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The development of bioplastic composites from various natural polymers reinforced with Precipitated Calcium Carbonate (PCC) has become a field of increasing interest. In this study, the effect of PCC on the physical, mechanical and thermal properties of a cassava starch matrix composite was examined. The bioplastic composites were made of cassava starch and mixed with glycerol as a plasticizer and 0-10% by weight of PCC. The material was then poured into a mold and oven dried. The physical, thermal and mechanical properties of bioplastic/PCC composites were investigated using Tensile Strength measurements, X-Ray Diffraction, Thermogravimetric Analysis, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). The optimum tensile strength was obtained upon the addition of 4 % PCC. The addition of PCC improved the thermal stability of bioplastic/PCC composites. The results of X-ray Diffraction testing showed an increase in the crystallinity of the bioplastic/PCC composites with increase in PCC content but there is a decrease in the moisture absorption. SEM images indicated that the PCC filler content was incorporated into the matrix. In general, FTIR indicated the bioplastic/PCC composites were hydrophilic and the addition of PCC reduced the hydrophilic properties by damaging the hydrogen bonding between starch molecules and water.

This study aimed to investigate the quality of gambier taken from gambier production center in West Sumatra, the characteristic of tanned leather which was tanned by gambier, and the relationship between gambier quality and tanned leather product. ABSTRAKPenelitian ini bertujuan untuk mengetahui kualitas gambir yang diambil dari sentra produksi gambir Sumatera Barat, mengetahui karakteristik kulit tersamak yang disamak menggunakan gambir tersebut dan mengetahui hubungan kualitas gambir dengan kulit tersamak yang dihasilkan. Penelitian dilakukan dengan mengambil sampel dari sepuluh lokasi secara acak, dilanjutkan dengan analisis karakteristik gambir serta aplikasinya dalam penyamakan kulit. Untuk mengetahui hubungan antara beberapa parameter gambir dengan parameter kulit tersamak yang dihasilkan digunakan regresi linier. Hasil penelitian menunjukkan karakteristik gambir dari sentra produksi di Sumatera Barat memiliki kualitas yang bervariasi pada kadar air, kadar tanin, katekin, kadar abu dan zat tak larut air. 60% lokasi sentra produksi memberikan gambir yang mampu menghasilkan kualitas kulit tersamak memenuhi standar mutu. Hubungan antara beberapa parameter gambir sebagai bahan penyamak dengan kualitas kulit tersamak menunjukkan hubungan yang sangat erat antara kadar tanin gambir dengan kadar tanin terikat pada kulit tersamak (r=0.980), kadar katekin pada gambir dengan kadar tanin terikat pada kulit tersamak (r=0.967), dan kadar abu pada gambir dengan kadar tanin terikat pada kulit tersamak (r=0.852). Tingginya kadar tanin gambir akan menghasilkan kulit tersamak yang baik.

Studi awal tanin dari kulit kayu A.auriculiformis …….. (Mutiar et al.) 41 Majalah Kulit, Karet, dan Plastik, 34(2), 41-48, 2018 ©Author(s), https://doi.org/10. 20543/mkkp.v34i2.3967 Studi awal tanin dari kulit kayu Acacia auriculiformis A. Cunn. ex Benth. dari hutan tanaman industri untuk bahan penyamak kulit ABSTRACT This study aims to determine the tannin content and extraction method of the content and levels of tannin from the bark of Acacia auriculiformis A. Cunn. ex Benth. The bark is obtained from PT. Arara Abadi. The extract methods are water bath, ultrasonic bath, autoclave, reflux, and microwave. The tannin extract produced was applied as a vegetable tanning agent. The extract which is the best yield of the method used. The results showed that the highest yield was obtained by the autoclave method which was 29.65%. The results of chemical analysis of the extract produced were 52.79% tannin content, 62.40% water soluble materials. Application of the tannin extract as a vegetable tanning agent on goat skin was carried out chemical analysis, observation of physical and organoleptic properties. The quality of tanned skin was seen from the chemical properties, i.e. water content of 15.02%, 3.20% fat content, 3.44% ash content, 3.57% water soluble substances, 43.79% raw skin substances, 30.98% bonded tannins, 70.74% degree of tannage. Observation of physical properties of tanned skin were tensile strength 254.21 kg/cm 2 , 63.95% elongation at break, 9.27 mm zwik resistance/crack (non-broken nerf), thickness 0.9 mm, and brown color. A. auriculiformis bark extract contains tannins and potential as tanning agent. ABSTRAKPenelitian ini bertujuan untuk mengetahui kandungan tanin dan metode ekstraksi terhadap karakteristik dan kadar tanin dari kulit kayu Acacia auriculiformis A. Cunn. ex Benth. Kulit kayu diperoleh dari HTI PT. Arara Abadi. Metode ekstrak yang digunakan water bath, ultrasonic bath, autoclave, refluks dan microwave. Ekstrak tanin yang dihasilkan diaplikasikan sebagai bahan penyamak nabati. Ekstrak yang digunakan adalah rendemen tertinggi dari metode yang digunakan. Hasil penelitian menunjukkan bahwa rendemen tertinggi diperoleh dengan metode autoclave yaitu 29,65%. Hasil analisis kimia dari ekstrak yang dihasilkan kadar tanin adalah 52,79%, bahan larut air 62,40%. Aplikasi ekstrak tanin sebagai bahan penyamak nabati menggunakan kulit kambing dilakukan analisis kimia, pengamatan sifat fisik dan organoleptis. Kualitas kulit tersamak ditinjau dari sifat kimia diantaranya kadar air 15,02%, kadar lemak 3,20%, kadar abu 3,44%, kadar zat larut air 3,57%, kadar zat kulit mentah 43,79%, kadar tanin terikat 30,98% dan derajat penyamakan 70,74%. Pengamatan sifat fisik kulit tersamak yaitu kekuatan tarik 254,21 kg/cm 2 , kemuluran 63,95%, ketahanan zwik/keretakan 9,27 mm (nerf tidak pecah), ketebalan 0,9 mm, warna coklat. Ekstrak kulit kayu A. auriculiformis mengandung tanin dan berpotensi untuk digunakan sebagai bahan penyamak kulit.

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