EPOXIDIZED SOYBEAN OIL

EPOXIDIZED SOY BEAN OIL
Epoxidized soy bean oil (ESBO) is a collection of organic compounds obtained from the epoxidation of soybean oil. It is used as a plasticizer and stabilizer in polyvinyl chloride (PVC) plastics. Epoxidized soy bean oil is a yellowish viscous liquid.
CAS Number: 8013-07-8
EC Number: 232-391-0

SYNONYM:
SCHEMBL11940813;K428;Soybean oil epoxide, contains 4,000 ppm monomethyl ether hydroquinone as inhibitor;ESO;MolPort-023-220-347;Epocizer P 206;; Epocizer W 1000;Epocizer W 100S;G 62;Flexol Plasticizer EPO;Estabex 2307 DEOD;Reoplast 39;Plastolein 9232;; Plastol 10;Peroxidol 780;NK 800; O 130P;; Lankroflex GE; Micro–Chek 11
IUPAC NAME:
Epoxidized Soya Bean Oil;Epoxidized soybean oil;Epoxidized Soybean Oil;ESBO;Plasticizer E;Soyabean Oil, Epoxidized;Soybean oil, epoxidised; ESBO
TRADE NAME:
Drapex 39;Drapex 391;Drapex 6.8;Epovinstab H800;Epoxidized soyabean oil;Epoxol D60;Epoxol D65;Epoxol D65S;Ergoplast ES;ESOPOL;ESOPOL LA;KALFLEX 13;KALFLEX 14;KALFLEX 14 A;KALFLEX 14NP;KALFLEX 14OA;KALFLEX 14OP;Lankroflex E2307;MAKPLAST SN;MAKPLAST SNS;MERGINATE ESBO;Plasticizer E;SDB CIZER E-03
OTHER NAME:
11114-05-9;11114-05-9;1182717-32-3;1182717-32-3;121853-93-8;121853-93-8;12768-71-7;193425-83-1;193425-83-1;220857-52-3;220857-52-3;37260-65-4;37260-65-4;37307-47-4;37307-47-4;37311-19-6;37311-19-6;39378-88-6;39378-88-6

Epoxidized Soy Bean Oil
Epoxidized soybean oil is manufactured from soybean oil through the process of epoxidation. Polyunsaturated vegetable oils are widely used as precursors to epoxidized oil products because they have high numbers of carbon-carbon double bonds available for epoxidation.The epoxide group is more reactive than double bond, thus providing a more energetically favorable site for reaction and making the oil a good hydrochloric acid scavenger and plasticizer. Usually a peroxide or a peracid is used to add an atom of oxygen and convert the -C=C- bond to an epoxide group.Food products that are stored in glass jars are usually sealed with gaskets made from PVC.Epoxidized soybean oil is one of the additives in the PVC gasket. Epoxidized soybean oil serves as a plasticizer and a scavenger for hydrochloric acid released when the PVC degrades thermally, e.g. when the gasket is applied to the lid and food product undergoes sterilization. Epoxidized soybean oil is also used in PVC cling films for wrapping foods and toys.
Epoxidized soybean oil, better known by its acronym, ESBO, is a plasticizer used in polyvinyl chloride (PVC) plastics. It serves as a plasticizer and as a scavenger for hydrochloric acid liberated from PVC when the PVC undergoes heat treatment.
Product Benefits:
1. Efficient Heat & Light Stabilization
2. Low Viscosity
3. High Detergent Resistance
4. Low Volatility
5. Improves Processing Speed
6. Excellent Pigment Wetting
7. Improves Plastisol Viscosity Stability
8. Low Styrene & Lacquer Mar
9. High Oil & Gas Resistance
Epoxidized soy bean oil (ESBO) is the oxidation product of soybean oil with hydrogen peroxide and either acetic or formic acid obtained by converting the double bonds into epoxy groups, which is non-toxic and of higher chemical reactivity. ESBO is mainly used as a green plasticizer for polyvinyl chloride, while the reactive epoxy groups imply its great potential in both the monomer synthesis and the polymer preparation fields. Functional polymers are obtained by different kinds of reactions of the ESBO with co-monomers and/or initiators shown in this chapter. The emphasis is on ESBO based epoxy cross-linked polymers which recently gained strong interest and allowed new developments especially from both an academic point of view and an industrial point of view.
