Dynamic mechanical characterization of a soy based epoxy resin system

Epoxidized allyl soyate (EAS), a novel soy based epoxy resin, has been prepared by the process of transesterfication and epoxidation of regular food grade soybean oil. Two types of crosslinking agents were employed in this study. The effects of the concentration of EAS and the type of crosslinking agent on the dynamic mechanical behavior of the soy based resin system have been investigated. The room temperature storage moduli (E′) and the glass transition temperatures (T_g) increased for the anhydride cured and decreased for the amine cured resins. The loss tangent maximum (tan δ)_max decreased for anhydride cured resins and increased for amine cured resins. The effect of frequency on the storage modulus was also studied. Master curves were constructed by the time‐temperature superpositioning technique (TTS) to predict the storage modulus at times and temperatures that are not experimentally feasible. The results indicate that soy based epoxy resins with appropriate concentrations hold great potential as a replacement for petroleum based materials in noise and vibration attenuation applications. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1772–1780, 2005     

Effect of functionality and content of epoxidized soybean oil on the physical properties of a modified diglycidyl ether of bisphenol A resin system

Partially epoxidized soybean oil (pESO) and fully epoxidized soybean oil (fESO) were used respectively to modify a diglycidyl ether of bisphenol A (DGEBA) resin system in this study. The pESO was prepared by epoxidizing soybean oil and the fESO was purchased as it was commercially available. DGEBA/ESO ratio of the epoxy resin system was changed from 100/0 to 70/30 and triethylenetetramine was used as a curing agent. Impact strength of the bio-epoxy resin system with fESO increased with ESO content, but the system with pESO decreased with ESO content. The bio-epoxy resin system with pESO showed higher tensile strength and elongation at break than the system with fESO at ESO 30 wt%. Tensile modulus and thermal degradation temperature decreased with ESO content and glass transition temperature was highest at 20 wt% ESO regardless of epoxide functionality of ESO. The performance of the DGEBA/ESO bio-epoxy resin system could be tailored by changing ESO content and functionality.     

环氧大豆油低聚物增韧环氧树脂胶粘剂

合成了三种环氧大豆油低聚物作为室温和高温固化环氧树脂增韧剂,对其增韧环氧体系的粘接性能和力学性能进行了考察。试验结果表明,环氧树脂低聚物对固化体系的初期粘度等性能没有影响,对固化体系粘接性能和力学性能等有较大影响。与未改性的环氧树脂相比,由顺丁烯二酸酐扩链的环氧大豆油低聚物改性的环氧树脂剪切强度提高了56.64%。     

Preparation and mechanical properties of green epoxy nanocomposites with cellulose nanocrystals

Epoxy resin is widely used to make composites, electronic and electric parts, adhesives, and coating materials because it has excellent thermal, electrical, and mechanical properties. Using natural materials in making epoxy composites and nanocomposites would make the final products greener. Therefore, in this study, epoxidized soybean oil (ESO) and cellulose nanocrystals (CNCs) were used to make green epoxy nanocomposites. ESO was prepared by epoxidation of soybean oil with peroxyacetic acid and it was confirmed by Fourier transform infrared spectroscopy. The ESO was mixed with diglycidyl ether of bisphenol A at different weight ratios (10%–50%) and the stoichiometric amount of ethylene diamine was used for curing. CNC content in the nanocomposites was changed from 0.125 to 1 phr. Mechanical properties of the epoxy samples and the nanocomposites were investigated by universal testing machine and izod impact tester. The epoxy sample showed best mechanical properties at ESO 30%. The nanocomposite with CNC 0.25 phr showed best mechanical properties. Fracture surfaces of the epoxy sample and the nanocomposites were investigated by scanning electronic microscope. POLYM. ENG. SCI., 60:439–445, 2020. © 2019 Society of Plastics Engineers     

Bio-based Epoxy Resins from Epoxidized Plant Oils and Their Shape Memory Behaviors

