Biobased epoxy resin derived from eugenol with excellent integrated performance and high renewable carbon content

Developing biobased epoxy resin with high renewable carbon content and outstanding integrated performance is beneficial for both sustainable development and applications in cutting‐edge fields. Herein, a biobased epoxy monomer (TEUP‐EP) with high renewable carbon content (100%) was synthesized from renewable eugenol with a sustainable process; TEUP‐EP was then blended with 4,4′‐diaminodiphenylmethane (DDM) to develop a new biobased epoxy resin (TEUP‐EP/DDM). The integrated performance of TEUP‐EP/DDM resin was studied and compared with that of petroleum‐based diglycidyl ether of bisphenol A (DGEBA)/DDM resin. Compared with DGEBA/DDM resin, TEUP‐EP/DDM resin has much better integrated performance and not only exhibits a glass transition temperature about 26 °C higher and a 24.4% or 57% increased flexural strength or modulus, but also shows outstanding flame retardancy. Specifically, the limiting oxygen index increases from 26.5% to 31.4% and the UL‐94 grade improves from no rating to the V‐0 level; moreover, the peak heat release rate and total heat release decreased by 63.1% and 57.4%, respectively. All these results fully prove that TEUP‐EP/DDM is a novel biobased high performance epoxy resin. The mechanism behind these attractive integrated performances is discussed intensively. © 2018 Society of Chemical Industry     

Synthesis and photosensitivity of acryloylmorpholine copolymers with a pendant (meth)acryloyl group

We have developed new photopolymers that have superior waterproof properties and that can easily interact with polyfunctional acrylate compounds, thus serving as hydrophobic photocrosslinking reagents. Acryloylmorpholine monomers whose homopolymers were less moisture absorbing than the usual water‐soluble polymers but were still water soluble to a good degree, were copolymerized with other acryloyl monomers. We then introduced the photosensitive (meth)acryloyl group to side chains of the resulting polymers. Among six copolymers examined, the copolymers composed of acryloyl morpholine, hydroxyethyl acrylate, ethyl, or methyl methacrylate, and methacryloyl isocyanate were found to have nicely balanced hydrophilicity and waterproof properties, in addition to good compatibility with hydrophobic photocrosslinking reagents. The composite polymers thus obtained were confirmed to be promising photopolymers usable even in a highly humid environment. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 684–692, 2003     

Moisture uptake and resulting mechanical response of biobased composites. I. constituents

The mechanical properties of the biobased fiber and resins have been characterized and moisture influence on the behavior of these materials has been studied. Commercially available biobased thermoset resins (Tribest, EpoBioX, Palapreg, Envirez SA, and Envirez SB) and regenerated cellulose fibers (Cordenka) have been conditioned at different levels of relative humidity (as received, dried, 41, 70, and 90%) to obtain materials with different moisture content. The following properties of polymers were measured: tensile, flexural (3P‐bending), impact strength (unnotched Charpy), and fracture toughness (compact tension). The results of characterization of biobased thermosets were compared against data for epoxy Araldite LY556, which is used as reference resin. RCF bundles (with and without twist, extracted from fabric) as well as single fibers separated from these bundles were tested in tension. In general biobased resins performed well, moreover EpoBioX showed better properties than synthetic epoxy. POLYM. COMPOS., 35:1150–1159, 2014. © 2013 Society of Plastics Engineers     

UV-PU双固化木器涂料的研制

介绍了以环氧丙烯酸酯、醇酸树脂和TDI加成物固化剂作为交联体系,制成了氨酯-环氧丙烯酸酯双固化的聚合物涂料。同时研究了环氧树脂、醇酸树脂、活性单体、固化剂以及组分配比对涂料性能的影响,并利用红外光谱、热重、DSC进行了表征,研究了该复合固化体系的反应特点。     

Development of a cashew nut shell liquid (CNSL)‐based polymer for antibacterial activity

