Propriedades mecânicas de nanocompósitos de polipropileno e montmorilonita organofílica
01 Jun 2006-Polimeros-ciencia E Tecnologia (Associação Brasileira de Polímeros)-Vol. 16, Iss: 2, pp 136-140
TL;DR: In this article, a mixture of polypropylene and commercial montmorillonite organophilic Cloisite 20A is used to construct a twoswrew extruder for melting.
Abstract: Nanocomposites of polypropylene and commercial montmorillonite organophilic Cloisite 20A containing 2.5%, 5%, 7.5% and 10% of clay with polypropylene-graft-maleic anhydride as coupling agent were prepared through the melt intercalation by twin-screw extruder. The materials were characterized by x-ray diffraction, tensile and impact properties according to ASTM D638 and D256 test methods, respectively. The x-ray diffraction results showed exfoliated or intercalated structures for different concentrations of the clay. The tensile modulus improved with the increase of the amount of the clay while the impact strength showed unsatisfactory results.
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TL;DR: A pesquisa em nanocompositos polimero/argila foi iniciada pela Toyota no final dos anos 80 as discussed by the authors, a partir deste marco, a comunidade cientifica worldial voltou sua atencao for this kind of material gracas as propriedades mecânicas, quimicas e termicas avancadas em comparacao com os compositos tradicionais.
Abstract: A pesquisa em nanocompositos polimero/argila foi iniciada pela Toyota no final dos anos 80. A partir deste marco, a comunidade cientifica mundial voltou sua atencao para este tipo de material gracas as propriedades mecânicas, quimicas e termicas avancadas em comparacao com os compositos tradicionais. Nao foi diferente no Brasil, tal atencao pode ser comprovada pelos inumeros trabalhos cientificos sobre nanocompositos que comecaram a despontar no inicio do seculo XXI. Assim, o presente artigo objetiva, apos discorrer sobre as definicoes que concernem nanocompositos polimero/argila, apresentar as pesquisas cientificas brasileiras em nanocompositos de polimeros de uso geral, de polimeros de engenharia e de outros tipos de polimeros, relacionando-os com o metodo de producao empregado, morfologia final e propriedades decorrentes da formacao de nanocompositos. Por fim, o mapa da pesquisa brasileira em nanocompositos polimero/argila e sua perspectiva para o futuro sao apresentados.
10 citations
TL;DR: O IPC foi obtido a partir de subprodutos da industrializacao de corvina, utilizando-se o processo de mudanca de pH as discussed by the authors.
Abstract: O objetivo deste trabalho foi avaliar as propriedades de biofilmes nanocompositos de isolado proteico de corvina (Micropogonias furnieri) com argila organofilica. Inicialmente, foi obtido isolado proteico de corvina (IPC) utilizando-se o processo de mudanca de pH. O IPC foi obtido a partir de subprodutos da industrializacao de corvina. Para o desenvolvimento dos filmes, foi executado um planejamento experimental de Box e Behnken, com tres niveis de IPC (2; 3,5; 5 g.100 g-1 de solucao), argila montmorilonita MMT (0,3; 0,5; 0,7 g.100 g-1 de solucao) e glicerol (25, 30, 35 g.100 g-1 IPC). Os filmes polimericos foram desenvolvidos pela tecnica de casting. Os valores de resistencia a tracao variaram entre 7,2 e 10,7 MPa, e os valores de alongamento, de 39,6 a 45,8%. Os valores de permeabilidade ao vapor de agua (PVA) variaram entre 3,2 e 5,5 g mm m-2 d-1kPa-1. O IPC apresentou teor medio de proteina de 97,87% (b. s.). Pode-se concluir que os filmes nanocompositos produzidos a partir de IPC com MMT foram promissores, desde o ponto de vista das propriedades mecânicas, da aparencia visual e do facil manuseio ate a baixa permeabilidade ao vapor de agua e a baixa solubilidade. Com relacao as propriedades mecânicas, as concentracoes de IPC e MMT foram os principais fatores que influenciaram o desenvolvimento dos filmes nanocompositos. Os resultados obtidos no planejamento experimental utilizado indicaram que 3,5 g de IPC.100 g-1 de solucao, 0,5 g de MMT.100 g-1 de solucao e 30 g de glicerol.100 g-1 IPC seriam os parâmetros ideais para a preparacao de filmes nanocompositos por casting.
9 citations
TL;DR: In this paper, the mechanical and thermal behavior of the nanocomposite high melt strength polypropylene (HMSPP) and a bentonite clay Brazilian Paraiba (PB), which is known as “chocolate” and is used in concentrations of 5% and 10% by weight, in comparison to the American Cloisite 20A clay nanocompositionites.
8 citations
Cites background from "Propriedades mecânicas de nanocompó..."
...This improvement can be attributed to the absorption of impact energy by the clay and a reduction in the propagation of microcracks (Paiva et al., 2006)....
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TL;DR: In this article, a compound of Biodegradable Poly(β)-Caprolactone (PCL) with Brasgel PA (MMT) and Cloisite Na (CLNa) was combined with maleic anhydride grafted poly(β-caprolacton) (pCL-g-MA).
Abstract: Biodegradable Poly (ɛ-caprolactone) (PCL) was compounded with Brasgel PA (MMT) and Cloisite Na (CLNa), and compatibilized with maleic anhydride grafted poly(ɛ-caprolactone) (PCL-g-MA). No evidence of degradation was verified during processing, as well as particle aggregates were absent as displayed through scanning electron microscopy (SEM) images. Compatibilized compounds upon clay addition achieved higher thermal stability as visualized by thermogravimetry (TG). Montmorillonite clays acted as nucleant agent during PCL melt crystallization as evidenced by differential scanning calorimetry (DSC). Mechanical behavior of PCL was preserved, and all compounds presented Elongation higher than 350% meanwhile the heat distortion temperature (HDT) was increased by 20% in PCL compounds, which may have wider range of application and better performance.
8 citations
11 Jun 2007
7 citations
References
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TL;DR: In this article, a review of polymer-layered silicate nanocomposites is presented, where the polymer chains are sandwiched in between silicate layers and exfoliated layers are more or less uniformly dispersed in the polymer matrix.
Abstract: This review aims at reporting on very recent developments in syntheses, properties and (future) applications of polymer-layered silicate nanocomposites. This new type of materials, based on smectite clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation, may be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer matrices is covered, i.e. thermoplastics, thermosets and elastomers. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfoliated nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filler level, usually inferior to 5 wt.%, such as increased Young’s modulus and storage modulus, increase in thermal stability and gas barrier properties and good flame retardancy.
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TL;DR: An overview of polymer-clay hybrid nanocomposites is provided with emphasis placed on the use of alkylammonium exchanged smectite clays as the reinforcement phase in selected polymer matrices as discussed by the authors.
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TL;DR: In this article, a polypropylene (PP)/clay nanocomposites (PPCN) were prepared via grafting-melt compounding by using a new kind of co-intercalation organophilic clay which had a larger interlayer spacing than the ordinarily organophilous clay only modified by alkyl ammonium.
562 citations
TL;DR: In this paper, the mesoscale structure and the strength of polymer-nanoparticle interactions have been investigated using viscoelastic measurements of layered silicate-based polymer nanocomposites.
Abstract: Layered silicate based polymer nanocomposites have gained significant technological interest because of the recent commercialization of nylon 6 and polypropylene based materials. Aside from the natural interests in understanding and improving the processing of these hybrids, viscoelastic measurements have also proven to be a sensitive tool to probe the mesoscale structure and the strength of polymer–nanoparticle interactions.
358 citations