Epoxy Diacrylate Research Articles

Photoacoustic spectroscopy applied in the monitoring of photocuring process in epoxy diacrylate resins: Positive effect

AbstractThe main goal of this study is to show that photoacoustic spectroscopy (PAS) can be applied in the monitoring of photocuring processes in epoxy diacrylate resins. The resin used was EBECRYL 3720‐TP25 with the photoinitiator Omnirad 808. Comparison between the conventional transmission and absorption photoacoustic spectra of the resin is presented. Amplitude and phase of the photoacoustic signal were used to monitor the photocuring. The wavelength of the modulated photocuring light and the concentration of the photoinitiator were the parameters varied in the monitoring. The novelty was found when the resin was irradiated by a continuous light, centered at the absorption peak of the photoinitiator and simultaneously with the modulated light. In the time window when this continuous light was on (off) the amplitude of the photoacoustic signal increased (decreased). This is called “positive effect,” as it has been observed when PAS was applied to study photosynthesis in leaves. A mechanism is proposed to correlate the positive effect with the oxygen inhibition effect during the photocuring of the epoxy diacrylate resin. The results suggest that the amplitude of the photoacoustic signal and the positive effect can be used as monitoring parameters in the studies of photocuring process in epoxy diacrylate resins.

Influence of TAS on photocrosslinking of the coatings on the base of acrylate, epoxide oligomers and monomers

AbstractThe influences of the triarylsulfonium hexafluoroantimonate salts (TAS) content in the range from 1 to 9 % of the total resin and monomer weight on photocrosslinking and properties of UV‐cured coatings based on epoxy diacrylate (EDA), hexanediol diacrylate (HDDA), epoxy resin modified by castor oil (CE) and 3,4‐epoxycyclohexyl‐methyl 3,4‐epoxycyclohexane carboxylate, a biscycloaliphatic diepoxide (BCDE), have been studied. It was shown that under UV‐exposure, photoinitiated radical polymerization of acrylate groups of EDA, HDDA and cationic polymerization of epoxy groups of CE, BCDE occurred very fast, leading to formation of interpenetrating polymer networks. The relationship between TAS content and polymerization of epoxy, acrylate groups as well as performance of UV‐cured coatings had optimal particularity with highest conversion rate of the groups and properties of the cured coatings containing 5 and 7 % of TAS.

Influence of CaCO3 on photocrosslinking and properties of UV‐cured coatings based on an epoxy diacrylate resin and hexanediol diacrylate

AbstractEffects of CaCO3 content on photocrosslinking and properties of UV‐curable coatings based on epoxy diacrylate resin (EDA), hexanediol diacrylate (HDDA) and photoinitiator I.184 have been studied. It was found that in investigated coatings with the weight ratio EDA/HDDA/I.184 = 50/50/3, CaCO3 content in the range of 10‐40 % provided fine and smooth films in used substrates. The presence of CaCO3 significantly reduced conversion of acrylate groups and quality of the UV‐cured coatings in comparison with the neat one. The increase of CaCO3 content slowed down the photocrosslinking process and inconsiderably affected to properties of investigated coatings in its range of 10‐20 %, but led to obvious decrease of their impact resistance and gloss in its further augment up to 40 %. Coating containing optimal CaCO3 content of 20 % from technical and economical points of view was determined to have gel fraction, relative hardness and gloss of 60o of 90 %; 0.94 %; 92.3 % after 2.4s of UV‐exposure, respectively.

Preparation of 3DPSL-1 Type Photosensitive Resin and Study on Its Properties

3DPSL-1(3D printing stereolithography No.1) type photosensitive resin was prepared with 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate (ERL-4221), bisphenol A type epoxy diacrylate (DH-306), tripropylene glycol diacrylate (TPGDA), Diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate(TDE-85), triethylene glycol divinyl ether (DVE-3), benzil dimethyl ketal (Irgacure651) and a mixture of triarylsulfonium hexafluoroantimonate salts (UVI-6976) as raw materials. Some properties of the photosensitive resin were investigated. The viscosity of the photosensitive resin at 30 ℃ was 355mPa.S, the glass transition temperature (Tg) of the UV-cured specimen was 52 ℃, and the weight loss of the UV-cured specimen at 200 ℃ was less than 4%. The photosensitive resin and its UV-cured specimen were also characterized by infrared (IR).