Epoxidized Soybean Oil (ESBO) is a non-toxic, clear to yellow liquid that is used as a plasticizer and stabilizer in plastic materials, especially PVC and its copolymers.
Epoxidized soy bean oil is also used as a pigment dispersing agent and acid/mercaptan scavenging agent as well as an epoxy reactive diluent.
Epoxidized soy bean oil is the most readily available and one of the lowest-cost vegetable oils in the world. Epoxidized soybean oil is the result of the oxidation of soybean oil with hydrogen peroxide and either acetic or formic acid. ESBO is industrially available in large volume at a relatively low price.
Epoxidized oils are important chemicals, normally used as plasticizers and stabilizers for PVC resins. Nowadays, it is very important to increase the epoxidized soybean oil (ESBO) productivity, because, this substance is a good substitute of phtalates, as plasticizer, since phthalates have been banned in many countries for their negative effects on health.
The epoxidation of vegetable oils, for example soybean oil, is normally carried out by reacting the double bonds of the oil with a peroxyacid (generally peroxyacetic or peroxyformic acid) generated in situ by reacting concentrated hydrogen peroxide with acetic or formic acid in the presence of a mineral acid as catalyst.
Due to its low cost and biodegradability over traditional phthalate plasticizers, ESBO is replacing dioctyl phthalate (DOP) in some applications.
Epoxidized soybean oil is a cost efficient choice for a variety of applications that also includes functional fluids, flavor and fragrances, sealants, coatings, and special inks.
Applications:
Epoxidized soybean oil (ESBO) is used as a plasticizer and stabilizer in plastic materials, especially PVC and its copolymers to keep these plastics soft and pliable.
The chemical is also used as a pigment dispersing agent and acid/mercaptan scavenging agent as well as an epoxy reactive diluent.
Soybean oil is one of the most readily available and lower-cost vegetable oils in the world. ESBO is industrially available in large volume at a relatively low price.
Due to its low cost non-toxic and environmentally friendly properties, as well as its biodegradability over traditional phthalate plasticizers, ESBO is replacing dioctyl phthalate (DOP) in some applications.
Epoxidized soy bean oil is also used as a pigment dispersing agent and acid/mercaptan scavenging agent as well as an epoxy reactive diluent. epoxidized soybean oil and other epoxide substances are used as raw materials for various applications that include functional fluids, fuel additives, polyol replacements, agricultural and pharmaceutical molecules, flavor and fragrances, reactive diluents and UV cure applications, surfactants, adhesives, sealants, coatings, and special inks.
Epoxy soybean oils have been found to be the best value of all stabilizing additives. They have been accepted as a standard industry formulation tool, effecting cost reductions and improving performancen in heat and light stability over those systems previously employing only metallic stabilizers. No other additive enjoys such universal acceptance for all types of vinyl compound. Epoxidized soybean oil functions as the most effective known synergist to metallic stabilizer compounds in vinyl systems.
Manufacturing Process:
Epoxidized soy bean oil is manufactured from soybean oil through the process of epoxidation. Polyunsaturated vegetable oils are widely used as precursors to epoxidized oil products because they have high numbers of carbon-carbon double bonds available for epoxidation. The epoxide group is more reactive than double bond, thus providing a more energetically favorable site for reaction and making the oil a good hydrochloric acid scavenger and plasticizer. Usually a peroxide or a peracid is used to add an atom of oxygen and convert the -C=C- bond to an epoxide group.
Uses:
Food products that are stored in glass jars are usually sealed with gaskets made from PVC. Epoxidized soy bean oil is one of the additives in the PVC gasket. It serves as a plasticizer and a scavenger for hydrochloric acid released when the PVC degrades thermally, e.g. when the gasket is applied to the lid and food product undergoes sterilization. Epoxidized soy bean oil is also used in PVC cling films for wrapping foods and toys.
