Khairiah Haji Badri

Characterisation of fucoidan extracted from Malaysian Sargassum binderi

Fucoidan is a sulphated polysaccharide that consists mainly of fucose, normally found in brown seaweeds. In this study, fucoidan was extracted from Sargassum binderi (Fsar) from Malaysia and subsequently characterised. The chemical characteristics of Fsar were found to be different than those of commercial food grade fucoidan (Fysk) and those of previously studied fucoidans. NMR analysis proposed that the main structure of Fsar is →3)fuc-2-OSO3(-)(1→3)fuc(1→. The molecular weight (47.87kDa) and degree of sulphation (0.20) of Fsar were higher than those of Fysk, at 27.98kDa and 0.15, respectively. However, Fsars polydispersity index (1.12) and fucose content (34.50%) were lower than those of Fysk, at 1.88 and 43.30%, respectively. Both Fsar and Fysk showed similar thermo-gravimetric properties with four mass losses, amorphous in nature and negative optical rotations. Results show that Fsar has fundamental characteristics of fucoidan with different structural conformation i.e. variation in glycosidic linkages and sulphate group orientation.

An Investigation on the Properties of Palm-Based Polyurethane Solid Polymer Electrolyte

Palm-based polyurethane electrolyte was prepared via prepolymerization method between palm kernel oil polyol (PKO-p) and 2,4′-diphenylmethane diisocyanate (MDI) in acetone at room temperature with the presence of lithium trifluoromethanesulfonate (LiCF3SO3). The effect of varying the concentration of LiCF3SO3 salt on the ionic conductivity, chemical interaction, and structural and morphological properties of the polyurethane solid polymer electrolyte was investigated. The produced film was analyzed using electrochemical impedance spectroscopy (EIS), attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The EIS result showed that the highest ionic conductivity was at 30 wt% LiCF3SO3 with a value of 1.6 × 10−5 Scm−1. Infrared analysis showed the interaction between lithium ions and amine group (–N–H) at (3600–3100 cm−1), carbonyl group (–C=O) at (1750–1650 cm−1), and ether group (–C–O–C–) at (1150–1000 cm−1) of the polyurethane forming polymer-salt complexes. The XRD result proved that LiCF3SO3 salt completely dissociates within the polyurethane film as no crystalline peaks of LiCF3SO3 were observed. The morphological study revealed that the films prepared have a good homogeneity and compatibility as no phase separation occurred.

Quasi-Static Behavior of Palm-Based Elastomeric Polyurethane: For Strengthening Application of Structures under Impulsive Loadings

In recent years, attention has been focused on elastomeric polymers as a potential retrofitting material considering their capability in contributing towards the impact resistance of various structural elements. A comprehensive understanding of the behavior and the morphology of this material are essential to propose an effective and feasible alternative to existing structural strengthening and retrofitting materials. This article presents the findings obtained from a series of experimental investigations to characterize the physical, mechanical, chemical and thermal behavior of eight types of palm-based polyurethane (PU) elastomers, which were synthesized from the reaction between palm kernel oil-based monoester polyol (PKO-p) and 4,4-diphenylmethane diisocyanate (MDI) with polyethylene glycol (PEG) as the plasticizer via pre-polymerization. Fourier transform infrared (FT-IR) spectroscopy analysis was conducted to examine the functional groups in PU systems. Mechanical and physical behavior was studied with focus on elongation, stresses, modulus, energy absorption and dissipation, and load dispersion capacities by conducting hardness, tensile, flexural, Izod impact, and differential scanning calorimetry tests. Experimental results suggest that the palm-based PU has positive effects as a strengthening and retrofitting material against dynamic impulsive loadings both in terms of energy absorption and dissipation, and load dispersion. In addition, among all PUs with different plasticizer contents, PU2 to PU8 (which contain 2% to 8% (w/w) PEG with respect to PKO-p content) show the best correlation with mechanical response under quasi-static conditions focusing on energy absorption and dissipation and load dispersion characteristics.

