Influence of processing on the ethylene-vinyl alcohol (EVOH) properties: Application of the
successive self-nucleation and annealing (SSA) technique

Urquiza, Edgar Adrian Franco; Santana, Oliverio J.; Gámez‐Pérez, José; Martínez, Alejandro Rosillo; Ll, M.

doi:10.3144/expresspolymlett.2010.20

Cited by 41 publications

(50 citation statements)

References 22 publications

(30 reference statements)

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“…The main thermal transition, the α′ peak, is associated with the glass temperature whereas the second peak represents the α″ temperature of EVOH copolymer caused by its crystalline degree. This α″ temperature peak has a more important value of intensity when a higher orientation of molecular chains exists in the crystal part of the EVOH . This α″ relaxation is not observed for a totally amorphous material.…”

Section: Resultsmentioning

confidence: 85%

“…. Particularly, Franco‐Urquiza et al . had proved the existence of thermal changes in EVOH without filler associated simply with the modification of the morphology.…”

Section: Resultsmentioning

confidence: 99%

“…Several works had already studied thermal variations of polymers with modifications of process (parameters, environmental conditions, etc.) . Particularly, Franco‐Urquiza et al .…”

Section: Resultsmentioning

confidence: 99%

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Antimicrobial materials based on poly(ethylene‐co‐vinyl alcohol) and silver acetate produced by reactive extrusion

Paillot

Farhat

Becquart

et al. 2019

J of Applied Polymer Sci

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The use of silver as an antimicrobial agent has exhibited great interest in recent years. In this research, poly(ethylene‐co‐vinyl alcohol) (EVOH)–silver acetate‐based antimicrobial materials were prepared at high temperature by reactive extrusion. Silver acetates were used without pretreatment. The thermal reaction of silver acetates in the material and their effect on the thermal and mechanical properties of the polymer were investigated as a function of their concentration. The dispersed silver acetate salts within the EVOH matrix have displayed a significant thermal reaction. This reaction of metallic salts was partial when the extrusion temperature was fixed at 190 °C and completed at 230 °C. The antimicrobial agents also had significant effects on the properties of the matrix. Reductions of glass temperature and storage modulus were observed by the analyses. All the variations were dependent on both the concentration of silver acetate and the extrusion parameters. The antimicrobial activity was studied and demonstrated a promising potential to create an antimicrobial material in a one‐step solvent free extrusion method. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47799.

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Section: Resultsmentioning

confidence: 85%

“…. Particularly, Franco‐Urquiza et al . had proved the existence of thermal changes in EVOH without filler associated simply with the modification of the morphology.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Antimicrobial materials based on poly(ethylene‐co‐vinyl alcohol) and silver acetate produced by reactive extrusion

Paillot

Farhat

Becquart

et al. 2019

J of Applied Polymer Sci

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show abstract

“…Two heating and a cooling run were carried out at 10°C/min heating and cooling rate in the temperature range of 30-300°C. Crystallinity was calculated from the enthalpy of fusion (157.8 J/g) of the EVOH single crystal of 100% crystallinity [61]. Crystalline structure was also studied by X-ray diffraction.…”

Section: Methodsmentioning

confidence: 99%

Decreased oxygen permeability of EVOH through molecular interactions

Péter¹,

Kenyó²,

Renner³

et al. 2014

Express Polym. Lett.

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The number of functional and smart packaging materials increases continuously and they are used already in everyday practice in increasing quantities [1][2][3][4]. The main functions targeted for various products are small oxygen permeability or oxygen scavenging [5][6][7], humidity control [8][9][10][11][12], regulated ethylene content [13], antimicrobial effect [14][15][16][17], adsorption of odorous materials, or the opposite, the release of desirable aromas [18,19]. Intensive research and development work is carried out on these materials all over the world, but mostly in industry.Controlling oxygen permeability is especially important in the pharmaceutical industry and in food packaging. The oxygen permeability of polymers varies in a wide range covering several orders of magnitudes from a few hundred to a few hundredths or even thousands of cm 3· mm/m 2 /24 h/bar [20]. Ethylene-vinyl alcohol copolymers (EVOH) offer extremely good protection against oxygen [20][21][22][23][24][25]. The barrier properties of these materials depend on ethylene content [23,26,27], crystallinity, temperature [22,28] and humidity [24,[26][27][28][29][30][31][32][33][34]. The last factor represents also the major drawback of EVOH, since permeability may increase by orders of magnitudes with increasing water content [28] Abstract. Poly(ethylene-co-vinyl alcohol) of 48 mol% ethylene content was modified with N,N!-bis(2,2,6,6-tetramethyl-4-piperidyl)-isophthalamide (Nylostab SEED) to decrease the oxygen permeability of the polymer. The additive was added in a wide concentration range from 0 to 10 wt%. The structure and properties of the polymer were characterized with various methods including differential scanning calorimetry, X-ray diffraction, mechanical testing, optical measurements and oxygen permeation. Interactions were estimated by molecular modeling and infrared spectroscopy. The results showed that oxygen permeation decreased considerably when the additive was added at less than 2.0 wt% concentration. The decrease resulted from the interaction of the hydroxyl groups of the polymer and the amide groups of the additive. The dissolution of the additive in the polymer led to decreased crystallinity, but also to decreased mobility of amorphous molecules. Stiffness and strength, but also deformability increased as a result. Above 2 wt% the additive forms a separate phase leading to the deterioration of properties. The success of the approach represents a novel way to control oxygen permeation in EVOH and in other polymers with similar functional groups capable of strong interactions.

