Displaying publications 1 - 20 of 57 in total

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  1. Umar Hamzah, Yong CY, Bashillah Baharudin, Abdul Rahim Samsudin
    Analisis kimia air telah dilakukan terhadap larutan yang diekstrak dari 85 sampel tanah yang dipungut di kawasan ternakan udang harimau di Kerpan. Sampel tanah dikorek pada kedalaman 2 m bermula dari garis pantai sehingga 20 km ke arah daratan. Selain daripada tanah, air bawah tanah juga disampel dengan penggerudian yang berkedalaman 10 hingga 25 m untuk dilakukan analisis kimia air. Hasil analisis hidrokimia larutan yang diekstrasi dari sampel tanah yang diambil pada kedalaman 1-2 m menunjukkan kepekatan klorida berjulat dari 12 hingga 6500 mg/L. Berdasarkan kepekatan ion tersebut, kawasan kajian telah dibahagikan kepada beberapa zon-zon iaitu zon masin dan payau. Kepekatan pepejal terlarut yang diukur adalah dalam julat 100 hingga 40,000 mg/L dengan julat ini merangkumi zon berair segar hingga masin. Zon berair masin yang ditafsir berdasarkan kepekatan pepejal terlarut adalah dalam lingkungan 1 km dari pantai manakala berdasarkan kepekatan klorida sempadan ini adalah disekitar 4-5 km. Kehadiran air masin boleh berasal dari penerobosan langsung dari laut ataupun melalui proses air pasang-surut dimana air laut masuk melalui sungai atau terusan berhampiran ke kawasan kajian. Kehadiran air masin juga disokong oleh pertambahan kepekatan unsur-unsur seperti naterium, kalium dan kalsium ke arah laut. Berdasarkan peta taburan spatial kepekatan klorida, pola kontur kemasinan tinggi didapati mengikut bentuk kolam ternakan udang. Oleh itu besar kemungkinan pengaruh air masin adalah dari proses infiltrasi air kolam ke kawasan sekitar. Untuk melihat samada proses penerobosan juga turut memainkan peranan dalam mempengaruhi kemasinan di kawasan kajian, sampel air dari lubang gerudi pada kedalaman 10-25 meter juga turut dibuat. Sampel air yang dipam dari lubang gerudi menunjukkan kepekatan klorida dalam julat 2030 hingga 13,000 mg/L manakala kepekatan pepejal terlarut berjulat 3233 hingga 9280 mg/L. Berdasarkan nilai kepekatan klorida dan pepejal terlarut sampel air lubang gerudi, kawasan di sekitar lubang gerudi khususnya pada jarak hampir 1 km dari pantai telah tercemar dengan kesan penerobosan air laut.
    Matched MeSH terms: Acrylates
  2. Uhammad Fahmi Abdul Ghani, Simon N, Goh TL, Tuan Rosli Tuan Mohamed, Abdul Ghani Rafek
    Sains Malaysiana, 2016;45:1509-1516.
    Perbukitan batu kapur di Lembah Kinta membentuk landskap muka bumi yang unik dan indah hasil daripada proses pelarutan batuan karbonat. Namun begitu, bergantung kepada kawasan perbukitan batu kapur tersebut, kehadiran pelbagai struktur geologi seperti struktur retakan dan kekar yang ekstensif mampu memberi ancaman kepada manusia dan harta benda. Kajian ini bertujuan melihat hubungan antara ketumpatan lineamen dan tahap kestabilan tujuh cerun gunung batu kapur di Lembah Kinta, Malaysia. Kajian ini terbahagi kepada dua peringkat, iaitu pemetaan ketumpatan lineamen dan penilaian kestabilan cerun dengan menggunakan kaedah Kekuatan Jasad Batuan (RMS). Sebanyak 599 lineamen rantau dikenal pasti dengan panjang keseluruhan lineamen mencapai 317 km. Seterusnya, peta ketumpatan lineamen yang dihasilkan dikelaskan kepada tiga kelas: Rendah (137.0-84.23) m, sederhana (84.22-46.83) m dan tinggi (46.82-0.0) m. Kaedah RMS yang dijalankan di lapangan pula adalah bertujuan bagi mengesahkan peta ketumpatan lineamen yang dihasilkan. Sebanyak dua belas stesen dinilai dengan tujuh parameter RMS iaitu kekuatan bahan batuan, tahap luluhawa, bukaan kekar, orientasi kekar, kelebaran kekar, ketakselanjaran dan aliran air bawah tanah. Setiap cerun yang dinilai dikelaskan kepada lima kumpulan daripada sangat lemah hingga sangat kuat. Skor RMS berdasarkan jumlah akhir setiap parameter yang dinilai. Hampir kesemua stesen yang dicerap berada pada kelas sederhana (Gunung Rapat, Datok, Kandu, Panjang, A, Tempurung) manakala hanya satu stesen (Gunung Lang) berada pada kelas lemah. Korelasi antara peta ketumpatan lineamen dan skor RMS menunjukkan korelasi yang baik dengan 73% ketepatan. Ini menunjukkan bahawa kestabilan cerun di Lembah Kinta dipengaruhi secara langsung oleh ketumpatan lineamen rantau.
