Acrylate-based photosensitive resin for stereolithographic three-dimensional printing

In this article, we report an acrylate-based three-dimensional (3D) printing stereolithography rapid-prototyping photosensitive resin with a low viscosity, small volumetric shrinkage, high photoreactivity, and excellent strength. The resin was a compound prepared with bisphenol A epoxy acrylate (BAEA) as the main matrix, 1,6-hexanediol diacrylate (HDDA) and tri(propylene glycol) diacrylate (TPGDA) as reactive diluents, pentaerythritol triacrylate (PETA) as the crosslinking agent, and 2-hydroxy-2-methyl propiophenone (1173) and diphenyl(2,4,6-trimethyl benzoyl)phosphine oxide (TPO) as photoinitiators. The photocuring kinetics of the resins with different photoinitiator types and loadings were studied via real-time IR spectroscopy, which provided insights into the optimization of photoinitiator composition and printing parameter settings. The results show that the content change of each component affected the viscosity of the photosensitive resin; this was accompanied by fluctuations in the volume shrinkage and mechanical strength of the cured products. Although an increase in the molar ratio of the reactive diluent remarkably reduced the viscosity of the photosensitive resin and thereby boosted photopolymerization, it also caused an increase in the volume shrinkage and a sacrifice of mechanical strength. Finally, as shown by a comparison of the other samples we studied, the resin composed of 30 mmol HDDA, 50 mmol TPGDA, 10 mmol PETA, 10 mmol BAEA, 2.5 mol % TPO, and 2.5 mol % 1173 achieved the best viscosity of 239.53 mPa s at 25 °C, the minimum shrinkage rate of 4.36%, and the maximum tensile strength of 43.19 MPa. The 3D printing curing products had the closest size to the design dimensions of the computer-aided design model; this indicated that the resin seemed to be a most promising candidate for 3D printing applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47487.     

Urethane acrylate-based photosensitive resin for three-dimensional printing of stereolithographic elastomer

Three-dimensional (3D) printing elastomers have received wide attention because of their wide applications in many fields. In this work, we report a urethane acrylate-based photosensitive resin compound for 3D printing whose cured materials are elastic. This resin consists of bifunctional urethane acrylate (Royji 426 as the main matrix, monofunctional urethane acrylate (Royji 425), and isobornyl methacrylate (IBMA) as the diluents, trimethylolpropane triacrylate (TMPTA) as the crosslinker, phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide (819) and 2-hydroxy-2-methyl propiophenone (1173) as photoinitiators. The results indicate that the mechanical properties of cured materials can be tuned by adjusting the content of different components, but it is also accompanied by the changes in viscosity and volume shrinkage. Real-time Fourier transform infrared spectroscopy was employed to explore the relationship between the photoinitiators and the rate of initiation, and then found the best photoinitiators formulation. The resultant resin exhibits tensile strength of 7.46 MPa, elongation of 180.6%, viscosity of 978.53 mPa·s at 25°C and the volume shrinkage rate of 4.15%. Some complicated structures can be printed with the photosensitive resin such as C₆₀, hollow ball, wrist strap, and porous lattices. These architectures have excellent dimensional accuracy and can undergo any large deformation without damage. This manifested that this resin can provide a solution for existing 3D printing of elastomers.     

Yellow resistant photosensitive resin for digital light processing 3D printing

Digital light processing (DLP) has been studied and developed in the field of three-dimensional (3D) printing in recent years due to its fast curing rate and high resolution. To reduce the cost and viscosity of the resin system, the aromatic polyurethane acrylates (PUAs) were used as oligomer. The matrix resin called PUH₂ consists of oligomers (PUA, bisphenol A polyoxyethylene ether dimethyl acrylate) and active diluents (hydroxyethyl acrylate, hydroxyethyl methacrylate). However, the photosensitive resin containing aromatic isocyanate groups was easily yellowed under ultraviolet light. In this article, we developed a resin for DLP 3D printing with yellowing resistance, excellent mechanical properties and high heat resistance. The optimal ratio of 3DP-PUH₂ resin was PUH₂/TPO/RYOJI-292/dye/nanosilica = 100/5/0.4/0.01/0.1, and its viscosity was 500 cp, which is suitable for DLP 3D printing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48369.     

