Synthesis And Properties Of Eugenol-based Biphenyl Epoxy Resin

Epoxy resins are widely used in coatings,adhesives,construction,electronic packaging,automotive and aerospace fields.However,the raw materials for its synthesis mainly come from petrochemicals,and bisphenol A is more toxic,especially for the human body secretion system.With the increasingly prominent resource and environmental issues,research and development of bio-based epoxy resins to replace traditional petroleum-based epoxy resins has become an important research direction in the field of polymer materials.Eugenol is the main component of plant essential oil(syringa oil),with low toxicity and stable source,which is relatively easy to obtain in large quantities.In recent years,polymer materials based on eugenol have received extensive attention,especially the research on epoxy resin systems based on eugenol.In this paper,natural eugenol is used as a raw material to design and synthesize a new type of bio-based epoxy resin monomer.The monomer molecule contains a biphenyl molecular skeleton structure,which has a high bio-based content.Then,to study the properties of its cured product,the main research contents are as follows:(1)Starting from eugenol,through its bimolecular oxidative coupling,the biphenyl molecular skeleton is constructed,and the eugenol biphenyl intermediate(DEU)with 100%bio-based content is obtained.By optimizing its synthesis reaction conditions and separation methods,characterizing its molecular structure and composition,it was found that DEU has a high purity,and realized a high-throughput(hundreds of grams)synthesis of DEU laboratory scale.Then,in the presence of a phase transfer catalyst,the intermediate and epichlorohydrin were subjected to a glycidation reaction,and the synthesis reaction conditions and purification method were optimized.Finally,the eugenol-based biphenyl epoxy monomer(DEU-EP)was obtained.The results showed that DEU-EP had a higher epoxy value(0.42)and a better purity(92%)by measuring 1H NMR and HPLC.(2)DDS(3,3-diaminodiphenyl sulfone)was used to cure DEU-EP,samples of epoxy cured products were prepared,and the glass transition temperature(Tg)and heat of DEU-EP/DDS cured products were studied.Stability(TGA),contact angle(CA),water absorption and mechanical properties,the results show that the cured product has a higher glass transition temperature,surface hydrophobicity,higher thermal stability,lower water absorption(about 3%).Furthermore,DDS(3,3-diaminodiphenylsulfone),MHHPA(methylhexahydrophthalic anhydride),and PACM(4,4’-diaminodicyclohexylmethane)were used as curing agents to cure E54 bisphenol A epoxy Resin(DGEBA)and DEU-EP,the Tg,TGA,CA,water absorption and mechanical properties of the two cured products under the same curing agent were studied.The results show that the DEU-EP/DDS cured spline has a higher energy storage mode Volume,higher carbon residue rate and larger contact angle,DEU-EP/MHHPA cured spline also has higher storage modulus,higher carbon residue rate and larger contact angle,DEU-EP/PACM and DGEBA/PACM cured splines have similar surface hydrophobicity.