Ultrasonic oscillations induced morphology and property development of polypropylene/montmorillonite nanocomposites

Zhao, Lijuan; Li, Jiang; Guo, Shaoyun; Du, Qin

doi:10.1016/j.polymer.2006.02.011

Cited by 73 publications

(42 citation statements)

References 38 publications

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“…Relevant studies are largely focused on polymer/layered clay systems. [14][15][16][17][18] However, very few works are devoted to research on polymer-filled, non-layered inorganic nanoparticles. In the current work, a special single screw extruder equipped with an ultrasound generator was used to compound a novel propylene-based plastomer with nanosilica.…”

Section: Introductionmentioning

confidence: 99%

Effects of ultrasound on the morphology and properties of propylene-based plastomer/nanosilica composites

Peng

Bao

et al. 2010

Polym J

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Propylene-based plastomer/nanosilica composites, with a filler content of 1-4 wt%, were prepared by a specially designed ultrasound-assisted extrusion system that was developed in our laboratory. The effects of ultrasound on the morphology, as well as the rheological and mechanical properties of the composites, were studied in this paper. In spite of slight ultrasound-induced degradation of the polymeric matrix, the results showed that the strength and elongation of the composites at break, in most cases, still improve in the presence of ultrasound because of ultrasound-induced homogeneous dispersion of nanoparticles in the polymeric matrix (as confirmed by scanning electron microscope, transmission electron microscope and differential scanning calorimetry studies). Dynamic rheological measurements also indicate that ultrasound-induced compatibilization has a more predominant role than does degradation. From dynamic mechanical measurements, it was found that ultrasound-induced degradation results in a drop in the dynamic storage modulus and glass transition temperature for composites with 4 wt% filler content, whereas ultrasound-induced compatibilization enhances their loss factor values. Polymer Journal (2011) 43, 91-96; doi:10.1038/pj.2010; published online 3 November 2010Keywords: extrusion; morphology; polymer-matrix composites (PMCs); properties; ultrasound INTRODUCTIONIn recent years, polymer/inorganic nanocomposites, in which the size of the dispersed particles is o100 nm in at least one dimension, have attracted tremendous interest in both academic and industrial researchers. Many studies report significant improvement in the desired properties of nanocomposites, such as their mechanical properties, barrier properties, optical transparency and solvent/heat resistance, compared with those of bulk polymers or conventional microcomposites. 1-3 These improvements can be achieved at a very low loading of the inorganic component (1-10 wt%) compared with conventional filled polymers, which require high loading (25-40 wt%). These studies indicate that polymer/inorganic nanocomposites are much lighter in weight and easier to process than conventional microcomposites. 4 To a large extent, improvement in these properties depends on the morphology and dispersion of the nanoparticles in the matrix. However, obtaining a homogeneous dispersion of nanoparticles in a polymeric matrix is a very difficult task when using only a simple mixing method, because of the strong tendency of nanoparticles to agglomerate. To break down the agglomerates of nanoparticles, many researchers have attempted various routes to prepare nanostructural composites in recent years, such as the sol-gel process, 5 in situ intercalative polymerization 6,7 and in situ polymerization in the presence of nanoparticles. 8 These methods, characterized by complex polymerization and special conditions, are not only incompatible with current industrial processes such as extrusion and injection molding, but are also inapplicable for the mass production of po...

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Section: Introductionmentioning

confidence: 99%

Effects of ultrasound on the morphology and properties of propylene-based plastomer/nanosilica composites

Peng

Bao

et al. 2010

Polym J

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“…O acúmulo de argila na superfície de material pode ser atribuída ou à decomposição da matriz por pirólise e/ou ao transporte das partículas de argila por bolhas formadas durante a degradação da matriz associado ao fluxo de massa fundida do interior para a superfície. A ação da argila é descrita como antagônica ao formar uma barreira e acelerar a ignição da matriz em combustão [20,23] . Os mecanismos de atuação da argila como agente de bloqueio para propagação de chama em nanocompósitos ainda não foram completamente esclarecidos.…”