A biobased polymer derived from cashew nut shell liquid (CNSL) as a renewable resource was investigated for use as an antibacterial material. CNSL is a mixture of aromatics containing cardanol as the main component and cardol and 2‐methylcardol as minor components. CNSL composition analyses showed that the minor components (i.e., cardol and 2‐methylcardol) in CNSL had higher contents of unsaturated structures than cardanol. These higher unsaturated contents promoted the thermal polymerization in the preparation of an epoxy CNSL prepolymer (ECNP). The biobased polymer film was fabricated by the reaction of amine compounds and ECNP without any organic solvent. The ECNP film took less than 2.0 h to reach a hardened dry condition at room temperature because of the crosslinking reaction between epoxy and amine groups. The antibacterial activities of the biobased polymer against Escherichia coli and Staphylococcus aureus were evaluated. CNSL showed antibacterial activity against S. aureus, whereas epoxy CNSL and ECNP alone showed no significant antibacterial activity against E. coli or S. aureus. This indicated that the antibacterial activity was based on the phenolic and catechol hydroxyl groups of CNSL. In addition, a biobased polymer film derived from CNSL and diamine showed antibacterial activity against both E. coli and S. aureus, even with alcohol conditioning. This suggested that the antibacterial activity was certainly fixed in the structure of the ECNP‐based polymers after the standard antisepsis treatment in medical facilities. Therefore, this biobased polymer could be useful in antibacterial materials as a coating and resin for health care applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42725.     

High‐performance biobased epoxy derived from rosin

Great achievements have been made in the research of biobased thermoplastic polymers, but the progress concerning thermosetting resins has been minor. In particular, research on high‐performance thermosetting polymers from renewable feedstock has not been reported elsewhere. A novel biobased epoxy was synthesized from a rosin acid. Its chemical structure was confirmed using ¹H NMR, ¹³C NMR and Fourier transform infrared spectroscopy. The results indicated that the rosin‐based epoxy possessed high glass transition temperature (T_g = 153.8 °C), high storage modulus at room temperature (G′ = 2.4 GPa) and good thermal stability. A rosin‐based epoxy with excellent properties was achieved. The results suggest it is possible to develop high‐performance thermosetting resins from renewable resources. Copyright © 2010 Society of Chemical Industry     

Effect of acrylation on the properties of waterborne epoxy: evaluation of physicochemical,thermal, mechanical and morphological properties

The present work addresses the critical requirements for the coating industry such as developing the sustainability of biobased materials and simultaneously achieving a balanced combination of coating properties. In this study, acrylated epoxidized soybean oil (AESO) has been successfully synthesized from epoxidized soybean oil and acrylic acid. Subsequently, AESO was modified using a biobased long chain diacid (Pripol-1009) with the assistance of a water/ethanol blend to form waterborne epoxy acrylate (WBEA). The properties of the cured WBEA with 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane as initiator were studied through spectral analysis, coating properties evaluation, corrosion resistance, and morphological and thermal analysis. The results revealed that WBEA exhibited relatively better mechanical, thermal and corrosion resistance characteristics over cured waterborne epoxy.     

Dual curing of carbon fiber reinforced photoresins for rapid prototyping

Photo-thermal dual-curing of a carbon fiber reinforced photoresin is reported in this study. The primary limitation of carbon fibers is that they are opaque to ultra-violet (UV) light, and the resin present inside the carbon fiber tow remains uncured if only a photolytic mechanism is used. Therefore, a dual-curing resin formulation was developed that consisted of acrylate ester of bisphenol A-epoxy (primary resin), 1-hydroxycyclohexyl phenyl ketone (a photoinitiator), and lauroyl peroxide (thermal initiator). The fibers were dispersed in the resin and photocured by UV radiation. Subsequently, the composites were thermally cured to solidify the resin present inside the fiber tow. Differential scanning calorimetry indicates that the thermal initiator activates at approximately 70°C. The dual-cured composites, processed by a dip-coating technique and also in a desktop photolithography unit, were tack-free and fully solidified in the interior. Thus, it was established that by using a dualcuring resin formulation, the resin present outside and inside the carbon fiber tow could be cured to produce a carbon fiber reinforced photoresin. Such a reaction scheme has application in composite photolithography where incorporation of carbon fibers into photopolymers can enhance electrical and thermal conductivities of rapid tooling materials.     

