; (2) very high degradation temperature; (3) very low water absorption capacity; (4) relatively fast enzymatic degradation, reaching 16.5% after 3 months; and (5) non-cytotoxic response in presence of epithelial cells, even when soluble molecular fragments coming from biodegradation are considered. These properties favor the future utilization of the new polyether-polyesteramide resin in the manufacturing of more sustainable products via 3D printing methods, such as stereolithography, that uses UV sources.     

Hyperbranched Polyurethane Acrylate Applied to UV Curable Flame Retardant Coatings

UV curable hyperbranched prepolymers based on amine-ester, ester-amide and ether-amide started with AB_2-type monomers have been prepared by the authors. A series of work on allyl ether maleate hyperbranched polyesters for UV curing coatings by Hult and his colleagues has been reported. However, the UV cured films from those materials are all flammable when attached to fire without addition of flame retardants. In this work, a new kind of hyperbranched polyurethane acrylate containing phosphorus     

Vegetable oil-based flame retardant epoxy/clay nanocomposites

Flammability of epoxy appears to be one of the greatest threats and hence limits its advanced applications. The present investigation, therefore, reports on vegetable oil-based self-extinguishing epoxy/clay nanocomposites for the first time. These nanocomposites were prepared by the ex-situ technique using mechanical shearing and ultrasonication at different loadings (1, 2.5 and 5 wt%) of nano-clay. Monoglyceride of Mesua ferrea L. seed oil, bisphenol-A and tetrabromobisphenol-A based epoxy resin was used as the matrix. XRD, TEM, SEM, FTIR and rheological studies confirmed partially exfoliated nanocomposites formation. The study demonstrates two fold improvements of tensile strength and scratch hardness, three-fold increase in adhesive strength and 20 units increase in gloss value without any change in impact resistance through nanocomposite formation. TG studied confirmed the enhancement of thermal stability of the nanocomposite by 25 °C. The limiting oxygen index values and UL 94 test indicated the self-extinguishing characteristic of the nanocomposites.     

UV curable electrodeposition systems

This article reviews the development of a UV curable electrodeposition system. Tailor-made acrylic functionalized polyurethane resins, which have been designed, are described and basic properties of the final e-coat system are shown. In addition several fundamental studies have been performed in order to analyze as well the homogeneity of the deposition as the efficiency of the UV curing process.     

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.     

Photo - DSC and real time - FT-IR kinetic study of a UV curable epoxy resin containing o-Boehmites

Nanocomposite coatings based on a cycloaliphatic epoxy resin (3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexane carboxylate - CE) with two different o-Boehmites (content ranging from 5 to 10 wt.%) were prepared by cationic photopolymerization. Two different in situ monitoring techniques, photocalorimetry (p-DSC) and real time FT-IR spectroscopy (RT-IR) were used in order to investigate the kinetics of the photopolymerization process. A theoretical approach for establishing the equivalence of the irradiation conditions in the two experimental set-ups was developed in order to compare the obtained results.A substantial correspondence of the two techniques was found for the qualitative trend of the final conversion of the epoxy groups of the filled formulations relatively to the pure CE resin. Conversely, the final conversion of the epoxy groups and the reaction rate were found to be quite different. Higher kinetic profiles were obtained in RT-IR experiments, in which were also observed lower final conversions of the epoxy groups relatively to the p-DSC measurements. The presence of the nanofillers resulted in a decrease in the reactivity of the epoxy system, which was attributed to the light absorbance of Boehmites due to scattering from the clusters in the micron-size range.All the nanocomposites exhibited a high level of transparency and high T_g values, which were found to decrease slightly with increasing the nanofiller content.     

Polymeric photoinitiators based on side-chain benzoin methyl ether and tertiary amine moieties for fast UV curable coatings

The synthesis is reported of a new series of polymeric photoinitiators obtained by copolymerization of a-methylolbenzoin methyl ether acrylate (MBA) with different N,N-dialkylamino alkyl acrylates. The copolymers have been fully characterized and employed in the photoinitiated polymerization and crosslinking reactions of a standard acrylic formulation for clear curable coatings. The photoinitiation activity of the above systems has been measured by using microwave dielectrometry and differential photocalorimetry, and compared with that found for the corresponding low-molecular-weight models. The results clearly indicate that the copolymeric systems display a remarkable decrease of the induction period and an improved overall activity in the UV curing of the acrylic coatings. An interpretation of the experimental findings is also reported.     

