Preparation and characterization of composites based on polyhydroxybutyrate and waste powder from coconut fibers processing

Macedo, Jeremias de Souza; Costa, Marysilvia Ferreira da; Tavares, Maria Inês Bruno; Thiré, Rossana Mara da Silva Moreira

doi:10.1002/pen.21669

Cited by 47 publications

(21 citation statements)

References 23 publications

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“…All composites showed higher thermal degradation resistance than pure PHB, although this increase was not very great. Nevertheless, the results were acceptable compared to other studies, such as those of J. Macedo et al [34] where the PHB composites reinforced with coconut fibers had a lower thermal resistance than pure PHB.…”

Section: Compositessupporting

confidence: 49%

Chemical Treatment of Natural Malva Fibers and Preparation of Green Composites with Poly(3-hydroxybutyrate)

Oliveira¹,

Marques

2015

ChChT

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Abstract. Malva fiber was submitted to alkali treatments with NaOH aqueous solutions at different concentrations, times and temperatures. Fiber samples were analyzed before and after treatments to study their effects on crystallinity, thermal stability and morphology. The results showed that the crystallinity index and thermal resistance significantly increased when the alkaline treatment was conducted with 7 % NaOH solution. Higher concentrations of NaOH, such as 10, 15 and 20 %, did not considerably increase the fiber crystallinity index. By X-ray diffraction, it was observed that defibrillation occurred in mercerized fibers, which is expected to be advantageous for use as fiber reinforcement in polymer matrices. The same fiber samples were mixed with a poly(3-hydroxybutyrate) matrix in a twin-screw miniextruder at 453 K. The composites were analyzed by TGA and DMA to evaluate the influence of fiber addition in mechanical and thermal properties of the polymer.

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Section: Compositessupporting

confidence: 49%

Chemical Treatment of Natural Malva Fibers and Preparation of Green Composites with Poly(3-hydroxybutyrate)

Oliveira¹,

Marques

2015

ChChT

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“…Both compression molding of thin composite sheets and processing on mini extruders and mini injection molding machines are limited processes due to the fact that they are difficult to relate to actual processing conditions. Composites with a PHBV matrix filled with fibers of plant origin such as coconut [34][35][36][37][38], bamboo [39][40][41][42][43][44][45][46], abaca [47,48], pineapple [32,49] and sisal [50][51][52] have been the subject of research.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Alkali Treatment of Flax and Hemp Fibers on the Properties of PHBV Based Biocomposites

2021

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This study assessed the impact of alkali treatment of hemp and flax fibers on mechanical properties (determined by means of the uniaxial tensile test, impact tensile strength test and hardness test), processing properties (the course of the extrusion and injection process) and usable properties (shrinkage of molded pieces, degree of water absorption) of biocomposites on the base of poly (3-hydroxybutyric-co-3-hydroxyvaleric acid) (PHBV) biopolymer. For this purpose, 1 mm of length flax and hemp fibers was surface-modified by means of aqueous solution of NaOH (sodium hydroxide) with concentrations of 2%, 5% and 10%. The composites were made using the extrusion technology. The test specimens were produced by injection molding technology. In total, eight types of biocomposites with modified and non-modified fibers were produced, and each biocomposite contained the same filler content (15 wt.%). Their properties were compared in some cases with pure PHBV polymer. In the case of biocomposites filled with hemp fibers, it was noted that an increase of the alkalizing solution concentration improved most of the tested properties of the obtained biocomposites. On the other hand, in the case of flax fibers, there was a significant decrease in most of the mechanical properties tested for the composite containing fibers etched by 10% NaOH solution. The obtained results were verified by examining fibers and the destroyed specimens with a scanning electron microscope (SEM) and an optical microscope, which confirmed, especially, the significant geometry changes of the flax fibers etched by 10% NaOH solution. This procedure also resulted in a significant change of processing properties—a composite of this fiber type required about 20 °C lower temperature during the extrusion and injection molding process in order to obtain the right product. These results lead to the important conclusion that for each filler of the plant-origin and polymer matrix, the fiber alkalization method should be selected individually in order to improve the specific properties of biocomposites.

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“…The PHB production on a large scale is still a relatively expensive process, mainly because of the process difficulties that due to their narrow processing conditions, since it is very instable near the melting point (180°C); allied to high crystallinity providing high fragility [5] . These facts lead studies to improve these properties [6][7][8] .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the influence of the use of waste from the processing of rice in physicochemical properties and biodegradability of PHB in composites

et al. 2014

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Abstract:The high calorific value of rice husks has elevated its reuse as an energy source; however, the burning of these shells generates a waste ash from rice husk ash (RHA), which makes its disposal a concern. Despite advances, biodegradable polymers are not yet able to compete with those of traditional thermoplastics, which have lower production cost and higher performance. Based on this background, this paper studies the feasibility of reuse of RHA as filler in polymer matrices replacing the conventional filler. This study consists of applying different percentages of RHA in the formulation of polyhydroxybutyrate composite (PHB) and the use of talc (TA) for comparison purposes as conventional filler. The composites used in this assay were obtained by twin-screw extrusion and injection molding of the polymer plus the fillers under study. Physicochemical and biodegradability properties of the composites were evaluated. The composite PHB/RHA was superior in the biodegradability tests and the properties remain practically unchanged in the presence of the filler. Thus, composites with RHA are promising because they take an abundant residue combined with degradation capacity of the polymer, therefore reducing cost and the environmental impact.

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Preparation and characterization of composites based on polyhydroxybutyrate and waste powder from coconut fibers processing

Cited by 47 publications

References 23 publications

Chemical Treatment of Natural Malva Fibers and Preparation of Green Composites with Poly(3-hydroxybutyrate)

Chemical Treatment of Natural Malva Fibers and Preparation of Green Composites with Poly(3-hydroxybutyrate)

Influence of the Alkali Treatment of Flax and Hemp Fibers on the Properties of PHBV Based Biocomposites

Evaluation of the influence of the use of waste from the processing of rice in physicochemical properties and biodegradability of PHB in composites

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