Synthesis study of blending lignin with PET towards producing novel carbon foam
Carbon foam possesses several merits as advanced materials including low density,high compressive strength,high electrical conductivity,porous framework,etc.It has potential application value in electromagnetic shielding,heat insulation materials,fuel cells and other fields.Among the diverse precursors for producing carbon foam,lignin has obtained increased interest due to its renewability,low-cost,high production yields,and high aroma-ticity.The commonly used materials for preparing carbon foams were coal,pitch,biomass,etc.Lignin is well-ac-knowledged for its complexed and unique thermal characteristics.Lignin usually exhibits thermal decomposition,sof-tening,cross-linking during the heat treatment.Based on the characteristics of lignin,a facile and simple method was developed to directly convert lignin powders into carbon foam.That is,the pyrolysis trend and melting-softening tem-perature of lignin was determined by the thermogravimetry(TG)and differential scanning calorimetry(DSC).The foamed carbon with regular morphology was prepared by adjusting the pretreatment temperature,heating rate and holding time of lignin without adding additional blowing agents and template agents.In order to further achieve the tai-loring of carbon foam's structures and properties,the blending of polyethylene terephthalate(PET)to lignin was pro-posed in this work,and then the PET's effect on the synthesis of lignin-based carbon foam,as well as the properties of the derived carbon foam,was investigated.The preliminary results indicated that a part of lignin had poor cell struc-ture and formed a tight structure.Nevertheless,PET could regulate the foaming process of the lignin conversion,and the new lignin-PET-based carbon foam could be successfully produced with different properties.Specifically,PET could significantly affect the bulk density,true density,porous structure,and compressive strengths of the derived carbon foam.It was evident that,when the PET content increased to 10％,the density,mechanical strength and the micro pores structure of carbon foamed were decreased,the true density and the compressibility were increased.On the other hand,results from X-ray diffraction(XRD)and Raman tests indicated that the blending of PET had virtual-ly no effect on the microcrystalline structure of the derived carbon foams.In addition,the results showed that when the PET blending ratio increased to 20％,the overall properties of the derived carbon foam decreased,which was probably resulted from the escalation of difficulties in blending PET to lignin.This study provides a new strategy of modifying the structure and properties of carbon foams via polymer blending to lignin,and would guide the synthesis and regulation of lignin-based carbon foam under the new production pathway.
国家科技期刊平台
NSTL
万方数据
维普
