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Cellulose carbamate (CC) was synthesized via hydrothermal process and mixed with graphene oxide (GO) to form a homogeneous cellulose matrix nanocomposite films. The properties of CC/GO nanocomposite films fabricated using simple solution-mixing method with different GO loadings were studied. Transmission electron microscope analysis showed the exfoliation of self-synthesized GO nanosheets within the CC matrix. X-ray diffraction results confirmed the crystalline structure of CC/GO films as the CC/GO mass ratio increased from 100/0 to 100/4. The mechanical properties of CC/GO film were significantly improved as compared to neat CC film. From thermogravimetric analysis result, the introduction of GO enhanced the thermal stability and carbon yields. The 3D homogeneous porous structures of the CC/GO films were observed under Field emission scanning electron microscope. These improvements in nanocomposite film properties could be confirmed by Fourier transform infrared spectroscopy due to the strong and good interactions between CC and GO. [ABSTRACT FROM AUTHOR]

Here, a stable derivative of cellulose, called cellulose carbamate (CC), was produced from Kenaf (Hibiscus cannabinus) core pulp (KCP) and urea with the aid of a hydrothermal method. Further investigation was carried out for the amount of nitrogen yielded in CC as different urea concentrations were applied to react with cellulose. The effect of nitrogen concentration of CC on its solubility in a urea-alkaline system was also studied. Regenerated cellulose products (hydrogels and aerogels) were fabricated through the rapid dissolution of CC in a urea-alkaline system. The morphology of the regenerated cellulose products was viewed under Field emission scanning electron microscope (FESEM). The transformation of allomorphs in regenerated cellulose products was examined by X-ray diffraction (XRD). The transparency of regenerated cellulose products was determined by Ultraviolet–visible (UV–Vis) spectrophotometer. The degree of swelling (DS) of regenerated cellulose products was also evaluated. This investigation provides a simple and efficient procedure of CC determination which is useful in producing regenerated CC products. [ABSTRACT FROM AUTHOR]

The hydrothermal pretreatment on kenaf core pulp (KCP) was carried out using an autoclave heated in a oil bath at 140 °C for 0.5/1/3/5 h. The hydrothermal pretreated kenaf (HPK) was dissolved in a LiOH/urea aqueous solution and subsequently used to produce cellulose membrane and hydrogel. The effects of hydrothermal pretreatment time on solubility, viscosity, crystallinity and morphology of the cellulose membrane and hydrogel were investigated. The hydrothermal pretreatment leads to higher cellulose solubility and higher viscosity of the cellulose solution. The formation of cellulose II and crystallinity index of the cellulose membrane and hydrogel were examined by X-ray diffraction (XRD). The pore size of the cellulose membrane and hydrogel displayed an upward trend with respect to the hydrothermal pretreatment period observed under a field emission scanning electron microscope (FESEM). This finding provides an efficient procedure to improve the solubility, viscosity and properties of regenerated cellulose products. [ABSTRACT FROM AUTHOR]

Commercial drying of rubberwood at high temperatures is still unknown. Freshly sawn rubberwood lumber was dried at 130°C from a green condition in a commercial-size prototype kiln. The dimensional stability of high temperature-dried rubberwood was determined in this study. The high temperature-dried and conventional temperature-dried (for control) rubberwood dimensional lumber with moisture content of 6-8% after drying was exposed to two equilibrium moisture content conditions in a conditioning chamber, with constant humidity-temperature settings at 30°C, 60% relative humidity (RH) and 30°C, 90% relative humidity. In both conditions, the high temperature-dried rubberwood was found to equilibrate at lower equilibrium moisture content than the control. The moisture exclusion efficiency of high temperature-dried rubberwood against the controls was respectively 24.20% (30°C, RH 60%) and 13.12% (30°C, RH 90%) during the adsorption process. X-ray diffraction analysis showed that the cellulose crystallite size of high temperature-dried rubberwood increased compared to conventional temperature-dried rubberwood. [ABSTRACT FROM AUTHOR]

Liquefaction of empty fruit bunches (EFB) in phenol was carried out in the presence of various types of acids as catalyst. Then the nonreacted EFB (residue) was analyzed using the X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), and scanning electron microscopy. The result show that strong acids produce lower residue compared to weak acids. The TGA results show that the residue possesses a better hydrophobicity and better heat resistance compared to the EFB. The XRD results show the crystallinity of cellulose has been reduced tremendously in the residue reacted with sulfuric acid. The FT-IR results show that for the lowest residue, some of the functional groups belonging to the lignin structure have vanished. [ABSTRACT FROM AUTHOR]