γ‐Form Transcrystals of Poly(propylene) Induced by Individual Carbon Nanotubes

Zhang, Shanju; Lin, Wei; Zhu, Lingbo; Wong, Ching‐Ping; Bucknall, David G.

doi:10.1002/macp.201000045

Cited by 16 publications

(12 citation statements)

References 42 publications

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“…[204][205][206][207] Nanotubes can induce complicated melting-recrystallization phenomena, indicating that claims about polymorphism in isotactic polypropylene must be substantiated with X-ray diffraction measurements casting significant doubt on the conclusions reached by the present author in the early paper. Recent papers describe a method where isotactic polypropylene in dichlorobenzene or high density polyethylene/ultrahigh molecular weight polyethylene was infiltrated into a nanotube aerogel which in turn led to some of the gamma crystalline form 208 or monoclinic (vs. the more typical orthorhombic) form, 209,210 respectively. To discuss the role of carbon nanotubes on lamellae and spherulite characteristics, it is first important to discuss the nucleation process in more detail.…”

Section: Semicrystalline Polymersmentioning

confidence: 99%

Effects of carbon nanotubes on polymer physics

Grady

2012

J Polym Sci B Polym Phys

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A single carbon nanotube has many similarities with an individual polymer chain including the fact that the end-to-end length of both are often about the same and the diameter of the chain is about the same (for single-walled nanotubes) or only $10 to 20 times larger (for multiwalled nanotubes). The combination of the solid surface and the similarity of the two materials means that polymer physics are altered in manners not seen with any other type of commonly used filler. The purpose of this review is to update a chapter that appears in a recent tome by Grady (2011) and describe how polymer physics is altered in composites that contain carbon nanotubes. Subjects that will be discussed include chain configuration, glass transition, polymer diffusion, unit cells and crystalline superstructure (lamellae, spherulites and shishkebabs), and crystallization kinetics. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: 2012

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Section: Semicrystalline Polymersmentioning

confidence: 99%

Effects of carbon nanotubes on polymer physics

Grady

2012

J Polym Sci B Polym Phys

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“…[33] Interestingly, the crystal polymorphism often occurs in the transcrystalline layer. [29,30,34] The single-fiber pull-out tests have demonstrated that transcrystalline microstructures markedly improve interfacial adhesion and stress transfer. [31,32] Clearly, polymer transcrystallization induced by the nanocarbon fibers is a facile approach to investigate interfacial interactions between polymers and nanocarbons.…”

Section: Introductionmentioning

confidence: 99%

Interfacial crystallization of isotactic polypropylene surrounding macroscopic carbon nanotube and graphene fibers

Abdou

Reynolds

Pfau

et al. 2016

Polymer

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A comparative study on interfacial crystallization of isotactic polypropylene (iPP) surrounding macroscopic carbon nanotube and graphene fibers has been carried out in single fiber polymer composites by means of in situ polarized optical microscope, scanning electron microscope and X-ray diffraction. Ordered interfacial microstructures of iPP nucleate on both nanocarbon fibers in the form of a transcrystalline interphase. Nanotube fibers tend to promote negative birefringence transcrystals whereas graphene fibers induce positive birefringence transcrystals. The microstructures of transcrystals are strongly dependent on the thermal history and the double-layered transcrystals consisting of a negative inner layer and a positive outer layer occur under certain conditions. Transcrystallization kinetics has been studied and the Lauritzen-Hoffman theory of heterogeneous nucleation used to analyze the dynamic crystallization process. While the fold surface energy of iPP transcrystals surrounding both nanocarbon fibers shows little difference, the nanotube fiber promotes shorter induction time than the graphene fiber. Thermal resistance test demonstrates that the ordered interfacial microstructures possess higher melting temperature in the nanotube fiber composites than those in the graphene fiber composites. Under appropriate conditions, the-form transcrystals of iPP are observed. The amount of the-form iPP surrounding the nanotube fiber is much higher than that surrounding the graphene fiber. A theoretical model is proposed to interpret the difference between the nanotube and graphene fiber composites and the mechanisms behind its influence on interfacial crystallization.

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“…Some questions remain as to the origin of enhanced nucleation at the fibre surface 1 , but it is well established that the TC significantly increases fibre-matrix adhesion 2 and results in an improvement in composite mechanical properties 3 . Macroscopic fibres made up of preferentially aligned carbon nanotubes (CNT) have also been shown to induce polymer transcrystallinity when embedded in isotactic polypropylene (PP), leading to a similar effect on composite mechanical properties 4 5 and often to the preferential nucleation of the γ-phase 6 . Similarly, nanoparticles used as fillers dispersed in semicrystalline polymer matrices have been widely observed to act as nucleating agents on account of their large surface-to-volume ratio.…”

mentioning

confidence: 99%

Macroscopic CNT fibres inducing non-epitaxial nucleation and orientation of semicrystalline polymers

Yue

Monreal-Bernal

Fernandéz‐Blázquez

et al. 2015

Sci Rep

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In the presence of macroscopic fibres of carbon nanotubes (CNT), various semicrystalline polymers are shown to present accelerated crystallisation through the formation of a transcrystalline (TC) layer perpendicular to the fibre axis. From differential scanning calorimetry, polarized optical microscopy and X-ray diffraction we establish this to be due to much faster nucleation rates at the fibre surface. The formation of a TC layers is demonstrated for polyvinyldene fluoride, isotactic polypropylene and poly(lactic acid) in spite of the large differences in their chemistry and structure unit cells, suggesting that epitaxy in terms of lattice type or size matching is not a prerequisite. For the three polymers as well as poly(ether ether ketone), the TC layer is identically oriented with the chain axis in the lamella parallel to the CNTs, as observed by wide and small angle X-ray scattering. These results point to polymer chain orientation at the point of adsorption and the formation of a mesomorphic layer as possible steps in the fast nucleation of oriented lamella, with wetting of the CNT fibre surface by the molten semi-crystalline polymer a key condition for heterogeneous nucleation to take place.

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γ‐Form Transcrystals of Poly(propylene) Induced by Individual Carbon Nanotubes

Cited by 16 publications

References 42 publications

Effects of carbon nanotubes on polymer physics

Effects of carbon nanotubes on polymer physics

Interfacial crystallization of isotactic polypropylene surrounding macroscopic carbon nanotube and graphene fibers

Macroscopic CNT fibres inducing non-epitaxial nucleation and orientation of semicrystalline polymers

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