In this study, bio‐based epoxy materials containing functionalized plant oil, such as epoxidized soybean oil (ESO) and epoxidized linseed oil (ELO), were processed with 4‐methylhexahydrophthalic anhydride (MHPA) as a curing agent. In the presence of tetraethylammonium bromide, the curing reaction of epoxidized plant oil and MHPA proceeded at 130 °C to give transparent plant oil‐based epoxy materials. The resulting bio‐based epoxy materials exhibited relatively soft and flexible characters, due to the aliphatic chains of plant oil. The thermal and mechanical properties of the ESO/MHPA polymers depended on the feed molar ratio of anhydride to oxirane. The mechanical properties such as tensile strength and Young's modulus of the ELO/MHPA polymer increased, compared with those of the ESO/MHPA polymer. The glass transition temperature of the ELO/MHPA polymer was higher than that of the ESO/MHPA polymer, because of the high oxirane number of ELO. Furthermore, the ELO/MHPA polymer showed excellent shape memory property.     

Study on the effect of woven sisal fiber mat on mechanical and viscoelastic properties of petroleum based epoxy and bioresin modified toughened epoxy network

Sisal fiber reinforced biocomposites are developed using both unmodified petrol based epoxy and bioresin modified epoxy as base matrix. Two bioresins, epoxidized soybean oil and epoxy methyl soyate (EMS) are used to modify the epoxy matrix for effective toughening and subsequently two layers of sisal fiber mat are incorporated to improve the mechanical and thermomechanical properties. Higher strength and modulus of the EMS modified epoxy composites reveals good interfacial bonding of matrix with the fibers. Fracture toughness parameters K_IC and G_IC are determined and found to be enhanced significantly. Notched impact strength is found to be higher for unmodified epoxy composite, whereas elongation at break is found to be much higher for modified epoxy blend. Dynamic mechanical analysis shows an improvement in the storage modulus for bioresin toughened composites on the account stiffness imparted by fibers. Loss modulus is found to be higher for EMS modified epoxy composite because of strong fiber–matrix interfacial bonding. Loss tangent curves show a strong influence of bioresin on damping behavior of epoxy composite. Strong fiber–matrix interface is found in modified epoxy composite by scanning electron microscopic analysis. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42699.     

新型环氧大豆油增韧酚醛树脂的合成与性质

A novel epoxidized soybean oil-toughened-phenolic resin（ESO-T-PR）has been synthesized by etheri- fication graft and multi-amine curing ESO.Fourier transform infrared spectroscopy（FTIR）was adopted to investi- gate its molecular structure and scan electron microscope（SEM）was used to observe the micro morphology of its impact fracture surface.This ESO-T-PR was adopted as the matrix resin to prepare paper copper clad laminate （P-CCL）and the properties of resulting P-CCL are found superior to the related Chinese National Standard.The toughing mechanism was investigated by comparing the impact strength,solderleaching resistance,flexural strength, peeling strength and morphology of this ESO-T-PR with those of other two ESO modified phenolic resins.It is demonstrated that during the synthesizing process of ESO-T-PR,the phenol hydroxyl is etherified by ESO or ESO epoxy resin prepolymer（ESO chain extension polymer）and the long ESO epoxy resin chain segments enhance the crosslink density of ESO-T-PR and consequently improve the impact toughness and solderleaching resistance of P-CCL made of ESO-T-PR.The ESO-T-PR is a cheap matrix resin with excellent properties to make P-CCL（elec- tric guide board）.     