    Matched MeSH terms: Acrylates
  3. Gorajana A, Kit WW, Dua K
    Recent Pat Drug Deliv Formul, 2015;9(2):167-82.
    PMID: 25714525
    OBJECTIVE: Norfloxacin has a low aqueous solubility which leads to poor dissolution. Keeping this fact in mind the purpose of the present study is to formulate and evaluate norfloxacin solid dispersion.

    METHODS: Solid dispersions were prepared using hydrophilic carriers like polyethylene glycol (PEG) 4000, polyvinylpyrrolidone (PVP) k30 and carbopol 974pNF (CP) in various ratios using solvent evaporation technique. These formulations were evaluated using solubility studies, dissolution studies; Fourier transmitted infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetery (DSC). The influence of polymer type and drug to polymer ratio on the solubility and dissolution rate of norfloxacin was also evaluated.

    RESULTS: FTIR analysis showed no interaction of all three polymers with norfloxacin. The results from XRD and DSC analyses of the solid dispersion preparations showed that norfloxacin existsin its amorphous form. Among the Norfloxacin: PEG solid dispersions, Norfloxacin: PEG 1:14 ratio showed the highest dissolution rate at pH 6.8. For norfloxacin: PVP solid dispersions, norfloxacin: PVP 1:10 ratio showed the highest dissolution rate at pH 6.8. For Norfloxacin: CP solid dispersions, norfloxacin: P 1:2 ratio showed the highest dissolution rate at pH 6.8.

    CONCLUSION: The solid dispersion of norfloxacin with polyethylene glycol (PEG) 4000, polyvinylpyrrolidone (PVP) k30 and carbopol 974p NF (CP), lends an ample credence for better therapeutic efficacy.

    Matched MeSH terms: Acrylates/pharmacokinetics; Acrylates/chemistry*
  4. Nur Hakimah Asnawi, Lam KC
    Sains Malaysiana, 2016;45:1869-1877.
    Penyelidikan ini dijalankan untuk mengesan perubahan guna tanah dan litupan bumi (LULC) di daerah Gombak, Selangor melalui pendekatan penderiaan jauh. Perbandingan data siri masa antara tahun 1989-1999, 1999-2014 dan 1989-2014 telah dilakukan bagi melihat perubahan LULC. Data yang digunakan ialah imej satelit Landsat (TM dan OLI-TIRS) dan Peta Guna Tanah Selangor 1990 terbitan Jabatan Pertanian Malaysia. Guna tanah dibahagikan kepada lima kategori utama, iaitu badan air, hutan, getah, kelapa sawit dan tepu bina. Penilaian ketepatan antara LULC hasil daripada pengelasan imej penderiaan jauh dengan peta guna tanah 1990 dikira berdasarkan Koeffisien Kappa menerusi teknik ralat matrik dan nilai ketepatan adalah 74.5%. Analisis GIS ke atas imej pasca klasifikasi menunjukkan perubahan sebenar LULC bagi tahun perbandingan 1989-1999 ialah 13.69%, seterusnya meningkat kepada 18.65% bagi tahun 1999-2014 dan terus meningkat bagi tahun bandingan 1989-2014, iaitu 24.25%. Guna tanah getah mengalami perubahan sebenar paling tinggi berbanding guna tanah lain dengan -47.73% bagi tahun bandingan 1989-1999, manakala tahun bandingan 1999-2014 menunjukkan guna tanah tepu bina mengalami perubahan paling tinggi dengan +44.53% dan pada tahun 1989-2014 pula guna tanah getah mengalami perubahan sebenar paling tinggi sebanyak -34.6%. Kemerosotan guna tanah getah sangat ketara di daerah Gombak dan mempunyai kaitan dengan peningkatan kawasan guna tanah tepu bina. Secara umumnya, pola perubahan guna tanah dan litupan bumi di daerah Gombak selari dengan perkembangan dan pelaksanaan pembangunan semasa oleh pihak berkuasa.