Preparation of a novel hybrid type photosensitive resin for stereolithography in 3D printing and testing on the accuracy of the fabricated parts

A novel hybrid type photosensitive resin for stereolithography in 3D printing was prepared with bisphenol A type epoxy diacrylate (EA-612), tripropylene glycol diacrylate (TPGDA), ethoxylated trimethyolpropane triacrylate(EO3TMPTA), cycloaliphatic diepoxide(ERL-4221), polycaprolactonepolyol(Polyol-0301),1-hydroxy-cyclohphenyl ketone(Irgacure184), and a mixture of triarylsulfonium hexafluoroantimonate salts (Ar3SSbF6). The novel hybrid type photosensitive resin was the photosensitive resin of an epoxy-acrylate hybrid system, which proceeded free radical polymerization and cationic polymerization in ultraviolet (UV) laser. Cuboid parts and double-cantilever parts were fabricated by using a stereolithography apparatus with the novel hybrid type photosensitive resin as the processing material, and the dimension shrinkage factor and the curl factor were tested. The shrinkage factor was less than 2.00%, and the curl factor was less than 8.00%, which showed that the accuracy of the fabricated parts was high with the photosensitive resin for stereolithography in 3D printing.

A Study of the Curing and Flammability Properties of Bisphenol A Epoxy Diacrylate Resin Utilizing a Novel Flame Retardant Monomer, bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl Phosphate.

A UV-curable, flame-retardant monomer, DAPP (bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl-phosphate), was synthesized based on BPDCP (4-tert-butylphenyl-dichloro phosphate) and HEA (2-hydroxy ethyl acrylate). DAPP was blended with regular bisphenol A epoxy acrylate (BAEA) in various ratios to yield various phosphorus contents. The TGA-IR (thermogravimetric analyzer interface with an infrared spectrometer) results demonstrate that compounding 30 mol % DAPP with BAEA significantly reduced the amount of released CO gas. In contrast, the peak intensity of CO2 is independent of phosphorus content. The limiting oxygen index (LOI), reaching the saturated value of 26, and the heat release rate (HRR) measured using a cone-calorimeter, 156.43 KW/m2, confirm the saturation point when 30 mol % DAPP was compounded into BAEA. A study of the kinetics of pyrolysis reveals that Ea decreases as the phosphorus content increases. Both the TGA-IR and pyrolysis results reveal that the phosphorus compound DAPP is easily decomposed during the initial stage of burning to form an insulating layer, which inhibits further burning of the resin and the consequent release of other flammable gases.

Photo-DSC Investigation of Acetonaphthone Type Photoinitiators at Different Light Intensities

The gelation of a 75% epoxy diacrylate (EA) and 25% tripropyleneglycol diacrylate (TPGDA) mixture (P-3038) was performed using 2-(N-methyl-N-phenyl)acetonaphthone (MPA) and morpholino acetonaphthone (MPM) as Type I photoinitiators at different light intensities by using a photo-differential scanning calorimetric (Photo-DSC) technique. Identical temperature values and initiator concentrations were used for the photopolymerization reactions. The results show that maximum rate of polymerization (Rpmax) and final conversion values present good correlation at different light intensities.