印刷油墨用醇溶性聚酰胺树脂的研制

介绍了一种由二聚酸和二元胺为主要原料制备而成的醇溶性聚酰胺树脂。通过共缩聚反应制备聚酰胺树脂的方法,探讨了配比及反应条件等对树脂性能的影响。结果表明:该聚酰胺树脂具有较好的醇溶性、抗凝胶性能以及凝胶恢复性能等特点,在作为塑印油墨的连接料时尤为适用。     

环氧树脂改性阳离子型水性聚氨酯的合成

为了提高水性阳离子聚氨酯涂膜的耐水性和力学性能,以异佛尔酮二异氰酸酯、聚醚二元醇、一缩二乙二醇、环氧树脂E-51、N-甲基二乙醇胺为主要原料,采用丙酮法合成出环氧树脂改性的阳离子聚氨酯乳液。研究了反应条件和配方对乳液及胶膜性能的影响。通过引入环氧树脂得到的涂膜耐水性大大提高。     

Preparation of polyester resin/graphene oxide nanocomposite with improved mechanical strength

Graphene oxide (GO) has attracted huge scientific interest due to its unique physical and chemical properties as well as its wide‐scale applicability including facile synthesis and high yield. Here, we report preparation of nanocomposites based on GO and unsaturated polyester resin (PE). The synthesized samples were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and tensile strength measurements. A good dispersion of the GO sheets within the resin matrix was observed from the morphological analysis. A significant enhancement in mechanical properties of the PE/GO composites is obtained at low graphene loading. Around 76% improvement of tensile strength and 41% increase of Young's modulus of the composites are achieved at 3 wt % loading of GO. Thermal analysis of the composite showed a noticeable improvement in thermal stability in comparison to neat PE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

New resin systems for high performance waterborne coatings

Restrictions on the emission of solvents have led to the search for environment-friendly coatings. Waterborne systems are an alternative to high solids and powder coatings. New single-component polyurethane dispersions are suitable for replacing many standard systems. A new generation of waterborne two-component polyurethane systems may be used for applications where high performance is expected.     

Thiol-terminated hyperbranched polymer for DLP 3D printing: Performance evaluation of a low shrinkage photosensitive resin

In order to lower the volume shrinkage of the DLP 3D printing photosensitive resins during printing, a thiol-terminated hyperbranched polymer (T-HBP) was synthesized and introduced into the bisphenol A epoxy acrylate (EA) based photosensitive resin system. The obtained T-HBP was characterized by FTIR and ¹H NMR spectra, and the grafting rate of sulfhydryl was determined. The mechanical properties of the photosensitive resins were measured by tensile and impact strength measurement. The glass transition temperature of the photosensitive resins was analyzed by DSC and the impact fracture surface was observed by SEM. T-HBP exhibited a much lower viscosity than its linear counterparts, and the addition of thiol improved the curing speed of the photosensitive resins. When the amount of T-HBP added was 20 wt%, the shrinkage of the photosensitive resins was reduced by about 45.5% and the impact strength increased by 33.9% compared with the control. The macromolecular spherical structure of T-HBP effectively reduced the functional group density of the photosensitive resins. In addition, the thiol-acrylate photopolymerization introduced by T-HBP further reduced the volume shrinkage of the photosensitive resins.     

Novel visible photoinitiators systems for free-radical/cationic hybrid photopolymerization

Free radical/cationic hybrid photopolymerization of acrylates and epoxides was induced using an initiator system comprised of the dye derivative 5,12-dihydroquinoxalino[2,3-b]quinoxaline or 5,12-dihydroquinoxalino[2,3-b]pyridopyrazine as the sensitizers and hexafluoroantimonate triarylsulfonium salt as the initiators. The curing experiments were carried out in the presence of air and the consumption of each monomer upon VIS-radiation was monitored in situ by real-time infrared spectroscopy. Hardness (H), elastic modulus (E) and the H/E ratio of the coatings obtained by visible-initiated acrylate/epoxide hybrid photopolymerization were determined using nanoindentation. DSC measurements show that the initiator system presented here may produce an interpenetrating polymer network. The pencil hardness of the obtained coatings indicates that the dye/hexafluoroantimonate triarylsulfonium salts systems studied here may have practical applications as visible-light hybrid initiators.     