    Matched MeSH terms: Acrylates
  5. Yusri, Othman A. Karim, Khairul Nizam Abdul Maulud, Mohd. Ekhwan Toriman
    Penggunaan tanah boleh mengakibatkan perubahan fungsi dari masa ke masa, sesuai dengan tujuan pembangunan. Kawasan Bandar Pekanbaru terdiri daripada 12 sub-kawasan persekutuan dengan jumlah keluasan kira-kira 632.26 km2. Tujuan kajian adalah untuk menganalisis perubahan guna tanah daripada aspek ruang dan masa. Data guna tanah yang diambil kira dalam analisis ini adalah peta guna tanah 1992 dan 2004. Hasil analisis dengan menggunakan perisian ArcView GIS versi 3.2 mendapati bahawa telah berlaku penurunan guna tanah signifikan, iaitu jenis perkebunan dan hutan tahun 2004. Peningkatan jenis lain-lain, penggunaan tanah seperti permukiman dan tumbuhan/semak tahun 2004 telah berlaku. Perubahan ini merupakan pengaruh daripada pembangunan bandar. Sebaliknya, pembangunan bandar boleh memberi impak negatif terhadap sekitaran jika pola perubahan guna tanah dirancang tanpa pengurusan yang baik.
    Matched MeSH terms: Acrylates
  6. Nuzlinda Abdul Rahman, Abdul Aziz Jemain, Kamarulzaman Ibrahim, Ahmad Mahir Razali
    Kajian ini bertujuan untuk memetakan kes kemortalan bayi mengikut daerah di Semenanjung Malaysia bagi tahun 1991 hingga 2000. Penganggaran risiko relatif berdasarkan kaedah Bayes empirik telah digunakan dalam kajian ini. Tiga kaedah penganggaran parameter dihuraikan iaitu kaedah momen, kaedah kebolehjadian maksimum dan kaedah penganggaran gabungan momen dan kebolehjadian maksimum. Keteguhan anggaran parameter yang diperoleh diuji menggunakan kaedah Bootstrap. Hasil kajian mendapati jurang antara kawasan berisiko rendah dengan kawasan berisiko tinggi adalah lebih besar pada awal dekad 2000 berbanding pada awal dekad 1990-an walaupun pada dasarnya kadar mortaliti bayi secara keseluruhannya adalah semakin berkurangan pada peringkat nasional. Kawasan pantai timur Semenanjung Malaysia masih pada takuk yang sama iaitu masih berada dalam kategori berisiko tinggi sepanjang tempoh yang dikaji. Seterusnya, gambaran terdapatnya tompokan risiko juga turut terpapar dalam peta yang dihasilkan. Berdasarkan kaedah Bootstrap, parameter-parameter yang dianggarkan dalam kajian ini adalah teguh.
    Matched MeSH terms: Acrylates
  7. Halib N, Mohd Amin MC, Ahmad I, Abrami M, Fiorentino S, Farra R, et al.
    Eur J Pharm Sci, 2014 Oct 1;62:326-33.
