Unique stiffness-deformability features of dendrimeric silica reinforced HDPE nanocomposites obtained by an innovative route

Cecílio, Duarte M.; Cerrada, María L.; Pérez, Ernesto; Fernandes, Auguste; McKenna, Timothy F. L.; Ribeiro, M. Rosário

doi:10.1016/j.micromeso.2021.111619

Cited by 3 publications

(10 citation statements)

References 36 publications

(49 reference statements)

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“…In fact, PCL-SBA9 shows a value that is 40 % higher than for the neat PCL. At similar loading contents, this increase is superior to that found in nanocomposites based on polypropylene [ 49 , 56 ] but is analogous to the one observed when polyethylene is used as the matrix [ 22 , 59 ].…”

Section: Resultsmentioning

confidence: 70%

Nanocomposites of PCL and SBA-15 Particles Prepared by Extrusion: Structural Characteristics, Confinement of PCL Chains within SBA-15 Nanometric Channels and Mechanical Behavior

et al. 2021

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A study of different nanocomposites based on poly(ε-caprolactone) (PCL) and mesoporous SBA-15 silica that were prepared by melt extrusion was carried out by analyzing the possible effect of this filler on the crystalline details of PCL, on its mechanical behavior, and on the eventual observation of the confinement of the polymeric chains within the hollow nanometric silica channels. Thus, simultaneous Small-Angle and Wide-Angle X-ray Scattering (SAXS/WAXS) synchrotron experiments at variable temperature were performed on these PCL nanocomposites with different mesoporous silica contents. The importance of the morphological and structural features was assessed by the changes that were observed during the mechanical response of the final materials, which determined that the presence of mesoporous particles leads to a noticeable reinforcing effect.

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Section: Resultsmentioning

confidence: 70%

Nanocomposites of PCL and SBA-15 Particles Prepared by Extrusion: Structural Characteristics, Confinement of PCL Chains within SBA-15 Nanometric Channels and Mechanical Behavior

et al. 2021

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“…Then, during ethylene polymerization an additional amount of MAO is required. In terms of final characteristics, the materials prepared by the DS-SA route displayed an improved mechanical response compared with that exhibited by the DS-MAO nanocomposites, which confirmed the potential of the novel SA methodology in producing highly reinforced composite materials [23]. The improved mechanical response of DS-SA materials was ascribed to their higher crystallinity and features at the polymer-nanofiller interfaces, along with a better dispersion of the nanofiller within the HDPE matrix.…”

Section: Introductionmentioning

confidence: 56%

“…The HNT-MAO method consisted in the addition of the appropriate amount of external MAO solution (2.03 g of MAO per 100 g of HNT supported catalyst, 5.259 mmol Al) to achieve an Al/Zr ratio of 1500 in the polymerization medium, followed by the addition of a vigorously stirred suspension containing the zirconocene catalyst supported onto MAO pretreated HNT, in order to achieve the desired support amount. This Al/Zr ratio was chosen to facilitate comparison with previous results using DS as support [22,23].…”

Section: Ethylene Polymerizationmentioning

confidence: 99%

“…However, a further increase of the support amount is accompanied by a decrease in average molar mass to values closer to that exhibited by the reference HDPE. Independently of the methodology, the incorporation of higher support amounts in the reaction medium results in a larger amount of Al, which comes from MAO, that increases the probability of chain transfer to the aluminum and gives rise to shorter chains at the end of polymerizations [23].…”

Section: Preparation Of the Hdpe-hnt Nanocompositesmentioning

confidence: 99%

“…This trend was also observed in our previous work where these two methodologies were applied to a different support, DS. It was proposed that the inherent features to the SA procedure may result in active species that are somewhat weakly bound to the support surface and thus, the support steric protection effect, preventing β-hydride transfer, might be not as effective as for the DS-MAO procedure [23].…”

Section: Preparation Of the Hdpe-hnt Nanocompositesmentioning

confidence: 99%

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A novel approach for preparation of nanocomposites with an excellent rigidity/deformability balance based on reinforced HDPE with halloysite

Cecílio

Cerrada

Pérez

et al. 2023

European Polymer Journal

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Polypropylene Nanocomposites Attained by In Situ Polymerization Using SBA-15 Particles as Support for Metallocene Catalysts: Effect of Molecular Weight and Tacticity on Crystalline Details, Phase Transitions and Rheological Behavior

et al. 2023

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In this study, nanocomposites based on polypropylene are synthesized by the in situ polymerization of propene in the presence of mesoporous SBA-15 silica, which acts as a carrier of the catalytic system (zirconocene as catalyst and methylaluminoxane as cocatalyst). The protocol for the immobilization and attainment of hybrid SBA-15 particles involves a pre-stage of contact between the catalyst with cocatalyst before their final functionalization. Two zirconocene catalysts are tested in order to attain materials with different microstructural characteristics, molar masses and regioregularities of chains. Some polypropylene chains are able to be accommodated within the silica mesostructure of these composites. Thus, an endothermic event of small intensity appears during heating calorimetric experiments at approximately 105 °C. The existence of these polypropylene crystals, confined within the nanometric channels of silica, is corroborated by SAXS measurements obtained via the change in the intensity and position of the first-order diffraction of SBA-15. The incorporation of silica also has a very significant effect on the rheological response of the resultant materials, leading to important variations in various magnitudes, such as the shear storage modulus, viscosity and δ angle, when a comparison is established with the corresponding neat iPP matrices. Rheological percolation is reached, thus demonstrating the role of SBA-15 particles as filler, in addition to the supporting role that they exert during the polymerizations.

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Unique stiffness-deformability features of dendrimeric silica reinforced HDPE nanocomposites obtained by an innovative route

Cited by 3 publications

References 36 publications

Nanocomposites of PCL and SBA-15 Particles Prepared by Extrusion: Structural Characteristics, Confinement of PCL Chains within SBA-15 Nanometric Channels and Mechanical Behavior

Nanocomposites of PCL and SBA-15 Particles Prepared by Extrusion: Structural Characteristics, Confinement of PCL Chains within SBA-15 Nanometric Channels and Mechanical Behavior

A novel approach for preparation of nanocomposites with an excellent rigidity/deformability balance based on reinforced HDPE with halloysite

Polypropylene Nanocomposites Attained by In Situ Polymerization Using SBA-15 Particles as Support for Metallocene Catalysts: Effect of Molecular Weight and Tacticity on Crystalline Details, Phase Transitions and Rheological Behavior

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