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“…Também é utilizado em outras aplicações no qual requerem materiais de alta barreira a gás, resistência a permeação de solventes orgânicos, óleos e gorduras, assim como boa resistência mecânica e à abrasão e boa elasticidade. No entanto, o copolímero é de caráter higroscópico e quando em ambientes com alta umidade relativa ocorre a diminuição da sua temperatura de transição vítrea, redução das propriedades de barreira e da resistência à tração [34,36,37]. …”

Section: Propriedades Do Evohunclassified

Blendas de amido termoplástico e poli (álcool vinílico-co-etileno)

Alves¹

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O crescente uso do amido como um material termoplástico tem despertado o interesse por esse polímero especialmente devido sua biodegradabilidade e por ser obtido de fontes renováveis. Porém suas propriedades mecânicas inferiores e a alta sensibilidade a umidade têm limitado sua utilização em diversas aplicações. O desenvolvimento de blendas poliméricas tem sido uma boa alternativa para obtenção de novos materiais à base de amido com suas propriedades melhoradas. Blendas de amido termoplástico (TPS) e poli(álcool vinílico -co-etileno) (EVOH), com 27 e 44%mol de etileno, foram obtidas em uma extrusora de rosca simples. O TPS foi produzido pela mistura de amido de milho e glicerol como plastificante (70:30). Para a obtenção das blendas foram acrescentados 5, 10 e 15% (m/m) do EVOH27% e EVOH44%, obtendo assim 6 blendas de diferentes composições. As técnicas de análise térmica dinâmico mecânica (DMTA), espectroscopia de infravermelho por transformada de Fourier (FTIR) e de microscopia eletrônica de varredura (MEV) foram empregadas para a verificação de possível miscibilidade da mistura. A existência de uma única Tg nas blendas foi um indicativo de um sistema miscível, porém os espectros de infravermelho não apresentaram deslocamento de bandas sendo muito semelhantes ao espectro soma que indica um material totalmente imiscível, nas imagens obtidas pelo MEV não ficou evidente a presença de duas ou mais fases, porém podem ter sido disfarçadas devido à similaridade da morfologia de ambos materiais. As análises termogravimétricas (TGA) não mostraram alterações na estabilidade térmica das blendas. A técnica de difração de raios-X mostrou que não houve um aumento significativo na cristalinidade das blendas em relação ao TPS. As blendas condicionadas em ambientes com umidades relativas controladas apresentaram redução na absorção de umidade e no coeficiente de difusão de água com o aumento do teor de EVOH e de etileno na sua composição. Com o aumento do teor de EVOH, foi observado um aumento na resistência mecânica à tração das blendas e uma redução no alongamento na ruptura e no módulo de elasticidade quando comparados com o TPS puro. The increasing use of starch as a thermoplastic material has aroused interest in this polymer especially due to its biodegradability and because it is obtained from renewable sources. However, its lower mechanical properties and the high sensitivity to humidity have limited its use in several applications. The development of polymer blends has been a good alternative to obtain new starch-based materials with their properties improved. Blends of thermoplastic starch (TPS) and poly (vinyl alcoholethylene) (EVOH) with 27 and 44 mol% of ethylene were obtained in a single-screw extruder. TPS was produced by mixing corn starch and glycerol as plasticizer (70:30). To obtain the blends, 5, 10 and 15% (w/w) of EVOH27% and EVOH44% were added, thus obtaining 6 blends with different compositions. Mechanical dynamic thermal analysis (DMTA), Fourier transform infrared spectroscopy (FTIR) and scanning electr...

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Influence of processing on the ethylene-vinyl alcohol (EVOH) properties: Application of the successive self-nucleation and annealing (SSA) technique

Cited by 41 publications

References 22 publications

Antimicrobial materials based on poly(ethylene‐co‐vinyl alcohol) and silver acetate produced by reactive extrusion

Antimicrobial materials based on poly(ethylene‐co‐vinyl alcohol) and silver acetate produced by reactive extrusion

Decreased oxygen permeability of EVOH through molecular interactions

Blendas de amido termoplástico e poli (álcool vinílico-co-etileno)

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