Effect of cooking temperature on the crystallinity of acid hydrolysed-oil palm cellulose

In this research, we studied the effect of acid hydrolysis temperature on the crystallinity of cellulose produced from empty fruit bunch (EFB). The hydrolysis temperature was studied from 120 to 140 °C at a fixed time and sulfuric acid, H2SO4 concentration which were 1 h and 1% (v/v) respectively. X-ray diffractometry (XRD) was carried out to measure the crystallinity of cellulose produced at varying hydrolysis temperatures. During hydrolysis, the amorphous region of α-cellulose was removed and the crystalline region was obtained. Percentage of crystallinity (CrI) for acid hydrolysed cellulose at 120, 130 and 140 °C were 54.21, 50.59 and 50.55 % respectively. Morphological studies using scanning electron microscope (SEM) showed that acid hydrolysis defibrilised to microfibrils in α-cellulose. The extraction process to produce α-cellulose has also been successfully carried out as the impurities at the outer surface, lignin and hemicellulose were removed. These findings were supported by the disappearance o...

X-Ray Diffraction Patterns of Oil Palm Empty Fruit Bunch Fibers with Varying Crystallinity

Crystallinity of oil palm fiber from empty fruit bunch (EFB) with and without tretaments was studied by analyzing the X-ray diffraction (XRD) pattern. In this paper, we focused on the effect of acid hydrolysis onto EFB on the crystallinity of the extracted cellulose. The reaction was carried out by soaking EFB in 1% (v/v) aqueous sulfuric acid (H2SO4) at different temperatures of 120, 130 and 140°C for 1 h. The XRD patterns significantly showed changes in the 2θ peaks before and after the treatment. These changes were described in term of polymorphs type present, reflection and allomorphs of the samples. XRD peak high and XRD deconvolution methods were used to calculate and compare the percentage of crystallinity of untreated EFB (UT-EFB) and acid hydrolyzed samples (AH-EFB). Based on the calculation, increment of about 1.3 times and 1.5 times were achieved by using WAXS and XRD deconvolution methods respectively. This is due to the removal of amorphous part contributed by lignin, hemicellulose and cellulose. Fourier Transform infrared (FTIR) spectra showed the presence of similar peaks in AH-EFB and commercial microcrystalline cellulose (C-MCC) at 1427, 1315, 895 and 1022 cm-1. The micrographic features showed the acid hydrolysis had successfully took place and separated the EFB microfibrils bundles.

Preparation and characterization of plasticized palm-based polyurethane solid polymer electrolyte

Palm-based polyurethane solid polymer electrolyte was prepared via prepolymerization method between palm kernel oil based polyols (PKO-p) and 2,4’-diphenylmethane diisocyanate (2,4’-MDI) in acetone at room temperature with the vary amount of lithium trifuoromethanesulfonate (LiCF3SO3) salt and polyethylene glycol (PEG). The film was analyzed using attenuated total reflection infrared (ATR-IR) spectroscopy, electrochemical impedance spectroscopy (EIS) and X-ray diffractometry (XRD). EIS result indicated ionic conductivity obtained with 30 wt% LiCF3SO3 increased to 6.55 × 10−6 S cm−1 when 10 wt.% of plasticizer was added into the system. FTIR analysis showed the interaction between lithium ions and amine (-N-H) at 3600–3100 cm−1, carbonyl (-C=O) at 1750–1650 cm−1 and ether (-C-O-C-) at 1150–1000 cm−1 of the polyurethane forming polymer-salt complexes. The XRD result confirmed that LiCF3SO3 salt completely dissociated within the polyurethane film with the absence of crystalline peaks of LiCF3SO3.