Preparation and properties study of waterborne polyurethane synthesized by mixing polyester diols and isocyanates

In view of environmental protection requirements, it is an inevitable trend for waterborne coatings to replace traditional coatings. Waterborne polyurethane (WPU), a kind of typical resin used in coatings, has become a research hot topic of waterborne coatings because of its advantages, such as non-polluting, safe and reliable, excellent properties, good compatibility, and easy modification. In this article, solvent-free WPU is prepared by mixing 4,4′-dicyclohexylmethane diisocyanate/ isophorone diisocyanate (HMDI/IPDI) and polycarbonate diol/ Polycaprolactone diol (PCDL/PCL). Through the comparison of the properties of the polymer, the best amount of raw materials was determined. Specifically, R = 1.35 (R is NCO/OH ratio), the content of dimethylolpropionic acid (DMPA) is 5.5%, the content of trimethylol propane (TMP) is 2.5%, the mole ratio of HMDI/IPDI is 2:1, the mole ratio of PCDL/PCL is 2:1, and the preeminent WPU shows the excellent thermal stability, the contact angle of 118.04°, the hardness is H. The chemical structures and rough surface morphologies of the WPU films were characterized by FT-IR, TG, AFM, and SEM, respectively. Therefore, considering the film properties, and the low cost, simple, and green process, this research will offer the possibility of application of this free-solvent WPU in industrial production and large-scale application.     

Near-visible stereolithography of a low shrinkage cationic/free-radical photopolymer blend and its nanocomposite

In this work, a newly prepared cationic/free-radical photopolymer, which consists of two epoxies and a tetrafunctional acrylate, is presented for the first time for a visible light stereolithography (SL), showing the advantages of both cationic and free-radical resins. An onium salt, commonly used as a cationic UV initiator, and a photosensitizer make the blend suitable for a near-visible (405 nm) SL. An increase in the polymerization rate and a drop in the induction period are observed for the newly prepared cationic/free-radical blend, compared with either only cationic systems or free-radical resins. This suggests that the combination of cationic and free-radical polymerizations in a single resin has a positive synergistic effect. The addition of silica nanoparticles to the blend provides a reinforcing and toughening effect. Indeed, the resin loaded with silica shows a 31% increase in the elastic modulus, compared with the unfilled resin. Regarding the values of tensile strength and elongation at break, they, respectively, grow by 47 and 15%, when the nanocomposite resin is compared with the neat resin. A very low volumetric shrinkage of 0.7% and a remarkable printing quality of objects obtained with this new photopolymer will enable the 3D printing of microrobots, bioengineering microdevices, and sensors. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48333.     

One‐pot curing system of epoxy resin imines initiated with water

The curing and adhesive properties of one‐component epoxy resins containing Epikote 828 and diimines, derived from N,N′‐di(1‐ethylpropylidene)‐m‐xylylenediamine, N,N′‐di(1‐ethylpropylidene)‐1,3‐diaminomethylcyclohexane (2), and N,N′‐di(1,3‐dimethylbutylidene)‐m‐xylylenediamine, which were used as water‐initiated hardeners, were examined. Diethyl ketone‐based imines with a lower electron density on the C?N carbon were efficiently hydrolyzed and showed curing activity. 2, a novel diethyl ketone‐based diimine, served as an efficient latent hardener of the epoxy resin. A paste of the epoxy resin with 2 showed good storage stability at room temperature and good adhesive properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 878–882, 2003     

Preparation and characterization of continuous basalt fibre with high tensile strength

Continuous basalt fibres (CBFs) produced directly from natural basalt seldom achieve adequate performance with high tensile strengths. Thus, formulation optimization is a key component of technological innovation in the field of CBFs. From this perspective, a series of experiments were designed to prepare a type of CBF using two natural forms of basalt. The average tensile strength of the fabricated CBF was 4111 MPa. Moreover, it is found that the amount of glass network modifier (Na₂O + K₂O) has a negative correlation with the tensile strength of CBF. By combining our results with past studies, two empirical formulas were proposed to quantify the relationship between viscosity (η) and viscosity modulus (Mη) for basalt melts at 1300 °C and 1400 °C: η(1300 °C) = ?91.22971 + 16.06614e^1.25983Mη and η(1400 °C) = ?30.57462 + 6.32023 e^1.18491 Mη. It was found that a value of Mη ranging between 2.2 and 2.6 is optimum for CBF production. We also established an important correlation between η, Mη and mix compositions, which could be an essential criterion to evaluate the characteristics and production technology of CBF, including basalt beneficiation and formulation optimization.     

