The role of lignin in polypropylene composites with semi-bleached cellulose fibers: Mechanical properties and its activity as antioxidant

Gadioli, Renan; Morais, J.; Waldman, Walter R.; Paoli, Marco-Aurélio De

doi:10.1016/j.polymdegradstab.2014.06.005

Cited by 63 publications

(64 citation statements)

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“…This reduction in the tensile modulus may have been caused by reduced adhesion between the SB2 fibers and the PA‐6 matrix. Therefore, the semibleached fibers showed an inferior reinforcement effect on PA‐6 relative to that observed for polypropylene composites by Gadioli et al .…”

Section: Resultsmentioning

confidence: 60%

“…Similarly, the SB1 fibers begin their weight loss process at 261°C, with the maximum rate reached at 334°C, which is also attributed to the degradation of α‐cellulose and hemicellulose. The TGA curves show that the weight loss stages of the bleached and semibleached cellulose fibers are similar to those of other lignocellulosic fibers . The presence of lignin in these fibers was barely detectable using the TGA technique, possibly because of its low concentration.…”

Section: Resultsmentioning

confidence: 75%

“…We demonstrated that lignin extracted from sugar cane bagasse presented a remarkable effect as thermostabilizer and photostabilizer in matrices such as polybutadiene, poly(styrene‐ co ‐butadiene), and poly( cis ‐isoprene) or natural rubber . In addition, we recently demonstrated that lignin present in semibleached cellulose fibers from Eucalyptus showed a measurable index of stabilization in PP composites .…”

Section: Introductionmentioning

confidence: 91%

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Polyamide‐6 composites reinforced with cellulose fibers and fabricated by extrusion: Effect of fiber bleaching on mechanical properties and stability

et al. 2015

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We prepared polyamide-6 (PA-6) composites using bleached and semibleached cellulose fibers from Eucalyptus species by processing in a corotating interpenetrating twin-screw extruder. PA-6 is a challenging matrix because of its high processing temperature, which overlaps the thermodegradation temperature of the fibers. The selection of the processing conditions for extrusion and the use of the lubricant ethylene bis (stearamide) permitted the production of composites with 20, 30, and 40 wt% of bleached fibers, which are lighter than the corresponding glass fiber composites. Composites with 30 wt% of bleached fibers yield the best mechanical properties and good fiber/matrix interaction, as demonstrated by mechanical tests and scanning electron microscopy. X-ray photoelectron spectroscopy studies showed that the natural moisture in the fibers promotes the fiber/matrix interaction through the formation of ester bonds. We assessed the effect caused by the presence of lignin in the fibers. Composites containing 30 wt% of semibleached fibers maintained the flexural properties and showed small improvements in thermal stability when compared with bleached fiber composites; however, there is a slight decrease in the tensile properties. Through accelerated aging tests, we observed that increased lignin concentration in the fibers reduced the formation of carbonyl compounds on sample surfaces, indicating a stabilization effect. POLYM. COMPOS., 00:000-000, 2015.

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Section: Resultsmentioning

confidence: 60%

Section: Resultsmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 91%

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Polyamide‐6 composites reinforced with cellulose fibers and fabricated by extrusion: Effect of fiber bleaching on mechanical properties and stability

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“…Al existir una compatibilidad entre la matriz del asfalto y un material adicional, se mejoran las propiedades reológicas de la mezcla evitando problemas como el desgaste de la carpeta de rodadura o un aumento a la resistencia de fatiga [29]. Se ha demostrado que la presencia de polímeros en el asfalto reduce efectos tales como el endurecimiento del asfalto y la pérdida de las propiedades físicas deseables, también conocidas como oxidación.…”

Section: Modificación Con Ligninaunclassified

“…Botaro y otros [29] estudian las características de una mezcla asfáltica modificada con poliestireno reciclado (PS), polvo de neumáticos (PPN) y lignina (LIG), sobre la que realizan ensayos como penetración …”

Section: Modificación Con Ligninaunclassified

Evaluación del efecto del envejecimiento del cemento asfáltico 80-100 modificado con lignina Daniella Rodríguez U, Cristian Rodríguez, Sindy R

U¹,

Rodríguez²,

Ramírez³

et al. 2016

ingeniare

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Esta investigación presenta un análisis de los resultados obtenidos de un asfalto modificado con lignina, un polímero abundante y de fácil acceso debido a su origen natural y su bajo costo de obtención el cual se crea mediante el proceso de fotosíntesis, compone el 30% de carbono orgánico no fósil y de un cuarto a una tercera parte de la masa seca de la madera, cumple con una función fundamental que se caracteriza por dar soporte estructural, impermeabilidad y resistencia contra agentes microbiológicos y estrés oxidativo. Esto hace que se convierta en un polímero muy resistente a la degradación. Para la mezcla modificada se utilizó un asfalto 80-100, y lignina producto de un desecho industrial papelero. El método empleado para esta investigación fue a partir de los ensayos de penetración y punto de ablandamiento (anillo y bola), consideradas como pruebas funda-mentales cuando se busca producir mezclas que presenten mayor temperatura de ablandamiento y menor temperatura de fractura. Con la lignina se utilizaron 6 porcentajes distintos; 5%, 10%, 15% y 20% en 400 gramos de asfalto 80-100. La lignina fue tamizada en el tamiz de 75 µm con el fin de obtener una mezcla homogénea y evitar grumos; el tiempo de mezcla fue de 30 minutos por cada porcentaje y la temperatura se manejó en un rango de 125°C a 135°C para prevenir la aparición de burbujas de aire.

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Antioxidants, Polymers

Kröhnke

Zäh

2022

Kirk-Othmer Encyclopedia of Chemical Technology

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Organic matter is subject to decomposition, particularly through reaction with oxygen. This leads to several reactive secondary products such as hydroperoxides and peroxy and alkoxy radicals. Antioxidants are used to slow down oxidative degradation by reacting with these reactive intermediates. On the one hand, this article explains the mechanism of the oxidation of polymers and, on the other hand, describes suited antioxidants and their influence on the stabilization of polymers during their processing in the melt and during their service life. Suitable antioxidants, including combinations of antioxidants, which act as free‐radical scavengers (primary antioxidants) and hydroperoxide or peroxide scavengers (secondary antioxidants), are explained. Traditional commercial antioxidants still play a role when used in industrially manufactured polymers. Moreover, the stabilization of polymer recyclates against oxidative degradation is gaining in importance. Furthermore, in recent years, unconventional antioxidants of natural origin have also increasingly come into focus. Methods for the analytical determination of antioxidants in polymeric substrates are also described, with which the consumption and effectiveness of these products can be examined.

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The role of lignin in polypropylene composites with semi-bleached cellulose fibers: Mechanical properties and its activity as antioxidant

Cited by 63 publications

References 25 publications

Polyamide‐6 composites reinforced with cellulose fibers and fabricated by extrusion: Effect of fiber bleaching on mechanical properties and stability

Polyamide‐6 composites reinforced with cellulose fibers and fabricated by extrusion: Effect of fiber bleaching on mechanical properties and stability

Evaluación del efecto del envejecimiento del cemento asfáltico 80-100 modificado con lignina Daniella Rodríguez U, Cristian Rodríguez, Sindy R

Antioxidants, Polymers

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