Feasibility Study of Chemical Treatments on Sorghum Fibres for Compatibility Enhancement in Polypropylene Composites

Abstract

Polypropylene (PP) is one of the biggest petro-polymers, which is used in very wide application nowadays. The environment problem due to materials such as plastics having very long time degradability, and critical petroleum sources have promoted some studies to empowerment of natural resources such as natural fibres for substituting or at least modifying petro-polymers. Because of biodegradability obtained from natural source, sorghum fibers are interesting to be used as filler in PP composites, despite of weak compatibility between them. Surface modification on the sorghum fibers through alkalinization prior to acetylation was aimed to improve the fiber compatibility to PP. The treatments were expected to substitute hydroxyl group in the sorghum fibers, into acetic ester group in order to increase their hydrophobicity as the fillers. Moreover, the treatments were able to unbundle single fibers into micro-fibrillated cellulose (MFC) fibres with increase in crystallinity index. Usage of this MFC fiber as filler in PP leads to improvement of the composite performances such as thermal properties. In this study, Fourier Transformation Infra-Red (FTIR) Spectroscopy, X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Field-Emission Scanning Electron Microscope (FE-SEM) were used to evaluate the performances of the Sorghum fibers after the treatments and as the filler in the Sorghum fibers/PP composites. The experimental results showed the MFC fibers as the smallest sizes in 5.0 microns and the highest crystallinity index up to 79.1 %, obtained from alkalinization with 2.5 M NaOH prior to acetylation with 17.4 M CH3COOH and the glacial (CH3CO2)2. Compatibility study of the treated Sorghum fibers on PP shows an improvement indicated by a strong interaction between the fibers and PP on morphology observation, increase in melting point of PP from 163.4°C (using virgin Shorgum fibers) into 163.6°C (using treated Sorghum fibers) in DSC measurements.

Pengaruh Perlakuan Kimia Alkalinasi dan Asetilasi terhadap Kekuatan Tarik dan Mikrostruktur Serat Abaka

“…Berdasarkan hal tersebut, untuk mengurangi limbah dan juga kepedulian terhadap lingkungan, maka limbah pisang digunakan sebagai serat alami pengganti serat sintetis yang dapat didaur ulang dan ramah lingkungan [4] karena serat limbah tanaman memiliki komposisi, sifat, dan struktur yang sesuai untuk digunakan sebagai serat pada komposit [10]. Kekurangan dari serat alam yang bersifat hidrofilik karena adanya kandungan hemiselulosa, lignin, dan pektin membuat material komposit berpenguat kurang baik pada sifat mekaniknya karena akan menyebabkan rendahnya kompatibilitas antara matriks komposit yang bersifat hidrofobik [6].…”

Innovative self-sensing fiber-reinforced cemented sand with hybrid CNT/GNP

“…The surfaces of the fibers were treated using the chemical method to increase the interaction and adhesion between the cementitious matrix and fibers [57][58][59][60][61]. In this route, The PP and Dyneema fibers were submerged into a bath of sulfuric acid and sodium dichromate solution for 24 h at 50 • C, and the glass fibers were dipped into hydrofluoric acid 40% for 18 h at 40 • C. Thereafter, the fibers were washed with water and dried at room temperature.…”