Thermoplastic starch (TPS) reinforced by 1 wt % nanofiber cellulose (NFC) reinforcing from water hyacinth was produced. Ultrasonic vibration time (UVT) was applied to bionanocomposites during gelation for 0, 15, 30 and 60 min. Morphology of the NFC was investigated using Transmission Electron Microscopy (TEM). Scanning Electron Microscopy (SEM) and tensile tests were performed to identify the fracture surface and determine the mechanical properties of the bionanocomposites, respectively. The Crystallinity index (CI) of untreated and treated bionanocomposites was measured using X-ray Diffraction (XRD). The average diameter of NFC water hyacinth was 10–20 nm. The maximum tensile strength (TS) and modulus elasticity (ME) of the bionanocomposite was 11.4 MPa and 443 MPa respectively, after 60 min UVT. This result was supported by SEM which indicated good dispersion and compact structure.

Shell Mould Strength of Rice Husk Ash (RHA) and Bentonite Clays in Investment Casting

Abstrak Biokomposit dari pati tapioka dan serat akar buah naga telah berhasil dibuat. Sebanyak 0, 2, 4, dan 6% serat (dari berat kering pati) digunakan sebagai penguat biokomposit. Fabrikasi biokomposit menggunakan metode solution casting. Pengujian serapan uap air digunakan untuk mengetahui persentase penyerapan uap air. Gugus fungsi dari biokomposit ditentukan dengan karakterisasi FTIR (Fourier Transform Infra-Red). Persentase penyerapan uap air menunjukkan bahwa, film pati tapioka mempunyai serapan uap 21,7%. Hasil ini lebih tinggi dibandingkan dengan film tapioka ditambah serat. Fenomena ini didukung dengan analisis FTIR pada gugus serapan air sekitar wavenumber 1647 cm-1. Pada daerah tersebut terlihat bahwa, film pati tapioka memiliki absorban yang tinggi dibandingkan film pati tapioka ditambah serat. Kata-kata kunci: biokomposit, pati tapioka, serat akar buah naga, FTIR, serapan uap air. Abstract Tapioca starch biocomposites reinforced dragon fruit root fiber was successfully produced. As much 0, 2, 4 and 6% fiber fractions (from dry starch weight basis) were used as reinforcement in biocomposites. The fabrication of biocomposites was solution casting method. Moisture absorption testing was used to know the percentage of moisture absorption. The functional group of biocomposites was determined by FTIR (Fourier Transform Infra-Red) characterization. The moisture absorption percentage of tapioca starch film was 21,7%. This result was higher than fiber-reinforced biocomposites film. This phenomenon was supported by FTIR analysis on functional group (water absorption band) at wavenumber 1647 cm-1. In this wavenumber, tapioca starch film has higher absorbance than fiber-reinforced biocomposites film. Keywords: biocomposites, tapioca starch, dragon fruit root fiber, FTIR and moisture absorption.