Epoxidized soy bean oil is produced from one of the most readily available and lowest-cost vegetable oils in the world. Epoxidized soy bean oil is produced through the oxidation of high iodine value unsaturated soybean oil with hydrogen peroxide and organic acids such as acetic acid or formic acid. Epoxidized soy bean oil is primarily used as a co-plasticizer for flexible polyvinyl chloride (PVC) and its copolymers to keep these plastics soft and pliable. The chemical is also used as a pigment dispersing agent and an epoxy reactive diluent. Epoxidized soy bean oil acts as a secondary heat and light stabilizer, and it is especially valuable as a low cost and effective synergist to metallic stabilizer compounds in vinyl systems. In addition, Epoxidized soy bean oil acts as an acid scavenger for soy-based inks, agricultural chemicals, and insecticides. Epoxidized soy bean oil can also be used as a chemical intermediate, additive for specialty coatings, adhesives, and urethanes, and in lubricants and cutting oils. Due to its low cost and biodegradability over traditional phthalate plasticizers, Epoxidized soy bean oil is replacing dioctyl phthalate (DOP) in some applications. Because Epoxidized soy bean oil is non-toxic, bio-based, bio-degradable, and phthalate-free, it is a prime choice for sustainable and eco-friendly formulations.
Suggestions for Use:
• Plasticization of all PVC flexible and semi-flexible compounds.
• Heat and light stabilization of all flexible, semi-rigid, and rigid PVC
compounds.
• Pigment dispersions as an outstanding grinding liquid.
• Plate-out resistant compounds requiring high epoxy levels.
• Acid acceptance in chlorinated hydrocarbons, phosphoric acid esters,
and natural resins.
• Plasticization of PVC and PVA emulsions.
• Plasticization of chlorinated rubber, nitrocellulose, and neoprene.
• Process improvement in certain rigid compounds.
• Acid scavenging in soy based ink compounds.
Applications in PVC Compounds:
• Floor covering, vinyl asbestos and homogenous.
• Coated fabrics: automotive and furniture upholstery, sporting
equipment, wall covering, clothing, luggage.
• Unsupported film.
• Pigment dispersions.
• Injection molding compounds.
• Wire and cable coatings.
• Plastisols & Organosols used in molding, dipping, and casting
applications.
• Extrusions: welting, gasketing, weather strip, beverage tubing, hose.
• Foam for padding, seating, automotive, packaging.
• Blow molded bottles.
• Printed semi-rigid and rigid laminate film.
Production of Epoxidized Soy Bean Oil
Epoxidized soybean Oil (ESO) is an additive to flexible Polyvinyl Chloride (PVC) that gains its name from the reaction that occurs with the unsaturated soybean oil. The epoxidation reaction takes place at a carbon to carbon double bond site.  The oxygen atom (usually in the form of a peroxide or a peracid) comes in and attaches itself between the two carbons to create a single bonded triangular ring between the three molecules called an oxirane. This oxirane can be used as a way of separate well formed ESO molecules from those that will be less effective. Those ESO molecules with higher oxirane percentages will product better results than those with low oxirane percentages.
Because epoxidized soybean oil is synthesized from the bio-based, renewable resource of soybean crops, the level of saturation of the soybean oil and ultimately the oxirane value of the ESO created from it, is dependent on the growing conditions of the soybeans.  Very hot, dry weather is known to inhibit the formation of the unsaturated C18-3 and C18-2 double bonds in the soybean oil and will therefore lead to lower oxirane values in the ESO produced from it.
The climate of American Midwest is very well suited to producing high oxirane value ESO.  The United States is responsible for about 32% of the total soybeans grown worldwide, with Brazil and Argentina also significant producers of the oilseed.
