Papers by Author: Li Jun Qu

Abstract: Abstract: With the purpose to improve the mechanical properties and cut costs of chitosan films, a series of gelatin-chitosan films were prepared. The effect of gelatin content on the mechanical properites of films was studied. FT-IR spectrum and X-ray diffraction analysis showed good compatibility between gelatin and chitosan. The composite films exhibited a higher TS(tensile strengths) and ES(elongation at break) compared with chitosan film, especially when the content of gelatin in blends was 30%. The TS and ES revealed that the interaction between chitosan and gelatin was the strongest when the content of gelatin in blends was 30%. The results obtained from percent water absorption indicated these two biopolymers were high hydrophilicity polymer. The water solubility of composite films was higher than chitosan films. The results suggest that the interactions between gelatin and chitosan was good for the mechanical properties of composite films.

Abstract: In this paper the components of Broussonetia Papyriferalvent (BP) white bast were tested and compared with some bast fibers such as hemp, flax, jute and and ramie, the cellulose content is as high as 63.76wt%. The bio-enzyme pre-trement and alkali-H2O2 one bath processing were employed to extract BP fibers. The effect of bio-enzyme pre-trement and alkali-H2O2 one bath processing on the morphological structure of cellulose was investigated with X-ray diffraction (XRD). The tensile and moisture properties of BP fibers were tested and discussed.

Abstract: A new flats-delivering device has been invented to improve the straight and parallel alevel of fibers in a friction spinning fram. The principle of the friction spinning based on the flats-delivering device called tapered pipe and open-space flats has been investigated. New concepts of the “curvilinear-transmitting” and the “parallel condensing” have been suggested to explain the theory of the new divice. The transmission experiments of this improved device has also been reported. It was found that this new device could achieve the effect of straighten and paralleled fibers when fibers sucked into the v-zone of the dust drums in a friction spinning fram.

Abstract: Adsorption of dye from dyeing wastewater had been investigated using cross-linked chitosan beads as an adsorbent. The chitosan adsorbent was characterized by SEM, FT-IR and porosity [P]. Various parameters such as concentration of adsorbent (0.5 g/200mL to 2.5 g/200mL), pH (3-11), initial concentration of dye (50-250mg/L) and temperature (15-45 ) of adsorbate were studied. Langmuir and Freundlich isotherms were used to analyze the equilibrium data at different temperatures. Freundlich isotherm showed better correlation coefficient than the other models at all temperatures studied. The cross-linked chitosan adsorbent exhibits a high adsorption capacity to remove dye. And the adsorbent still has good adsorption capability after being reclaimed for 6 times. This study indicates that cross-linked chitosan is a promising adsorbent for removing dye from dyeing wastewater.

Abstract: The main objective of this paper was to investigate a low cost pretreatment method, namely microwave-assisted extraction(MAE) pretreatment, which could be applied to hemp degumming with low environmental impact. Degumming index, contrast of different pretreatment methods, transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and single fiber tensile testing were used to characterise the effect of pretreatment on hemp fibers. In this paper, the results of degumming effect were given comparing MAE pretreatment with acid pretreatment for hemp degumming. It was found that the MAE pretreatment could remove non-cellulosic compounds from hemp bundles effectively with very short period of time. Meanwhile, seen from SEM micrographs, the fibers pretreated by MAE were cleaner than that of fibers pretreated by acid. These results suggested that MAE pretreatment was higher efficiency and more environmental friendly than traditional pretreatment methods.

Abstract: The morphology and structure of Broussonetia papyrifera(BP) bast and fiber were investigated by SEM, OM, FT-IR and X-ray analysis, and chemical composition of BP bast was analyzed. The results show that the cellulose content in the BP bast can be as high as 63.76%. BP fibers arrange parallel in the bast, which are linked by pection. The cross-section of PB fibers are irregular round with lumens that are almost invisible in the completely mature fibers. The crystallinity of the fiber could reach 83.26%. Most impurities such as hemi-cellulose, lignin, pectin could be effectively removed by degumming, while cellulosic structure is not changed. BP fiber has good mechanical properties, but the single fiber is too short to spin alone.