Surface molecular characterisation of different epoxy resin composites subjected to UV accelerated degradation using XPS and ToF-SIMS

Epoxy resin composites reinforced with E-glass (E), 3D glass (3D) and carbon fibre (CF) were subjected to an intense UV and high temperature accelerated degradation environment. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to provide a molecular characterisation of the surface of the degraded composites. The response at the surface of the epoxy resin composites to oxidative degradation is influenced by the composite reinforcement type and characteristics. XPS results indicate that 3D resin composites exhibit more surface oxidation as a result of the accelerated degradation in comparison with E and CF composites. Principal components analysis (PCA) of the ToF-SIMS positive ion spectra showed that E and 3D resin composites suffered chain scission while CF composites suffered chain scission and cross-linking reactions as a result of the intense UV exposure. The extent of the surface oxidation, cross-linking/condensation reaction and loss of low molecular weight (lower than C₄H_x) aliphatic hydrocarbons may be indicated using PCA of both the ToF-SIMS positive and negative ion spectra. PCA also provides insight for proposing epoxy resin chain scission and oxidation reaction mechanisms.     

混杂光固化体系的原理及应用

混杂光固化或双重固化是指在同一体系中采用两种或两种以上不同类型的聚合反应来使体系固化的方法,它是原位改性高分子的一种新方法.混杂光固化体系包括自由基-阳离子混杂光固化体系、自由基-缩聚混杂体系和自由基-自由基混杂体系等.本文综述了混杂光固化体系的原理及其应用.     

紫外光固化脂环族环氧丙烯酸酯涂料的制备及性能

通过丙烯酸（AA）与脂环族环氧树脂的开环反应合成了可紫外光（UV）固化的脂环族环氧丙烯酸酯树脂（CEA）。采用红外光谱（FT-IR）对树脂结构进行了表征,研究了反应温度、反应时间对产率的影响。用活性稀释剂与CEA制备了涂料预聚物,用转板黏度计测定了预聚物的黏度,采用差示扫描量热（DSC）仪、综合热分析仪和铅笔硬度计对树脂固化膜进行了分析。结果表明：当丙烯酸与环氧基团摩尔比为1.03,120°C下反应25.8 h时,反应转化率可达96.58%。CEA固化膜的玻璃化转变温度为64°C,初始分解温度为314°C,活性稀释剂的加入增强了固化膜的耐热性,固化膜铅笔硬度可达6H。     

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.     

Exploitation of introducing of catalytic centers into layer galleries of layered silicates and related epoxy nanocomposites. I. Epoxy nanocomposites derived from montmorillonite modified with catalytic surfactant‐bearing carboxyl groups

Montmorillonite (MMT) was modified with the acidified cocamidopropyl betaine (CAB) and the resulting organo‐montmorillonite (O‐MMT) was dispersed in an epoxy/methyl tetrahydrophthalic anhydride system to form epoxy nanocomposites. The intercalation and exfoliation behavior of the epoxy nanocomposites were examined by X‐ray diffraction and transmission electron microscopy. The curing behavior and thermal property were investigated by in situ Fourier transform infrared spectroscopy and DSC, respectively. The results showed that MMT could be highly intercalated by acidified CAB, and O‐MMT could be easily dispersed in epoxy resin to form intercalated/exfoliated epoxy nanocomposites. When the O‐MMT loading was lower than 8 phr (relative to 100 phr resin), exfoliated nanocomposites were achieved. The glass‐transition temperatures (T_g's) of the exfoliated nanocomposite were 20 °C higher than that of the neat resin. At higher O‐MMT loading, partial exfoliation was achieved, and those samples possessed moderately higher T_g's as compared with the neat resin. O‐MMT showed an obviously catalytic nature toward the curing of epoxy resin. The curing rate of the epoxy compound increased with O‐MMT loading. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1192–1198, 2004