Although ESO was first introduced into the plastics market over thirty years ago as a bio based plasticizer that could be a drop-in replacement to Dioctyl phthalate (DOP), it has found a strong niche as a secondary plasticizer due to its heat and light stabilization effects in PVC compounds.  The epoxide group is more reactive than a double bond, thus providing a more energetically favorable site for reaction and making it a good hydrochloric acid scavenger and plasticizer.
Epoxidized Soybean Oil (ESO) is a non-toxic, non-hazardous, and naturally-based plasticizer and stabilizer for flexible PVC applications.
Plasticizers, the largest application segment for Epoxidized Soybean Oil:
Plasticizers are the colorless and odorless chemicals mainly phthalate esters, which are used to enhance the elasticity of polymers mainly polyvinyl chloride (PVC). Around more than 90% of plasticizers are used in production of PVC also known as vinyl. Plasticizers are also used in paints, rubber products, adhesives & sealants, printing inks and so on. Without the use of plasticizers in PVC applications, it will be rigid and can be used in limited applications such as wastewater pipelines. However, the use of plasticizers in PVC magnifies its use in wide variety of applications.
The most commonly used phthalates are hexyl phthalate, dioctyl phthalate, and dibutyl phthalate. However, stringent regulations on use of phthalates by authorities such as Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) have depleted its use in various applications due to its effects on skin and other health related issues. This in turn led the plasticizer producers to opt for renewable and safer products. ESBO, being environmentally friendly plasticizer, has been considered as most preferred bio-based plasticizer over petrochemical-based plasticizer. Hence, ESBO finds high growth opportunities in PVC stabilization process.
Plasticizers are the colorless and odorless chemicals mainly phthalate esters, which are used to used enhance the elasticity of polymers mainly polyvinyl chloride (PVC). Around more than 90% of plasticizers are used in production of polyvinyl chloride also known as vinyl. Plasticizers are also used in paints, rubber products, adhesives & sealants, and printing inks etc. Without the use of plasticizers in PVC applications, it can remain rigid and can be used in limited applications such as wastewater pipelines. However, the use of plasticizers in PVC magnifies its use in wide variety of applications.
The most commonly used phthalates are hexyl phthalate, dioctyl phthalate, and dibutyl phthalate. However, stringent regulations on use of phthalates by authorities like Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) has depleted its use in various applications due to its effects on skin and other health related issues. Which in turn led the plasticizer producers to opt for renewable and safer products. ESBO, being environmentally friendly plasticizer, has been considered as most preferred bio-based plasticizer over petrochemical based plasticizer. Hence ESBO finds high growth opportunities in PVC stabilization process.
ESBO used as in food & beverages industry such as in gaskets of commercial lids for food packaging, laminate in drink cartons, and plastic coatings. ESBO also used in metal lid gaskets of glass jar that are used to store baby foods. These gaskets come in contact with food products during sterilization and storage and can cause contamination of ESBO with food products, which can lead to hazardous health effects.
Food:
A Swiss survey in June 2005 showed that (among many other plasticizers exceeding the legal limits) migration of ESBO into foods reached up to 1,170 mg/kg. Rapid Alert System in Food and Feed (RASFF) had also reported cases of food product rejection in EU for exceeding SML under EU Legislation (EC/2002/72). Enforcement authorities took measures to force producers respecting the legal limits.
Legislation:
In Europe, plastics in food contact are regulated by Regulation (EU) 10/2011. It establishes a specific migration limit (SML) for ESBO of 60 mg/kg. However, in the case of PVC gaskets used to seal glass jars containing infant formulae and follow-on formulae as defined by Directive 2006/141/EC or processed cereal-based foods and baby foods for infants and young children as defined by Directive 2006/125/EC, the SML is lowered to 30 mg/kg. This is because babies have higher food consumption per body weight.
Toxicity:
The tolerable daily intake (TDI) of ESBO defined by the Scientific Committee on Food (SCF) of the EU is 1 mg/kg body weight. This value is based on a toxicological assessment performed by the British Industrial Biological Research Association (BIBRA) in the late 1997. Repeated oral administration had been shown to affect the liver, kidney, testis and uterus of rats. According to the conventional European rules for food packaging materials, the TDI became a basis for the SML of 60 mg/kg.

