21 research outputs found

    Styrene-Methyl Methacrylatemodified Natural Rubber From Deproteinized Natural Rubber Latex.

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    Kajian ini adalah mengenai pempolimeran in situ stirena (S) dan metil metakrilat (MMA) getah asli terubahsuai stirena-metil metakrilat di dalam lateks getah asli ternyahprotein menggunakan ammonium persulfat (N2H8O8S2) untuk menghasilkan getah asli terubahsuai S-MMA (S-MMA-NR) pada darjah ubahsuai yang berbeza, 10, 20 dan 30 % berat dengan berat monomer stirena dan MMA yang digunakan adalah sama (50/50 berat/berat). The study reported here is concerned with the in situ polymerization of styrene (S) and methyl methacrylate (MMA) in deproteinized natural rubber latex using ammonium persulfate (N2H8O8S2) as initiator to obtain S-MMA-modified natural rubber (S-MMA-NR) at different degree of modification, 10, 20 and 30 wt% of equal amount of styrene and MMA monomer (50/50 w/w)

    Preparation and characterization of Styrene-Methyl Methacrylate in Deproteinized Natural Rubber Latex (SMMA-DPNR)

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    The graft polymerization of Styrene and Methyl Methacrylate (MMA) onto deproteinized natural rubber latex (SMMA-DPNR) was carried out using ammonium peroxy disulfate (N2H8O8S2) as an initiator. The suitable reaction conditions based on the higher monomer conversion was determined. The SMMA-DPNR at 6 hours reaction time was successfully prepared with degree of conversion more than 99 %. The copolymers composition of the resultant SMMA-DPNR was obtained using 1H-NMR Spectroscopy. As expected, composition of styrene in DPNR was higher than that of MMA due to the higher reactivity ratio of styrene monomer as compared to MMA monomer and the structure of the NR backbone

    Effect of Indigenous Microorganisms (IMO) and rice husk on pH of soilless media and yield of Cucumis sativus

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    A field experiment was conducted to study the effect of Indigenous Microorganisms (IMO) and rice husk on pH of soilless media and yield of Cucumis sativus (cucumber). Ten polybags were provided for each treatment that consisted of IMO treated media (T1), rice husk treated media (T2), and control media (T3). Every treatment was supplied with 1.9 dS/m EC nutrient solutions and the pH was being measured every two consecutive days until the plants had been harvested. Based on the results, there were significant differences in the pH media and the fruit yield between the treatments. The media containing rice husk had a significant increase in the pH media and was consistent in maintaining the average pH media within the range of 6.6 to 6.7, while fruit yield of cucumber recorded the highest number as compared with the other treatments. The findings had revealed that T2 had resulted in 60 cucumbers (22.66 kg) being harvested, followed by T3 with 45 cucumbers (17.53 kg) and T1 with 45 cucumbers (17.11 kg). It can be safely concluded that the medium containing treated RHA was the best for obtaining high yield of cucumber in soilless media as a local growing media due to the superior of its potential constraint of chemical fertiliser while keeping the stability to continue the growth and fruit production for a long period of time

    Characterisation of andrographolide in andrographis paniculata under different cultivation conditions

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    The trend in the practical uses of herbal medicine has gained increasing momentum in recent years. One of the trends includes the use of the andrographolide-containing Andrographis paniculata, which is a herb that is traditionally used as medicine. There are not many studies have investigated the cultivation of this plant. The aim of this study is to develop a standard of procedure for cultivating Andrographis paniculata using the fertigation technique. A total of 6 treatments in 2 growth medium compositions were studied; treatments T1, T3, and T5 in Cocopeat-RHA (70:30) and treatments T2, T4, and T6 in 100 % cocopeat. 3 magnesium compositions of 10 ppm (T1 and T2), 50 ppm (T3 and T4), and 70 ppm (T5 and T6) in nutrient solution were also studied. Treatments T1, T3, and T5 showed the potential for better growth quality with a maximum plant height of 32.51 cm, 32.51 cm, and 31.75 cm. The andrographolide content was comparable with controls 1 and 2 (0.67-0.70 µg/mL). In higher magnesium compositions of the nutrient solution, the dry herb yield of T5 and T6 decreased from 2.4 g to 1.6 g and 2.4 g to 1.2 g. The T3 and T5 treatments exhibited a higher yield than T4 and T6 based on a comparison of dry herb yield. The incorporated fertigation technique showed an on-par quantity of andrographolide yield to that of conventional techniques (0.67-0.70 µg/mL) although it showed an advantage of overcoming the cleanliness problem faced in this study. Hence, the T3 standard of procedure was deemed the best, as it gave better plant growth quality with a maximum plant height of 31.75 cm, a maximum number of leaves (141 total count), a good dry herb yield of 2.2 g, and better andrographolide content 0.7 µg/mL. The fertigation technique incorporated with the combined Cocopeat-RHA medium and 50 ppm magnesium composition in the nutrient solution is suggested for the cultivation of Andrographis paniculata

    Natural rubber derivatives for adhesives applications: a review

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    The purpose of this review is to describe the utilisation of natural rubber and its modified form in adhesive applications. Adhesive can be defined as material that capable of joining two or more surfaces permanently by the adhesion process. Recently, natural rubber has gaining great interest in the adhesive application in comparison to its counter parts synthetic rubber due to environmental reason as well as good mechanical and thermal properties. In this review, the adhesive properties along with mechanical and thermal properties of the natural rubber are reviewed. The recent advances in the modified natural rubber such as epoxidized natural rubber, liquid natural rubber, telechelic natural rubber and other modified natural rubber are also included and highlighted

