Starch-grafted-polypropylene/kenaf fibres composites. Part 2: thermal stability and dynamic-mechanical response

Abstract

Kenaf fibres of different aspect ratios (L/D ¼ 30 and 160) were melt compounded in an internal mixer with two types of starch-grafted-polypropylene matrices (G906PF and G906PJ) at various loadings, i.e. 10, 20 and 30 wt%. The compound was then compression-moulded into plaques of 1-mm thickness. Thermal, rheological and dynamic mechanical properties of the composite samples were investigated by several techniques involving differential scanning calorimetry, thermogravimetric analysis, melt flow index, Vicat softening point and dynamic mechanical thermal analysis. The results indicated that both thermal and mechanical properties of the composites were remarkably improved by kenaf fibres. Loss modulus and loss factor showed a shift of peak transitions to higher temperatures. Finally, the properties of the investigated composite materials were not affected by the fibre aspect ratio.

Effects of various surface treatments on Aloe Vera fibers used as reinforcement in poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) biocomposites

“…It can be noticed that Tg slightly increases up on adding both untreated and treated AVF to PHBHHx, in particular for alkaline-organosilanes treated biocomposite. This is due to stiffening effect resulting from the restriction of polymer chains mobility in the amorphous phase [35]. Similar trend is also observed for Tm and Tcc when AVF are incorporated in PHBHHx matrix.…”

“…untreated PHBHHx/AVF and the alkaline treated one show lower Tmdr comparatively to the polymer matrix. This result is logic since it is related to the simultaneous degradation of PHBHHx, cellulose and lignin [35]. In PHBHHx/alkaline treated AVF, lignin is partially or totally removed from the fibers, while in untreated AVF, the presence of impurities like pectin, waxes and other extractible, could be responsible for the decrease in Tmdr.…”

Melt behavior of polypropylene‐co‐ethylene composites filled with dual component of sago and kenaf natural filler

“…12 Under shear stress, the kenaf powder restricts the mobility of PPcoE melt, thus their viscosities are extracted at 20 phr kenaf powder loading where it is the highest filler loading added to the composites. 17 When more kenaf powder loading was added, the collision between kenaf particles also increased as the fillerfiller interaction became superior. As a result, it hindered the normal flow of TPS melt and caused higher resistance toward flow.…”

Experimental analysis and theoretical modeling of the mechanical behavior of starch‐grafted‐polypropylene/kenaf fibers composites

“…Furthermore, kenaf has great availability and low material cost in comparison to other natural fibers . Numerous researchers have reported on the study of KF reinforced polymer composites using various polymer matrices, such as polypropylene , starch‐grafted polypropylene , unsaturated polyesters , polyurethane , epoxy , etc.…”

“…To the best of our knowledge, research on the starch‐g‐PP/KF composites is not extensively reported in the open scientific literature. In our previous work, we have reported the improvement of tensile properties, hardness, creep stability and tensile impact stress after incorporation of KF into the starch‐g‐PP , along with thermal, rheological, and dynamic mechanical properties . Since there is lack of study on the starch‐g‐PP/KF composites, a more fundamental study on their mechanical properties is necessary.…”