Epoxidized soybean oil (ESO) is the bio-based product from the epoxidation of soybean oil with hydrogen peroxide and either acetic or formic acid obtained by converting the double bonds into epoxy groups, which is non-toxic and of higher chemical reactivity . Epoxidized soybean oil is mainly used as a green plasticizer for many plastics currently . Meanwhile it has also attracted an increasing attention as a green epoxy resin utilizing the reactive epoxy groups into both the monomer synthesis and the polymer preparation due to its low cost, little toxicity, and large production, which imply its great potential in industrial process .Epoxidized soybean oil can be converted by different kinds of reactions with co-monomers and/or initiators . Permanent network that comes from the directing cross-linking of epoxidized soybean oil and hardeners endows epoxidized soybean oil with great stability, superior mechanical properties and satisfying chemical resistance, which make the products competitive among a variety of materials. In addition, the chemical modification of epoxidized soybean oil has gained more and more attention in recent years. Introducing hydroxyl groups to make polyols for polyurethanes synthesis is one of the most important chemical modification methods.
Acrylated epoxidized soybean oil (AEPOXİZED SOYBEAN OİL) obtained by ring opening esterification between acrylic acid and epoxidized soybean oil is of high reactivity for thermal and UV initiated polymerization . This chapter reviews the applications epoxidized soybean oil and its derivatives for the preparation of a series of bio-based polymeric materials.Epoxidized soybean oil is a kind of widely used plasticizer for polyvinyl chloride and stabilizer, can significantly improve plastic products hot photostability, and epoxidized soybean oil is the characteristics of have nontoxic, transparent, is suitable for making the plasticizer of packaging material for food.Epoxidized soybean oil for glycerine fatty acid ester blends, primary raw material be soybean oil, organic acid and hydrogen peroxide simultaneously The oxidation in the presence of catalyst, the production technology of existing conventional epoxy soybean oil is mainly using the side that alkali refining is refined Method, is refined with concentrated base low temperature process, is affected by raw material, processing conditions, and traditional handicraft control condition is main except generating.
Glycerine fatty acid ester admixture outside, can also produce all kinds of impurity not waited containing quantity, such as phosphatide, protein, pigment, moisture Presence Deng, these materials undoubtedly affects epoxidation reaction and product quality, and conventional process conditions to the clearance of impurity compared with It is low, and as condition control is limited, do not accomplish the control of precision so that the epoxidized soybean oil of preparation is in purity and quality And all than relatively low in efficiency .Epoxidized soybean Oil (ESO) based polymers were developed using diamine curing agents and BF3:NH2C2H5 as catalyst. Reactions involved the curing process were explored and monitored by DSC and IR analysis. Amine-epoxy addition reactions governed the main curing reaction at the temperature range of 60--235°C, and the supplementary reactions at higher temperatures were either homopolymerization or etherification reaction. In the aliphatic curing reactions, the epoxy-rich system favored the supplementary reactions at high temperature, however, epoxidized soybean oil cured with 1,6 hexanediamine (HDA) always produced the high temperature reaction products, due to some side reactions and the high volatile nature.
The curing reaction with aromatic diamines produced inherent rigidity to the cured epoxidized soybean oil network, which decreased the high temperature reactions. The system cured with a short aromatic diamine epoxidized soybean oil, produced a small extent of high temperature reaction, as well. Epoxidized soybean oil was believed that the long length diamine with wide separation of the two amines underwent an intermolecular cross-linking reaction, and derived better properties than the shorter diamine. A post-cure process was used to improve the final polymer properties by increasing the temperature after the initial curing reaction was quenched due to gelation. Extending the time of post-curing did not significantly improve properties of the final epoxidized soybean oil polymers. Exposing the cured samples at 180°C for longer than 12 hours decreased the properties of the cured material, due to thermal strain generating in the network structure. To increase time efficiency, short heat cycles were performed by post-curing right after gelation, and the cured epoxidized soybean oil polymer had tensile strength of 32 MPa, modulus 750 MPa and toughness 1.3 MPa. With the introduction of epoxidized soybean oil, the mechanical properties of a new epoxidized soybean oil polymer improved; having strength above 40 MPa, modulus great than 1,000 MPa, and Tg higher than 40°C.
