| The industrial lignin resources are very abundant in our country, pulp and paper industrycan produce about30million tons of lignin by-products every year.At present， ligninby-products are mainly burned off to recycle the alkali and heat.Less than10%of the ligninby-products are applied as industrial additives areas through chemical modification As themarket capacity of industrial additives is limited，it’s difficult for the field of industrialadditives to digest the whole lignin by-products of pulp and paper industry. Ligninby-products need to be used in the other areas.In recent years, domestic and foreign scholars try to blend lignin and plastic resin toprepare the composite material, which can not only solve the utilization problem of industriallignin, but also reduce the dependence of resin industry on oil resources. it has importantsignificance to the environmental protection and sustainable developmentBall milling, jet milling methods were used to get alkali lignin(AL) particles of differentsize. The results showed that pneumatic milling AL had the finest particle size, its size was3μm.These AL particles were respectively blended with HDPE to prepare AL/HDPEcompositesThe result showed that the tensile strength of composite increased with the increasing ofAL content. When containing the same addition, the composite prepared by finer AL particleshad higher tensile strength.The tensile strength of blank HDPE sample is22.33MPa, thetensile strength of composite produced by40wt%jet milling AL was26.54MPa,4.21MPahigher than the blank HDPE sample. As for the elongation at break of composites, resultsshowed that after adding AL, the elongation at break of composites decreased sharplycompared with blank HDPE sample. More AL adding in composites, smaller the elongation atbreak is. The elongation at break of blank HDPE is269.1%, when adding10wt%AL, itdecreased to95.0%; when the content increased40wt%, it decreased only to15%. Theparticle size of AL has little effect on elongation at break.The rheological properties showed that the addition of AL can increase the apparentviscosity (η) and complex viscosity (η*) of the composites, and the linear viscoelastic regionturned narrow, the storage modulus (G’) and the loss modulus (G") also gradually declined with the increasing AL content. The TG curve showed that AL lowered the thermostability ofcomposites. Considering the properties of composites and economic benefit, we select the200-300mesh AL as the raw material to prepare the composite, and it’s content is20wt%.Plasticizer, lubricant, coupling agent and solubilizer were added to prepare compositescontaining20wt%AL, result showed that the adding of plasticizer had the best effect toproperties.The alkali AL/HDPE composites were prepared respectively with dioctyl phthalate(DOP), dibutyl phthalate (DBP) and epoxidised soybean oil (ESO). The influence ofplasticizer on mechanical properties of composites was studied. The results showed that thoseplasticizers could increase the elongation at break of composites and DOP had the best effect.When added7.5g DOP, the elongation at break of composites was146.28%, which was62.4%higher than that of composites without DOP. Composites were prepared with differentcontent of DOP to study the influence of DOP on mechanical properties, fracture morphologyand rheological properties of composites. The mechanical properties of composites showedthat the increasing DOP content was beneficial to the increasing of elongation at break. TheSEM showed that the fracture surfaces of composites became coarser with the addition ofDOP, and the toughness of composites increased. The rheological properties showed that theaddition of DOP can lower the apparent viscosity (η) and complex viscosity (η*) of thecomposites, and the linear viscoelastic region turned narrow, the storage modulus (G’) and theloss modulus (G") also gradually declined with the increasing DOP content. According to theanalysis it was concluded that DOP can adsorb on the surface of AL particles and suppress theagglomeration of AL particles in HDPE, which improve the dispersion of AL particles inHDPE and reduce the interaction force between the AL molecule and the molecular chain ofPE, thus the mechanical properties and rheological properties of the composites wereimproved.Spray drying method were used to prepare EHL/CaCO3composite fillers, which is addedto HDPE to prepare composite containing20wt%fillers. When the ratio of composite filler is1:1, it’s composite has the best properties, the elongation at break is80.08%,13.88%higherthan that of composite prepared by20wt%CaCO3,17.76%higher than that of compositeprepared by20wt%EHL, the tensile strength is25.53MPa,1.12MPa higher than that ofcomposite prepared by20wt%CaCO3,5.51Mpa higher than that of composite prepared by 20wt%EHL... |
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