    PMID: 24932712 DOI: 10.1016/j.ejps.2014.06.004
    This paper focuses on the micro- and nano-topological organization of a hydrogel, constituted by a mixture of bacterial cellulose and acrylic acid, and intended for biomedical applications. The presence of acrylic acid promotes the formation of two interpenetrated continuous phases: the primary "pores phase" (PP) containing only water and the secondary "polymeric network phase" (PNP) constituted by the polymeric network swollen by the water. Low field Nuclear Magnetic Resonance (LF NMR), rheology, Scanning Electron Microscopy (SEM) and release tests were used to determine the characteristics of the two phases. In particular, we found that this system is a strong hydrogel constituted by 81% (v/v) of PP phase the remaining part being occupied by the PNP phase. Pores diameters span in the range 10-100 μm, the majority of them (85%) falling in the range 30-90 μm. The high PP phase tortuosity indicates that big pores are not directly connected to each other, but their connection is realized by a series of interconnected small pores that rend the drug path tortuous. The PNP is characterized by a polymer volume fraction around 0.73 while mesh size is around 3 nm. The theoretical interpretation of the experimental data coming from the techniques panel adopted, yielded to the micro- and nano-organization of our hydrogel.
    Matched MeSH terms: Acrylates/chemistry*
  8. Sirajudeen AAO, Annuar MSM, Subramaniam R
    Biotechnol Appl Biochem, 2021 Apr;68(2):307-318.
    PMID: 32314420 DOI: 10.1002/bab.1928
    A microbial fuel cell is a sustainable and environmental-friendly device that combines electricity generation and wastewater treatment through metabolic activities of microorganisms. However, low power output from inadequate electron transfer to the anode electrode hampers its practical implementation. Nanocomposites of oxidized carbon nanotubes and medium-chain-length polyhydroxyalkanoates (mcl-PHA) grafted with methyl acrylate monomers enhance the electrochemical function of electrodes in microbial fuel cell. Extensive polymerization of methyl acrylate monomers within mcl-PHA matrix, and homogenous dispersion of carbon nanotubes within the graft matrix are responsible for the enhancement. Modified electrodes exhibit high conductivities, better redox peak and reduction of cell internal resistance up to 76%. A stable voltage output at almost 700 mV running for 225 H generates maximum power and current density of 351 mW/m2 and 765 mA/m2 , respectively. Superior biofilm growth on modified surface is responsible for improved electron transfer to the anode hence stable and elevated power output generation.
    Matched MeSH terms: Acrylates/chemistry*
  9. Siti Rohana Ahmad, Salmah Husseinsyah, Kamarudin Hussin
    MyJurnal
    A chemical modifier (acrylic acid) was used to improve the thermal properties of polypropylene/ ethylene propylene diene terpolymer/calcium carbonate (PP/EPDM/CaCO3) composites. Treated
    and untreated PP/EPDM composites were filled by CaCO3 at 0, 20 and 40% wt. The composites
    were prepared using Z-blade mixer machine at 180oC and 50 rpm of rotor speed. Thermogravimetric
    analysis (TGA) and differential scanning calorimetry (DSC) methods were used to analyze the thermal properties of the composites. Thermogravimetric analysis indicated that the total weight loss of PP/EPDM/CaCO3 composites decreased with the increasing filler loading for the treated and untreated composites. Meanwhile, the presence of acrylic acid was found to have increased the thermal stability and crystallinity of PP/EPDM/CaCO3
    .
    Matched MeSH terms: Acrylates
  10. Sofian Ibrahim, Keong, Chai Chee, Ratnam, Chantara Thevy, Khairiah Badri
    ASM Science Journal, 2018;11(2):67-75.
    MyJurnal
    Radiation pre-vulcanised natural rubber latex (RVNRL) prepared by using gamma irradiation technique has many advantages over the conventionally prepared sulphur pre-vulcanised natural rubber latex (SPVL). Despite the fact that many potential latex dipped products can be made from RVNRL, little effort was made to fully commercialise the products because of the inferior strength of RVNRL products compared to SPVL products. An attempt was made to improve the tensile strength of RVNRL by combining both radiation and peroxide vulcanisation in order to ensure that the products will not tear or fail, and has sufficient stretch. Hexanediol diacrylate (HDDA) plays the main role as sensitizer during radiation vulcanisation and tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer in peroxide vulcanisation. Pre-vulcanised natural rubber latex dipped films via hybrid radiation and peroxidation vulcanisations obtained showed tensile strength of 26.7 MPa, an increment of more than 15% compared to controlled film (22.5 MPa). Besides, the crosslink percentage of the rubber films also showed around 5% increment from 90.7% to 95.6%.
