Multiple melting and crystallization of nylon‐66/montmorillonite nanocomposites

Zhang, Qingxin; Yu, Zhong‐Zhen; Yang, Mingshu; Ma, Jun; Mai, Yiu‐Wing

doi:10.1002/polb.10608

Cited by 77 publications

(60 citation statements)

References 39 publications

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“…Because the clay surfaces were full of the growing points of the crystals, the crystals grew homogeneously from all over the clay surfaces to the outsides, forming lamellar crystal structures but not spherulites. Although some publications have shown that clay can obviously de- crease the spherulite sizes of polymers, 53,54 no publications have shown the lamellar crystal structures. Yalcin and Cakmak 55 showed that from the surfaces to the cores of injection-molded samples, the crystals of PA 6 changed from lamellar types to spherulites.…”

Section: Semmentioning

confidence: 96%

Crystal structures and their effects on the properties of polyamide 12/clay and polyamide 6–polyamide 66/clay nanocomposites

Zhang

Yang

Ellis

et al. 2006

J of Applied Polymer Sci

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Both polyamide 12 (PA 12)/clay and polyamide 6 -polyamide 66 copolymer (PA 6/6,6)/clay nanocomposites were prepared by melt intercalation. The incorporation of 4 -5 wt % modified clay largely increased the strength, modulus, heat distortion temperature (HDT), and permeation resistance to methanol of the polyamides but decreased the notched impact strength. Incorporation of the clay decreased the melt viscosities of both the PA 12 and PA 6/6,6 nanocomposites. Incorporation of the clay increased the crystallinity of PA 6/6,6 but had little effect on that of PA 12, which explained why the clay obviously increased the glass-transition temperature of PA 6/6,6 but hardly had any effect on that of PA 12. The dispersion and orientation of both the clay and the polyamide crystals were studied with transmission electron microscopy, scanning electronic microscopy, and X-ray diffraction. The clay was exfoliated into single layers in the nanocomposites, and the exfoliated clay layers had a preferred orientation parallel to the melt flow direction. Lamellar crystals but not spherulites were initiated on the exfoliated clay surfaces, which were much more compact and orderly than spherulites, and had the same orientation with that of the clay layers. The increase in the mechanical properties, HDT, and permeation resistance was attributed to the orientated exfoliated clay layers and the lamellar crystals.

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Section: Semmentioning

confidence: 96%

Crystal structures and their effects on the properties of polyamide 12/clay and polyamide 6–polyamide 66/clay nanocomposites

Zhang

Yang

Ellis

et al. 2006

J of Applied Polymer Sci

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“…Because of the MMT's hydrophilic features, little difficulty should be encountered using polar polymers to develop MMT-based nanocomposites, if the MMT surface is modified with certain organic surfactants (e.g. alkylammonium cation, the modified MMT is thus denoted O-MMT in the following) [10,13]. The incorporation of organic surfactants will expand the MMT's interlayer spacing and offer a positive enthalpic effect for mixing.…”

Section: Introductionmentioning

confidence: 98%

“…The successful pioneering work on these nanocomposites was conducted on the polyamide 6 (PA 6)/montmorillonite (MMT) clay system by Toyota Inc. [1,2]. Since then, the anticipated versatile applications have led to vigorous researches on other polymer/clay nanocomposite systems, in which the polymeric matrix includes polyolefins [3][4][5][6], epoxy [7], polyesters [8][9][10][11], polyamides [12][13][14], styrenic polymers [15,16], polyurethanes [17], etc.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the polyamide 6/organoclay nanocomposites with or without a maleated polyolefin elastomer as a toughener

Chiu

Lai

Chen

et al. 2005

Polymer

146

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“…In Nylon 66/clay [115] nanocomposites, the presence of delaminated clay layers resulted in an heterogeneous nucleation, as evidenced by an increased crystallization temperature. Moreover, the spherulitic size was decreased dramatically and the symmetry of spherulites was destroyed due to the presence of MMT.…”

Section: Nylon 66mentioning

confidence: 99%

“…In the case of nanocomposites of Nylon 66 with organoclay, it was noted that the addition of MMT induced the γ -form of PA66 [115,119] .…”

Section: Polymorphism In Nylon 66mentioning

confidence: 99%

Crystallization in Polymer Nanocomposites

Jog

2010

Optimization of Polymer Nanocomposite Properties

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Over the past decade, polymer nanocomposites have been a topic of great interest to research groups in both pure and applied materials science [1 -4] . These nanocomposites are two -phase materials wherein a fi ller with at least one dimension in the range of 1 to 100 nm is dispersed in the polymer matrix. Various nanofi llers such as carbon nanotube s ( CNT s), inorganic nanoparticles, or layered silicates such as clay are used. These nanocomposites show remarkable property improvements as compared to virgin polymers; moreover, this occurs at very low fi ller loadings when compared to conventional microcomposites. The properties of these nanocomposites are dependent on the morphology generated during their processing. In the case of semi -crystalline polymers, this is more crucial as the crystallization of polymers takes place during processing. A knowledge of the crystallization process, and the effect of these nanofi llers on the crystallization behavior of polymer nanocomposites, is therefore imperative to acquire an understanding of structure -property relationships in polymer nanocomposites.Crystallization in polymers has been the subject of great academic interest, as polymers are known to exhibit a variety of structures at various length scales, such as the unit -cell, lamella, and spherulites. The crystallization of polymers results in different morphologies, depending on the crystallization conditions and the presence of other components. The presence of a second phase either a polymer or a low -molecular -weight compound or inorganic fi ller has a profound effect on the crystallization of the polymer. In nanocomposites, the dimensions of the second phase are close to the chain dimensions, and a number of studies have attempted to elucidate the effect of nanosized fi llers on the crystallization kinetics, the crystalline morphology, and the crystalline forms of polymers. In this chapter, a brief review is presented of recent investigations into the effects of nanofi llers on various aspects of crystallization, such as isothermal crystallization, nonisothermal crystallization, spherulitic growth, and polymorphism.

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Multiple melting and crystallization of nylon‐66/montmorillonite nanocomposites

Cited by 77 publications

References 39 publications

Crystal structures and their effects on the properties of polyamide 12/clay and polyamide 6–polyamide 66/clay nanocomposites

Crystal structures and their effects on the properties of polyamide 12/clay and polyamide 6–polyamide 66/clay nanocomposites

Investigation on the polyamide 6/organoclay nanocomposites with or without a maleated polyolefin elastomer as a toughener

Crystallization in Polymer Nanocomposites

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