Finally, a rice hull particleboard was developed using the cured epoxidized soybean oil resin as adhesive, and the board had strength comparable to the National Bureau of Standards minimum requirement for particleboard. A 35 wt % of epoxidized soybean oil resin imparted the highest strength for the rice hull board, with a value of 15.5 MPa.Epoxidized soybean oil (ESO) was employed as a novel penetrant cooperating with a conventional rejuvenator (CR) for the recycling of reclaimed asphalt pavement (RAP). The influence of epoxidized soybean oil on the diffusibility and the regenerating effects of CR on RAP were investigated. The diffusibility testing result shows that the diffusibility of CR is enhanced by the addition of epoxidized soybean oil because the epoxy group in epoxidized soybean oil can facilitate asphaltene dispersion due to its high polarity, which simultaneously reduces the viscosity and improves the fluidity of aged bitumen so as to allow diffusion of the rejuvenator into the aged bitumen. Road performance testing of a recycled hot mix epoxidized soybean oil indicates that the fatigue and cracking resistance properties as well as the water stability of RHMA containing CR can be improved by the addition of epoxidized soybean oil due to the diffusibility enhancement of CR, which boosts the regenerating effect of CR on aged bitumen in RAP.
The fatigue and cracking resistance properties as well as the water stability of the recycled hot mix asphalt mixture containing CR with 7 wt % epoxidized soybean oil approximate those of the hot mix asphalt mixture composed of the same virgin aggregates and bitumen. Taking into account the rutting resistance decline versus the addition of epoxidized soybean oil, the content of epoxidized soybean oil should not exceed 7 wt % of the conventional rejuvenator.Majorly, food and beverage industry have accounted most of the epoxidized soybean oil market whereas its application in plasticizer segment has controlled the market trailed by UV curing; this application is likely to rise meaningfully in upcoming years. Another cause is epoxidized soybean oil’s easy availability in huge volumes, at the lesser price which has propelled the usage in an application such as plasticizers, UV cure applications, fuel additives application this is directly driving the market of epoxidized soybean oil globally. Other key factor encountered, that lifts the market growth of epoxidized soybean oil worldwide is its usage as a replacement in PVC applications against phthalate-free stabilizers and hence epoxidized soybean oil is used extensively as an additive in plasticizers.
The high growth of this market is due to the increase in demand from its application segment. These applications are growing because of which epoxidized soybean oil demand is generating; this drives the market globally. Asia-Pacific excluding Japan, all over Europe, North and Latin America are the leading regions for high consumption of epoxidized soybean oil market.Although demand and necessity of epoxidized soybean oil in the industrial market are seen significantly, but uncertainty   of the toxicity is hindering the market, many types of research is under taken to check the toxicity level, this is important because according to the researchers high usage of ESBA in food and beverages can affect the kidney, liver, testis and uterus; which can hinder the market growth of epoxidized soybean oil to a certain extent.Regarding geography, the global Epoxidized Soybean oil market has been categorized into seven key regions including North and Latin America, Eastern Europe, Western Europe, Asia-Pacific excluding Japan, Japan, and the Middle East & Africa.
The Epoxidized Soybean Oil market is globally expected to register healthy CAGR during the forecast period. Regarding value and volume, North America is the largest market in the epoxidized soybean oils to rule this market in upcoming years; this is because of the countries including U.S, Mexico and Canada are attaining rise in the usage of epoxidized soybean oil in the plasticizer application industry. In Eastern Europe, Latin America and Asia Pacific excluding Japan are the other leading regions which are showing tremendous growth in the market of ESBO; this is because of the easy accessibility of raw materials in huge amounts and at lesser costs.The curing processes of epoxidized soybean oil or the mixture of epoxidized soybean oil and commercial epoxy resin have been investigated, and some of these systems have been made into composites through adding fibers , clay and other reinforcement .
