Construction Of Photo-responsive Flame Retardant Polyurethane Foam And The Application In Oil-water Separation

As one of the most important energy sources in the country,oil is known as"the blood of industrial economy",which has accelerated the pace of scientific development.Whereas,with the exploitation,transportation and use of a large amount of oil,leakage accidents occur frequently.In addition,the leakage of organic solvents and the random discharge of oily industrial wastewater have also caused serious harm to the ecosystem.Since the 18th National Congress,the CPC Central Committee has focused on the overall development of the Party and the country,emphasizing targeted,scientific and law-based pollution control,and resolutely winning the battle against pollution.Therefore,how to clean up oil pollution with high efficiency and low cost is urgent and an important guarantee for the long-term development of energy economy.At present,among the common oil spill treatment methods,physical adsorption method stands out owing to its advantages of high adsorption efficiency,recoverable oil products,easy operation and no secondary pollution.As a typical three-dimensional adsorption material,polyurethane foam is an ideal choice for cleaning up oil due to the excellent oil storage capacity,fast adsorption rate,decent recycling and stability.However,when it is applied to the field of oil-water separation,there are still some problems such as poor selectivity of oil-water,inflammability and low adsorption efficiency of sticky oil.Based on this,the novel polyurethane foam adsorption material with hydrophobic and oilophilic,flame retardantcy and photothermal conversion performance is designed to solve the above problems.The main research work is as follows:(1)An efficient and environmentally friendly polyurethane foam(PMP-PU)is prepared by one-step method,wherein PDA/MXene is mechanically mixed with foam materials(N330 and PANI).The PMP-PU modified foam has super-hydrophobicity,excellent mechanical properties and photothermal performance.The surface temperature can reach 99℃under the irradiation of the simulated light source(1 kW/m~2)for 600 s.The maximum adsorption capacity of low viscosity oil and organic solvents can be up to 70 times of its own weight at room temperature,and the adsorption capacity of high viscosity silicone oil under the irradiation of simulated light source is28.2 g/g,which is 206.5%higher than pure PU.Furthermore,compared with pure PU,the PHRR,THR,PSPR and TSP of PMP-PU can decrease by 24.5%,46.0%,29.5%and20.9%,respectively.At the same time,the melt dripping phenomenon disappears during combustion of the modified foam,which remarkably improves the fire safety.(2)PDA/MXene and PDA/RGO modified fillers are introduced into the polymer system by physical blending method,so as to directly participate in the construction of foam skeleton and give excellent performance to PMRP-PU.The semiconductor material PDA/MXene and carbon-based material PDA/RGO successfully constructed a collaborative photothermal system to further enhance the photothermal conversion ability.The surface temperature of the PMRP-PU modified foam can reach 105℃after irradiation for 600 s.At room temperature,PMRP-PU modified foam has outstanding adsorption performance for low viscosity oil and organic solvents,and the maximum adsorption capacity can reach 70.1 g/g.Meanwhile,the adsorption capacity of high viscosity silicone oil is also 202.1%higher than that of pure PU.Moreover,the modified foam has preeminent acid and alkali resistance and high temperature resistance stability,which greatly improves the environmental adaptability.The PHRR,THR,PSPR and TSP also showed a decreasing trend compared with pure PU,with the maximum decreasing range of 21.6%,35.6%,14.1%and 28.5%,respectively.(3)The environmentally friendly PA/PANI micro-nanometer coatings are assembled on the surface of PDA/MXene-PU matrix by in-situ polymerization.Thanks to the synergistic effect of MXene and PANI,PMPP-PU has more preeminent photothermal conversion performance compared with the PMP-PU and PMRP-PU,with the highest absorbance up to 1.95.Additionally,the heating rate is accelerated under the irradiation of the light source,the surface temperature quickly rises to 96℃after 60 s,and reached118℃for 600 s.With the increase of light density to 1.5 kW/m~2 and 2.0 kW/m~2,the temperature further rises to 131℃and 148℃,respectively.Compared with pure PU,the adsorption capacity of PMPP-PU modified foam is notably enhanced,which can absorb61 times its own weight of chloroform and 29 times its own weight of high viscosity silicone oil.Moreover,the MCC test results show that the modified foam has excellent flame retardancy,the maximum reduction of PHRR and THR of the modified foam is71.2%and 63.8%in comparison with pure PU.In the alcohol lamp ignition test,the foam can self-extinguish after leaving the flame.