Synthesis And Properties Of Castor Oil Modified Polymers

With the forthcoming depletion of fossil fules,it is very urgent to explore renewable,low toxicity and low cost of biomass energy and then synthesis a series of functional polymers,such as polyurethane,epoxy curing agent and unsaturated resin.Castor oil,a kind of common non-staple oil crops with an huge annual production of about 200,000 tons in China,has gained wide attention due to its active double bond,ester bond and hydroxyl.Now it has been widely used in many fields,such as plastics,coatings,adhesives and rubber.In this paper,the castor oil-based functional polymers such as,IPN,flame retardant epoxy resin and flame retardant vinyl ester resin copolymers were prepared,and these work could offer the guidance for the exploration and applications of functional resins with high perfprmance.The main research contents are as follows:Epoxidized castor oil(ECO)was synthesized via epoxidation using castor oil(CO)as raw material.Next the prepared ECO was cured with toluene diisocynate(TDI)at 80 or 150℃,and then two kinds of interpenetrate polymer network(IPN)materials were obtained,and also their molecular structures and comprehensive properties were all studied.The results showed that the IPN material at 150 ℃ possessed typical polyurethane-oxazolidone double crosslinking molecular structure.Compared with the unmodified castor oil polyurethane material,the prepared two IPN materials had higher tensile strength,hardness and high glass transition temperature.Thermogravimetric analysis showed that all cured materials owned good thermal stability,the heating initial decomposition temperature of cured material was all above 280℃.A novel bio-based binary acid for flame-retardant epoxy curing agent named ricinoleic acid modified with itaconic anhydride(IDDRA)was synthesized from castor oil via epoxy ring-opening,epoxy ring-closing,ring-opening addition and esterification.Its chemical structure were characterized by FT-IR and 1H-NMR.And then the epoxy curing behavior of the IDDRA was studied by using different scanning colorimetry(DSC).We prepared a series of mixed curing agents by mixing IDRAE with certain proportions of methyl nadic anhydride(MNA),then these mixed curing agents were used to cure E51 epoxy resin and obtained a series of structure fusion and retardant epoxy polymer materials.And then its comprehensive properties were investigated.The results showed that the IDRAE60/MNA40 epoxy copolymer had optimum comprehensive tensile mechanical properties(34.21 MPa,93.87%).With the increase of IDRAE content,the materials’ tensile strength decrease and their elongation at break increase.The LOI values increased from 22.5% to 23.8% with the increase of IDRAE content.Dynamic mechanical analysis(DMA)showed that the glass transition temperature decreased from 60.40 to 17.33 ℃ with the increase of IDRAE content,indicating that the addition of IDDRA could remarkably improve the toughness and flame retardant property of epoxy cured materials.The results of epoxy curing behavior showed that the optimized curing process conditions of the curing systems was 130℃/2h+160℃/3h,the Ea was 113.21kJ/mol and the curing degree could achieve 86.40% within 15 min at 130℃.A novel bio-based flame-retardant thermosetting vinyl ester resin monomer was synthesized from castor oil.In order to improve its rigidity and expand its application in the field of bio-based materials,a novel bio-based flame-retardant dipentene vinyl ester resin monomer(MDDMD)was synthesized.The chemical structures of the preparaed monomers were characterized by FT-IR and 1H-NMR.Next these two VER monomers were mixed with certain proportions of another diluent PDA,and then a series of VER copolymers were obtained with thermal curing method.The prepared flame-retardant VER copolymers’ comprehensive properties were all investigated.The results showed that the limiting oxygen index was above 23% in all copolymers.The MDRAE20/MDDMD5/PDA30 copolymerized system had the optimum comprehensive tensile mechanical properties(8.7 MPa,20.3%).With the increase of MDRAE content,the copolymers’ tensile strength decrease and their elongation at break increase,elongation at break could up to 35.5%,the hardness decreased from 40.2 to 5.1HD.Thermogravimetric analysis showed that the copolymers had excellent thermal stability,the heating initial decomposition temperature of all polymers were all above 270℃.All these evidences indicated that the addition of MDRAE could remarkably improve the toughness,and all the copolymerization system had excellent flame retardant property and thermal stability.