3D打印用光敏树脂及功能化研究进展

本文介绍了3D打印用光敏树脂的研究现状,综述了三类光敏树脂的原料及引发机理,同时对光敏树脂的功能化研究进行了一定的总结,最后对光敏树脂基3D打印材料的发展趋势及应用前景进行了分析和展望。     

Superhydrophobic surfaces with silane‐treated diatomaceous earth/resin systems

Superhydrophobic coatings were prepared using fluorosilane‐treated diatomaceous earth (DE) with either polyurethane or epoxy binders. The surface wettability and morphology of the films were analyzed using contact angle measurements and scanning electron microscopy (SEM), respectively. The water contact angles were studied as a function of the fluorocarbon fraction on DE and the particle loadings of treated DE in the coating. The contact angles exceeded 150° for coatings with at least 0.02 fluorocarbon fraction (mass of fluorosilane/mass of particle) on the DE and with 0.2 particle loadings (mass of treated particles/mass of coating). The water contact angles of the surfaces were dependent on the nature of the binder below 0.2 particle loadings of the superhydrophobic DE particles, but were independent of the binder type after attaining superhydrophobicity. The results were consistent with the superhydrophobicity resulting from the migration of the superhydrophobic DE moving to and covering the surfaces completely. It was also shown that the treatment with fluorosilanes restricted the pores in DE and reduces the specific surface area of the material. However, these changes had effectively no effect on the superhydrophobicity of the coatings. The results of this work clearly identify some important considerations relative to producing superhydrophobic coatings from inexpensive diatomaceous earth. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44072.     

聚氨酯改性环氧树脂耐磨涂料的研制

以2,4-甲苯二异氰酸酯和蓖麻油为原料,合成了聚氨酯预聚体。使用该聚氨酯预聚体对环氧树脂进行了改性。对各种固化剂进行了筛选。最后研制了一种双组分常温固化耐磨涂料。通过正交实验和单因素实验确定了涂料的最佳配方:聚氨酯5 g,环氧树脂10 g,填料3 g,固化剂2．3 g。由此获得的耐磨性优良的涂膜性能为:表干时间10 h,实干时间不到40 h;耐磨性实验中,磨痕弦长5．4 mm;附着力0级,硬度5 H。     

新型高强度单组分环氧树脂胶粘剂的研制

采用新工艺制备了一种新型高强度单组分环氧树脂胶粘剂。实验结果表明,新型环氧树脂体系具有良好的力学性能、疏水性及耐热性。     

挠性覆铜板用高剥离强度环氧胶的制备及性能

用液体端羧基丁腈橡胶(CTBN)对环氧树脂E-51进行改性,合成了CTBN/E-51预聚物。采用红外光谱、示差扫描量热仪、万能试验机及电子显微镜表征了产物结构,确定了固化工艺,研究了预聚反应温度、时间,CTBN含量对环氧胶剥离强度的影响,并观察了剥离断面的形貌。结果表明,CTBN质量分数为15%,预聚温度为90℃,反应时间2 h所制得环氧胶的剥离强度最高,其粘接强度随预聚时间的增加而增加。该胶可满足挠性覆铜板的生产需要。     

Anticorrosion epoxy coating enriched with hybrid nanozinc dust and halloysite nanotubes

In this study, the performance of an epoxy coating with hybrid nanozinc dust and halloysite nanotube (HNT) fillers on the corrosion protection of a carbon steel substrate was investigated. The epoxy resin was mixed with a constant amount of nanozinc dust (1%) and different contents of HNTs (0, 0.5, 1, and 1.5%) with a high speed mixer. Fourier transform infrared spectroscopy and thermogravimetric analysis were used to analyze the interactions between the components in the coating material and the thermal stability of the epoxy coating, respectively. Open‐circuit potential, salt spray testing, and microscopy were also used to assess the corrosion resistance of the carbon steel substrate coated with these coating materials. The incorporation of nanozinc in the epoxy coating enhanced the corrosion protection of the carbon steel substrate compared with the pure coating. Furthermore, HNTs further enhanced the corrosion protection. The best protection was achieved when 1% nanozinc and 1% HNT were used. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 955‐960, 2013     

Preparation and characterization of organic–inorganic hybrid composites based on multiepoxy silsesquioxane and cyanate resin

A multiepoxy cubic silsesquioxane was prepared by the hydrolysis and polycondensation of trifunctional monomer (γ‐glycidoxypropyl)trimethoxysilane in a solvent mixture of methyl isobutyl ketone and anhydrous ethanol with a tetraethyl ammonium hydroxide aqueous solution acting as the catalyst, and it was successfully introduced into a cyanate resin and formed highly crosslinked organic–inorganic hybrid composites on a molecular level via a mutual cure reaction. The properties of the multiepoxy cubic silsesquioxane/bisphenol A dicyanate ester resin composites were investigated, and the results showed that introducing the cubic silsesquioxane unit into the cyanate resin successfully modified the local structure of the molecule, made the chain more rigid, restricted the chain mobility, and eventually improved the thermal stability and flame retardancy of the resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3652–3658, 2006