Vegetable oil-derived epoxy monomers and polymer blends: A comparative study with review (original) (raw)
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Epoxidized Glycidyl Ester of Soybean Oil as Reactive Diluent for Epoxy Resin
Epoxidized glycidyl esters of soybean oil (EGS) have been synthesized and used as reactive diluents for partial replacement of a commercial, bisphenol A-based epoxy resin (DGEBA). The EGS merits include a higher epoxy content and lower viscosity than the epoxidized triglyceride soybean oil (ESO). Thermosetting resins were fabricated from DGEBA systems blended with various amounts of EGS and ESO, using 4-methyl-1,2-cyclohexanedicarboxylic anhydride as a curing agent and 2-ethyl-4-methylimidazole as catalyst. The curing behavior and glass transition were monitored by differential scanning calorimetry (DSC), the performance of thermosetting resins was studied by measurement of thermal stability and flexural properties. The results indicate that EGS resins provide better compatibility, intermolecular crosslinking, and yield materials that are stronger than materials obtained using ESO. However, the EGS resin systems significantly reduce viscosity compared to either pure DGEBA or ESO-ble...
Industrial & Engineering Chemistry Research, 2017
The present research is based on, a comparative study of anhydride cured bio-based and petroleum based epoxy network. The effect of epoxidized soybean oil (ESO) bioresin on petroleum based epoxy (DGEBA) at varying composition cured with methylhexahydrophthalic anhydride (MHHPA) as curing agent and 2-methyl imidazole (2-MI) as the catalyst has been investigated. The tensile strength of virgin epoxy (42.94 MPa) increased to 48.62 MPa with the addition of 20% of ESO. The fracture toughness parameters; critical stress intensity factor (K IC) and critical strain energy release rate revealed enhancement of toughness in the bio-based blends. Differential scanning calorimetry (DSC) studies confirmed an enhancement in the peak temperature and a reduction in the heat of curing in virgin epoxy on incorporation of ESO content. The thermomechanical and fracture morphological properties of virgin epoxy, ESO and its bio-based blends were investigated by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), atomic force microscopy (AFM) and scanning electron microscopy (SEM) respectively.
Composites Part B: Engineering, 2011
The influences of different amounts of epoxidized soybean oil (ESO) on the curing kinetics and thermal properties of diglycidyl ether of bisphenol A (DGEBA) epoxy resin, cured with p-aminobenzoic acid (p-ABA) were investigated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), near infrared chemical imagistic (NIR-CI) and thermogravimetry (TGA). SEM and NIR-CI data reveal that a statistical distribution in the structure of DGEBA/p-ABA/ESO was obtained. The DSC data showed that the activation energy of the curing reaction increases with ESO content increase. On the other hand the glass transition temperature decreases. Also, the activation energy of the thermal degradation decreases with ESO amount increase.
From Natural Oils to Epoxy Resins: A New Paradigm in Renewable Performance Materials
Journal of Polymers and the Environment, 2021
The direct conversion of natural products to useful engineering materials is desirable from both economic and environmental considerations. We are describing the synthesis and properties of 100 % oil-based epoxy resins generated from three epoxidized oils. The catalyst, tris(pentafluorophenyl)borane (B(C6F5)3) in toluene, allowed for controlled cationic polymerization at a very low concentration. Epoxidized oils (derived from triolein, soybean, and linseed oil) had varying epoxy content, rendering resins of different cross-link density. The polymerization was carried out at room temperature followed by post-curing at elevated temperature to speed up conversion. Epoxy resins were amorphous transparent glasses with glass transitions below glass transitions and hard rubbers above. Despite their high cross-link density, these materials show relatively low Tg's reflecting the aliphatic nature of fatty acids and the presence of plasticizing "dangling" chains. The structure of the triglyceride starting oils influenced the properties of the resulting materials: the more regular structure of triolein compared to the very heterogeneous structures of soybean and linseed oils seemed to have enhanced some properties of the polymer networks. These epoxy polymers are potentially useful as encapsulating and potting compounds for electronic applications.
Curing and mechanical characterization of a soy-based epoxy resin system
Journal of Applied Polymer Science, 2004
A potentially inexpensive alternative epoxy resin system based on soybean oil has been developed for polymer composite applications. Epoxidized methyl soyate (EMS) and epoxidized allyl soyate (EAS) have been synthesized at the University of Missouri-Rolla. These materials consist of mixtures of epoxidized fatty acid esters. The epoxidized soy-based resins provide better intermolecular crosslinking and yield materials that are stronger than materials obtained with commercially available epoxidized soybean oil (ESO). The curing behavior and glass transition have been monitored with differential scanning calorimetry. Neat resin test samples have been fabricated from resin systems containing various amounts of EMS, EAS, and ESO. Standardized tests have shown that the addition of EAS enhances the tensile and flexural properties of the base epoxy resin system. Therefore, epoxidized soy ester additives hold great potential for environmentally friendly and lower cost raw materials for the fabrication of epoxy composites for structural applications.
Epoxidized Vegetable Oils for Thermosetting Resins and Their Potential Applications
Springer series on polymer and composite materials, 2017
In the recent decades, bio-based polymers have gained increasing interest, especially for composite materials. These polymers and their respective monomers are derived from renewable resources, being thermoplastics or thermosetting resins which are biodegradable or non-biodegradable. Thermosettings are strong, rigid polymer materials and cannot be easily processed by melting after their hardening. At present, thermosetting resins are obtained using highly toxic and volatile petrochemicals, which require human and environmental safety monitoring. Considering the wide range of diverse renewable monomers available, vegetable oils (VOs) are especially well-suited when it comes to the synthesis of thermosetting resins due to their carbon-carbon double bonds, highly desirable for this type of application as these unsaturated bonds can be chemically modified in order to increase reactivity toward further polymerization. Thus, epoxidation, which consists of introducing a single oxygen atom to each non-saturated bond to yield in an epoxidic cycle, is a simple, effective method to modify these VOs. The resulted thermosetting resins exhibit improved toughness and environmental-friendly behavior. VOs, especially soybean oil which is abundant and cheap, are typically mixtures of unsaturated fatty acids with numerous bonds that can be easily converted into the more reactive oxirane rings through the reaction with peracids or
Journal of Materials Processing Technology, 2008
In the earlier study about polymer network of phenolic and epoxies resins mixed with linseed oil, only Phencat 15 was used as the catalyst for the phenolic resin. In this study, Phencat 382 and UH (a urea hydrochloride solution based on a 1 : 1 mole ratio of urea : hydrochloric acid 32%) will be used as catalysts to study their effects on the polymer network of phenolic and epoxy resins mixed with epoxidized linseed oil (ELO) (58%). The effect of each one of these catalysts on the curing and the properties of the formed network were investigated. It was discovered that Phencat 382 was the best catalyst for the composites. It was also discovered that ELO can play its role as plasticiser in the blends of epoxy and phenolic resins and does improve the flexural strength and other mechanical properties of the prepared resins. The storage modulus, flexural modulus, stress at peak and glass transition temperature decreased with increasing percentage by weight of ELO added irrespective of the catalysts used, while the strain yield increased. The cross-link density decreased with the increasing amount of ELO in the resins. The best properties were obtained for the 80/20 epoxy/phenolic resin blends after post-curing for 4 hours.