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Kenaf core pulp has been successfully autohydrolysed using an autoclave heated in oil bath at various reaction temperature at 100, 120 and 140 °C. Membranes, hydrogels and aerogels were then prepared from autohydrolysed kenaf in urea/alkaline medium by casting on the glass plate, by using epichlorohydrin (ECH) as cross-linker via stirring and freeze-drying method, respectively. The autohydrolysis process reduced the molecular weight of cellulose and enhanced cellulose solubility and viscosity. Structure and properties of the regenerated products were measured with Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Ultraviolet–visible (UV–Vis) spectrophotometer and swelling testing. As the autohydrolysis temperature increased, the porosity of cellulose membranes (as seen from the morphology) increased. The autohydrolysis process improved the swelling porperties and transparency of regenerated cellulose hydrogels. This finding is expected to be useful in reducing molecular weight of cellulose in order to produce regenerated bio-based cellulose materials. [ABSTRACT FROM AUTHOR]

Cellulose carbamate (CC) was produced from kenaf core pulp (KCP) via a microwave reactor-assisted method. The formation of CC was confirmed by Fourier transform infrared spectroscopy and nitrogen content analysis. The degree of substitution, zeta potential and size distribution of CC were also determined. The CC was characterized with scanning electron microscopy, X-ray diffraction and thermogravimetry analysis. The CC particles were then dispersed in silicone oil to prepare CC-based anhydrous electric stimuli-responsive electrorheological (ER) fluids. Rhelogical measurement was carried out using rotational rheometer with a high voltage generator in both steady and oscillatory shear modes to examine the effect of electric field strength on the ER characteristics. The results showed that the increase in electric field strength has enhanced the ER properties of CC-based ER fluid due to the chain formation induced by electric polarization among the particles. [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]

Highlights • Properties of needle punched thick EFB and fine kenaf fibres were compared. • The performance of EFB fibre in nonwoven fabric preform was revealed. • Effects of type of fibres and nonwoven fabrics on physical properties of PP composite were studied. • EFB has higher tensile strength in nonwoven preform but lower in composite as compared with kenaf. Abstract The empty fruit bunch (EFB) and kenaf polypropylene (PP) nonwoven composites in this study were prepared via needle punching nonwoven process followed by compression moulding. As compare to the fine kenaf fibre, the thick and rough fibre such as EFB is uncommon in the nonwoven process although it could be a cheap alternative material. To establish EFB as a new raw material in needle punching nonwoven composite, the effect of type of fibre, fibre content, fabric direction and fabric weight on mechanical properties of polypropylene nonwoven preform and composite was studied. Statistical Analysis of Variance (ANOVA) has been used to analyse the effects of the parameter to the preform and composite properties. The punching density, fabric weight and natural fibre content were set at 0, 150 and 300 punches/cm2; 300, 400 and 700 g/m2; 40, 50 and 60%, respectively. This study showed that type of fibre has significant influence on the tensile strength of the nonwoven preform especially at 60% fibre content as compare to the nonwoven composite. The fibre content and fabric direction were also the main factors affecting the tensile strength and the tensile elongation of the nonwoven preform. It was proven that EFB has great potential applications as nonwoven fabric and alternative reinforcement material in nonwoven composites. [ABSTRACT FROM AUTHOR]

Bleached kenaf core pulps (BKC) were hydrolyzed in H 2 SO 4 (0.5 M) at different time (0 min to 90 min) at room temperature. After the hydrolysis process, the viscosity average molecular weight ( M ŋ ) for BKC sample has reduced from 14.5 × 10 4 to 2.55 × 10 4 . The hydrolyzed BKC was then dissolved in NaOH:urea:water and in LiOH:urea:water mixed solvent at the ratio of 7:12:81 and 4.6:15:80.4, respectively. The increased in hydrolysis time has decreased M ŋ of cellulose leading to easy dissolution process. Higher porosity and transparency with lower crystallinity index (CrI) of regenerated membrane produced can be achieved as the M ŋ reduced. The properties of membrane were observed through FESEM, UV–vis spectrophotometer and XRD. This study has proven that acid hydrolysis has reduced the M ŋ of cellulose, thus, enhanced the properties of regenerated membrane produced with assisted by alkaline/urea system. [ABSTRACT FROM AUTHOR]