Effect of compatibilization and reprocessing on the isothermal crystallization kinetics of polypropylene/wood flour composites

Rodrigues, Arieny; Carvalho, Benjamim de Melo; Pinheiro, Luís Antônio; Bretas, Rosário Elida Suman; Canevarolo, Sebastião V.; Marini, Juliano

doi:10.4322/polimeros.2013.032

Cited by 14 publications

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“…Similar n values were reported for PLA/nucleating agent (MFC, CNC, talc, and uracil) composites by other studies, where the Avrami exponent n is in the range of 2.8-4.9 [44][45][46][47][48]. Moreover, the k value for neat PLA and PLA/CNF nanocomposites increased with the T c and then decreased after reaching a maximum value at 100 • C due to the difficulty of crystal nucleation at elevated temperature [49]. Figure 5a,b represents the correlation between CNF content with crystallization halftime and crystallization rate for PLA melt-crystallized isothermally at 90, 100 and 110 • C. As seen in Table 2 and Figure 5a, incorporation of CNF up to 3 wt.% effectively reduced the t 1/2 values to 4.99, 1.40 and 26.63 min from the 158.01, 92.72 and 165.59 min of the neat PLA, respectively, when isothermally crystallized at 90, 100 and 110 • C. This proves the nucleating property of CNF that leads to faster crystallization.…”

Section: Isothermal Crystallization Kineticssupporting

confidence: 86%

“…Similar n values were reported for PLA/nucleating agent (MFC, CNC, talc, and uracil) composites by other studies, where the Avrami exponent n is in the range of 2.8–4.9 [ 44 , 45 , 46 , 47 , 48 ]. Moreover, the k value for neat PLA and PLA/CNF nanocomposites increased with the T c and then decreased after reaching a maximum value at 100 °C due to the difficulty of crystal nucleation at elevated temperature [ 49 ].…”

Section: Resultsmentioning

confidence: 99%

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Functionality of Cellulose Nanofiber as Bio-Based Nucleating Agent and Nano-Reinforcement Material to Enhance Crystallization and Mechanical Properties of Polylactic Acid Nanocomposite

et al. 2021

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Polylactic acid (PLA), a potential alternative material for single use plastics, generally portrays a slow crystallization rate during melt-processing. The use of a nanomaterial such as cellulose nanofibers (CNF) may affect the crystallization rate by acting as a nucleating agent. CNF at a certain wt.% has been evidenced as a good reinforcement material for PLA; nevertheless, there is a lack of information on the correlation between the amount of CNF in PLA that promotes its functionality as reinforcement material, and its effect on PLA nucleation for improving the crystallization rate. This work investigated the nucleation effect of PLA incorporated with CNF at different fiber loading (1–6 wt.%) through an isothermal and non-isothermal crystallization kinetics study using differential scanning calorimetry (DSC) analysis. Mechanical properties of the PLA/CNF nanocomposites were also investigated. PLA/CNF3 exhibited the highest crystallization onset temperature and enthalpy among all the PLA/CNF nanocomposites. PLA/CNF3 also had the highest crystallinity of 44.2% with an almost 95% increment compared to neat PLA. The highest crystallization rate of 0.716 min–1 was achieved when PLA/CNF3 was isothermally melt crystallized at 100 °C. The crystallization rate was 65-fold higher as compared to the neat PLA (0.011 min–1). At CNF content higher than 3 wt.%, the crystallization rate decreased, suggesting the occurrence of agglomeration at higher CNF loading as evidenced by the FESEM micrographs. In contrast to the tensile properties, the highest tensile strength and Young’s modulus were recorded by PLA/CNF4 at 76.1 MPa and 3.3 GPa, respectively. These values were, however, not much different compared to PLA/CNF3 (74.1 MPa and 3.3 GPa), suggesting that CNF at 3 wt.% can be used to improve both the crystallization rate and the mechanical properties. Results obtained from this study revealed the dual function of CNF in PLA nanocomposite, namely as nucleating agent and reinforcement material. Being an organic and biodegradable material, CNF has an increased advantage for use in PLA as compared to non-biodegradable material and is foreseen to enhance the potential use of PLA in single use plastics applications.