Comparison of curing agents for epoxidized vegetable oils applied to composites

Interest in polymers from renewable sources, as alternatives to petroleum‐based polymers, remains strong; however, their performance must be acceptable. To improve performance of epoxidized vegetable oils (EVO) in composite matrix applications, five amine curing agents were evaluated and compared with an anhydride agent used previously. Curing agents were tested in matrices for composites containing a petroleum‐based epoxy resin plus 0% or 30% epoxidized oil from canola (ECO) and soybean (ESO). The two amines with the highest glass transition temperature, determined by differential scanning calorimetry, were selected for characterization by dynamic mechanical analysis; bis (p‐aminocyclohexyl) methane (PACM) showed the highest performance. Amine: epoxy ratios 0.6 to 1.6 were then evaluated; ratios of 0.8 and 1.0 showed superior performance. E‐glass fiber reinforced composites with PACM/EVO showed thermal and mechanical performance slightly lower than the composites with 0% EVO and comparable with those of the anhydride curing agent. Therefore, ECO or ESO blended with petroleum‐based epoxy resins cured with PACM are recommended for its application in E‐glass reinforced composites. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Fracture toughness and impact strength of anhydride‐cured biobased epoxy

Biobased neat epoxy materials containing functionalized vegetable oils (FVO), such as epoxidized linseed oil (ELO) and epoxidized soybean oil (ESO), were processed with an anhydride curing agent. A percentage of diglycidyl ether of bisphenol F (DGEBF) was replaced by ELO or ESO. The selection of the DGEBF, FVO, and an anhydride‐curing agent resulted in an excellent combination to produce a new biobased epoxy material having a high elastic modulus and high glass transition temperature. Izod impact strength and fracture toughness were significantly improved dependent on FVO content, which produced a phase‐separated morphology. POLYM. ENG. SCI., 45:487–495, 2005. © 2005 Society of Plastics Engineers     

Catalyzed crosslinking of highly functional biobased epoxy resins

Crosslinking reactions involving epoxy homopolymerization of 100% biobased epoxidized sucrose esters (ESEs) were studied and the resulting coatings properties were compared against epoxidized soybean oil (ESO) and petrochemical-based soybean fatty acid ester resins. The low viscosity of ESE resins allowed for formulations to be developed with minimal volatile organic content. ESEs were found to have superior coatings properties, compared to ESO and the petrochemical-based soybean esters, attributable to a higher glass transition temperature (T _g) and a higher modulus. The rigid sucrose core on ESEs provided an increase in coating performance when compared to coatings from epoxidized resins synthesized with tripentaeryithritol as a core. The degree of conversion and optimization of the curing conditions were studied using differential scanning calorimetry (DSC). Thermal analysis of cured coatings was performed using DSC, dynamic mechanical analysis, and thermogravimetric analysis. In order to further enhance the coatings properties, small amounts of bisphenol A epoxy resin were added which resulted in higher moduli and T _gs.     

Physicochemical properties and fracture behavior of soy‐based resin

A soy‐based resin was prepared by the process of transesterfication and epoxidation of regular food‐grade soybean oil. The soy‐based resin was used as a reactive diluent and also as a replacement of bisA epoxy resin in an anhydride‐cured polymer. The curing efficiency of soy epoxy resin was studied using differential scanning calorimetry. Physicochemical properties and fracture behavior of soy‐based resin polymers were studied using dynamic mechanical analysis and fracture toughness measurements, respectively. Toughness measurements were carried out using the compact tension geometry following the principles of linear elastic fracture mechanics. Tests showed that the addition of soy‐based epoxy resin to the base epon resin improved the toughness of the blend. Morphology of the fractured specimens has been analyzed by scanning electron microscopy. The soy‐based resins hold great potential for environmentally friendly, renewable resource based, and low cost materials for structural applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of epoxidized soybean oil on mechanical properties of woven jute fabric reinforced aromatic and aliphatic epoxy resin composites

