Nucleating Effect of Montmorillonite Nanoparticles in Polypropylene

Pozsgay, András; Fráter, Tünde; Papp, L.; Sajó, István E.; Pukánszky, Béla

doi:10.1081/mb-120013095

Cited by 96 publications

(74 citation statements)

References 33 publications

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“…[5][6][7][8][9]11,67,68 According to Deshmane et al, 10 the nucleating effect of MMT on polypropylene is high, whereas polyethylene remains almost unaffected. The addition of 4% MMT to polypropylene reduces the spherulite diameter from 210 to 14 μm, whereas the spherulite size of polyethylene remains unchanged.…”

Section: Resultsmentioning

confidence: 99%

“…Whereas many polymers start to crystallize when the melt is moderately cooled below the melting temperature, pure PP only starts to crystallize when it is undercooled by more than 50°C. 5,16 Consequently, PP is strongly susceptible to additives that change the crystallization behavior. Particularly with polypropylene the crystallization has frequently been found to propagate via a blocky mesophase.…”

Section: Introductionmentioning

confidence: 99%

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Properties and Semicrystalline Structure Evolution of Polypropylene/Montmorillonite Nanocomposites under Mechanical Load

et al. 2011

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Small-angle X-ray scattering (SAXS) monitors tensile and load-cycling tests of metallocene isotactic polypropylene (PP), a blend of PP and montmorillonite (MMT), and two block copolymer compatibilized PP/MMT nanocomposites. Mechanical properties of the materials are similar, but the semicrystalline nanostructure of the PP differs. This is explained by a nucleation effect of the MMT. Competitive crystal growth diminishes crystallite sizes. The reinforcing effect of the MMT filler appears consumed by weakening the PP matrix. Decays of mechanical and nanostructure response in dynamic load cycling indicate materials fatigue. Lifetimes describe the reinforcing and weakening effects. Addition of 3% MMT halves the fortifying effect of the PP nanostructure. A net gain of reinforcement (11%) is observed with the highly compatibilized composite in which the strength of the semicrystalline PP is reduced to 25%. Other results concern the evolution of Strobl's block structure and void formation during tensile loading.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Properties and Semicrystalline Structure Evolution of Polypropylene/Montmorillonite Nanocomposites under Mechanical Load

et al. 2011

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“…18 On the other hand, Pozsgay et al also found a clay collapse, but in polypropylene nanocomposites. 19 They suggested that it could be due either to the degradation of organic compounds or to the evaporation of the water molecules present in the clay interlayers. These hypotheses are supported by several publications, because it has been shown that the organic molecules [20][21][22] coming from OLSs, normally alkyl ammonium salts, decompose by the Hofmann mechanism under the operating conditions (around 200 C) normally used for the polypropylene melt process.…”

Section: Introductionmentioning

confidence: 99%

“…23 However, sufficient proof is missing to support some of the latest explanations. 19 The present work shows the results of polypropylene nanocomposites prepared by the melt-mix method using a set of different OLSs. Moreover, because the compatibilizer also has a key role in the interactions between a polymer and a clay, three different compatibilizers were studied for each of the OLSs used to evaluate their importance in the final results.…”

Section: Introductionmentioning

confidence: 99%

Polypropylene/clay nanocomposites: Effect of different clays and compatibilizers on their morphology