Refractive index increase of acrylate‐based polymers by adding soluble aromatic guest‐molecules

This work presents the influence of dopants on viscosity in an uncured liquid state as well as on refractive index, Abbe number, optical loss, and glass transition temperature of different polymer compositions. The base material consists of Genomer 2263, a bisphenol, an epoxy diacrylate as matrix polymer, and benzyl methacrylate as comonomer. As dopants, the soluble aromatic guest‐molecules 9‐bromophenantrene and 9‐vinylcarbazole are investigated. The viscosity can be adjusted by different mixtures of the matrix polymer and comonomer from 3000 down to 4 mPa sec. Depending on the type and content of the dopants, the refractive index, Abbe number, and the glass transition temperature can be adjusted. The refractive indices increase linear at 589 nm and 20°C from 1.572 to 1.638 by doping, with Abbe numbers between 20 and 30. At this wavelength, the optical losses were determined to be around 2 dB · cm−1. The glass transition temperature can be tailored between 50 and 98°C. A way to use high amounts of optical dopants is presented, which opens up the way for different shaping technologies like inkjet printing of optical components. Copyright © 2016 John Wiley & Sons, Ltd.

Synthesis and characterization of polymerizable epoxy resin surfactants

ABSTRACTPolymerizable epoxy resin (PER) surfactants have been prepared from the reaction of bisphenol A epoxy resin with acrylic acid, followed by the reaction with polyethylene glycol (PEG) with different molecular weights. The reaction procedures were monitored by chemical titrations, infrared spectroscopy, and NMR. The products show typical surface‐active properties as but much higher water solubility than nonpolymerizable nonionic surfactant OP‐10. With the increase of PEG's molecular weight, the HLB value, the water solubility, and the critical micellar concentration (CMC) of the PER surfactants, the cloud point of the PER surfactant solutions, as well as the solubilization capability of the PER surfactants to organic compounds increase under the experimental conditions. The copolymerization under UV radiation indicated that about 75–80 wt % of PER surfactants participated in the copolymerization with epoxy diacrylate (EdA), except for the PER surfactant with the lowest PEG molecular weight of 1 k. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42598.

The Influence of Reactive Diluents on the Properties of UV Dual Cured Polyurethane-Modified Epoxy Monoacrylates Films

The UV-curable liquid compositions were developed with different oligomers (epoxy diacrylates, EDA; epoxy monoacrylates, EMA; or polyurethane-modified epoxy monoacrylates, PMEMA), reactive diluents and photoinitiators. Thin films were prepared by curing these mixtures using a high pressure mercury lamp. The change of absorption peaks of double bond and epoxy group were identified by Fourier Transform Infrared (FTIR) spectra during UV dual curing process. Gel content, mechanical, volume shrinkage and thermal characterizations of the UV-cured films were investigated. The gel content, youngs modulus and stress at break turned to maximum values as the degree of polymerization achieved the maximum value, except for the strain at break. The flexibility of UV dual cured films using PMEMA as oligomer was improved due to grafting of the soft chain segments (polyurethane). The volume shrinkage test indicated that the UV dual cured films exhibited lower internal stress and higher cohesive force than simple radical UV cured films. The thermogravimetric analysis of UV cured films revealed that UV dual cured films prepared from PMEMA showed excellent thermal stability.

Enhancement of barrier property of plastic substrate by intra-gallery polymerization for nanocomposites

2-(Methacryloyloxy)ethyl(4-benzoylbenzyl) dimethyl ammonium bromide (MDAB) was successfully synthesized and used as a photo initiator and intercalation agent to induce intra-gallery polymerization. MDAB effectively replaced the sodium ions in the inter-gallery layer of sodium montmorillonite (Na+-MMT) by the cationic exchange reaction, which was confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The modification of Na+-MMT with MDAB increased the d-spacing, with the MDAB/Na+-MMT ratio of 2:1 doubling the initial d-spacing. Clay with modified MDAB was used to make a nanocomposite layer formation on a poly(ethylene naphthalate) (PEN) substrate by the photopolymerization of bisphenol A type epoxy diacrylate (EpA). Intra-gallery polymerization using MDAB attained more effective intercalation and better dispersion of the clay than extra-gallery polymerization using commercial organoclay. The clay content affected the barrier properties, and the best result was obtained at 5 wt% clay content, producing a water vapor transmission rate (WVTR) of 0.39 g/m2 day while maintaining the optical transmittance. Open image in new window