A systematic study was performed to describe the effect of epoxidized soybean oil (ESO) on storage modulus, glass transition temperature (T _g) and mechanical properties in epoxy resin composites reinforced by jute fabric. In addition to aromatic diglycidylether of bisphenol‐A (DGEBA) resin, a glycerol (GER)‐and a pentaerythritol (PER)‐based aliphatic resin was applied as base resin, which can be also synthesized from renewable feedstock. Based on strip tensile test results, the usual alkali treatment of jute fabric was avoided. By increasing the ESO‐content in aliphatic composites the T _g increases, whereas in case of DGEBA, it decreases. The results indicate that although ESO has a significant softening effect, the jute fiber‐reinforced DGEBA composite can be replaced without significant compromise in mechanical properties by a potentially fully bio‐based composite consisting of 25 mass% ESO‐containing aliphatic PER‐reinforced by jute fibers. POLYM. COMPOS., 38:884–892, 2017. © 2015 Society of Plastics Engineers     

Thermal and mechanical properties of acrylated expoxidized‐soybean oil‐based thermosets

A series of epoxidized‐soybean oil (ESO) with different epoxyl content were synthesized by in situ epoxidation of soybean oil (SBO). The acrylated epoxidized‐soybean oil (AESO) was obtained by the reaction of ring opening of ESO using acrylic acid as ring opener. The acrylated expoxidized‐soybean oil‐based thermosets have been synthesized by bulk radical polymerization of these AESOs and styrene. The thermal properties of the resins were characterized by differential scanning calorimetry (DSC) and thermo‐gravimetric analysis (TG). The results showed that these resins possess high thermal stability. There were two glass transition temperature of each resin due to the triglycerides structure of the resins. The tensile strength and impact strength of the resins were also recorded, and the tensile strength and impact strength increased as the iodine value of ESO decreased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Development of Novel Bio-Based Soybean Oil Epoxy Resins as a Function of Hardener Stoichiometry

Bio-based epoxy materials were prepared from epoxidized soybean oil (ESO) with an anhydride-curing agent. Variation of anhydride/epoxy ratio (R) was found to have significant effect on the resulting properties of the materials. The properties were studied and compared by dynamic mechanical analysis (DMA), izod impact, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The glass transition temperature reaches the maximum at stoichiometric ratio related to the cross-link density of the formed networks. These materials are thermally stable but exhibit a rapid decrease as the anhydride/epoxy ratio was increased.     

Synthesis and characterization of waterborne epoxy derived from epoxidized soybean oil and bioderived C-36 dicarboxylic acid

This study focuses on synthesis of waterborne epoxy (WBE) derived from epoxidized soybean oil (ESO) and its compatibility with water-dispersible curing agent Pripol 1009, which is a bioderived long-chain dimer acid. The reaction parameters involved in the synthesis of WBE from ESO have been optimized based on physicochemical properties like hydroxyl value, epoxy equivalent value and degree of solubility of WBE. The WBE obtained after 5 and 6 h of reaction time was found to be of optimum composition with balanced physicochemical properties. The mechanical, thermal and physicochemical properties of WBE obtained after 6 h of reaction time revealed relatively better performance characteristics as compared to ESO.     

Preparation and properties of biocomposites composed of epoxidized soybean oil,tannic acid,and microfibrillated cellulose

As a new biobased epoxy resin system, epoxidized soybean oil (ESO) was cured with tannic acid (TA) under various conditions. When the curing conditions were optimized for the improvement of the thermal and mechanical properties, the most balanced properties were obtained when the system was cured at 210°C for 2 h at an epoxy/hydroxyl ratio of 1.0/1.4. The tensile strength and modulus and tan δ peak temperature measured by dynamic mechanical analysis for the ESO–TA cured under the optimized condition were 15.1 MPa, 458 MPa, and 58°C, respectively. Next, we prepared biocomposites of ESO, TA, and microfibrillated cellulose (MFC) with MFC contents from 5 to 11 wt % by mixing an ethanol solution of ESO and TA with MFC and subsequently drying and curing the composites under the optimized conditions. The ESO–TA–MFC composites showed the highest tan δ peak temperature (61°C) and tensile strength (26.3 MPa) at an MFC content of 9 wt %. The tensile modulus of the composites increased with increasing MFC content and reached 1.33 GPa at an MFC content of 11 wt %. Scanning electron microscopy observation revealed that MFC was homogeneously distributed in the matrix for the composite with an MFC content of 9 wt %, whereas some aggregated MFC was observed in the composite with 11 wt % MFC. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Cationic UV-cured coatings containing epoxidized soybean oil initiated by new onium salts containing tetrakis(pentafluorophenyl)gallate anion

