New Trimeric Epoxy Resin Curing Agent At Room Temperature Compound Research

Epoxy resin will form a highly cross-linked network structure after adding curing agent,which is widely used in various aspects,but in some special occasions,such as concrete crack repair,heating construction is difficult,and it cannot be cured at room temperature.The room temperature curing agent can not only meet some occasions that are not suitable for medium and high temperature curing,but also a curing method with energy saving and simple curing process.Therefore,it is of great significance to study the room temperature epoxy resin curing agent.In our laboratory,low molecular weight polyamide 650 is used as the curing agent for curing epoxy resin at room temperature,but the curing time is very long,which is not conducive to construction.Therefore,we consider controlling the curing time to reduce the trouble caused by the long curing time in the construction process.By consulting the data,comparing low molecular weight polyamide,aliphatic and cycloaliphatic amine curing agents at room temperature,we found the research idea of this experiment,that is,using polyvinyl polyamine and isophorone diamine curing agent to compound low molecular weight polyamide It is formulated into a two-component curing agent,and then undergoes room temperature curing reaction with the laboratory-made trimer epoxy resin.This not only improves the brittleness of aliphatic and alicyclic cured products,but also greatly shortens the curing time of low molecular weight polyamides.Through the performance test of the cured product,the curing law of the curing agent at room temperature is studied,and the curing time is controlled to obtain an ideal curing system.The epoxy resin with trimer(TDI-T)was synthesized from bisphenol A(BPA),epichlorohydrin(ECH)and toluene diisocyanate trimer(TDI-T),and then cured with low molecular weight polyamide 650(PA650)/isophorone diamine(IPDA)composite curing system at room temperature.Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry(DSC),thermogravimetric(TG),and mechanical properties were used to study the cured products of the four compound systems.The results showed that different proportions of IPDA curing agent had a great effect on the cured product.When the amount of IPDA was 2%,the maximum compressive strength reached 111.3 MPa,the tensile strength was 27.6 MPa,and the elongation at break was 7.45%.The cured product of IPDA/PA650 resin had both elastic and plastic deformation during tensile process.With the increase of the amount of IPDA,the curing time is gradually shortened.When the amount of IPDA is 6%,the curing time is 3 h,and the maximum temperature during the curing process can reach 52.4℃;DSC test results show that IPDA/PA650 is used as curing agent for curing,the resin has better thermal stability when the temperature is lower than 200℃.On the basis of the experiment in the previous chapter,the curing agent of isoflurone diamine is changed into diethylene triamine,triethylene tetramine and tetraethylene pentamine.The epoxy resin TDI-T/EP was cured at room temperature with low molecular weight polyamide 650/diethylenetriamine(DETA),low molecular weight polyamide 650/triethylenetetraamine(TETA)and low molecular weight polyamide 650/tetraethylenepentamine(TEPA)in different proportions.The curing time of the cured product was determined by the FT-IR spectrum,and the curing time was shortened from several days to several hours,which effectively realized the controllability of the curing time;the experimental results showed that with the increase of the dosage of polyvinyl polyamine curing agent,the heat released during the curing process of the four systems also increased greatly,and the temperature rose from room temperature to 52.4℃,72.6℃,69.3℃ and 53.6℃.When tetraethylenepentamine is added,the elongation at break of the cured product is obviously larger than that of polyethylenepolyamine in the same proportion,and the maximum elongation at break can reach 49.4%.The highest compressive strength is the resin cured by DETA-6/PA650,reaching 113.8 MPa,which is significantly higher than that of pure PA650;The test results show that the compressive strength of the cured resin after corrosion is not much different from that of the uncorroded sample,indicating that the resin after adding polyvinyl polyamine curing agent has a certain corrosion resistance.The DSC test results show that for the curing agent of different proportions in the same compound system,with the increase of the amount of polyethylene polyamine,the glass transition temperature of the cured product also increases.