Palza

Vergara

Yazdani‐Pedram

et al. 2009

J of Applied Polymer Sci

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A set of organically modified clays (OLS) were mixed with different compatibilizers to alter their interactions with either homopolymer or heterophasic polypropylenes when they were melt-mixed, and the relation between the OLS/compatibilizer system and the composite morphology was studied. X-ray diffraction (XRD) showed that depending on the specific OLS/compatibilizer system, it is possible to obtain several morphologies in the composites. In particular, some samples prepared with compatibilizers based on itaconic acid and OLSs, which had the highest cation exchange capacity and were organically modified with a set of quaternary ammonium salts, presented longer clay interlayer distances than the original OLSs, whereas other composites showed a clay collapse associated with shorter interlayer distances. Moreover, some composites presented both kinds of morphologies together. By means of diffuse reflectance spectroscopy and thermogravimetric analysis, it was possible to show that the OLSs were stable under the operating conditions, so the decrease in the interlayer distance found in some samples was not related to degradation processes. On the other hand, high-resolution transmission electron microscopy (HR-TEM) showed that collapsed clays were formed by tactoid and immiscible structures with poor dispersion in the polymer matrix. However, samples with intercalate state from XRD presented very well dispersed multilayer stacks about 10 nm thick. Finally, those samples with both collapsed and intercalate morphologies presented tactoid and immiscible structures together with well dispersed multilayer stacks in the corresponding HR-TEM images.

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“…The very strong nucleating effect of talc in PP was proved many times [64,65]. Similarly to talc, layered silicates, and especially montmorillonite (MMT), were shown to nucleate polypropylene quite strongly [66][67][68][69][70]. The influence of other fillers and reinforcements is not so clear.…”

Section: Crystalline Matrices Nucleationmentioning

confidence: 99%

Particulate Fillers in Thermoplastics

Móczó

Pukánszky

2017

Fillers for Polymer Applications

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The characteristics of particulate filled thermoplastics are determined by four factors: component properties, composition, structure and interfacial interactions. The most important filler characteristics are particle size, size distribution, specific surface area and particle shape, while the main matrix property is stiffness. Segregation, aggregation and the orientation of anisotropic particles determine structure. Interfacial interactions lead to the formation of a stiff interphase considerably influencing properties. Interactions are changed by surface modification, which must be always system specific and selected according to its 2 goal. Under the effect of external load inhomogeneous stress distribution develops around heterogeneities, which initiate local micromechanical deformation processes determining the macroscopic properties of the composites. INTRODUCTUIONParticulate filled polymers are used in very large quantities in all kinds of applications. The total consumption of fillers in Europe alone is currently estimated as 4.8 million tons (Table 1) [6]. In spite of the overwhelming interest in nanocomposites, biomaterials and natural fiber reinforced composites, considerable research and development is done on particulate filled polymers even today. The reason for the continuing interest in traditional composites lays, among others, in the changed role of particulate fillers. In the early days fillers were added to the polymer to decrease price.However, the ever increasing technical and aesthetical requirements as well as soaring material and compounding costs require the utilization of all possible advantages of fillers.Fillers increase stiffness and heat deflection temperature, decrease shrinkage and improve the appearance of the composites [9][10][11][12][13]. Productivity can be also increased in most thermoplastic processing technologies due to their decreased specific heat and increased heat conductivity [9,10,[14][15][16][17]. Fillers are very often introduced into the polymer to create new functional properties not possessed by the matrix polymer at all like flame retardancy or conductivity [18][19][20][21]. Another reason for the considerable research activity is that new fillers and reinforcements emerge continuously among others layered silicates [7,[22][23][24][25][26][27][28][29], wood flour [30][31][32][33][34][35][36][37], sepiolite [38][39][40][41][42][43][44][45][46][47][48][49], etc.The properties of all heterogeneous polymer systems are determined by the same four factors: component properties, composition, structure and interfacial interactions [9,50]. Although certain fillers and reinforcements including layered silicates, other nanofillers, or natural fibers possess special characteristics, the effect of these four factors is universal and valid for all particulate filled materials. As a consequence, in this paper 3 we focus our attention on them and discuss the most important theoretical and practical aspects of composite preparation and use accordingly. The general rules of h...

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Nucleating Effect of Montmorillonite Nanoparticles in Polypropylene

Cited by 96 publications

References 33 publications

Properties and Semicrystalline Structure Evolution of Polypropylene/Montmorillonite Nanocomposites under Mechanical Load

Properties and Semicrystalline Structure Evolution of Polypropylene/Montmorillonite Nanocomposites under Mechanical Load

Polypropylene/clay nanocomposites: Effect of different clays and compatibilizers on their morphology

Particulate Fillers in Thermoplastics

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