Preparação e avaliação de nanocompósitos de poliestireno - hidróxido duplo lamelar HDL de ZnAl – organofuncionalizado com laurato/palmitato

Abstract

ResumoEste trabalho descreve a síntese e caracterização de nanocompósitos de poliestireno (PS) e hidróxido duplo lamelar (HDL) formado pelos cátions de ZnAl via polimerização in situ. O HDL utilizado neste trabalho foi modificado com uma mistura de dois ânions, laurato e palmitato. Para caracterização da estrutura e morfologia dos nanocompósitos sintetizados, foram realizadas análises por difração de raios X (DRX) e microscopia eletrônica de transmissão (MET). As caracterizações térmicas, mecânicas e de flamabilidade foram realizadas via análise termogravimétrica (TGA), ensaio de flexão e ensaio de flamabilidade, respectivamente. Os resultados obtidos neste trabalho sugerem que os nanocompósitos sintetizados possuem, de uma forma geral, uma morfologia intercalada/esfoliada com melhoras em suas propriedades térmicas e mecânicas, quando comparados com o PS puro. Entretanto, não foi observado melhora na propriedade de flamabilidade. Palavras-chave: nanocompósitos, poliestireno, hidróxido duplo lamelar, propriedade térmica, propriedade mecânica. AbstractThis work describes the synthesis and characterization of polystyrene (PS) and layered double hydroxide (LDH) nanocomposites formed by ZnAl cations via in situ polymerization. The LDH used in this study was modified with a mixture of two anions: laurate and palmitate. The characterization of structure and morphology for the synthesized nanocomposites was developed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The thermal, mechanical and flammability characterizations properties were carried out via thermogravimetric analysis (TGA), bending test and flammability test, respectively. The results suggest that the nanocomposites have in general intercalated/ exfoliated morphology with improvements in thermal and mechanical properties compared to the neat PS. However no significant improvement was observed on the flammability property.

In situ synthesis of polystyrene nanocomposites with layered double hydroxide with an unusual anion arrangement: Morphology and thermal and mechanical properties

“…The determination of the mechanical properties for polymer nanocomposites has great importance because many applications for these nanocomposites depend on their mechanical properties . Despite this great importance, studies of mechanical properties of PS/LDH nanocomposites are still scarce.…”

“…LDHs with unusual anion arrangements are obtained when they are synthesized with carboxylate anions, and these anions are used in excess, as reported in articles that focus on the LDH synthesis and characterization . With the use of this anion arrangement, it is possible to synthesize LDHs with higher basal spacing; this decreases the effect of the higher charge density and enables the synthesis of nanocomposites with better morphologies and properties …”

Synthesis of Biuret Derivatives as Potential HIV‐1 Protease Inhibitors Using (LDHs‐g‐HMDI‐Citric Acid), as a Green Recyclable Catalyst

“…27,28 Due to the ability to combine a wide variety of metal cations and anions and specific structure of LDHs, they have exhibited various applications. 24,25 The applications contain adsorbents, anion exchangers, medical applications ranging from simple antacids to targeted drug delivery mechanisms, [29][30][31][32][33] additives in polymers, 34 anti-wear additives in lubricants like motor oil, 35,36 flame retardants, 37,38 the formation of interesting nano-composite materials, [39][40][41][42][43][44][45] as well as catalysts and precursors to mixed metal oxide catalysts. [46][47][48][49] In recent years, the development of magnetic LDH-based nanoparticles (MLDHs) with a large surface area as a magnetic nanocatalyst is in great attention.…”

Obtenção e caracterização de compósitos poliméricos com óxido de grafeno reduzido.

“…Nanocompósitos são materiais onde pelo menos uma dimensão da carga reforçante está na escala nanométrica, geralmente, menor do que 100 nm [21] . A obtenção e caracterização destes compósitos têm crescido expressivamente na indústria e na academia, pois estes materiais apresentam propriedades únicas e superiores as encontradas nos compósitos tradicionais, utilizando uma porcentagem não superior a 5% em massa de fase dispersa [22,23] .…”