Study On The Preparation Of Nitrogen-containing Polymers And Their Performances As Corrosion Inhibitors

Four kinds of corrosion inhibitions are synthesized which contain nitrogen atom located in side chain or in main chain,respectively,poly N-vinylimidazole?PVI?,polyhexamethyene biguanidine?PHMB?,dicyandiam-formaldehyde condensation product?DCF?and poly?5-vinyltetrazole??PVT?in the paper.The corrosion inhibition effects of them on Q235 carbon steel were investigated in different temperatures and acidities of hydrochloric acid?HCl?solution.Product morphology observation?IR?GCP and polarization curves,electrochemical impedance spectroscopy?ESI?and scanning electron microscopy?SEM?techniques were used.At the same time,the mechanism of corrosion inhibition was investigated in the paper.The results show that all of these four kinds of inhibitors have corrosion inhibition effects on Q235 carbon steel in hydrochloric acid solutions.The corrosion inhibition effection of PVI or DCF can reach up more than 84%.The ability of anti-high temperature of DCF is more stronger than PVI.While the corrosion inhibition efficiencies of PHMB and PVT are effective in the condition of high temperature and acidity,but the usage is so heavy.But corrosion inhibition efficiencies are different,so are the type and the mechanism of them.The results are as follows:?1?The inhibition efficiency of PVI can reach 90.1%in 1 mol·L^-1 hydrochloride acid with 2 mg·L^-1 PVI at 298 K,and it can reach above 84%at high temperature?328K?in solution of high acidity(2 mol·L^-1).The electrochemical measurements suggest that PVI is a kind of mixed type inhibitor,the adsorption of PVI on the surface of metal obeys the Langmuir adsorption isotherm,free energies of adsorption calculated indicate that PVI exhibits strong tendency of adsorption on metal via chemical adsorption.?2?The inhibition efficiency of PHMB can reach 93%in 0.5 mol·L^-1and 1 mol·L^-1hydrochloride acid with 250 mg·L^-1 PHMB and the result can reach 90.2%in 2 mol·L^-1with 400 mg·L^-1 at 298 K,moreover it only reach 60%in 1 mol·L^-1at 328 K.The electrochemical measurements suggest that PHMB is a kind of mixed type inhibitor,the adsorption of PHMB on Q235 carbon steel obeys the Langmuir adsorption isotherm,free energies of adsorption calculated indicate that PVI exhibits strong tendency of adsorption on metal via physical adsorption.?3?The inhibition efficiency of DCF can reach 90.1%in 1 mol·L^-1 hydrochloride acid with 3 mg·L^-1 DCF at 298 K,and it can reach above 85%at high temperature?328K?in solution of high acidity(2 mol·L^-1).The electrochemical measurements suggest that DCF is a kind of mixed type inhibitor,the adsorption of DCF on the surface of metal obeys the Langmuir adsorption isotherm,free energies of adsorption calculated indicate that DCF exhibits strong tendency of adsorption on metal via physical and chemical adsorption.?4?The inhibition efficiency of PVT can reach 95%in 1 mol·L^-1 hydrochloride acid with 250 mg·L^-1 PVT at 298 K.With the increase of concentration of corrosion inhibitor,the corrosion inhibition efficiency will reduce.It can reach above 90%at high temperature?328 K?in solution of high acidity(2 mol·L^-1).The electrochemical measurements suggest that DDF is a kind of mixed type inhibitor,the adsorption of PVT on Q235 carbon steel obeys the Langmuir adsorption isotherm,free energies of adsorption calculated indicate that PVT exhibits strong tendency of adsorption on metal via chemical adsorption.