Alfi Asben

Cellulose nanofibers isolation and characterization from ramie using a chemical-ultrasonic treatment

ABSTRACT The novelty of this work lies in isolating cellulose nanofibers from ramie (Boehmerianivea (L.) Gaud) using chemical-ultrasonication treatment. The cellulose nanofibers were successfully isolated from ramie with a diameter and length of 9.9–89.1 nm and 1 μm, respectively. The samples were characterized by scanning electron microscopy, transmission electron microscopy, particle size analysis, Fourier transform infrared spectroscopy, X-ray diffraction analysis, and thermogravimetric analysis. Indeed, there is a decrease in the hemicellulose and lignin content while the cellulose content increases due to the pulping and bleaching processes. The chemical-ultrasonication treatment results in a high yield of cellulose nanofibers (89.35%).

Studies on Ramie cellulose microfibrils reinforced cassava starch composite: influence of microfibrils loading

ABSTRACT Composites were fabricated from Ramie cellulose microfibrils (RCMF) with cassava starch as matrix and glycerol as a plasticizer. Different composites were fabricated with microfibrils loadings of 0, 2, 4, 8, and 10 wt%. The Particle Size Analyzer results show the average size of RCMF as 1.573 μm. The addition of RCMF considerably influenced the physical, crystalline, thermal, and tensile properties of composites. The addition of RCMF enhanced the crystallinity index (CI) from 32% to 36.67%. Thermogravimetric analysis and tensile test results showed improvement in thermal stability and tensile strength of composite up to 6 wt% microfibrils addition.

Kajian kualitas gambir dan hubungannya dengan karakteristik kulit tersamak

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. This study was conducted by firstly taking the samples from ten location randomly, secondly analizing some of its characteristics, and later applicating them in leather tanning. The relationship between some gambier parameters with tanned leather was determined by linear regression. The result was finding that the quality was varied among different gambier production centers, comprise of water content, tannin level, cathecin level, ash level and water-insoluble substances. Sixty percent of producton centers had given gambier which was capable to produce leather met the quality requirements. The result also found there were a strong relationship between gambier characteristics and quality of tanned leather, e.g. gambier tannin level and bonded-tannin in tanned leather (r=0.980), gambier catechins level and bonded-tannin in tanned leather (r=0.967) and gambier ash content and bonded-tannin in tanned leather (r=0.852). Highest tannin level would produce good tanned leather. Keywords: gambier, tanning, tanned leather, the correlation. ABSTRAK Penelitian 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. Kata kunci :gambir, penyamakan, kulit tersamak, korelasi