    Matched MeSH terms: Acrylates
  11. Abdul Razak Daud, Azleen Mohd. Zain, Azali Muhamad
    A single wall single image x-ray radiographic technique was adopted to investigate thickness variation of steel specimens caused by uniform corrosion. The ability of the 100 kV-160 kV x-rays to produce a meaningful film density for steel was also investigated. The thickness contour maps of corroded steel plates were found matching with the x-ray film density contour maps of the plates. The results confirm that x-ray radiography can be used to detect the thickness reduction of steel caused by uniform corrosion.
    Bagi mengesan perubahan ketebalan keluli akibat kakisan seragam maka radiografi sinar-x teknik imej tunggal dinding tunggal telah digunakan. Kemampuan sinar-x 100 kV-160 kV menghasilkan ketumpatan filem yang sesuai untuk keluli telah juga dikaji. Peta kontur ketebalan bagi spesimen kepingan keluli yang telah mengalami kakisan seragam didapati sepadan dengan peta kontur ketumpatan filem radiografi sinar-x bagi spesimen tersebut. Kajian ini menunjukkan radiografi sinar-x boleh digunakan bagi mengesan penipisan keluli akibat kakisan seragam.
    Matched MeSH terms: Acrylates
  12. Nor Erma Shuhadah Abdul Razak, Shahrir Hashim, Abdul Razak Rahmat
    Sains Malaysiana, 2011;40:1179-1186.
    Oil palm empty fruit bunch graft poly (acrylic acid-co-acrylamide) superabsorbent composite (OPEFB-g-(PAA-co-PAM) SAPC) was synthesized by graft copolymerization of the acrylic acid (AA) and acrylamide (AM) comonomer onto OPEFB fibre using ammonium persulfate (APS) and N,N-methylene bisacarylamide (MBA) as an initiator and crosslinker, respectively. The absorbency in various chloride salt solutions indicated that the absorbency decreased with increasing ionic strength of the salt solutions. Moreover, the absorbency under load (AUL) of SAPC was investigated at various applied loading and results show that, AUL decreased with increasing applied loading. Infrared Spectroscopy (IR) and Thermogravimetric Analysis (TGA) were carried out to confirm the chemical structure and thermal properties of the synthesized superabsorbent, respectively.
    Matched MeSH terms: Acrylates
  13. Abeer MM, Amin MC, Lazim AM, Pandey M, Martin C
    Carbohydr Polym, 2014 Sep 22;110:505-12.
    PMID: 24906785 DOI: 10.1016/j.carbpol.2014.04.052
    Acrylated abietic acid (acrylated AbA) and acrylated abietic acid-grafted bacterial cellulose pH sensitive hydrogel (acrylated AbA-g-BC) were prepared by a one-pot synthesis. The successful dimerization of acrylic acid (AA) and abietic acid (AbA) and grafting of the dimer onto bacterial cellulose (BC) was confirmed by 13C solid state NMR as well as FT-IR. X-ray diffraction analysis showed characteristic peaks for AbA and BC; further, there was no effect of increasing amorphous AA content on the overall crystallinity of the hydrogel. Differential scanning calorimetry revealed a glass transition temperature of 80°C. Gel fraction and swelling studies gave insight into the features of the hydrogel, suggesting that it was suitable for future applications such as drug delivery. Scanning electron microscopy observations showed an interesting interpenetrating network within the walls of hydrogel samples with the lowest levels of AA and gamma radiation doses. Cell viability test revealed that the synthesized hydrogel is safe for future use in biomedical applications.
    Matched MeSH terms: Acrylates/chemical synthesis; Acrylates/chemistry*
  14. Salih AM, Ahmad MB, Ibrahim NA, Dahlan KZ, Tajau R, Mahmood MH, et al.
    Molecules, 2015;20(8):14191-211.
