Characterization and photooxidative behaviour of nanocomposites formed with polystyrene and LDHs organo-modified by monomer surfactant

Leroux, Fabrice; Meddar, Lynda; Mailhot, Bénédicte; Morlat‐Thérias, Sandrine; Gardette, Jean‐Luc

doi:10.1016/j.polymer.2005.03.044

Cited by 73 publications

(38 citation statements)

References 21 publications

(27 reference statements)

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“…These phenomena have been reported for several kinds of polymer used and were mainly attributed to a reduction of the photo-oxidation induction time [9][10][11][12][13][14][15][16][17]. This, in turn, was attributed to several factors, such as the presence of iron ions catalyzing the photo-oxidation process [9,10], the formation of catalytic acidic sites or radicals following the decomposition of the organo-modifier (involving both the alkyl chain and the ammonium ions) [10][11][12]17].…”

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confidence: 71%

Accelerated weathering of PP based nanocomposites: Effect of the presence of maleic anhydryde grafted polypropylene

Morreale¹,

Dintcheva²,

Mantia³

2013

Express Polym. Lett.

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The use of nanometric-scale sized fillers for the preparation of thermoplastic polymer composites is of topical interest in the academia, because of the significant improvements achievable in terms of technological properties, such as the elastic modulus, the tensile strength, the barrier properties, the flexural modulus [1][2][3][4][5][6][7][8]. These enhancements are promising and attracting also the interest from industrial world, in sight of several applications which could benefit from them. On the other hand, it is known [3] that polymer based nanocomposites have been struggling to conquer mainstream volume market shares, and this can be attributed to some weaknesses. One of these is represented by their environmental stability, especially when outdoor applications (i.e. furnishing, building, packaging, automotive) are concerned. It is known from the literature that polymer/silicate nanocomposites can show significant effects due to photo-oxidation (in particular, higher photo-oxidation rates and thus reduction of the mechanical prop- Abstract. Polymer nanocomposites are currently a topic of great interest. The increasing importance they are gaining also in the standpoint of industrial applications, is giving concerns regarding their environmental stability and, in general, their behaviour in outdoor applications, under direct solar irradiation. Papers available in the literature have highlighted the different influences of different nanosized fillers, in particular clay-based nanofillers; however, few data are available regarding other nanosized fillers. Furthermore, the research on polymer nanocomposites has clearly pointed out that the use of compatibilizers is required to improve the mechanical performance and the dispersion of polar fillers inside apolar polymer matrices, especially when complex mechanisms such as intercalation and exfoliation, typical of clay-filled nanocomposites, are involved. In this work, the photo-oxidation behaviour of polypropylene/clay and polypropylene/calcium carbonate nanocomposites containing different amounts of maleic anhydride grafted polypropylene (PPgMA) and subjected to accelerated weathering, was investigated. The results showed significant differences between the two nanofillers and different degradation behaviours in presence of the compatibilizer. In particular, PPgMA modified the dispersion of the nanofillers but, on the other hand, higher amounts proved to lead to the formation of some heterogeneities. Furthermore, PPgMA proved to positively affect the photo-oxidation behaviour by decreasing the rate of formation of the degradation products.

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confidence: 71%

Accelerated weathering of PP based nanocomposites: Effect of the presence of maleic anhydryde grafted polypropylene

Morreale¹,

Dintcheva²,

Mantia³

2013

Express Polym. Lett.

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“…Previous studies [15,16,[19][20][21] suggested that photo-degradation generates carbonyl and hydroxyl groups through chain scission and hydrogen abstraction from the polymer backbone. The degradation process is summarised in Fig.…”

Section: Changes In Elemental Composition Due To Uv Exposurementioning

confidence: 98%

Environmental degradation of epoxy–organoclay nanocomposites due to UV exposure. Part I: Photo-degradation

Woo

Chen

Zhu

et al. 2007

Composites Science and Technology

144

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The environmental degradation mechanisms of epoxy-organoclay nanocomposites due to accelerated UV and moisture exposure are studied. Various characterisation tools, including FTIR, SEM, XRD and XRF analyses, were used to evaluate the effects of clay content on the progressive changes in chemical element, topography and colour of the nanocomposite. It is found that microcracks started to appear on both the neat epoxy and nanocomposite surface after about 300 h of UV exposure. The nanocomposite exhibited thicker and shallower cracks with a less degree of discoloration than the neat epoxy due to the diffusion barrier characteristics of organoclay with high aspect ratio. The presence of transition metal ions along with low-molecular-weight organic modifiers in organoclay, however, accelerated the degradation of polymer, counterbalancing the above ameliorating barrier properties of clay. FTIR analysis indicated that photo-degradation generated carbonyl groups by chain scission and the rate was slightly higher for the nanocomposites than for the neat epoxy. While moisture further accelerated the photo-degradation process through the enhanced mobility of free radicals and ions, the organoclay could limit the deteriorating effect of moisture, resulting in much better overall resistance to photo-degradation in the presence of moisture for the nanocomposite than the neat epoxy.