Kinetics of free radical polymerization of bisphenol A diglycidyl ether diacrylate initiated by barbituric acid

Non-isothermal radical polymerization kinetics for barbituric acid (BTA)/epoxy diacrylate (EA) and benzoyl peroxide (BPO)/EA (serving as the reference) in NMP were investigated. The DSC data showed that the activation energy of the polymerization of EA initiated by BTA was much lower than that initiated by BPO. For polymerizations of BTA/EA and BPO/EA except BPO/EA=3/100 (w/w), the reaction mechanism involving nucleation, followed by nucleus growth in the first stage was proposed. For the polymerization of BPO/EA [3/100 (w/w)], the reaction system was adequately described by the instantaneous nucleation and nucleus growth mechanisms in the first stage. Moreover, the nucleation and subsequent growth of microgel nuclei were primarily governed by the propagation reaction and diffusion-controlled termination reaction for the polymerization system of BTA/EA or BPO/EA. In the second stage (in the conversion range 0.75–0.90), the diffusion-controlled propagation and termination reactions governed the development of highly crosslinked macrogel (i.e., macroscopic agglomerate).

A dual electrochemical microsensor for simultaneous imaging of oxygen and pH over the rat kidney surface

In this study, a dual microsensing electrochemical probe for measuring oxygen (O2) and pH levels was developed based on a dual recessed Pt disk electrode (each disk diameter, 10 μm) with the use of two Ag/AgCl reference electrodes (one for each disk of the dual electrode). One of the recessed Pt disks of the dual electrode was electrodeposited with a porous Pt layer and then coated with a hydrophobic photocured polymer (partially fluorinated epoxy diacrylate, abbreviated as FED). The Pt-FED covered disk was used as an amperometric O2 sensor and exhibited a linear current increase that was proportional to the PO2 level (partial O2 pressure) with high sensitivity (168.4 ± 33.8 pA mmHg(-1)) and fast response time (t90% = 0.17 ± 0.05 s). The other recessed Pt disk was electrodeposited with an IrO2 layer. The potential between the IrO2 deposited electrode and the Ag/AgCl reference electrode produced a reliable Nernstian response to pH changes (58.3 ± 1.5 mV pH(-1)) with a t90% of 0.43 ± 0.09 s. The sensor displayed high stability in the in vitro organ tissue measurements for at least 2.5 h. By using the developed dual O2/pH microsensor as a probe tip for scanning electrochemical microscopy, the two-dimensional images of the location-dependent PO2 and pH levels were simultaneously acquired and could be used to assess the surface of a rat kidney tissue slice. When compared to the corresponding medullary levels, both PO2 and pH were observed to be higher in the cortex area, while the modest level gradient was observed near the cortex-medulla border. This finding suggests that there is a direct relationship between the tissue O2 supply/consumption and pH, which is mainly determined by metabolite, such as CO2, production.

Preparation of RPSL-02 Type Photosensitive Resin for Stereolithography Material and Investigation on its some Properties

RPSL-02 type photosensitive resin for stereolithography material was prepared with 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate (UVR 6110), bisphenol A type epoxy diacrylate (EA-612), trimethyolpropane triacrylate (TMPTA), polycaprolactone polyol (polyol-0301), triethylene glycol divinyl ether (DVE-3), benzil dimethyl ketal (Irgacure651) and a mixture of triarylsulfonium hexafluoroantimonate salts (UVI-6976) as raw materials. Some properties of the photosensitive resin were investigated. The viscosity of the photosensitive resin at 30°C was 395mPa.S, The glass transition temperature (Tg ) of the UV-cured specimen was 52°C, and the weight loss of the UV-cured specimen at 200°C was less than 5%. The photosensitive resin and its UV-cured specimen were also characterized by infrared (IR).