    Preparation and characterization of styrene-methyl methacrylate In deproteinized natural rubber latex (SMMA-DPNR)

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    The graft polymerization of Styrene and Methyl methacrylate (MMA) onto deproteinized natural rubber latex (DPNR) was carried out using ammonium peroxy disulfate ( N2H8O8S2) as an initiator. The suitable reaction conditions based on the higher monomer conversion was determined. The degree of grafting and the copolymers composition of the resultant SMMA-DPNR were obtained using H-1 NMR Spectroscopy. As expected, composition of styrene in DPNR was higher than that of MMA due to the higher reactivity ratio of styrene monomer as compared to MMA monomer and the structure of the NR backbone. The mechanism of seeded emulsion polymerization leading to graft copolymer of styrene and MMA onto NR was studied and elucidated

    Preparation and characterization of hydroxyl terminated liquid epoxidized natural rubber

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    Hydroxyl terminated liquid epoxidized natural rubber (HTLENR) was successfully synthesized via oxidative degradation of liquid epoxidized natural rubber (LENR) in the presence of cobalt (II) acetyl acetonate (CAA) as the oxidizing agent. The effect of reaction time on molecular weight, chemical structures and hydroxyl content of HTLENR were investigated. The weight average molecular weight (Mw) and polydispersity index (PDI) of the prepared HTLENR were determined using gel permeation chromatography (GPC). The result shows that as the reaction time increased, the Mw decreased indicating the occurrence of higher chain scission. It was found that the lowest Mw was achieved at 10 h reaction time where the Mw and Mn were 37,545 g/mol and 3,233 g/mol. The structural analysis and hydroxyl content of HTLENR on the other hand, were studied by using fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). The presence of OH group was confirmed by FTIR analysis with the appearance of broad peak at 3,200 – 3,600 cm-1. Subsequently, NMR analysis also confirmed that the highest amount of hydroxyl content which is 7.56 % was achieved at the longest reaction time which is 10 h

    Optimisation of model-based fertiliser formulation for sustainable agriculture

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    Agriculture management for better decision making is important due to increased needs for agricultural products and increased pressure on land, water, and other natural resources. Balanced nutrient requirements are essential for increasing tropical crop yield and reducing the risk on the negative environmental impact. Reduce fertiliser consumption and optimise the fertiliser used subjected to waste of fertiliser into the environment are the best way to achieve sustainable agriculture. The nutrient coverage includes macronutrient such as nitrogen (N), phosphorous (P), potassium (K), sulfur (S), magnesium (Mg) and calcium (Ca). In this study, the data and procedures used to set up the model as well as the assumptions made for tropical crops. The main objective of the study is to develop a systematic methodology for fertiliser formulation in fertigation system. The sub-objective of the study is to design fertigation fertiliser formulation by using computer-aided approaches which can minimise the environmental impact by reducing the over-used fertiliser leakage. The methods consist of three steps including data collection, the design of fertiliser formulation and verification of fertiliser formulation. The fertiliser formulation will be formulated by using general optimisation problem as the mixed-integer nonlinear program (MINLP). The results in Stage 1 is expected to be the design formulation of fertiliser sources which gives the minimum cost that is subjected to the plant requirements and the results will further verify in Stage 2. This model-based formulation is the starter for another tropical crop model

    Pineapple Leaves Fiber (PALF) crosslinked with chitosan for antimicrobial properties

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    The goal of this study is to treat pineapple leaves fiber (PALF) with chitosan for antimicrobial properties. The treated PALF with chitosan was then crosslinked with crosslinking agent; butanetetracarboxylic acid (BTCA) to preserve chitosan in the PALF structure. The effectiveness of chitosan and crosslinking agent towards PALF was determined using untreated PALF, PALF treated chitosan, PALF treated chitosan (wash), PALF treated chitosan/BTCA and PALF treated chitosan/BTCA (wash). After the treatment with chitosan and BTCA, the treated PALF undergone the washing process to determine the effectiveness of BTCA to avoid the removal of chitosan from PALF during washing. The presence of chitosan in the PALF was confirmed using Fourier Transform Infra-red (FTIR) analysis. The treated PALF was then characterised in terms of its antimicrobial activity and mechanical properties. Antimicrobial activity test confirmed the presence of chitosan successfully retarded the growth of microbe. Tensile test analysis revealed the untreated PALF has the highest tensile strength compared to all treated PALF. In contrast, young modulus of the treated PALF shows increment relative to the untreated PALF. This study is particularly important for the further application of PALF or other natural fibers especially in medical and textile industry

    The mechanical properties of photopolymer prepared via 3D stereolithography printing: The effect of UV curing time and anisotropy

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    Stereolithography is a high accuracy additive manufacturing process that uses a laser beam to cure photopolymer resin according to the computer-aided design file. Anisotropy in mechanical properties is one of the major challenges that are faced by additive manufacturing technologies. This study is conducted on PR 48 photopolymer samples using FORM 2 SLA printer. Elastic modulus and hardness of printed samples of 50 and 100 μm resolutions were tested at 0°, 45° and 90° orientations using nanoindentation testing machine. The samples were cured using UV, and the effect of UV curing time was investigated. Results for 100 μm print resolution showed that elastic modulus and hardness for 0° orientation is higher than 45° orientation by 35 % and 390 % for 90° print orientation. For 50 μm print resolution, elastic modulus and hardness for 0° orientation are higher than 45° orientation by 106 % and higher by 92 % for 90° orientation. The results show a strong dependency of mechanical properties on print orientation, resolution and UV curing time and temperature
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