Synthesis And Study On The Inhibition Performance Of Polymer Inhibitor PMA-AEO-3

The fatty alcohol polyoxyethylene ether maleate monoester?MA-AEO-3?is obtained by esterification of fatty alcohol polyoxyethylene ether?AEO-3?with maleic anhydride?MA?,and then a novel polymer inhibitor PMA-AEO-3 is prepared through free radical polymerization with maleic anhydride and MA-AEO-3 as well as potassium persulfate.The target polymer is characterized by infrared spectroscopy?IR?and mass spectrometry?MS?;the corrosion inhibition performance of PMA-AEO-3 against A3 carbon steel is studied by weight-loss method;the mechanism of scale inhibition of PMA-AEO-3 is investigated using SEM and XRD technologies;the effects of monomer ratio,initiator dosage,reaction time and reaction temperature on the inhibition performance of PMA-AEO-3 against calcium carbonate scale are also studied by static experiments.The optimal conditions of esterification reaction are:n?MA?:n?AEO-3?=1.05:1,and reaction at 70°C for 4 h;while the optimal conditions for the polymerization reaction are:n?MA?:n?MA-AEO-3?=6:1,the amount of potassium persulfate is 12%of the total MA mass,reaction is kept at 80°C for 5 h and followed by further conversion at 85°C for 2 h.The static experimental results show that when the addition amount is 2 mg/L,PMA-AEO-3 has the best performance against calcium carbonate and the efficiency is 98%;for the same dosing,the scale inhibition performance of PMA-AEO-3 increases slightly with the increase of Ca²⁺concentration at firstly and followed by a slightly decrease;the inhibition performance of PMA-AEO-3 against calcium carbonate scale decreases significantly with elevated p H value;the inhibition performance of PMA-AEO-3 against calcium sulfate scale is positively correlated with the dosing of inhibitor,i.e.,when the dosing is 20 mg/L,the scale inhibition efficiency is 95.8%;compared with commercial inhibitors?such as PAA,HPMA,and HEDP?,PMA-AEO-3 has the advantage in preventing calcium carbo nate scale but fails in high hardness and high alkalinity conditions.The addition of PMA-AEO-3 can not only change the crystals morphology of calcium carbonate and calcium sulfate,but also alter the relative content of various crystal forms in the crystal;the corrosion inhibition efficiency of PMA-AEO-3 to carbon steel is proportional to the adosage of inhibitor,when the addition amount is 10 mg/L,the corrosion inhibition efficiency of PMA-AEO-3 to A3 carbon steel reaches 56%,in this case the amount of scale inhibitor molecules adsorbed on the surface of carbon steel has saturated already.Compared with commercial inhibitors?such as HPMA,PAA and HEDP?,PMA-AEO-3 has the best corrosion inhibition efficiency.Finally,the commercially available HPMA is selected as a representative of polycarboxylic acid scale inhibitors,the effects of Ca²⁺,SO₄^2-,PO₄^3-,Mg²⁺,SiO₃^2-,Cl^-,and H⁺ions in circulating cooling water on the performance of polycarboxylic acid scale inhibitors against calcium carbonate scale are systematically studied.The results show that SO₄^2-,Cl^-,and SiO₃^2-can enhance the performance of HPMA in inhibiting calcium carbonate scale at certain concentrations;but the presence of PO₄^3-and Mg²⁺may impair the ability of HPMA;while p H value has a significant effect on the performance of HPMA.