Producing critical exponents from gelation for various photoinitiator concentrations; a photo differential scanning calorimetric study

Photoinitiated radical polymerization of an 80wt% epoxy diacrylate (EA) and 20wt% tripropyleneglycoldiacrylate (TPGDA) mixture with various 2-Mercaptothioxanthone (TX-SH) photoinitiator concentrations was studied by using photo-differential scanning calorimetric (Photo-DSC) technique. Photopolymerization reactions were carried out under the same conditions of temperature and light intensity. It was observed that all conversion curves during gelation at various photoinitiator concentration present nice sigmoidal behavior which suggests application of the percolation model. The critical time, where polymerization reaches the maximum rate (Rpmax) is called the glass transition point (tg). The gel fraction exponents, β were produced from the conversion curves around tg. The observed critical exponents were found to be around 0.55, predicting that the gel system obeys the percolation model. Rpmax and final conversion (Cs) values were found to be increased as the photoinitiator concentration was increased. On the other hand tg values decreased as photoinitiator concentration was increased, indicating higher TX-SH concentration causes early glass transition during radical polymerization.

Critical phenomenon during photoinitiated gelation at different temperatures: A Photo-DSC study

The behaviour of photoinitiated radical polymerization of an 80wt% epoxy diacrylate (EA) and 20wt% tripropyleneglycoldiacrylate (TPGDA) mixture with 2-mercaptothioxanthone (TX-SH) photoinitiator was studied at different temperatures by using photo-differential scanning calorimetric (Photo-DSC) technique. All photopolymerization reactions were carried out under the same conditions. It was observed that all conversion curves during gelation at different temperatures present nice sigmoidal behaviour which suggests the application of the percolation model. Observations around the critical time, called the glass transition point (tg), taken to reach the maximum rate of polymerization (Rpmax) show that the gel fraction exponent (β) obeyed the percolation model. The produced β values were found to be around 0.50, predicting that the system under consideration belongs to the same universality class. However, Rpmax and the final conversion (Cs) values were found to increase when the temperature was increased up to a certain value. On the other hand, tg values decreased and became saturated as the temperature was increased.

Synthesis and photoinitiating activity study of polymeric photoinitiators bearing BP moiety based on hyperbranched poly(ester‐amine) via thiol‐ene click reaction

AbstractA series of polymeric photoinitiators (BP‐HPEAs) bearing BP moiety based on hyperbranched poly(ester‐amine) were synthesized via the thiol‐ene click reaction of 3‐(4‐benzoylphenoxy)propyl 2‐mercaptoacetate (BPPM) with acrylated HPEA. BPPM was obtained by the esterification of (4‐(3‐hydroxypropoxy) phenyl) phenyl methanone (HPPM) with mercaptoacetic acid in the presence of p‐toluene sulphonic acid as a catalyst. HPEA was prepared through Michael addition of piperazine with tri(hydroxymethyl)propane triacrylate. Their molecular structures were confirmed by the 1H NMR, 13C NMR, and FTIR analysis. The UV–vis spectrum analysis results showed that BP‐HPEAs exhibit the stronger n–π* absorption at ∼ 340 nm with over two times higher molar extinction coefficients than BP at the concentration of 1.00 × 10−3M. The photoinitiating activity study showed that the maximum photopolymerization rates of 1,6‐hexanediol diacrylate initiated by BP‐HPEAs in the absence of coinitiator were obtained by two times higher than that by BP in the presence of triethylamine as a coinitiator. Moreover, the excellent miscibility of BP‐HPEAs with the commercial bisphenol A epoxy diacrylate was achieved according to the Ts/Tg ratios of over 9.0 from DMTA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Preparation of RPSL-01 Type Photosensitive Resin for Stereolithography and Study on its some Properties