New biobased carboxylic acid hardeners for epoxy resins

Soybean oil was modified into a novel biobased polyacid hardener by thiol‐ene coupling with thioglycolic acid. The structure of the initial soybean oil and polyacid triglyceride was carefully analyzed using ¹H NMR and titration. The thermal crosslinking reaction between acid hardener and epoxidized resin was studied by differential scanning calorimetry (DSC) and rheology. Then, the synthesized biobased acid hardener was employed as a novel curing agent for bisphenol A diglycidyl ether to elaborate new partially biobased materials. These materials, formulated in stoichiometry ratio, were characterized by DSC, thermogravimetry analyses, dynamic mechanical analyses and exhibit interesting properties for coatings. Practical applications: The products of the chemistry described in this contribution, i.e., polyacid from soybean oil and thioglycolic acid, provide biobased building blocks for further epoxy resin syntheses by reaction with epoxy groups. The obtained epoxy resins are partially biobased and may be applied as binders and coatings.     

Development of Biobased Epoxy Matrices for the Preparation of Green Composite Materials for Civil Engineering Applications

Epoxy matrices are successfully used for structural strengthening in civil engineering applications by means of carbon fiber reinforced polymers (CFRPs). In the context of sustainable development, the aim of this study is to develop biobased epoxy matrices as an alternative to the traditional petroleum‐based epoxy matrices used in CFRPs. This study focuses on two biobased epoxy monomers: a diglycidyl ether of bisphenol A (DGEBA) and a sorbitol polyglycidyl ether (SPGE). These monomers are reacted with a biobased curing agent, a phenalkamine (PhA), derived from cardanol. After in‐depth characterization of the chemical structures of the three monomers, the reactivity of both systems, DGEBA‐PhA and SPGE‐PhA, is studied using differential scanning calorimetry and rheology. The properties of the networks are characterized via dynamic mechanical analysis and water uptake measurements for polymers with partial or full conversion of epoxy groups, which are obtained by crosslinking at room temperature or at high temperature, respectively. The results reveal that the two systems are good candidates for the preparation of green composite materials as they meet the requirements necessary for manufacturing composites in civil engineering applications.     

Comprehensive study of metal on the characteristic properties of epoxy resins

A series of different type of epoxy resins containing metal(s) have been prepared by the using cobalt acrylate (CoA₂), nickel acrylate(NiA₂),bismuth acrylate (BiA₃) during resinification. The values of epoxide equivalent weight, chlorine content increases whereas hydroxyl content, refractive index decreases in the presence of metal acrylate(s). The influence of complex formation of metal acrylate with ether linkage of epoxy resins were investigated by spectroscopy. Epoxy resins containing cobalt acrylate which was cured by p‐acetylbenzilidinetriphenylarsoniumylide (p‐ABTAY) shows better conducting properties in comparison to NiA₂ and BiA₃ containing epoxy resins. The dispersion of metal(s) in epoxy resins matrix was confirmed by scanning electron microscope (SEM). The glass transition temperature of epoxy resins containing CoA₂ is lower than that of blank epoxy resins and epoxy resins containing bismuth and nickel acrylate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Novel biobased nanocomposites from functionalized vegetable oil and organically-modified layered silicate clay

The new biobased nanocomposites are processed from anhydride-cured epoxidized linseed oil (ELO)/ or octyl epoxide linseedate (OEL)/diglycidyl ether of bisphenol F (DGEBF) epoxy matrix and organomontmorillonite clay. The selection of anhydride curing agent and biobased epoxy resulted in an excellent combination to provide an epoxy matrix having high elastic modulus, high glass transition temperature, and high heat distortion temperature (HDT), with higher amounts of functionalized vegetable oil (FVO), compared with amine-cured biobased epoxy. The sonication technique was utilized to process the organically-modified clay nanoplatelets in the glassy biobased epoxy network resulting in nanocomposites where the clay nanoplatelets are almost completely exfoliated and homogeneously dispersed in the epoxy network. The processed exfoliated clay nanocomposites showed higher storage modulus compared with the neat epoxy containing the same amount of FVO. Therefore, the lost storage modulus with larger amount of FVO can be regained with exfoliated clay nanoreinforcement.     

