Extruded starch–nanoclay nanocomposites: Effects of glycerol and nanoclay concentration

Abstract

Wheat starch‐Cloisite Na+ nanoclay composites containing different glycerol and nanoclay concentrations were extruded using a twin‐screw extruder. X‐ray diffraction and transmission electron microscopy were used to determine the extent of nanoclay dispersion and thermogravimetric analysis was used to characterize thermal stability of composites. Also, water absorbance was measured for each sample. The extent of nanoclay dispersion in samples containing 47 wt% total plasticizer concentration depended on glycerol concentration. For these samples, adding 5 wt% glycerol produced mostly exfoliated nanoclay, whereas adding 10 or 15 wt% glycerol produced intercalated nanoclay. Also, nanoclay composites exhibited improved thermal stability and reduced water uptake compared to samples with no nanoclay. However, thermal stability and water absorbance were not affected by the extent of nanoclay dispersion. POLYM. ENG. SCI., 47:1898–1904, 2007. © 2007 Society of Plastics Engineers

Effects of preparation methods on the structure and mechanical properties of wet conditioned starch/montmorillonite nanocomposite films

“…Recently several attempts were 70 reported in the literature for the preparation of TPS nanocomposites. In most cases 71 TPS/montmorillonite nanocomposite films were prepared by melt blending (in internal batch 72 mixer or in a twin screw extruder) (Avella, De Vlieger, Errico, Fischer, Vacca & Volpe, 2005; 73 Chen & Evans, 2005;Chiou, Wood, Yee, Imam, Glenn & Orts, 2007; Chivrac, Pollet & 74 Averous, 2009;Chivrac, Pollet, Dole & Averous, 2010; Dean, Yu & Wu, 2007; Huang, Yu & 75 Ma, 2004;Magalhaes & Andrade, 2009;Muller, Laurindo & Yamashita, 2012; Ray & 76 4 Bousmina, 2005;Tang, Alavi & Herald, 2008) or solution mixing (film casting) (Chaudhary 77 & Liu, 2013;Chivrac, Pollet & Averous, 2009; Cyras, Manfredi, Ton-That & Vazquez, 2008; 78 Kampeerapappun, Aht-Ong, Pentrakoon & Srikulkit, 2007; Kelnar, Kapralkova, Brozova, 79 Hromadkova & Kotek, 2013; Majdzadeh-Ardakani, Navarchian & Sadeghi, 2010; Masclaux, 80 Gouanve & Espuche, 2010;Pandey & Singh, 2005; Ray & Bousmina, 2005; Schlemmer, 81 Angelica & Sales, 2010). The results clearly demonstrated that the incorporation of 82 organophilic montmorillonite with apolar character led to the formation of conventional 83 microcomposites, while due to the polar nature of both starch and Na-montmorillonite 84 (NaMMT) the application of NaMMT results in an intercalated/exfoliated structure of TPS 85 nanocomposites (Chivrac, Pollet & Averous, 2009; Ray & Bousmina, 2005).…”

“…Several studies proved that the use of glycerol contents larger than 10 wt% led to the 89 formation of intercalated structures with interlayer basal spacing (d001) increasing from 1.2 to 90 1.8 nm (Chiou, Wood, Yee, Imam, Glenn & Orts, 2007;Chivrac, Pollet & Averous, 2009; 91 Pandey & Singh, 2005). It is difficult to verify whether the starch or the glycerol molecules 92 intercalate between the clay layers, because both have a tendency to penetrate into the silicate 93 layers, but penetration of glycerol is favored owing to its smaller molecular size (Aouada, 94 Mattoso & Longo, 2011;Chaudhary & Liu, 2013).…”

“…Several investigations confirm the strong 95 influence of the polyol plasticizer on the exfoliation process and thus on the resulting 96 morphology. This effect is likely related to the hydrogen bonds established between glycerol 97 and MMT platelets, which could decrease the attractive forces between starch and clay 98 (Chiou, Wood, Yee, Imam, Glenn & Orts, 2007;Chivrac, Pollet & Averous, 2009; Pandey & 99 Singh, 2005). Exfoliated/intercalated morphology is found to be dependent also on NaMMT 100 content.…”

Desenvolvimento de embalagem biodegradável ativa a base de fécula de mandioca e agentes antimicrobianos naturais.

“…Na literatura, encontram-se resultados interessantes em relação ao uso de diferentes tipos de argilas para incorporação como nanocargas em filmes biodegradáveis a base de amido. Os nanocompósitos argila/amido estudados demonstraram uma melhoria nas propriedades mecânicas, térmicas e de barreira (MCGLASHAN;HALLEY, 2003;AVELLA et al, 2005;CHIOU et al, 2007;KAMPEERAPAPPUN et al, 2007;CYRAS et al, 2008; (DAGLIA, et al, 1998;KECHICHIAN et al, 2010), mel (TAORMINA; NIEMIRA;…”

“…Na literatura, encontram-se resultados interessantes em relação ao uso de diferentes tipos de argilas para incorporação como nanocargas em filmes biodegradáveis a base de amido. Os nanocompósitos argila/amido estudados demonstraram uma melhoria nas propriedades mecânicas, térmicas e de barreira (PARK et al, 2002;MCGLASHAN;HALLEY 2003;PARK et al, 2003;WILHELM et al, 2003;AVELLA et al 2005;CHIOU et al 2007;KAMPEERAPAPPUN et al 2007;RAQUEZ et al, 2007;CYRAS et al 2008;CHIVRAC et al, 2008; Assim como os plastificantes interagem com o amido, supõe-se que eles também desempenhem um importante papel junto às nanopartículas de argila, afetando, dessa forma, a formação da nanoestrutura e as propriedades mecânicas e de barreira de filmes biodegradáveis nanocompósitos a base de amido e argila.…”