Judul: Produksi Plastik Komposit dari Campuran Tapioka-Onggok Termoplastis dengan Compatibilized Polietilen
Abstrak: One of alternative solution for plastic disposal problem is by developing biodegradable plastic. The typical drawbacks of starch-based plastic is inferior of its physico-mechanical properties. In order to improve the physico-mechanical properties and compatibility of blending system, tapioca-casava bagasse was modified into thermoplastic tapioca-casava bagasse blends while polyethylene was compatibilized by addition maleic anhydride. The aim of this research was to produce composite plastic from thermoplastic tapioca-casava bagasse blends and compatibilized polyethylene (compt-HDPE, compt-LDPE and compt-LLDPE). This research investigated the effect of fiber content in formulating the tapioca-casava bagasse blends, as 5, 10, 15 and 20%; glycerol (as plasticizer) concentration, as 30, 35 and 40% to the mechanical, thermal, biodegradability and surface morphological properties of composite plastics. The result showed that fiber contents in blends tapioca-casava bagasse up to 15% can improve physico-mechanical properties (tensile stress at yield, tensile stress at break and thermal properties) but addition of glycerol more than 30% can decrease mechanical composite plastic properties especially for HDPE. Introduction of thermoplastic tapioca-casava bagasse in polyethylene composite plastic generally can decrease physico-mechanical properties plastic. Synthetic polymer that suitable with thermoplastic blends tapioca-casava bagasse was compt-HDPE. The best result gained from 40% thermoplastic blends with HDPE, 15% of fiber and 30% of glycerol contents. Biodegradability test showed that composite plastic can be degraded, but only natural component such as starch and fiber was degraded.
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Judul: Rekayasa proses produksi bioplastik berbahan baku pati termoplastik dan polietilen
Abstrak: Plastics have been used widely for packaging materials. However, plastic wastes can pollute environment because of its persistency to be biodegraded by microorganisms. Efforts have been conducted to develop environmental friendly plastic from renewable resources. Problems encountered in the manufacture of bioplastic are poor physical-mechanical properties and incompatibility between hydrophilic/polar and hydrophobic/non-polar materials. The modification of raw materials and use of compatibilizer can be applied to improve the compatibility between the two material blends. The purpose of this study is to develop a process of manufacturing bioplastic by modifying the raw material characteristics and the use of compatibilizer. This study consisted of three steps, namely preparation of thermoplastic starch, preparation of maleic anhydride (MA) grafted with LLDPE/HDPE (LLDPE-g-MA/HDPE-g-MA) and manufacturing process of bioplastic. Thermoplastic was prepared by mixing distilled water and glycerol with tapioca, and then allowed to aging for 8 days to a mixture of distilled water and glycerol can be absorbed completely into raw materials (tapioca). Grafting of maleic anhydride with LLDPE/HDPE (LLDPE-g-MA and HDPE-g-MA) was carried out in a twin screw extruder. There were three levels of maleic anhidride concentration namely 2.5%, 5%, 7.5% (w/w) and dicumyl peroxide 0.1% (w/w polymer) used in this experiment. After mixing LLDPE-g-MA and HDPE-g-MA compatibilizer with thermoplastic starch (TPS), the resulting mixtures were then extrudered with LLDPE/HDPE. Four ratios between LLDPE/HDPE and TPS were investigated namely 0:100; 20:80; 40:60; and 60:40. The plastic properties observed included melt flow rate, density, thermal, mechanical, barrier, and degradation properties. The results showed that increasing thermoplastic starch content decreased melt flow rate, melting temperature, mechanical, oxygen transmition rate properties and increased density, water vapor transmition rate and its biodegradability. The presence of LLDPE-g-MA/HDPE-g-MA compatibilizer resulted in better physical and mechanical properties of bioplastic. The compatibilizer improved surface adhesion and decreased surface tension between TPS and LLDPE/HDPE matrix. The best formulation for wrapping applications was the LLDPE-TPS with 40% of TPS and 5% MA with 6,96% of grafting degree, whereas that for plastic bag applications was HDPE-TPS with 30% of TPS and 7,5% MA with 3,21% of grafting degree. Stability tests of bioplastic TPS-LLDPE and TPS-HDPE for packaging applications at room and low temperature showed no significant changes in the mechanical properties, permeability, and morphology, and therefore the product has the ability to maintain mechanical properties at low temperature.
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Judul: Babesiosis pada kuda
Abstrak: Babesiosis pada kuda adalah penyakit menular yang di- sebabkan oleh Babesia caballi dan Babesia equi, yaitu pa- rasit protozoa perusak sel darah yang termasuk dalam genus Babesia. B. equi diduga oleh beberapa ahli termasuk dalam genus Theileria. Karena itu klasifikasi genus Babesia di- bicarakan dan siklus hidup B. caballi dan B. equi diulas. Kuda pada semua umur dapat terserang oleh dua parasite tersebut di atas. Tetapi kuda-kuda yang sudah dewasa (tua) lebih rentan jika dibandingkan dengan kuda-kuda yang masih muda. Kasus-kasus yang paling sering dijumpai adalah kasus-kasus yang bersifat akut walaupun kasus-kasus yang bersifat perakut, subakut dan kronik kadang-kadang terlihat. Serangan oleh parasit Babesia biasanya menyebabkan kerusаkan sel darah merah yang hebat sehingga kuda-kuda yang terserang menderita anemia hebat yang dapat menyebabkan kematian bila tidak segera diobati. Untuk mengatasi hal tersebut perlu dilakukan diagnosis yang tepat dan sedini mungkin. Diagnosis dapat dilakukan dengan cara memeriksa gejala-gejala klinik, preparat ulas darah, inokulasi hewan lain dan dengan mengadakan pemeriksaan secara serologik. Gejala-gejala klinik babesiosis pada kuda yang bersifat akut yang paling sering terlihat, ialah : nafsu makan menurun/hilang, lesu, bulu suram dan tidak mau bergerak. Kuda yang dilepaskan di padang rumput akan mengasingkan diri dan jalan sempoyongan. Faeces yang keluar berwarna cok- lat gelap, diselaputi lendir yang berwarna kekuningan dan urimenya berwarna merah tua. Temperatur tubuh meningkat menjadi 39.5 - 41°C dan pulsus meningkat. Terlihat dispnoe, perdarahan petechi pada mukosa membrana nictitans dan conjunctiva yang lebih pucat dari normal dan juga icteris. Kasus-kasus yang bersifat subakut gejala-gejalanya lebih ringan, tetapi bila tidak segera diobati maka gejala- gejala tersebut secara cepat menjadi hebat. Persendian lutut dan persendian gelang puyuh membengkak dan padanya ter- lihat oedema. Pada abdomen, dada dan kepala juga dapat di- temukan oedema. Gejala-gejala klinik yang terlihat pada kasus kronik adalah penurunan kondisi tubuh kuda secara progresif walaupun diberi makan yang banyak. Perubahan temperatur tidak jelas, nafsu makan berubah-ubah, icterus tidak jelas dan anemia mungkin hanya dapat dideteksi dengan menghitung sel darah merah dan kadar hematocrit…dst
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