    PMID: 26248072 DOI: 10.3390/molecules200814191
    Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA) from an epoxidized palm oil product (EPOP) as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated.
    Matched MeSH terms: Acrylates/chemical synthesis*; Acrylates/chemistry
  15. Sabran SF, Mohamed M, Abu Bakar MF
    PMID: 26881002 DOI: 10.1155/2016/2850845
    This study documented ethnomedical knowledge of plants used for the treatment of tuberculosis (TB) and its related symptoms as practiced by the Jakun community of Kampung Peta, situated in Endau Rompin Johor National Park, Johor, Malaysia. Eight key informants were selected by snowball sampling technique and data about medicinal plants were collected by semistructured interviews, participatory observations, and focus group. Qualitative analysis was undertaken using thematic analysis. There were 23 species of plants (22 genera, 20 families) documented and herbarium specimens were deposited at the UTHM Herbarium. Dipterocarpus sublamellatus was recorded for the first time with ethnomedical uses while other species were previously reported. The qualitative approach employed in this study demonstrates the emic perspective in terms of perceptions on traditional herbal medicine, transfer of knowledge, significant taboos related with medicinal plants, and their conservation efforts. Local and biomedical terminology in treatment of TB showed substantial correspondence. The outcomes obtained in the study are worth being further investigated for conservation strategies and are worthy of verifying their ethnomedical claims scientifically.
    Matched MeSH terms: Acrylates
  16. Mohtar, A., Neefa Bibi, B., Badri, Y.
    MyJurnal
    Introduction : Mersing, a district in north-east Johore was also affected by the recent worst flood in 100 years that striked Johore. Orang Asli settlements were among the worst affected by the flood in Mersing due to their location along the river. For Kg. Peta, not only flooded, the communications as well as the access roads were also tarnished. This settlement situated very deep interior about 100 km from Mersing town and next to Endau- Rompin National Park. Besides the distance, the geography and the communication issues make the flood operation even more difficult. Even then, the welfare of this minority group was never been neglected. Our Medical and Health Teams made a move in but unfortunately were also been trapped in between the flood waves.
    Methodology : It was a qualitative finding. The data for this report were collected from various means. Some data were collected through informal interview among the staffs that being trapped, head villager and the dwellers, local head departments of government and non-government organizations. Others were from the relevant photographs, formal flood returns as well as through the observation.
    Finding : The existence of very good involvement, cooperation and coordination from various agencies was the main factor that ensures all the villagers of Kg. Peta received our services despite of many difficulties or challenges. During this disaster, no outbreak of infectious disease or death from the settlement was reported. The welfare and the needs of all who affected and those involved in the flood operation were taken care off. Therefore, we believed that without good support and cooperation from others, we will not be able to deliver our services and their welfare especially when health was concerned will be deprived. The objectives of this write up were to share our experience in managing flood in very remote area and to show the importance of good integration between agencies in disaster management.
    Matched MeSH terms: Acrylates
  17. Salih, A.M., Wan Md. Zin Wan Yunus, Khairul Zaman Mohd Dahlan, Mohd Hilmi Mahmood, Mansor Ahmad
    MyJurnal
    Synthesis of palm oil based-urethane acrylate (POBUA) resins was carried out by acrylation of epoxidizedpalm oil (EPOP) using acrylic acid in the presence of a catalyst and followed by isocyanation to obtainthe POBUA. Using the monomer as a diluent in the formulation, 4% of photoinitiator and incorporationof organoclay (1-5% wt), nanocomposites were obtained upon UV irradiation. The X-ray DiffractoryXRD study revealed that the nanocomposites obtained were of the exfoliation type. The presence ofthe clay improved the hardness and did not affect the thermal stability. Similarly, it increased the glasstransition temperature Tg but reduced the modulus as the clay content was increased. The improvementof the tensile strength was only obtained when the clay concentration was 5 phr.
    Matched MeSH terms: Acrylates
  18. Mohd Sofian Alias, Nik Ghazali Nik Salleh, Khairiah Badri, Mohd Hamzah Harun, Mahathir Mohamad, Mohd Yusof Hamzah, et al.
