Isothermal and non-isothermal crystallization kinetics of composites of poly(propylene) and MWCNTs

Coburn, Nigel J.; Douglas, Paula; Kaya, Derya; Gupta, J. Sen; McNally, Tony

doi:10.1016/j.aiepr.2018.06.001

Cited by 39 publications

(33 citation statements)

References 32 publications

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“…After adding DMDBS, the yielding stress increased from 2.7 MPa to 3.1 MPa. At the same time, the tensile stress of the sample decreased gradually with the increase of the number of tensile cycles, showing the phenomenon of stress softening, which is similar to the Mullins effect [39]. Most of the mechanical hysteresis and stress softening occurred in the first cycle of multiple cycles.…”

Section: Resultsmentioning

confidence: 97%

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The Influence of DMDBS on Crystallization Behavior and Crystalline Morphology of Weakly-Phase-Separated Olefin Block Copolymer

Zhao

Yao²,

Chang³

et al. 2019

Polymers

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Olefin block copolymer (OBC), with its low hard segments, can form unique space-filling spherulites other than confined-crystallization morphologies, mainly due to its weak phase-separation. In this work, 1,3;2,4-Bis(3,4-dimethylbenzylidene) sorbitol (DMDBS), a well-known nucleating agent, was used to tailor the crystallization behavior and crystalline morphology of OBC. It was found that DMDBS can precipitate within an OBC matrix and self-assemble into crystalline fibrils when cooling from the melt. A non-isothermal crystallization process exhibited an increased crystallization rate and strong composition dependence. During the isothermal crystallization process, DMDBS showed a more obvious nucleating efficiency at a higher crystallization temperature. OBC showed typical spherulites when DMDBS was added. Moreover, a low addition of DMDBS significantly decreased the crystal size, while a large addition of DMDBS induced aggregates, due to the limited miscibility of DMDBS with OBC. The efficient nucleating effect of DMDBS on OBC led to an increased optical transparency for OBC/DMDBS composites.

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Section: Resultsmentioning

confidence: 97%

“…By adding a small amount of DMDBS, the transparency of the composites could be significantly affected. In general, decreased crystal size is favorable for enhancing optical transparency [39]. The optical properties of OBC composites with different content of DMDBS are compared in Figure 7.…”

Section: Resultsmentioning

confidence: 99%

The Influence of DMDBS on Crystallization Behavior and Crystalline Morphology of Weakly-Phase-Separated Olefin Block Copolymer

Zhao

Yao²,

Chang³

et al. 2019

Polymers

View full text Add to dashboard Cite

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“…Crystallization of polymers is an important phenomenon, and knowledge of the underlying molecular processes, such as nucleation, is important when it comes to understanding the resulting morphology changes [10]. Crystallization is carried out when the material is transported to the solidification point or when the solvent evaporates from matrix; although the material has crystalline regions, there could also be amorphous regions in the polymer structure.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the cooling rate strongly influences the degree of crystallinity of the system even when the material is isothermally crystallized; then, different morphologies can be obtained by changing the degree of undercooling operating either in isothermal or in non-isothermal conditions [1,13,14]. Non-isothermal crystallization process of polymers has become increasingly important technologically since its conditions are closer to the actual industrial processing of polymers [10,15]. The modelling of non-isothermal crystallization implies a knowledge of the kinetics and morphology developed at each isothermal crystallization temperature ( ).…”

Section: Introductionmentioning

confidence: 99%

“…The modelling of non-isothermal crystallization implies a knowledge of the kinetics and morphology developed at each isothermal crystallization temperature ( ). Various theories and experimental techniques have been employed to determine the kinetic parameters for non-isothermal crystallization of polymers [10] including the methods of Mo [16] and Jeziorny [17]. When crystallization is performed at high undercooling, reduced molecular mobility enhances the nucleation rate compared to the growth rate of the crystals, which leads to the formation of a large number of smaller crystals [11].…”

Section: Introductionmentioning

confidence: 99%

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Use of Chemically Modified Titanium Dioxide Particles to Mediate the Non-isothermal Cold Crystallization of Poly(latic acid)

et al. 2020

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In this work, the effect of the chemical modification of titanium dioxide particles on the non-isothermal crystallization process of polylactic acid (PLA) was studied. Cold crystallization in some polymers occurs above the glass transition temperature (Tg) when the polymer chains gain sufficient mobility to organize themselves into the ordered structure (i.e. the crystal structure) by folding the chains. Cold crystallization in general is caused by the ordering of the molecular chains in the crystalline PLA due to the increased mobility during heating. Through an analysis of the cool crystallization process in DSC at different cooling rates, it was observed that the behavior of PLA and its composites made with titanium dioxide, neat and functionalized with dicarboxylic acids, can be described through the models used for crystallization of the polymer carrying out during cooling, such as Mo’s and Jeziorny’s model. In addition, it was determined that the chemical modification of TiO2 performed with silane increases the crystallization rate in the last step of the process; while the chemical modification with dicarboxylic acid has an accelerated effect on the crystal formation process attributed to the affinity between the aliphatic part of this group and the polymer chains. Also, it was shown that the inclusion of the silanized particles has no effect on the energy requirement compared to the pure PLA process; however, the addition of particles with the dicarboxylic acid decreases the energy value required to complete the crystalline state due to affinity at the surface to immobilize the polymer chains. Finally, it is emphasized that the activation energy required to perform the crystallization of PLA and its composites has positive values, which is an indicator that the crystallization was performed while heating, after reaching and passing the glass transition temperature and before melting.

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Characterization of Polymer Crystallization by Using Thermal Analysis

Yang

Zhang

Venkataraman

et al. 2023

Polymer Crystallization

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Isothermal and non-isothermal crystallization kinetics of composites of poly(propylene) and MWCNTs

Cited by 39 publications

References 32 publications

The Influence of DMDBS on Crystallization Behavior and Crystalline Morphology of Weakly-Phase-Separated Olefin Block Copolymer

The Influence of DMDBS on Crystallization Behavior and Crystalline Morphology of Weakly-Phase-Separated Olefin Block Copolymer

Use of Chemically Modified Titanium Dioxide Particles to Mediate the Non-isothermal Cold Crystallization of Poly(latic acid)

Characterization of Polymer Crystallization by Using Thermal Analysis

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