Preparation and mechanism of free-radical/cationic hybrid photosensitive resin with high tensile strength for three-dimensional printing applications

A ultraviolet (UV)-curing free-radical/cationic hybrid resin is designed and developed by blending epoxy resin with an acrylic resin, including N-acryloyl morpholine, polyurethane acrylic ester (PUA), free-radical and cationic photoinitiator. During UV-curing, crosslinking locks the acrylate and epoxide polymers together through non-covalent interaction. Most likely, the interpenetrating polymer network (IPN) structure can be generated in the three-dimensional (3D)-printed objects. The obtained results from Fourier transform infrared spectroscopy (FT-IR) show that bisphenol A epoxy resin and acrylic resin are both successfully involved in the UV-curing process. In addition, the effects of the mass ratio of epoxy to acrylic resin and the UV irradiation time on the properties of the hybrid resin are systematically investigated using liquid crystal display (LCD) 3D printers. It is found that the tensile strength of the hybrid resin increases in a certain range and the elongation at the break maintains an upward trend with the increasing mass ratio. Finally, it is found that the shrinkage of the hybrid resin also depends on the mass ratio of epoxy to acrylic resin, which decreases with the increase of the epoxy resin content in a certain range. Thus, herein we propose a feasible UV-curing mechanism for the synthesis of hybrid resins for 3D printing applications.     

环氧改性丙烯酸酯结构胶的研究

以环氧丙烯酸酯树脂、端羧基丁腈橡胶改性环氧预聚物、多官能度环氧作为改性环氧树脂,对传统的第二代丙烯酸酯结构胶黏剂进行改性研究,测试表征了耐高温性、耐水性、伸长率、贮存性能等。结果表明,同时采用多种改性环氧树脂对丙烯酸酯结构胶进行改性,其综合性能明显提高:180℃剪切强度由0.3MPa提高到2.7MPa、28d浸水试验剥离强度保持率由2%提高到75%、断裂伸长率由3.5%提高到19.3%。     

Solution properties of anionic hydrophobic association polyacrylamide modified with fluorinated acrylate

The anionic hydrophobic association polyacrylamide (AFPAM) modified with fluorinated acrylate have been synthesized of acrylamide (AM), 2-acrylamide-2-methyl propanesulfonic acid (AMPS) and 2-(perfluorooctyl)ethyl acrylate (FEA) by free radical micellar copolymerization in aqueous solution utilizing sodium dodecyl sulfate(SDS) as the surfactant and potassium persulfate(KPS)/sodium bisulfite(SBS) as the redox initiator. The solution properties of these polymers were investigated. The results show that there are strong hydrophobic associations in the AFPAM aqueous solution. The intrinsic viscosity decreases and Huggins constant increases with the increase of hydrophobic FEA content. The addition of NaCl and CaCl₂ results in an increase of solution viscosity which indicate the good salt-resistant performance. The polymers exhibit good temperature tolerance property, shear-thickening and thixotropy behavior. Additionally, the AFPAM has higher surface activity in salt solution than in water.     

High-performance waterborne UV-curable polyurethane dispersion based on thiol–acrylate/thiol–epoxy hybrid networks

Synthesis, characterization, and film performance of waterborne thiol–acrylate/thiol–epoxy hybrid coatings are highlighted in this article. A dimer acid-modified epoxy (DME) polyol, containing both hydroxyl and epoxy functional groups, was prepared by reacting epoxy resin (EEW = 190 g/equi) with dimer fatty acid at 2:1 molar ratio. Further, a base UV-curable polyurethane acrylate dispersion (UV-PUD), with a pendant epoxy functional group, was prepared by reacting polyol (DME), isophorone diisocyanate, and dimethylol propionic acid and end-capped with hydroxyethyl methacrylate with subsequent dispersion in water. Prepared intermediates were characterized for the parameters relevant to the study by physical, spectroscopic, and chemical methods. UV-curable thiol–acrylate/thiol–epoxy hybrid coatings were prepared by blending UV-PUD with trimethylolpropane tris(3-mercaptopropionate) (TMPMP) at four different thiol ratios (0, 0.3, 0.6, and 1.0) with respect to acrylate/epoxy groups. Cured films of the hybrid coating were identified by FTIR spectroscopy. The impact of thiol ratio on film performance was evaluated in terms of mechanical, chemical, thermal, and coating properties. The gel content measurements confirm that the addition of TMPMP increased the double bond conversion along with the epoxy group. Evaluation of cured samples shows the significant improvement in storage modulus, glass transition temperature, tensile strength, and hardness with increase in thiol ratio. The cured films possessed excellent water and acid resistance (<4%) even after 28 days of immersion. Moreover, the notable improvement was alkali resistance of cured films, i.e., as thiol ratio was increased from 0 to 1, weight loss in alkaline environment deceased from 49.5 to 4.5% after 28 days. Better properties of the thiol–acrylate/thiol–epoxy hybrid films will allow it as a potential application in low-volatile high-performance coatings.     