RPSL-01 type photosensitive resin for Stereolithography was prepared with 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate (UVR 6110), bisphenol A type epoxy diacrylate (EA-612), tripropylene glycol diacrylate (TPGDA), pentaerythritol triacrylate(PETA), triethylene glycol divinyl ether (DVE-3), benzil dimethyl ketal (Irgacure651) and a mixture of triarylsulfonium hexafluoroantimonate salts (UVI-6976) as raw materials. Some properties of the photosensitive resin were investigated. The viscosity of the photosensitive resin at 30°C was 425mPa.S, The glass transition temperature (Tg ) of the UV-cured specimen was 47°C, and the weight loss of the UV-cured specimen at 200°C was less than 5%. The photosensitive resin and its UV-cured specimen were also characterized by infrared (IR).

Photopolymerization behavior and properties of highly branched poly(thioether-urethane) acrylates used for UV-curing coatings

Abstract The highly branched poly(thioether-urethane) acrylate (BPTUA) was synthesized through an “oligomeric A 2 + B 3 ” approach. The thiol-endcapped difunctional oligomeric A 2 was obtained by the addition reactions of isophorone diisocyanate with 1,4-butanediol, and then further with 1,4-butanediol bis(thioglycolate). Trimethylolpropane triacrylate was used as a B 3 monomer. The addition conduct of 1,6-hexanediol diacrylate with 1,4-butanediol bis(thioglycolate) was introduced into the polymeric chain for preparing the modified BPTUA (m-BPTUA). The molecular structures were characterized with FT-IR and 1 H NMR spectroscopy, and GPC analysis. The number average molecular weights ( M n s) of BPTUA and m-BPTUA were experimentally measured to be 13,500 g mol −1 and 17,900 g mol −1 with the polydispersity indices of 1.86 and 1.94, respectively. A series of UV-curable resins were fabricated based on bisphenol-A epoxy diacrylate (EB600) and tripropylene glycol diacrylate with the addition of either BPTUA or m-BPTUA in different ratios, and exposed to a UV lamp for obtaining the cured films in the presence of 1-hydroxycyclohexylphenyl ketone as a photoinitiator. From the photo-DSC measurements, the polymerization rate at the peak maximum decreased, whereas the final unsaturation conversion in cured film increased, along with the increase of either BPTUA or m-BPTUA. The elastic modulus in the rubbery plateau and the glass transition temperature from DMTA, as well the tensile strength and Young's Modulus of UV-cured film decreased with increasing either BPTUA or m-BPTUA loading, whereas the elongation at break, flexibility and strike performance were greatly enhanced. Moreover, for the m-BPTUA series, the enhancive effects on the properties were much more obviously than the BPTUA series. The water swelling test and thermogravimetric analysis indicated that the water absorption resistance and the oxidative stability of cured films were improved by the incorporation of thioether linkage into the crosslink networks.

Preparation of HBWSL-1 Type Photosensitive Resin for Stereolithography and Study on the Accuracy of its Fabricated Parts

HBWSL-1 type photosensitive resin for Stereolithography was prepared with bisphenol A type epoxy diacrylate (EA-612), polyethene glycol (200) diacrylate (PEGDA), ethoxylated trimethyolpropane triacrylate (EO3TMPTA), cycloaliphatic diepoxide (ERL-4221), polycaprolactone polyol(Polyol-0301), 1-hydroxycyclohexyl phenyl ketone (Irgacure184) and a mixture of triarylsulfonium hexafluoroantimonate salts (UVI-6976). The main parameters of the photosensitive resin were as follows: the penetration depth was 0.15mm, the critical exposure was 16.6mJ/cm2, the viscosity at 30°C was 215mPa.s, and the density at 30°C was 1.13g/cm3. With the photosensitive resin as the processing material, cuboid parts and double-cantilever parts were fabricated by using a stereolithography apparatus, and the dimension shrinkage factor and the curl factor were studied. The shrinkage factor was less than 1.00%, and the curl factor was less than 8.00%, which showed that the accuracy of the fabricated parts was high with the photosensitive resin for stereolithography.