Synthesis and Properties of Bio-Based Thermosetting Resins Based on Engenol
Author:Dai Jin Yue
Supervisor:liu xiao qing
As an indispensable component parts of bio-based polymers,bio-based thermosetting resins not only have excellent properties that traditional thermosetting resins own,such as excellent acid and alkali resistance,good thermal stability and excellent dimensional stability,but also have the dual efficacy of saving resources and protecting the environment by reducing the dependence of polymer materials on petrochemical resources.Therefore,developing bio-based thermosetting resins to replace the traditional petroleum-based thermosetting resins is of great significance for the current strategy of green and sustainable development.In this paper,a series of bio-based thermosetting resins were prepared from the bio-based monomer eugenol,and the relationship between their structure and properties was studied systematically.The main contents are as follows:(1)Two bio-based monomer EM2G and EM3G were synthesized from eugenol,and they were used as active diluent to copolymerize with acrylated epoxidized soybean oil(AESO)to prepare a series of plant oil-based thermosetting resins.The influence of EM2G and EM3G on thermal and mechanical properties of AESO curing system was studied.Then on the base of these,the possibility of its application in coatings industry was discussed.Results demonstrated that not only the thermal and mechanical properties such as Tg and tensile strength,but also the coating performances of the cured AESO were increased significantly with the increasing content of EM2G and EM3G.(2)Two allyl derivatives EAE and DAI were prepared from eugenol and itaconic acid.Then,a series of bio-based thermosetting films were synthesized by the "click" chemistry reaction of EAE and DAI with multi thiols.Their thermal and mechanical properties were studied by adjusting the proportion of EAE and DAI in raw materials.Results showed that the Tg,modulus and tensile strength of the bio-based thermosetting films were significantly improved with the content of DAI increasing.Therefore DAI played a very good strengthening role,which solved the problem of the insufficient thermal and mechanical properties of polymer prepared by "click" chemistry reaction.In addition,these bio-based thermosetting films also showed well efficiency in killing common bacteria(e.g.S.aureus and E.coli)in the antibacterial test,and the antibacterial effect was improved with the content of EAE increasing.Finally,the possibility of application of eugenol derivatives in functional materials was also discussed.(3)Three bio-based organosilicon epoxy precursors SIE-EP,SIEP-EP and D4E-EP were designed and synthesized from eugenol,siloxane and epichlorohydrin And the effects of different siloxane structures and different curing agents on the thermal and mechanical properties of the final curing products were studied with the commercial products of bisphenol A glycidyl ether epoxy resin DER331 as control.Compared with commercial DER331,these bio-based epoxy resins showed better performance in thermal stability and dielectric properties due to the structure of siloxane,but with poorer mechanical properties and dynamic mechanical properties Among these bio-based epoxy resins,D4E-EP/DMM system showed excellent thermal stability,and its R800 in nitrogen atmosphere was as high as 41.5%.Besides,D4E-EP epoxy also showed excellent dielectric properties(4)Several bio-based main-chain type benzoxazines were synthesized from eugenol derivatives(SIE)and different diamine.The thermal and mechanical properties of the polybenzoxazines were studied by adjusting the length of the aliphatic chain in diamine.Results demonstrated that these polybenzoxazine films exhibited good thermal stability and mechanical properties,In addition,they also exhibited good coating properties,such as high hardness,excellent adhesion,good flexibility and outstanding solvent resistance.(5)Based on the work of previous chapter,a series of noval furfuramine terminated main chain type benzoxazine were prepared by introducing a mono functional amine source,which solved the low storage stability of traditional main chain type benzoxazine.The feasibility of these benzoxazines as RTM resin was also discussed.Results showed that these noval main chain type benzoxazines had the stable viscosity lower than 1 Pa·s in the temperature range from 60℃ to 190℃ and their processing window was found to be wider than 160℃,which was very suitable for RTM.Moreover,the polybenzoxazines exhibited excellent thermal stability and good thermal and mechanical properties,showing Td10%of 406℃C and Tg higher than 110℃.Due to the addition of silicone moieties,the cured polybenzoxazines also exhibited hydrophobic property and extremely low moisture absorption.