Preparation Of Polyetheramine And Its Application In Epoxy Resin

In this paper,different molecular weights of novel amines with flexible polyoxypropylene side chain(AFPEs)were synthesized through propylene oxide(PO)of anionic ring-opening polymerization(AROP),and different molecular weights of tetraamine terminated polyoxypropylene with urethane and urea(TAPEUs)were prepared successfully.Then,the obtained AFPEs and TAPEUs were used as toughening agent for diglycidyl ether of bisphenol A(DGEBA)/diethylene triamine(DETA)system,respectively.The relationships of structure and properties were studied in detail.Firstly,the reaction condition of ketimine was determined,and the structure of ketimine was detected by gas chromatography(GC)and Fourier Transform Infrared Spectroscopy(FT-IR).Then,the reaction conditions for PO of AROP,such as reaction temperature,pressure,the species and the amount of catalyst were studied,when ketimine was as the initiator.The results showed that the AFPEs with low molecular weight distribution and low viscosity were successfully prepared,when the temperature was at 120?130?,reaction pressure was at 0.3?0.4 MPa,and potassium hydroxide was used as catalyst.Finally,TAPEUs were prepared through the reaction of ketimine and NCO-terminated polyoxypropylene prepolymers,and the structures were characterized by FT-IR and nuclear magnetic resonance(1H NMR).Differential scanning calorimeter(DSC)was used to study the non-thermal curing kinetic of DGEBA/AFPEs.The results showed that with the increasing molecular weight of AFPE,the apparent activation energy increased,the reaction enthalpy and the percentage of autocatalytic reaction decreased.The morphology,structure and mechanical properties of AFPEs toughened DGEBA/DETA systems were studied by curing degree,DSC,dynamic mechanical analysis(DMA),and scanning electron microscope(SEM).The results showed that the curing degree,a relaxation temperature,P relaxation temperature and crosslinking density decreased with the increasing molecular weight or the content of AFPEs,while impact strength improved,but tensile strength and flexible strength decreased.Shear band can be observed on the tensile fracture of AFPE 10 toughened DGEBA/DETA system,while cavitation-shear banding can be observed on the tensile fracture of AFPE20,AFPE30 and AFPE40 modified DGEBA/DETA system,and the size of cavitation was increasing with the higher molecular weight of AFPE.The morphology,structure and mechanical properties of TAPEUs toughened DGEBA/DETA systems were also studied.The results showed that with the increasing molecular weight or content of TAPEU,the curing degree and crosslinking density decreased,and density of hydrogen bond increased.However,the elongation at break and impact strength increased appreciably,while the tensile strength,flexural strength and modulus decreased.With the increasing content of TAPEU1000 in the system,the elongation at break and impact strength increased,while the tensile and flexural strength enhanced firstly,then decreased.With the increasing content of TAPEU2000 or TAPEU4000,the tensile and flexural strength decreased immediately,and microphase separation can be observed on the tensile fractures.