Poly (lactic acid) (PLA)/chitosan (CS) natural polymer/epoxidised natural rubber (ENR) composites were successfully prepared through a solution casting method. The morphological characteristics of fabricated composites were investigated by scanning electron microscopy (SEM) and optical microscopy. The microstructure of PLA/ENR was significantly altered with the addition of CS. SEM analysis of composites fractured surfaces revealed smooth and homogeneous texture and good dispersion of CS. However for 15 wt% CS composites, the phase segregation and poor adhesion between the polymers were observed. Fourier transform infrared spectroscopy revealed some levels of attractive interaction between CS, PLA, and ENR in the composites. The mechanical properties of composites in terms of tensile strength and tensile modulus were significantly improved with the addition of CS into the matrix while the percent elongation at break decreased. The tensile strength increased up to 5 wt% CS loading for both PLA/CS and PLA/ENR/CS and thereafter decreased while Young’s modulus increased up to 10 wt%. However, when the CS content was increased to 15 wt%, the tensile strength and tensile modulus were slightly decreased. These improvements were attributed to good dispersion of CS at the optimum filler levels and attractive interaction between the composites components.

Natural fibers are environment-friendly, biodegradable, nonabrasive, and less costly and exhibit high initial modulus and high moisture absorption. However, they have nonuniformity in their mechanical, physical, chemical, and thermal properties at different portions. For this reason, long jute fiber was cut into three different portions and subsequently characterized using single fiber tensile test, differential scanning calorimetric, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy according to top, middle, and cutting portions. The crystallinity and moisture content were measured by XRD data and moisture absorption test of the different portions of the raw jute fiber, respectively. The middle portion had better mechanical, thermal, chemical, and crystalline properties compared to the other two portions of the jute fiber. The diameter gradually became thinner from cutting to top portions. Thus the middle portion of jute fiber would be the better choice while being used as reinforcement in composites.

Use of combination of natural fiber in hybrid composite ensures environment-friendly product and a balanced pursuit of required properties. Present research focuses on preparing a completely new hybrid composite reinforcing jute and sheep wool fiber into polypropylene (PP) matrix using a hot press machine. Jute fiber was chemically treated with 5% NaOH and diazonium salt at alkali, acidic, and neutral media to increase compatibility with sheep wool fiber and PP matrix. Total jute and sheep wool fiber loading was fixed at 15 wt%, with a ratio of 3:1. Both treated and untreated jute fibers were utilized during composite preparation. Mechanical, structural, thermal, and water absorption tests of prepared composites were subsequently conducted. Five percentage of NaOH treatment reduced the hydroxyl group in jute fiber, while diazonium salt treatment converted the hydroxyl group into the diazo group. Hybrid PP composite containing neutral media diazonium salt-treated jute fiber and untreated sheep wool fiber had the best of mechanical properties, thermal stability, and lowest water absorption among all prepared composites.