A urethane block copolymer as binder for fire-resist palm-based fibreboard

The mechanical properties and fire resistance of medium-density fibreboard (MDF) consisting of empty fruit bunch fibre (EFB) and palm-based pre-polyurethane (pPU) as the green binder were investigated. The EFB was in the size range of 300 to 500 μm with ATH varied at 5, 10, and 15%w/w of the total mass of the resin and was added into the pPU matrix at a ratio of 65:35 of the EFB to pPU. This study discovered the significant of mixing sequence to the strength enhancement of the fibreboard. A direct proportionality was noted between the Shore D hardness and the amount of ATH with an increase up to 17% with increasing ATH content. Furthermore, this is contributed to well-disperse ATH in the pPU matrix which also increased the impact and flexural strengths. An increase in impact strength of 13, 20 and 33%, with increasing ATH loading percentage was observed. The maximum increase in flexural strength was 33%, which was associated to ATH content of 15%. On the other hand, the burning rate decreased from 6.0 to 3.2 mm·s−1 with increasing ATH content.

Chemical properties and toxicology studies of fucoidan extracted from Malaysian Sargassum binderi

Fucoidan is a sulfated polysaccharide that consists mainly of fucose and is found in brown seaweeds. In this study, fucoidan was extracted from Sargassum binderi (Fsar) from Malaysia and subsequently characterized in terms of composition, structure and toxicology. It was found that the molecular weight, polydispersity index, monosaccharide profile and degree of sulfation of Fsar differed from those of commercial food-grade fucoidan (Fysk). NMR analysis suggested that the main structure of Fsar was →3)fuc-2-OSO3−(1→3)fuc-2-OSO3−(1→. A cytotoxicity study employing up to 200 mg/mL Sargassum binderi extract showed that cell inhibition was less than 50% (IC50), while acute toxicity results classified S. binderi as category 5 (unclassified) according to the OECD Guideline 423, as no mortality was observed at the highest dosage (2,000 mg/kg). Both toxicity results showed that this material is safe to be consumed. The chemical characteristics and non-toxicity of Fsar demonstrate its potential in biological and food product applications.

Formation of protein complex with the aid of polyethylene glycol for deproteinized natural rubber latex

The effect of polyethylene glycol (PEG) as a deproteinizing agent in commercial natural rubber latex (NRL) onto the physicochemical properties of the NRL was investigated. Three types of PEG were used namely PEG200, PEG4000 and PEG20000 (molecular weight of 200, 4000 and 20000 g/mol respectively). The optimum amount of PEG in NRL was determined from viscosity changes, protein content and Fourier Transform Infrared spectroscopy. Level of protein reduction was affected by molecular weight of PEG. The addition of PEG in NRL reduced the protein content of NRL (3.30 %) to the lowest (2.01 %) at 0.40 phr of PEG200 due to more attractive hydrophobic interactions between short chains PEG compared to PEG4000 (2.24%) and PEG20000 (2.15%). This was verified through FTIR spectroscopy analysis by observing the primary and secondary amide peak where PEG4000 has lesser absorption at the region compared to with PEG20000.

Enhancing mechanical properties of prevulcanized natural rubber latex via hybrid radiation and peroxidation vulcanizations at various irradiation doses

ABSTRACT At present, there are three popular vulcanization processes being used in natural rubber latex industries, which are sulfur, radiation and peroxide vulcanization. Sulfur vulcanization produced products with superior mechanical properties compared to radiation and peroxide vulcanization. This paper discussed the effect of gamma irradiation dose on hybrid radiation and peroxidation vulcanizations in improving the mechanical properties of radiation vulcanized natural rubber latex (RVNRL). Latex compounding formulations are developed based on 2.5 parts per hundred rubber (phr) of hexanediol diacrylate (HDDA) as the sensitizer, 0.1 phr of tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer and 2.5 phr of Aquanox LP antioxidant. The RVNRL was prepared and irradiated at various gamma radiation doses of 2, 4, 6, 8, 10 and 12 kiloGray (kGy). The rubber film obtained from irradiation at 6 kGy had tensile strength, modulus @ 500% and modulus @ 700% of 27.0, 3.0 and 11.0 MPa, respectively, which is more than 37% increment compared to the control film. Besides, the crosslink percentage of the rubber film showed 4% increment from 90% to 94%.