Effect of bone ash fillers on mechanical and thermal properties of biobased epoxy nanocomposites

In this study, the fabrication and characterization of bone ash filled biobased epoxy resin (Super SAP 100/1000, contains 37% biobased carbon content) nanocomposites are presented. Biosource bone ash was modified by size reduction and surface modification processes using a combination of ball milling and sonochemical techniques and characterized using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The modified bone ash particles were incorporated into biobased epoxy with noncontact mixing process. The as-fabricated nanocomposites were characterized using various thermal and mechanical analyses. The nanocomposites showed significant improvement in flexural strength (41.25%) and modulus (34.56%) for 2 wt% filler loading. Dynamic mechanical analysis (DMA) results showed improvement in both storage modulus and loss modulus. Additionally, DMA results showed a slight reduction in glass transition temperature which also complies with differential scanning calorimetry results. Thermomechanical analysis results showed a reduction in the coefficient of thermal expansion. Thermogravimetric analysis results showed improved thermal stability at both onset of degradation and the major degradation. These enhanced thermal and mechanical performances of the epoxy nanocomposites allows them to be suitable for lightweight aerospace, automotive, and biomedical applications.     

甲基丙烯酸接枝环氧树脂的制备与性能测试

通过丙烯酸类单体与环氧树脂接枝共聚反应,在环氧树脂中引入强亲水性基团-COOH,制备水性环氧乳液。探索了不同单体用量和加水温度对所得水性乳液的pH值、黏度、粒径、水分散性和储存稳定性的影响;考察了涂膜固化条件对涂膜的附着力、耐冲击性、耐水性的影响。试验结果表明,随着甲基丙烯酸用量增加,所制备的水性环氧乳液水分散稳定性增强,pH值降低,粒径变小;随着加水温度的增加,储存稳定性变差;固化剂含量占环氧树脂含量的15%和固化温度为120℃时,涂膜的外观、附着力、耐冲击性、耐水性等综合性能最好。     

香草醛分子印迹聚合物的制备及其性能研究

采用分子印迹技术，以香草醛为模板分子，甲基丙烯酸为功能单体，乙二醇二甲基丙烯酸酯为交联剂，偶氮二异丁睛为引发剂，在乙腈溶液中制备了香草醛分子印迹聚合物。用于液相色谱固定相可将其与结构类似物阿魏酸基线分离，并用紫外光谱法对功能单体进行了选择。     

Rheology and curing characteristics of dual-curable automotive clearcoats using thermal radical initiator derived from O-imino-isourea and photo-initiator

The curing characteristics of clearcoats, including a thermal curing initiator (TRI) newly designed from O-imino-isourea and photo-initiator (PI), were investigated by means of different mono-curing and dual-curing pathways. The competitive relationship between TRI and PI on the curing pattern, reacting with acrylate double bonds in a clearcoat was elucidated by altering the UV and thermal sequence in the dual-curing process, through various experimental methods. From the rheological properties of clearcoats along the curing time, two dual-curing methods showed the different evolution of curing patterns. In the UV–thermal dual-curing case, the initial infusion of UV light promoted free radical polymerization during the subsequent thermal curing by generating considerable free radicals, and exhibiting a higher growth rate of elastic modulus during the curing in comparison with the thermal–UV dual-curing case. However, the final modulus value in the thermal–UV dual-curing case was higher due to the suppression of thermal curing by the steric hindrance in the UV–thermal dual-curing. The level of crosslinked networks in clearcoats via different curing steps can be explicitly figured out from the double bond conversion from FT-IR, curing pattern from rigid-body pendulum test, and scratch properties from nano-scratch test.