    MyJurnal
    UV curable coating formulation comprises urethane acrylate resin and nanosilica as filler were synthesized to develop UV curable inorganic organic hybrid composite (PUA). The surface of the nanosilica was chemically modified to improve its chemical interaction within the urethane acrylate matrix. The modification had been undertaken by applying vinyltrymetoxysilane (VTMOS) that acted as a coupling agent to produce organophilic silica shell (SIMA). The shell is linked to the silica via reaction with the surface silanol group of the silica. The disappearance of metoxy groups in VTMOS was demonstrated by FTIR spectrum. The percentage of silica particles in UV curable hybrid formulation were varied on 5%, 10%, 15%, 20% and 250% respectively. In this work, the formulation was applied on medium density fiber board (11/IDF) substrate and subsequent has been irradiated under UV light. Then, the coated MDF were characterized by several testing equipments (TGA, DSC, scratch tester, instron, SEM). From the result, we found that the addition of silica nanoparticles exhibit significant improvement in coating film properties as compared to film without silica nanoparticle includes significant improvement in its modulus and scratch resistance. This make them as promising coating candidate for MDF product. On the other hand, we also found that an increase of silica particle up to 25 wt%, the viscosity has increased rapidly indicates that it is not suitable for acrylate coating formulation due to disappearance of desired effect known as tixotrophy.
    Matched MeSH terms: Acrylates
  19. Mohd. Hilmi Mahmood, Shahrol Najmin Baharom, Rida Tajau, Mek Zah Salleh, Khairul Zaman Mohd. Dahlan, Rosley Che Ismail
    MyJurnal
    Various palm oil (RBD Palm Olein) based urethane acrylate prepolymers (UPs) having different structures and molecular weights were synthesised from palm oil based polyols, diisocyanate compounds and hydroxyl terminated acrylate monomers by following established synthesis procedures described elsewhere. The products (UPs) were compared with each other in terms of their molecular weights (MW), viscosities and UV curing performances of pressure sensitive adhesives (PSA) UP based formulations. The molecular structure of diisocyanate compounds and hydroxyl acrylate monomers tend to determine the molecular weights and hence viscosities of the final products of urethane acrylate prepolymers (UP), whereas, the MW of the UP has no direct effects on the coatings and adhesive properties of UV curable UP based PSA.
    Matched MeSH terms: Acrylates
  20. Jamil SNAM, Daik R, Ahmad I
    Materials (Basel), 2014 Sep 01;7(9):6207-6223.
    PMID: 28788187 DOI: 10.3390/ma7096207
    A synthesis of acrylonitrile (AN)/butyl acrylate (BA)/fumaronitrile (FN) and AN/EHA (ethyl hexyl acrylate)/FN terpolymers was carried out by redox polymerization using sodium bisulfite (SBS) and potassium persulphate (KPS) as initiator at 40 °C. The effect of comonomers, BA and EHA and termonomer, FN on the glass transition temperature (Tg) and stabilization temperature was studied using Differential Scanning Calorimetry (DSC). The degradation behavior and char yield were obtained by Thermogravimetric Analysis. The conversions of AN, comonomers (BA and EHA) and FN were 55%-71%, 85%-91% and 76%-79%, respectively. It was found that with the same comonomer feed (10%), the Tg of AN/EHA copolymer was lower at 63 °C compared to AN/BA copolymer (70 °C). AN/EHA/FN terpolymer also exhibited a lower Tg at 63 °C when compared to that of the AN/BA/FN terpolymer (67 °C). By incorporating BA and EHA into a PAN system, the char yield was reduced to ~38.0% compared to that of AN (~47.7%). It was found that FN reduced the initial cyclization temperature of AN/BA/FN and AN/EHA/FN terpolymers to 228 and 221 °C, respectively, in comparison to that of AN/BA and AN/EHA copolymers (~260 °C). In addition, FN reduced the heat liberation per unit time during the stabilization process that consequently reduced the emission of volatile group during this process. As a result, the char yields of AN/BA/FN and AN/EHA/FN terpolymers are higher at ~45.1% and ~43.9%, respectively, as compared to those of AN/BA copolymer (37.1%) and AN/EHA copolymer (38.0%).
    Matched MeSH terms: Acrylates
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