Different formulations containing epoxidized soybean oil (ESO) and a commercial cycloaliphatic epoxy resin (UVR6110) were cured by onium tetrakis(pentafluorophenyl)gallate (Gallate) on steel panels. The resulting coatings were clear and their mechanical properties were tested by the Sward hardness test, cross-hatch tape adhesion test and MEK double rub test. The new initiators have the advantage of good solubility, high reactivity, and the production of colorless coatings. The best formulations obtained contain 50% ESO, 50% UVR6110, and 0.5% silwet if sulfonium gallate is used as initiator, and 60% ESO, 40% UVR6110, and 0.5% silwet if iodonium gallate is the initiator. Center for Photochemical Sciences, Bowling Green, Ohio 43403.     

Spider Silk Inspired Robust and Photoluminescent Soybean-Protein-Based Materials

Development of mechanical robust and functional biomass-based materials still remains challenging. Here, a design strategy inspired by spider silk structure is proposed to prepare strong, robust, and photoluminescent soybean protein isolate (SPI)-based materials, by integrating epoxy soybean oil (ESO) and SPI as soft phase matrices and graphene oxide quantum dots (GQDs) as hard phase. The results show that the soft–hard coordination network can form a close covalent/hydrogen bond network. The tensile strength, elongation at break, and toughness of the SPI/ESO/GQD film are 13.22 MPa, 209%, and 22.54 MJ m⁻³, respectively. In addition, SPI/ESO/GQD has strong photoluminescence intensity due to the ring-opening polymerization of amino structure with epoxy resin. The prepared SPI-based materials are promising candidates for optical coatings and provide new ideas for the intelligent research of other protein-based materials.     

Biocomposites synthesized from chemically modified soy oil and biofibers

Composites with good mechanical properties were prepared from chemically modified soy oils and biofibers without additional petroleum‐based polymers. These composites were prepared from maleic anhydride and epoxide functionalized soybean oils that were cured in the presence of various biofibers (e.g., kenaf, kayocell, protein grits, and solka‐floc) by a flexible amine catalyst. Rigid thermosets characterized by a high‐crosslink‐density network and a high gel fraction were obtained. Fourier transform infrared was used to follow the cure reaction via the disappearance of the characteristic anhydride adsorptions. Composites with high tensile strength and low elongation were obtained when kenaf fibers were treated with (2‐aminoethyl)‐3‐aminopropyl‐trimethoxysilane and then added to the epoxidized/maleated soy matrix and cured with hexamethylenediamine. These biobased composites could provide inexpensive epoxy resin alternatives for a wide variety of industrial applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 69–75, 2006     

环氧大豆油改性透明环氧树脂胶粘剂的研究

以环氧大豆油(ESO)为环氧树脂(EP)的增塑剂、环氧氯丙烷(ECH)和丙烯腈(AN)改性己二胺为固化剂,制得ESO改性EP胶粘剂。探讨了增塑剂种类和含量对EP胶粘剂性能的影响。结果表明:当n(己二胺):n(ECH):n(AN)=1:0.3:1.5、w(ESO)=20%时,相应EP胶粘剂的剪切强度、断裂伸长率和外推起始温度分别比纯EP体系增加了10%、400%和20%;ESO是一种高增韧性、高耐热性的环保型增塑剂,相应EP胶粘剂的透明性、柔韧性和耐高(低)温性俱佳。