Polycaprolactone matrix composites reinforced with brown coir: Rheological, crystallization, and mechanical behavior

Abstract

Polycaprolactone matrix composites reinforced with natural and chemically treated coir were prepared in a laboratory internal mixer and studied by differential scanning calorimetry (DSC) and tensile tests. The aim of this work was to evaluate the influence of the filler and its surface modification on the rheological, mechanical, and crystallization behaviors of the composites. According to rheological analysis, the higher the filler content, the higher the viscosity of the material and the lower its local pseudoplasticity index. DSC analyses showed that the presence of coir anticipates the crystallization process; however, it does not affect the absolute crystallinity of the matrix. Mechanical tests indicated that an increase in filler content leads to an increase in Young's modulus and a decrease in the elongation at break. Additionally, composites with filler content from 20% can stand higher tensile stress than the neat polymer, and this effect is intensified by the surface modification applied to the filler. POLYM.

Thermal and Rheological Characterization of Recycled PET/Virgin HDPE Blend Compatibilized with PE-g-MA and an Epoxy Chain Extender

“…Analysis of temperature T(t) and torque Z(t) as functions of processing time at the last stages of melt processing allows us to estimate the rheological characteristics (viscosity dependence on temperature and shear rate) of the processed material and to evaluate incipient degradation rate during processing [ 33 , 34 , 35 , 36 , 37 ].…”

“…The change in crystallinity during the event is given by: where is the latent heat of melting of the 100% crystalline polymer. values of 293 J/g and 145 J/g for HDPE and PET, respectively, are provided in the literature [ 36 , 37 ]. In this work, it was assumed that both the HDPE and the compatiblizer (PE-g-MA) crystallize and melt at the same temperature, and that their limit latent heats are equal; therefore, in the compatibilized blends, the weight fraction in Equation (13) was considered to be the sum of the fractions of HDPE and PE-g-MA.…”

Polycaprolactone (PCL)/alumina and PCL/niobium pentoxide composites: Rheology, crystallization, and mechanical properties

“…The values of n and β can be calculated using several tests with pure PCL processed at different wall temperatures and different rotor rotational speeds through linear regressions of Equation . According to the literature, for PCL, n ≈ 0.95 and β ≈ 0.018/°C. As the amount of oxide added to form the composites is small, the n and β values of the composites were considered to be the same as those of pure PCL.…”

“…ASTM D638 type IV tensile test specimens and ASTM D256 impact test specimens (63.5 × 12.7 × 3 mm) were prepared for each composition by compression molding in a hydraulic press according to the procedure described in Lima et al.…”

“…In this same work, the procedure for preparation of compression‐molded films in a hydraulic press is also described. This procedure was applied in the present study to produce films for visualization in the optical microscope and particle distribution analysis.…”