Section: Resultsunclassified

Inflamabilidade de Nanocompósitos de Polipropileno/Argila Organofílica

Alves¹,

Barbosa²,

Carvalho³

et al. 2014

Polímeros

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Resumo: A inflamabilidade de nanocompósitos com três tipos de polipropileno (homo e copolímeros) contendo 5% de argila montmorilonita organofílica (Cloisite 20A), 5 e 15% de polipropileno enxertado com anidrido maleico como agente compatibilizante e 0, 0,5 e 1% de cis-13-docosenamida (Erucamida) como agente co-intercalante foi estudada através do teste de queima horizontal UL94HB. Concentrados foram preparados em misturador interno e diluídos com a matriz de polipropileno em extrusora de dupla rosca corrotacional com diferentes configurações de rosca e velocidades rotação de 240 e 480 rpm. Os resultados indicaram aumento da velocidade de queima dos compósitos quando comparados às das matrizes e que a velocidade de queima não foi afetada pelas condições de processamento. Em todos os casos, foi observado durante o ensaio uma redução da emissão de fumaça, ausência de gotejamento de material e a formação de uma camada carbonácea, levando à preservação da estrutura interna da amostra. Palavras-chave: Polipropileno, compósitos, processamento, inflamabilidade. Flammability of Polypropylene/Organoclay NanocompositesAbstract: The flammabilities of nanocomposites made with three polypropylene grades (homo and copolymers) with 5 wt % of organoclay (Cloisite 20A), 5 or 15 wt % of maleated polypropylene as compatibilizer, and 0, 0.5 or 1 wt % of cis-13-docosenamide (Erucamide) as co-intercalant, were studied using the horizontal burning test UL94HB. Masterbatches prepared in an internal mixer were diluted in the polypropylene matrix using a corotating twin-screw extruder, with different screw configurations and operating at 240 or 480 rpm. Results indicate that the high burning rate of the composites was not affected by the processing conditions. For all formulations was observed a significant reduction in smoke release, lack of dripping and the formation of a char surface layer, that protected the core of the samples. Keywords: Polypropylene, nanocomposites, processing, flammability. IntroduçãoOs polímeros têm muitas aplicações na construção civil e nas indústrias de transporte terrestre e aéreo onde o comportamento de materiais expostos ao fogo é crucial, tanto para a segurança pessoal, quanto para as propriedades dos materiais [1] . Como a maioria dos produtos orgânicos, os polímeros são inflamáveis e durante o aquecimento há a liberação de pequenas moléculas que atuam como combustíveis em presença do fogo [2] . Em algumas aplicações, evitar a combustão é fundamental, o que tem incentivado o desenvolvimento de formulações capazes de retardar a combustão e a velocidade de propagação da chama (reduzindo a probabilidade de combustão durante a fase de iniciação do fogo) e/ou reduzir a emissão de fumaça. Pelas crescentes exigências das normas de segurança, em algumas aplicações, a inflamabilidade é uma das barreiras de utilização de alguns polímeros [3] . Resistência ao fogo, retardamento de chama ou características autoextinguíveis podem ser definidas como uma baixa velocidade de queima quando em contato com a fonte de calor ...

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“…It was found in our previous research [17][18][19][20][21][22][23][24] that ultrasound assisted melt processing had both physical and chemical effects on the polymer and its blends and composites.…”

Section: Introductionmentioning

confidence: 97%

“…With the physical effect of ultrasound，the dispersion of the small particles in polymer matrix could be improved [24][25]. In addition, with the chemical effect of ultrasound, the polymers, such as PS, EPDM and PA6, would be degraded.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ultrasound on Molecular Structure Development of Polylactide

Bao¹,

Wu²,

Guo³

et al. 2014

Polymer-Plastics Technology and Engineering

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ABSTRACT:In this work, effect of ultrasound on molecular structure development of Polylactide (PLA) was studied. It was found that the intrinsic viscosity of PLA decreased with increasing treating time, temperature and ultrasound time. Different from traditional thermal degradation of PLA, the degradation of PLA under ultrasound treatment showed that chain scission and chain combination of PLA competed with each other in the degradation process, which could be divided into two steps. The mechanism of ultrasound degradation of PLA was proposed. Furthermore, Thermal properties were characterized by DSC to show heat and ultrasound effects on molecular structure development of PLA.

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Ultrasonic oscillations induced morphology and property development of polypropylene/montmorillonite nanocomposites

Cited by 73 publications

References 38 publications

Effects of ultrasound on the morphology and properties of propylene-based plastomer/nanosilica composites

Effects of ultrasound on the morphology and properties of propylene-based plastomer/nanosilica composites

Inflamabilidade de Nanocompósitos de Polipropileno/Argila Organofílica

Effect of Ultrasound on Molecular Structure Development of Polylactide

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