Effects Of Steam Explosion On The Plant Fiber Composition And Properties

Steam explosion is a physical pretreatment technology and it’s a high efficient,non-polluting and environmentally friendly technology. Steam explosion has been applied invarious fields. In different fields, the requirement of intensity of steam explosion is totallydifferent and different plant fibers with the same explosion show different performance. It isof great significance to do systematic research on the effect of steam explosion on plantfibers.In this paper, the self-designed screw steam explosion machine was used and the typhafiber（PB-Fs） and eucalyptus fiber (AB-Fs) were continuously and repeatedly pretreated bysteam explosion. By the analysis of the chemical component, surface composition,morphology, thermal properties and crystal properties of steam explored fibers, the effect ofsteam explosion on plant fibers was studied.The result of chemical component analysis showed that the content of hemicellulose inthe PB-Fs and AB-Fs decreased as the times of steam explosion increased. The content ofhemicellulose in the PB-Fs and AB-Fs have decreased by32%and26%，respectively. Theacid-insoluble lignin of AB-Fs decreased with the increasing of the times of steam explosion,and the content of acid-insoluble lignin has decreased by32%after the9th steam explosions.However, the acid-insoluble lignin of PB-Fs began to increase after the7th steam explosions.It is attributed to which the condensation of lignin is stronger than the depolymerization oflignin with the times increase of steam explosion.According to the SEM images, the intercellular layers and primary walls of PB-Fs andAB-Fs were completely destroyed, and the secondary wall suffered different degrees ofdamage. After the9th steam explosions, the S1layers of PB-Fs and the S2layers of AB-Fscould be seen，respectively. XPS analysis showed that the content of lignin in the surface ofPB-Fs and AB-Fs decreased and the content of extract in the surface of PB-Fs and AB-Fsincreased. They were attributed to the collapse of the intercellular layers, the primary wallsand the secondary wall. Two glass transition temperature of lignin in PB-Fs and AB-Fs could be observed in theDSC curves. The glass transition of lignin in PB-Fs was more obvious. It was attributed towhich there were more P-hydroxy phenyl propane lignin in PB-Fs and the molecular chain ofthem could move easily. The TG results showed that the thermal stability of PB-Fs and AB-Fswere improved. The XRD results showed that the crystallinity of PB-Fs and AB-Fs decreased.