Rotational molding of polyethylene composites based on agave fibers

Abstract

In this study, agave fiber/linear medium density polyethylene composites were manufactured by rotational molding. A laboratory scale biaxial machine was used, where the internal air temperature during the processing cycle was measured. Two sizes of agave fibers (50 and 100 mesh) were used separately and mixed together (50/50) at concentrations varying between 0 and 15 wt%. The initial mixtures were obtained by dry blending, rotomolded under different operation conditions (oven temperature, processing cycle time, and rotational speeds), and the final pieces were compared. For each process condition, a complete morphological analysis was performed to relate with mechanical properties in terms of tensile, impact, and flexural strength. The results show that there is an optimum fiber concentration around 10%, and blending fiber sizes gave better tensile properties than using each size alone.

Polylactic acid–agave fiber biocomposites produced by rotational molding: A comparative study with compression molding

“…For R‐BCs at 40 wt.%, the strength decreased by 90% (from 59 MPa for PLA to 6 MPa), and 53% (from 60 MPa for PLA to 29 MPa) for 40 wt.% CM‐BCs. Rotomolded composites presented lower tensile strengths due to their higher porosity limiting adequate stress transfer as also reported for PLA composites reinforced with agave, coir and pine, sisal, bamboo, and kenaf, as well as in polyolefin composites and foams …”

Rotational Molding of Polymer Composites Reinforced with Natural Fibers

“…In addition, with fiber surface treatments (alkali treatment with NaOH and maleated polyethylene (MAPE)), mechanical properties were improved (35% for flexural modulus), and it was also possible to introduce up to 25 wt% of fibers. 13 Also, López-Bañuelos et al 14 investigated the effect of agave fibers on LMDPE, while Wang et al 15 studied the influence of various fiber treatments (benzoylation, silane, peroxide) and their reinforcing effects on different matrices (LLDPE, HDPE, LLDPE, and HDPE) for compounds prepared by twin-screw extrusion. Jayaraman et al 16 investigated the effect of sisal fibers to reinforce LMDPE, while Ortega et al 17 studied the effect of banana and abaca fibers to reinforce metallocene polyethylene.…”

Thermal analysis of foamed polyethylene rotational molding followed by internal air temperature profiles

“…They concluded that the optimum PIAT depends on several parameters such as the polymer grade, the nature of the stabilizer, the type of atmosphere inside the mold, and any parameter affecting heat transfer rates. IAT was also used to determine the effect of particle size and shape on the sintering stage , or the effect of natural fibers in rotomolding composites . Furthermore, the reduction of cycle times has been monitored by IAT, applying pressure inside the mold or using molds with extended surfaces of different geometries .…”

“…In the most cases it is very important to know the PIAT to avoid material degradation. For example, in the case of composites with natural fiber the PIAT should not exceed the degradation temperature of the fiber . In the polymer foaming process, the PIAT will be determinant to ensure the complete decomposition of the foaming agent .…”