Viscoelastic properties, mechanical properties and many other analyses have been studied to evaluate their applicability to be used in industry. The partially bio-based polymers show great potential to replace fully petroleum-based polymers in many areas according to the testing results. Glass-transition (Tg) and viscoelastic properties of amine-cured epoxidized soybean oil can be enhanced by increasing the amount of epoxidized soybean oil or triethylene glycol diamine (TGD). Epoxidized soybean oil endows the polymer with similar viscoelastic properties to a commercial rubber and a higher Tg than TGD does . In this respect, the biopolymers made from epozxized soybean oil and amines have great potential to replace some synthetic rubbers or plastics . Besides, the quasi-static and dynamic compressive properties of the cured products based on epoxidized soybean oil and amines and the corresponding composites reinforced by clay have also been investigated to develop compressive one-dimensional stress-strain material models .Solid freeform fabrication method has been applied to the preparation of epoxidized soybean oil-based composites and proved to be a suitable method for this kind of curing system.
Epoxidized soybean oil/TETA/clay composites show controllable biodegradability, low cost, good thermal and mechanical properties, and these properties indicates that the composites may work as alternative to petroleum-based polymers in the field of insulation materials and coating materials . For clay-reinforced composites based on commercial epoxy resin the addition of epoxidized soybean oil can enhance the impact strengths . More interestingly, the product from epoxidized soybean oil and TETA can be made into an ion-exchange resin through hydrolysis . Usually, epoxy groups in the internal of the long aliphatic chain exhibits much poorer reactivity than those terminal epoxy groups. Due to this fact, the reported curing processes of epoxidized soybean oil usually needs higher temperature and longer time than commercial petroleum-based epoxy resin, such as bisphenol A epoxy resin. However, the combination of the hardener, dicyandiamide (DICY), and the accelerator, carbonyldiimidazole (CDI), can make the gelation of epoxidized soybean oil occur within 13 min at 190°C.
Moreover, the gelation of the mixture of epoxidized soybean oil and DGEBA is achieved with the aid of DICY and CDI within 3 min at 160°C .Fully or high bio-based polymers are also attractive to researchers owing to people’s strong attention to environment concerns. A series of fully bio-based elastomers have been synthesized through the ring-opening reaction between epoxidized soybean oil  and a bio-based amine hardener, decamethylene diamine, and they can be cross-linked by further reaction with another bio-based anhydride hardener, succinic anhydride . These fully bio-based elastomers have great potential to replace some petroleum-based rubbers in engineering because of their good damping property, low water absorption and weak degradability in phosphate buffer solution .The investigation of green anhydride curing agents is one of the research priorities. Maleopimaric acid (MPA), which comes from rosin acid, has been used for epoxidized soybean oil curing to obtain new polymeric thermosets with a high bio-based content . The total heat release is only 31.7 kJ/mol epoxy group.
Compared with its petroleum-based analogues, MPA endows the polymer with larger breaking elongation, higher storage modulus and better thermal stability. Sebacic acid is another bio-based curing agent fore poxized soybean oil  in lab. A fully bio-based composite with highly improved thermal and mechanical properties can be produced through interaction between sebacic-cured epoxidized soybean oil and PLA. What’s more, sebacic acid-cured epoxidized soybean oil can be applied in the field of superhydrophobic materials to make a sustainable and biodegradable superhydrophobic material . Other bio-based chemicals, such as terpene , vegetable oils  and citric acid , are all the optional raw material for green curing agents. A terpene-based acid anhydride has been found to endow epoxidized soybean oil with higher Tg, higher tensile strength and greater modulus than maleinated linseed oil and hexahydrophthalic anhydride do.