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“…Estes materiais apresentam como composição química [M , CO 3 , etc) e m representa o número de moléculas de água [5][6][7][8][9] . Os HDL's apresentam uma estrutura semelhante à da brucita (Mg(OH) 2 ), podem ser sintetizados por meio de rotas relativamente simples a um custo relativamente baixo, com controle de tamanho e uniformidade na distribuição de tamanho das partículas.…”

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Síntese e caracterização de Nanocompósitos Esfoliados de Poliestireno: Hidróxido Duplo Lamelar via polimerização in situ

et al. 2011

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Resumo: Nanocompósitos Esfoliados de Poliestireno (PS) e Hidróxido Duplo Lamelar (HDL) composto por zinco, alumínio e dodecil sulfato de sódio, como ânion interlamelar, foram sintetizados via polimerização in situ. O efeito de diferentes composições de HDL (0,5, 1, 3 e 5% em massa) foi avaliado. Os nanocompósitos obtidos foram caracterizados através de ensaios de Difração de Raios X (DRX), Espectroscopia no Infravermelho por Transformada de Fourier (FTIR), Microscopia Eletrônica de Transmissão (MET) e Análise Termogravimétrica (TGA). Os resultados obtidos através das análises de DRX e MET mostraram que todos os nanocompósitos produzidos apresentaram morfologia esfoliada. Os resultados das TGA, quando se utilizam 50% de perda de peso como ponto para comparação, apresentaram ganhos significativos de estabilidade térmica para todas as composições dos nanocompósitos em comparação ao poliestireno puro. Este comportamento possibilita uma vasta gama de aplicação destes novos materiais em diversos campos da indústria e pesquisa. Palavras-chave: Nanocompósito, hidróxido duplo lamelar, poliestireno, polimerização in situ. Synthesis and Characterization of Exfoliated Polystyrene-Layered Double Hydroxide Nanocomposites Via In Situ PolymerizationAbstract: Exfoliated nanocomposites of polystyrene (PS) and layered double hydroxide (LDH) compound of zinc, aluminium and sodium dodecyl sulfate, as interlayer anion, have been synthesized via in situ polymerization. The effect from the LDH compositions (0.5, 1, 3, 5% weight) was studied. The nanocomposites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Thermogravimetric Analysis (TGA). The XRD and TEM results showed an exfoliated morphology for the nanocomposites in all compositions. With the 50% weight loss taken as a reference, the TGA results indicated significant improvement in thermal stability for all compositions of the nanocomposites, in comparison to pure polystyrene. This is promising for the application of these new materials in many fields of industry and research. Keywords: Nanocomposite, layered double hydroxide, polystyrene, in situ polymerization. IntroduçãoOs nanocompósitos podem ser definidos como materiais híbridos em que pelo menos um dos componentes tem dimensões nanométricas [1][2][3] . Nanocompósitos poliméricos apresentam recente desenvolvimento e têm como marco inicial a publicação de um trabalho na década de 80/90 pelo grupo de pesquisa da empresa Toyota, onde foi produzido um nanocompósito de nylon 6 e o argilomineral (montimorilonita). O novo nanocompósito produzido apresentou uma extraordinária melhora nas suas propriedades mecânicas, térmicas e físicas quando comparado ao polímero puro [4] . Entre os nanocompósitos poliméricos, muitos estudos mostram como a dispersão de compostos lamelares em uma matriz polimérica afeta as propriedades do material obtido, no entanto, na maioria dos trabalhos são utilizados argilominerais trocadores catiônicos naturais, como a mon...

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Characterization and photooxidative behaviour of nanocomposites formed with polystyrene and LDHs organo-modified by monomer surfactant

Cited by 73 publications

References 21 publications

Accelerated weathering of PP based nanocomposites: Effect of the presence of maleic anhydryde grafted polypropylene

Accelerated weathering of PP based nanocomposites: Effect of the presence of maleic anhydryde grafted polypropylene

Environmental degradation of epoxy–organoclay nanocomposites due to UV exposure. Part I: Photo-degradation

Síntese e caracterização de Nanocompósitos Esfoliados de Poliestireno: Hidróxido Duplo Lamelar via polimerização in situ

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