Changes in the structure and composition of pineapple leaf fiber after alkali and ionic surfactant pretreatments and their impact on enzymatic hydrolysis.

The current study investigated the effects of two different pretreatments (NaOH and alkaline surfactant assisted) on the chemical, morphological and enzymatic saccharification of pineapple leaf fiber (PALF). Results showed that both pretreatments significantly reduced lignin content of the biomass, achieving a 69.6 and a 76.3% reduction for NaOH and surfactant pretreated materials, respectively. SEM, CLSM and FTIR-ATR techniques were used to evaluate morphological changes in the fibers after pretreatments. Images obtained revealed cellulose exposure and lignin redistribution in the pretreated fibers. Surfactant pretreated material provided the best results after enzymatic hydrolysis compared to NaOH and untreated PALF. A final enzymatic hydrolysis yield of 81.8% was obtained after a 24 h process using surfactant pretreated fibers, in comparison to 75.9 and 45.1% yields for NaOH pretreated material and raw fibers, respectively. Nowadays, the use of agricultural residues for high added value products is of great importance for sustainable development. This work specifically studied an effective and green approach for lignin removal and enzymatic hydrolysis from pineapple leaf fiber that is an abundant waste in Costa Rica and an interesting feedstock for biorefinery processes design.

Assessing Mechanical Properties of Jute, Kenaf, and Pineapple Leaf Fiber-Reinforced Polypropylene Composites: Experiment and Modelling.

The application of natural fibers is increasing rapidly in the polymer-based composites. This study investigates manufacturing and characterization of polypropylene (PP) based composites reinforced with three different natural fibers: jute, kenaf, and pineapple leaf fiber (PALF). In each case, the fiber weight percentages were varied by 30 wt.%, 35 wt.%, and 40 wt.%. Mechanical properties such as tensile, flexural, and impact strengths were determined by following the relevant standards. Fourier transform infrared (FTIR) spectroscopy was employed to identify the chemical interactions between the fiber and the PP matrix material. Tensile strength and Izod impact strength of the composites significantly increased for all the composites with different fiber contents when compared to the pure PP matrix. The tensile moduli of the composites were compared to the values obtained from two theoretical models based on the modified "rule of mixtures" method. Results from the modelling agreed well with the experimental results. Tensile strength (ranging from 43 to 58 MPa), flexural strength (ranging from 53 to 67 MPa), and impact strength (ranging from 25 to 46 kJ/m2) of the composites significantly increased for all the composites with different fiber contents when compared to the pure PP matrix having tensile strength of 36 MPa, flexural strength of 53 Mpa, and impact strength of 22 kJ/m2. Furthermore, an improvement in flexural strength but not highly significant was found for majority of the composites. Overall, PALF-PP displayed better mechanical properties among the composites due to the high tensile strength of PALF. In most of the cases, T98 (degradation temperature at 98% weight loss) of the composite samples was higher (532-544 °C) than that of 100% PP (500 °C) matrix. Fractured surfaces of the composites were observed in a scanning electron microscope (SEM) and analyses were made in terms of fiber matrix interaction. This comparison will help the researcher to select any of the natural fiber for fiber-based reinforced composites according to the requirement of the final product.

A novel approach for pineapple leaf fiber processing as an ultimate fiber using existing machines.

This research aims to study the spinnability of pristine PALF and PALF blended cotton using the existing spinning machines. Apron draft ring spinning frame and flyer jute spinning frame were used to produce 100% PALF yarn and the yarns count were found 121 tex and 138 tex separately. Besides, 90:10 and 80:20 cotton-PALF blended 30 tex yarn spun in a cotton spinning system with different twist factors. With both yarns, two samples; 1/1 plain and 3/1 twill fabrics, were fabricated through equal density. For plain and twill fabric, PALF yarn of 121 tex and 138 tex were used in the warp way, respectively and PALF blended cotton yarn of 60 tex was used in the weft way. Through the study, physio-mechanical properties of the samples were explored and FTIR & XRD patterns were analyzed to perform the task for diversified use as an ultimate fiber in industrial and domestic purposes.