But maleinated linseed oil makes the thermoset easier to biodegrade. Biodegradable and biocompatible elastomers, which may be competitive in the field of implantable materials, can be obtained by curing epoxidized soybean oil and epoxidized linseed oil (ELO) with phosphorylated castor oil . Carboxylic acid functionalized MWCNTs are always used as the filler for fully bio-based epoxidized soybean oil/citric acid system . The produced composites with good mechanical properties and high bio-based content may be applied in the field of industry . Physical tests of fully sustainable polymers obtained from curing epoxized soybena oil with different dicarboxylic acids show the decreases of Tg and elongation at break, and the increases of tensile strength and Young’s modulus with the increasing of chain-length of the curing agents .In this respect, besides bio-based micromolecular chemicals, bio-based dicarboxyl-terminated polymers are also able to work as green curing agents for epoxidized soybean oil to make fully bio-based polymers .
Polymer curing agents with long chain length can avoid the short, brittle and amorphous cross-link structures which may be the reason for the poor performance of epoxidized soybean oil-based thermosets .Like the situation occurring in amine-cured systems, anhydride-cured epoxidized soybean oil with a high bio-based content usually cannot exhibit excellent properties as petroleum-based polymers do. In order to overcome this deficiency epoxidized soybean oil usually works together with some petroleum-based chemicals. For this kind of complicated reaction systems, many factors are worth investigations. We are going to discuss this kind of reaction systems in terms of the properties of epoxides, the addition of commercial curing agents, the influence of the catalysts and the incorporation of fillers.
The internal epoxy rings in epoxidized soybean oil exhibits lower reactivity than terminal ones do and the epoxy equivalent weight of epoxidized soybean oil is usually higher than commercial epoxy resins. The addition of epoxidized soybean oil in the mixture of DGEBA and epoxidized soybean oil results in the increase of peak exothermic temperature, and activation energy and the decrease of enthalpy of reaction [36, 48]. Tensile strength, modulus, fracture toughness, impact strength, storage modulus (E′) in the glassy state and Tg of the cured products decrease because of the addition of epoxidized soybean oil. Besides, the thermal and mechanical properties of the cured products has a positive correlation with the epoxide content of epoxidized soybean oil.
Aside from the alteration of epoxides, the properties of the cured products can be enhanced with the aid of commercial curing agents.Bio-based foams based on methyltetrahydrophthalic anhydride (MTHPA)-cured epoxized soybean iol show similar mechanical properties to synthetic epoxy foams and the contents of epoxidized soybean oilcan be larger than 55 wt%, which indicates that this kind of green foams can be valuable alternative for commercial epoxy foams . Polymers with anhydride groups [47] and dicarboxylic acids  are also able to work as curing agents for epoxidized soybean oil. The carboxylic acid-terminated polyesters can work with epoxidized soybean oil to produce green pressure-sensitive adhesives, which are environmentally friendly , thermal stable and with flame retardance .
In this kind of curing systems, the molecular weight of the polymer curing agents obviously have a great influence on the curing process and the physical properties of the cured bio-based products . One of the remarkable advantages of bio-based polymers is their potential biodegradability. Lower crosslink density usually means higher biodegradability for epoxidized soybean oil-based thermosets . The cross-link density of the cured product reaches maximum at stoichiometric ratio between epoxidized soybean oil and hardener.Not only the properties of the main reactants, but the loading and type of the catalyst have a great influence on the on the curing process  final polymers . The curing kinetics of epoxidized soybean oil /methyl hexahydrophthalic anhydride (MHHPA) system show a significantly autocatalytic characteristic and epoxidized soybean oil with 1.5 phr (parts per hundreds of resin) of 2-ethyl-4-methylimidazole (EMI) catalyst is a recommended composition for EPOXİZED SOYBEAN OİL/MHHPA system to be cured effectively at relative low temperature and short time Epoxidized soybean oil -based thermosets can also be used as good matrixes for organoclays , organo-montmorillonite clay , proteins , regenerated cellulose  and other fillers. These works show that the thermal and mechanical properties of the composites can be improved significantly with the addition of different fillers.