Construction of room temperature phosphoresence aerogels using lignin/acrymide
As an important component of vascular plant cell walls,lignin is the second most abundant biomass resource after cellulose on earth.Lignin is also the most abundant natural aromatic polymer in nature.There is still limited re-search on its photoluminescence characteristics.In order to achieve lignin-based products with high-added value,this study used sodium lignosulfonate,a common by-product in the pulp and paper industry,as the chromophore and ac-rylamide as the polymerization monomer,the LS@PAM hydrogel was prepared using a one-step polymerization me-thod at 60 ℃ for 1 h.The aerogel was accomplished by freeze-drying the hydrogel.High strength phosgene gel mate-rial was succeeded by using acrylamide rigid and multi hydrogen bond matrix environment limited lignin.The structural properties and photophysical properties of aerogels were analyzed by the Fourier transform infrared spectroscope(FT-IR),X-ray diffraction(XRD),scanning electron microscope(SEM)and steady state/transient fluorescence spec-troscopy.The infrared spectroscopy showed that the acrylamide was successfully polymerized.The X-ray diffraction results showed that there was an obvious bulge peak at 22°,indicating that the aerogel had no obvious crystal struc-ture.The scanning electron microscope showed that the aerogel had an ordered porous network structure and the net-works were interconnected.The phosphorescence spectrum analysis revealed that the longest phosphorescence lifetime of 287.43 ms was detected at 510 nm(green light)when the excitation wavelength was 320 nm,while the fluores-cence spectrum showed the LS@PAM gel had fluorescence excitation dependence.As the excitation wavelength in-creased from 270 to 350 nm,its fluorescence emission center also gradually shifted to red,while under the excitation of 365 nm ultraviolet lamp,the aerogel showed blue fluorescence.Since the aerogel was a rigid block,the mechanical test was carried out.The test results indicated that its tensile strength was 24.24 MPa,and its compressive strength was 9.39 MPa under 10％compression strain.By utilizing the sensitive response of acrylamide matrix to iron ions,effec-tive detection of iron ions can be achieved.Compared with the existing resistance/capacitance humidity sensors,phos-phorous gas gel realized the visual sensing of humidity.When the relative humidity increased from 30％to 50％,the afterglow color of gel changed significantly.This study effectively constructed high mechanical strength phosphorescent materials by using a simple polymerization freeze-drying method and a rigid acrylamide matrix to limit the domain of sodium lignosulfonate.The results of this study provide more utilization methods for the development and utilization of lignin,expanding the preparation strategies and application fields of afterglow emitting materials using forest biomass as raw materials.
万方数据
维普
