Coir and palm fibers from agricultural waste were investigated as reinforcement for low density polyethylene (LDPE). The effect of fiber preparation with alkaline treatment and with/without bleaching on fiber physical properties was also an objective of this study. The chemical composition and FTIR (Fourier transform infrared spectroscopy) results confirmed that palm fibers had less impurity than coir fibers. This could be the reason for a greater fiber-matrix interfacial interaction of the palm fibers as compared to that of coir fibers, which was in good agreement with the estimation of surface free energy of the dispersion component. Moreover, fiber bleaching improved the single fiber pullout stress. Composites with both alkaline treated and bleached fibers, at different fiber contents (5, 10, 15, and 20 wt.%), were manufactured using a compression molding machine. Addition of both fibers in the LDPE matrix resulted in composites with a higher Young’s modulus compared to that of homopolymer. The Young’s modulus of the composites increased with the effect of either fiber content or fiber bleaching. Differential scanning calorimetry (DSC) showed that composites reinforced with both types of fibers had a single melting temperature peak, indicating the existence of only one type of crystalline species. Moreover, there were no significant differences in the melting temperatures for the fiber reinforced composites and the homo-LDPE. The heat of fusion decreased in the case of fiber reinforced composites.

This research aims to utilize sericin, which is the waste from boiling silk cocoon, for the supramolecular scaffold preparation with chitosan. A suitable method for the self-assembled scaffold formation of sericin and chitosan at 1:1 stoichiometry is presented and the morphological and physical properties of the scaffold are studied. The effect of an alcohol/NaOH solution on the secondary structure of sericin protein within the sericin-chitosan scaffold, with adjusted pH, was investigated. Additionally, the scaffold was tested in a native phosphate buffer solution (PBS). The results show that sericin increases the porosity of scaffold while chitosan increases the rigidity. The self-assembled sericin and chitosan material is nontoxic to human cells and which can adhere and spread well on such support. For the effect of the molecular weight of chitosan (15,000 and 100,000 g/mol), the scaffold made from lower molecular weight (MW) chitosan provides a somewhat smaller porosity, but a similar swelling ratio and water uptake. On the basis of this research, sericin, which is a silk waste from the textile industry, can be utilized to produce a self-assembled scaffold with chitosan in order to increase the porosity of the scaffold. This type of scaffold is not toxic and can be used for the adhesion of fibroblast cells.

In this article, we investigated the properties of thermoplastic starch (TPS) with pineapple leaf fiber (PALF)/poly(lactic acid) (PLA) composite compared to both TPS with a PALF composite and TPS/PLA blend. The composite is prepared by a single-screw extruder. It appears that the TPS with PALF/PLA composite gives better mechanical properties and water resistance than the TPS/PLA blend, but it presents the same flow behavior (based on the power law index) as the PLA alone.

Pineapple leaf fiber (PALF) was treated by silane and isocyanate treatments at 0–20% prior to being used as reinforcement in low-density polyethylene (LDPE) and polypropylene (PP) composites. The reactive groups of silane and isocyanate on PALF surface were confirmed by Fourier transform infrared spectroscopy. Scanning electron micrographs also showed the fiber surface coated with layers of treated chemicals as compared with the untreated one. These surface treatments reduced the water absorption of PALF. The physical properties of the PALF-reinforced composites were investigated. The resulting composites possessed higher tensile strength and lower crystallinity than the untreated composites. Silane treatment gave better PALF/LDPE composites in terms of composite strength as compared to isocyanate treatment. For treated PALF/PP composites, fiber pullout was reduced both silane and isocyanate treatments.