Non-isothermal crystallization kinetics of partially miscible ethylene-vinyl acetate copolymer/low density polyethylene blends

Jin, Junhong; Chen, S. J.; Zhang, J.

doi:10.3144/expresspolymlett.2010.19

Cited by 21 publications

(15 citation statements)

References 36 publications

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“…DSC investigations were used to determine stearic acid influence on the polyolefin‐calcium carbonate composites crystallization behavior. After converting DSC crystallization curves at different cooling rates (Φ = 5, 10, 20, 30°C/min), relative crystallinity as a function of time and temperature was determined . Calculations were based on the following equations:

X true(t true) = \frac{X_{t} (t)}{X_{t} (\infty)} = \frac{\int_{0}^{t} (d H (t) / d t) d t}{\int_{0}^{\infty} (d H (t) / d t) d t}

X true(T true) = \frac{X_{T} (T)}{X_{T} (\infty)} = \frac{\int_{0}^{T} (d H (T) / d T) d T}{\int_{0}^{\infty} (d H (T) / d T) d T}

where X t ( t ), X T ( T ), and X t (∞), X T (∞) indicated relative crystallinity at time t and temperature T and at the end of the crystallization process, whereas dH(t)/dt and dH(T)/dT were the heat flow rates.…”

Section: Resultsmentioning

confidence: 99%

“…To analyze the mechanism of crystallization at its early stage, crystallization kinetics analysis was undertaken by applying Avrami theory modified by Jeziorny . The model of crystallization that was used allowed to determine crystallization kinetics parameters during nonisothermal crystallization after an adequate correction of the crystallization rate:

1 - X (t) = exp [- Z_{t} t^{n}]

…”

Section: Resultsmentioning

confidence: 99%

“…In case of highly‐filled composites (that contain between 30 and 50 wt % of the filler) designated for cast film production, the evaluation of crystallization kinetics, especially during primary crystallization, is necessary. Various papers present the application of the modified Avrami theory with regards to nonisothermal crystallization of several polymers . It should be mentioned that only few papers focused on crystallization kinetics behavior of highly‐filled composites .…”

Section: Introductionmentioning

confidence: 99%

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Nonisothermal crystallization of highly‐filled polyolefin/calcium carbonate composites

Barczewski

Kloziński

Jakubowska

et al. 2014

J of Applied Polymer Sci

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Nonisothermal crystallization kinetics of highly‐filled polyolefin composites was studied by means of differential scanning calorimetry (DSC). Two types of commercial calcium carbonate based fillers (modified with stearic acid and nonmodified one) were used for our investigations. In order to evaluate the crystallization kinetics changes of composites, the Avrami theory modified by Jeziorny was used. Validity of mineral fillers modification with stearic acid has been proved by thermal analysis. Because of the suppression of the heterogeneous nucleation effect resulting from calcium carbonate with stearic acid modification, an increase in the processability of highly‐filled polyolefin cast films might occur. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41201.

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X true(t true) = \frac{X_{t} (t)}{X_{t} (\infty)} = \frac{\int_{0}^{t} (d H (t) / d t) d t}{\int_{0}^{\infty} (d H (t) / d t) d t}

X true(T true) = \frac{X_{T} (T)}{X_{T} (\infty)} = \frac{\int_{0}^{T} (d H (T) / d T) d T}{\int_{0}^{\infty} (d H (T) / d T) d T}

Section: Resultsmentioning

confidence: 99%

1 - X (t) = exp [- Z_{t} t^{n}]

…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nonisothermal crystallization of highly‐filled polyolefin/calcium carbonate composites

Barczewski

Kloziński

Jakubowska

et al. 2014

J of Applied Polymer Sci

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“…Binary melt blends of several kinds of polyethylenes and EVAs with various vinyl acetate contents were extensively investigated and known to be partially compatible, leading to matrix disperse morphology at low contents and co-continuous morphology at high content of disperse phase (Jin, 2010). In most of the applications, small amounts of polyethylene 98…”

Section: Blend Morphologymentioning

confidence: 99%

Sealability and Seal Characteristics of PE/EVA and PLA/PCL Blends

Najarzadeh

Tabasi

Ajji

2014

International Polymer Processing

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Seal strength behavior of low density polyethylene and ethylene vinyl acetate copolymer (PE/EVA) blends as well as that of blends of as eal grade PLA with aliphatic polyester (PCL) was studied. Polyethylene is commonly used for seal application in packaging multilayer structures and amorphous PLA is considered to be its counterpart for compostable and/or biodegradables ones. Incorporation of EVA in polyethylene improves its sealability in terms of ad ecrease in seal initiation temperature and broadness of sealability plateau. This was interpreted as due to the formation of finer crystals, adecrease in the melting point and presence of vinyl acetate polar group. These were supported by results obtained from differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). For the PLA/PCL system, the dispersed phase was stretched into elongated ellipsoidald omains. This type of morphology affected the mechanical and seal properties of the blends. As aresult of blending, both hot-tack initiation temperature and strength as well as seal initiation temperature were enhanced. The enhancement in these seal properties was significant when the concentration of the dispersed phase exceeded 20 wt% in the blend. Hot-tack strength of up to twice of pure PLA was achieved through blending. This was attributed to the lower glass transition temperature of PCL, resulting in enhanced mobility of PLA chains and also the high aspect ratio of the dispersed phase. The maximum obtained hot-tack strength (1 200 g/25 mm) at 40 %d ispersed content compared advantageously to commercially available polyolefin based sealant resins. The seal and hottack initiation temperatures were shifted to lower temperatures by as much as 30 8 C, which can allow faster and more energy efficient sealing process. 1I ntroductionHeat sealing is an important operation in packaging. Modern vertical and horizontal form fill seal (VFFS and HFFS) machines have aneed for operating at higher speeds. This requirement and the fact that the final package integrity is ultimately dependent on the results of the sealing process requires that the polymers used for the seal layer have superior hot-tack strength, low seal initiation temperature and wider sealing temperatures range. Although resin suppliers provide awide range of resins for the seal layer, with avariety of performances and physical properties, materials optimization is still achallenge. This challenge is even greater when the production line aims to use biodegradable materials which still cannot provide as superior properties as commercially available resins. Achieving sufficient adhesion upon sealing two semicrystalline polymer films in the fully or partially molten state is mainly ascribed to chain interdiffusion across the interface, amorphous fraction of material, and polymer chain functional groups.Coextrusion of low density polyethylene (LDPE) and ethylene vinyl acetate copolymer(EVA) has been used in industry to tailor as ealant layer. However, studies on correlation of physical properties ...