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Section: Isothermal Crystallization Kineticssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Functionality of Cellulose Nanofiber as Bio-Based Nucleating Agent and Nano-Reinforcement Material to Enhance Crystallization and Mechanical Properties of Polylactic Acid Nanocomposite

et al. 2021

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“…Then, the crystallinity of r‐HDPE decreased with 50% cupula fiber loading. This may had been caused by the nucleation effect of untreated cupula flour like nucleation effect of wood flour . This situation was not observed in the alkali‐treated cupula fiber‐filled composites and the crystallinity of r‐HDPE decreased with the increase of the cupula fiber ratio.…”

Section: Resultsmentioning

confidence: 99%

Effect of alkali treatment on composites made from recycled polyethylene and chestnut cupula

2019

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The objective of this study is to investigate the effects of alkali treatment on the mechanical, physical properties of cupula fibers reinforced recycled high density polyethylene (r-HDPE) composites. The composites were produced with different chestnut (Castanea sativa Mill.) cupula fiber contents, up to 50%, and polyethylene-grafted maleic anhydride. The mechanical, physical, thermal, and morphological properties of the treated and untreated samples were investigated. In addition, the Fourier transform infrared spectroscopy (FTIR) was used to observe the interactions and functional groups between cupula fiber and r-HDPE in the composite samples. The alkali treatment with 5 wt% NaOH solution had an affirmative effect on the tensile and flexural properties. It was found that an increase of 20% in flexural strength values with up to 40 wt% alkali treated cupula fiber loading in polymer matrix compared to that of untreated samples. After 5 wt% NaOH treatment, the crystallinity decreased with the increase of the chestnut cupula fiber ratio. As excepted, the FTIR analysis showed that the alkali treatment resulted in removal of hemicellulose, and lignin from cupula fiber.The results revealed that the alkali treated chestnut cupula fiber can be used successfully in polymer composites as a natural fiber filler. K E Y W O R D Scomposites, FT-IR, mechanical properties, polyethylene (PE), waste

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“…3160 crystallinity degree (Xc) values than virgin HDPE. The Xc values increased with increasing wood filler content, which could be due to the nucleation effect of wood flour (Lei et al 2007;Rodrigues et al 2013). Compared with the untreated alder wood-filled HDPE composites, the heattreated alder wood-filled HDPE composites had a lower crystallinity degree.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 91%

Technological and Thermal Properties of Thermoplastic Composites Filled with Heat-treated Alder Wood

et al. 2016

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This study investigated the effect of heat-treated wood content on the water absorption, mechanical, and thermal properties of wood plastic composites (WPCs). The WPCs were produced from various loadings (30, 40, and 50 wt%) of heat-treated and untreated alder wood flours (Alnus glutinosa L.) using high-density polyethylene (HDPE) with 3 wt% maleated polyethylene (MAPE) coupling agent. All WPC formulations were compression molded into a hot press for 3 min at 170 ºC. The WPCs were evaluated using mechanical testing, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The mechanical property values of the WPC specimens decreased with increasing amounts of the heattreated wood flour, except for the tensile modulus values. The heat treatment of alder wood slightly increased the thermal stability of the WPCs compared with the reference WPCs. The crystallization degree (Xc) and the enthalpy of crystallization of the WPCs slightly decreased with increasing content of the heat-treated wood flour. However, all WPCs containing the heat-treated alder wood flour showed a higher crystallinity degree than that of the virgin HDPE.

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Effect of compatibilization and reprocessing on the isothermal crystallization kinetics of polypropylene/wood flour composites

Cited by 14 publications

References 0 publications

Functionality of Cellulose Nanofiber as Bio-Based Nucleating Agent and Nano-Reinforcement Material to Enhance Crystallization and Mechanical Properties of Polylactic Acid Nanocomposite

Functionality of Cellulose Nanofiber as Bio-Based Nucleating Agent and Nano-Reinforcement Material to Enhance Crystallization and Mechanical Properties of Polylactic Acid Nanocomposite

Effect of alkali treatment on composites made from recycled polyethylene and chestnut cupula

Technological and Thermal Properties of Thermoplastic Composites Filled with Heat-treated Alder Wood

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