Effect Of Chemical Pretreatment Of Eucommia Ulmoides Seed Shell On Extraction Efficiency And Properties Of Eucommia Ulmoides Gum

Eucommia ulmoides gum(EUG)is a very precious natural rubber resource in my country.It is a kind of natural polymer material.It has exactly the same chemical composition as natural rubber(NR),but the two are isomers of each other.Its main composition is Trans-1,4-polyisoprene mainly deposited in eucommia cells,and eucommia seed shell contains more gum.Because EUG has good insulation,wear resistance,acid and alkali resistance,low heat generation,low rolling resistance,impact resistance,etc.,it has been widely used in the manufacture of aerospace tires,submarine cables,damping materials,medical equipment and sports goods and other fields.On account of EUG exists in plant cells,it makes the extraction of EUG difficult.It needs to be hydrolyzed to destroy the plant cell wall during extraction,so that the cell wall becomes loose and the glue filament is dissolved.However,the extraction rate is low and the purity is directly extracted with petroleum ether.EUG has low pigment content and high pigment content,so it is necessary to pre-treat the husk of Eucommia ulmoides seed before extraction,which can increase the extraction rate,remove macromolecular impurities such as pigment,and improve the purity of the gum.This paper mainly adopts H₂O₂pretreatment and H₃PO₄/H₂O₂from the pretreatment schemes of hot alkali solution treatment,ultrasonic assisted alkali solution treatment,microwave assisted alkali solution treatment,H₂O₂pretreatment,H₃PO₄/H₂O₂mixed solution treatment,and cellulase auxiliary treatment.The mixed liquor pretreated the husks of Eucommia ulmoides,and then studied the effect of these two pretreatment methods on the extraction efficiency of EUG.The effect of H₂O₂pretreatment of Eucommia ulmoides seed hulls on the extraction efficiency of EUG was studied through single factor and orthogonal experiments.The extracted EUG was characterized by FT-IR,¹H-NMR and GPC.The experimental results show that the optimal conditions for H₂O₂pretreatment are as follows:H₂O₂concentration is 4%(mass fraction),material-to-liquid ratio is 1:14(g/m L),p H=7,after pretreatment at 80?for 2h,and petroleum ether With 85?reflux extraction,the EUG extraction rate was 29.79%,which was 17.43%higher than that without pretreatment.FT-IR and ¹H-NMR results show that H₂O₂pretreatment has no effect on EUG molecular chain structure and chemical composition.The GPC results show that the EUG product extracted by H₂O₂pretreatment is pure,without macromolecular impurities,and its molecular weight is slightly lower than that of direct extraction.Compared with acid-base conditions,the molecular weight is the highest under neutral conditions.The effect of the H₃PO₄/H₂O₂mixture pretreatment of Eucommia ulmoides seed hulls on the extraction efficiency of EUG was studied.The optimal experimental conditions of H₃PO₄/H₂O₂pretreatment were determined through single factor and orthogonal experiments,and the extracted EUG was characterized FT-IR,¹H-NMR and GPC.The experimental results show that the optimal process conditions for the pretreatment of H₃PO₄/H₂O₂are as follows:the ratio of material to liquid is 1:10(g/m L),and the volume ratio of 3%H₃PO₄(mass fraction)and 3%H₂O₂(mass fraction))The mixed solution was pretreated at 80?for 1h,and petroleum ether with 85?reflux extraction,the EUG extraction rate was 38.82%,which was 24.85%higher than that of the untreated solution.The results of FT-IR and ¹H-NMR showed that the H₃PO₄/H₂O₂pretreatment had no effect on the structure and chemical composition of EUG molecular chain.The GPC results demonstrate that the EUG product extracted by H₃PO₄/H₂O₂pretreatment was pure without macromolecular impurities,and its molecular weight was slightly lower than that of direct extraction.