Isolation and Characterization of Nanocrystalline Cellulose from Totally Chlorine Free Oil Palm Empty Fruit Bunch Pulp

Nanocrystalline cellulose (NCC) was isolated from a totally chlorine free (TCF) bleached oil palm empty fruit bunch (OPEFB) pulp via acid hydrolysis using a 58 % sulfuric acid concentration and ultrasonic treatment. The effects of acid concentration and hydrolysis time were investigated. Characterization of OPEFB–NCC was carried out using TEM, FTIR, ¹³C-NMR, XRD, zeta potential and TGA. The optimal hydrolysis time was 80 min as indicated by the leveling off of the OPEFB–NCC dimensions (length 150 nm and diameter 6.5 nm) with no significant loss of crystallinity at this point. The presence of a shoulder peak at 1231 cm^?1 (assigned to a sulfate group) in the FTIR spectrum of NCC is indicative of a successful esterification. This is further corroborated by the ¹³C-NMR analysis whereby the distinct C4 amorphous and crystalline peaks present in OPEFB–TCF pulp had almost disappeared and the cluster of signals for C2, C3, C5, and a well separated signal of C6 had merged into one single peak in the OPEFB–NCC sample. These observations allude to most of the amorphous region having been removed and to the strong possibility of sulfonation having not only occurred on the C6, but also on C2 and C3. OPEFB–NCC isolated over shorter hydrolysis time was more thermally stable; however, the char fraction decreases with hydrolysis time despite having a higher zeta potential. The results of this investigation demonstrate that NCC can be produced from pulp made by chlorine free environmentally benign processes with ensuing savings in energy and chemicals.     

Tensile,Thermal and Physical Properties of Washightonia Trunk Fibres/Pineapple Fibre Biophenolic Hybrid Composites

Journal of Polymers and the Environment - In this work, hybrid composites reinforced with Washightonia trunk fibres (GW)/Pineapple fibre (PALF) in bio-phenolic matrix were fabricated with...     

Mechanical,Morphological and Dynamic Mechanical Analysis of Pineapple Leaf/Washingtonia Trunk Fibres Based Biophenolic Hybrid Composites

In this article, flexural, impact and dynamic mechanical properties of the Pineapple leaf fibres (PALF) and Washingtonia trunk fibres (GW) based bio-phenolic hybrid composites were examined. The pure and hybrid composites were fabricated using the hand lay-up technique with an overall fibre weight ratio of 50% in which GW and PALF were maintained in the fibre weight ratios of 50:50, 30:70, and 70:30 denoted as 1G1P, 3G7P, and 7G3P, respectively. Hybrid composites displayed better flexural strength, flexural modulus and impact strength than the GW composites and better viscoelastic properties than the PALF composites. Results revealed that 1G1P hybrid composites exhibited 25% and 12% improvements in flexural strength and modulus compared to the GW composites. 3P7K composites showed a twofold increase in impact strength than GW composites. The storage modulus of the pure and hybrid composites declined rapidly beyond the glass transition temperature. Furthermore, it was observed that the values of storage modulus for all the composites at 150 °C were similar regardless of the composite configuration. The Peak of loss modulus was found to increase in the following order: GW?>?7G3P?>?3G7P?>?1G1P?>?PALF. Furthermore, the temperature at the peak tan delta was improved, and a reduction in the tan delta peak was observed for hybrid composites compared to the pure composites. Finally, the PALF and GW hybrid combinations can be suitable for use in various applications such as textiles, machinery part production industries, medicine, automobiles, etc.

     

Recycled Natural Fiber Polypropylene Composites: Water Absorption/Desorption Kinetics and Dimensional Stability

Detailed analysis of the effects of recycling process on long-term water absorption, thickness swelling and water desorption behavior of natural fiber polypropylene composites is reported. Composite materials containing polypropylene and wood flour, rice hulls or bagasse fibers were produced at constant fiber loading and were exposed to a simulated recycling process consisting of up to five times grinding and reprocessing under controlled conditions. A wide range of analytical methods including water absorption/desorption tests, thickness swelling tests, density measurement, scanning electron microscopy, image analysis, contact angle, fiber length analysis and Fourier transform infrared spectroscopy was employed to understand the hygroscopic behavior of the recycled composites. Water absorption and thickness swelling behaviors were modeled using existing predictive models. Results indicated that generally the recycled composites had considerably lower water absorption and thickness swellings as compared with the original composites which were attributed to changes in physical and chemical properties of the composites induced by the recycling process.     

Sisal/Carbon Fibre Reinforced Hybrid Composites: Tensile, Flexural and Chemical Resistance Properties

The variation of mechanical properties such as tensile and flexural properties of randomly oriented unsaturated polyester based sisal/carbon fibre reinforced hybrid composites with different fibre weight ratios have been studied. The chemical resistance test of these hybrid composites to various solvents, acids and alkalies were studied. The effect of NaOH treatment of sisal fibres on the tensile, flexural and chemical resistance properties of these sisal/carbon hybrid composites has also been studied. The hybrid composites showed an increase in tensile and flexural properties with increase in the carbon fibre loading. The tensile properties and flexural properties of these hybrid composites have been found to be higher than that of the matrix. Significant improvement in tensile properties and flexural properties of the sisal/carbon hybrid composites has been observed by alkali treatment. The chemical resistance test results showed that these untreated and alkali treated hybrid composites are résistance to all chemicals except carbon tetra chloride. Hand lay-up technique was used for making the composites and tests are carried out by using ASTM methods.     

Synthesis,Characterization, and Evaluation of Degussa P25/Chitosan Composites for the Photocatalytic Removal of Sertraline and Acid Red 18 from Water

Journal of Polymers and the Environment - Degussa P25 titanium dioxide/chitosan composites (P25/CS) were prepared using three different methods and two different chitosan materials. The obtained...