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“…Os coeficientes de correlação são todos bastante próximos ou iguais a 1 (r 2 ≥ 0,99; exceção da amostra PEAD-Mrf resfriada em 5 °C/min cujo r 2 = 0,982). Isto contradiz algumas investigações [16,17] , onde perdas consideráveis na correlação linear são verificadas nos últimos estágios da cristalização, o que costuma dividir as curvas do modelo de Jaziorny em dois estágios com inclinações distintas atribuídos a cristalização primária e a cristalização secundária. Dentro das condições investigadas, o modelo parece indicar que o mecanismo de cristalização secundária ocorre apenas em pequena extensão, pois os coeficientes de correlação refletem uma dependência linear significativa.…”

Section: Cinética De Cristalização Não-isotérmicaunclassified

Cinética de cristalização não-isotérmica de resíduos de polietileno de alta densidade (PEAD)

et al. 2014

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Resumo: Nesta investigação, diversos resíduos incolores ou coloridos pós-consumo de polietileno de alta densidade (PEAD) foram caracterizados através do índice de fluidez (MFI) e da calorimetria exploratória diferencial (DSC). A equação de Avrami modificada por Jeziorny, e os modelos de Kissenger e Friedman foram utilizados para descrever a cinética de cristalização não-isotérmica das amostras. Foi verificado que os pigmentos presentes no PEAD têm diferentes habilidades nucleantes durante o processo de cristalização, bem como diferentes efeitos sobre a taxa de cristalização e a energia de ativação necessária para o transporte de segmentos macromoleculares para a superfície do cristal em crescimento. Palavras-chave: Polietileno de alta densidade, análise térmica, cinética, cristalização. Non-isothermal Crystallization kinetics of High-density Polyethylene (HDPE) ScrapsAbstract: In this study, miscellaneous uncolored and colored post-consumption high-density polyethylene (HDPE) scraps were characterized by melt flow index and differential scanning calorimetry (DSC). Avrami equation modified by Jeziorny, Kissenger and Friedman methods were employed to describe the non-isothermal crystallization kinetics of the samples. The colorants present in HDPE have different nucleating abilities during the crystallization process, as well as different effects upon the crystallization rate and the activation energy for the transport of macromolecular segments to the growing crystal surface. Keywords: High-density polyethylene, thermal analysis, kinetics, crystallization. IntroduçãoO consumo massivo de bens e serviços é uma das características da sociedade moderna. Ele se reflete na necessidade de um desenvolvimento industrial contínuo e na cobrança de um elevado preço do ponto de vista ambiental. Promulgada no dia 2 de agosto de 2010, após amplo debate com governo, universidades, setor produtivo e entidades civis, a Política Nacional de Resíduos Sólidos pode modificar profundamente o cenário. A lei lança uma visão moderna na luta contra um dos maiores problemas do planeta, o lixo urbano, tendo como princípio a responsabilidade compartilhada entre governo, empresas e população. A nova legislação impulsiona o retorno dos produtos às indústrias após o consumo e obriga o poder público a realizar planos para o gerenciamento do lixo [1,2] . No entanto, o problema da reciclagem de resíduos, em especial a de materiais poliméricos, ainda não encontra uma solução satisfatória. Se, por um lado, a reciclagem primária possui mercado garantido uma vez que consiste na regeneração de um único tipo de resina separadamente e é, geralmente, associado à produção industrial (pré-consumo); por outro lado, a reciclagem secundária é um mercado cujo crescimento está condicionado ao encontro de novas tecnologias para processar os vários subtipos de materiais plásticos presentes rotineiramente no lixo urbano, particularmente poliolefinas -polietileno de alta densidade (PEAD), polietileno de baixa densidade (PEBD), polietileno linear de baixa densidade (P...

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Non-isothermal crystallization kinetics of partially miscible ethylene-vinyl acetate copolymer/low density polyethylene blends

Cited by 21 publications

References 36 publications

Nonisothermal crystallization of highly‐filled polyolefin/calcium carbonate composites

Nonisothermal crystallization of highly‐filled polyolefin/calcium carbonate composites

Sealability and Seal Characteristics of PE/EVA and PLA/PCL Blends

Cinética de cristalização não-isotérmica de resíduos de polietileno de alta densidade (PEAD)

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