Multiple melting behaviour of annealed crystalline polymers

Shan, Gui‐Fang; Yang, Jie; Tang, Xue-Gang; Yang, Mei; Xie, Bin; Fu, Qiang; Mai, Yiu‐Wing

doi:10.1016/j.polymertesting.2009.11.011

Cited by 50 publications

(28 citation statements)

References 28 publications

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“…6a), we can see that PA6 forms two melting peaks. Previous study showed that the two melting peaks were not due to the existence of two crystal forms but originated from the different distribution of the lamellar thickness [59]. The addition of EPDM or EPDM‐ g ‐MAH to PA6/HDPE binary blends remains T m of PA6 almost unchanged.…”

Section: Resultsmentioning

confidence: 94%

Information support for cancer survivors

Hesse

Arora

Beckjord

et al. 2008

Cancer

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Survivors' information-seeking behavior has traditionally been documented through analysis of inquiries to hotlines and cancer information services. Data from these self-selected inquiries tend to be restricted to a time around diagnosis, and to those populations possessing the wherewithal and motivation to seek information actively. The current study used data from a general population survey to assess 1) the prevalence of information-seeking behavior among survivors in the general population, 2) characteristics of seekers versus nonseekers, 3) ratings of information-seeking experience, and 4) actual versus

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Section: Resultsmentioning

confidence: 94%

Information support for cancer survivors

Hesse

Arora

Beckjord

et al. 2008

Cancer

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“…Multiple crystallization curves are often seen in PE with low crystallinity and are attributed to the insertion of thin lamellae crystals forming at lower temperatures, whereas the thicker lamellae are formed at higher temperatures [44]. This is due to the branching effects and molecular weight distribution of the PE, where the linear regions tend to crystallize first at higher temperatures into thick lamellae excluding the branches which form thinner less perfect lamellae at low temperatures, hence different fractions of crystallites can occur as the PE is re-crystallized from the melt.…”

Section: Thermal Propertiesmentioning

confidence: 99%

Morphology and crystallization kinetics of polyethylene/long alkyl-chain substituted Polyhedral Oligomeric Silsesquioxanes (POSS) nanocomposite blends: A SAXS/WAXS study

Heeley

Hughes

Aziz

et al. 2014

European Polymer Journal

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The dispersal, quiescent crystallization kinetics and morphology of a series of unique polyethylene -polyhedral oligomeric silsesquioxanes (PE-POSS) nanocomposite blends is presented. POSS molecules with long linear alkyl-chain substituents were blended at one composition into a commercial low density polyethylene. Time-resolved Small-and WideAngle X-Ray scattering (SAXS/WAXS) and thermal techniques were used to elucidate the affect that POSS and its substituent groups have on the dispersal and crystallization kinetics of the host polymer. The miscibility and dispersal of the POSS molecules was seen to increase with the increasing alkyl-chain length substituents suggesting increased compatibility and interaction with the host polymer chains. The POSS molecules act as nucleating agents increasing the crystallinity, crystallization kinetics and influencing the final lamellar morphology. Thus, these unique POSS compounds show great potential as nancomposite filler particles in polyolefins where the alkyl-chain substituent plays a vital role in its compatibility and subsequent improvement of physical properties in the host polymer.

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“…It is an important research subject in the field of polymer science to gain a basic understanding of the structural evolution related to thermal history (i.e., crystallization conditions) and to provide a deep insight into the crystallization and melting processes of semicrystalline polymers. As summarized in the literature [25,36,37], possible origins of the complex melting phenomenon are as follows: (1) the presence of more than one crystal forms (polymorphism), (2) the presence of different morphologies (such as lamellar thickness, distribution, perfection, or stability), (3) melting, recrystallization, and remelting processes during heating, (4) physical aging and/or relaxation of the rigid amorphous fraction, (5) different molecular weight species, and so on.…”

Section: Introductionmentioning

confidence: 99%

Calorimetric analysis of the multiple melting behavior of melt-crystallized poly(l-lactic acid) with a low optical purity

Song

Chen

Wei

et al. 2012

J Therm Anal Calorim

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The polymorphous crystallization and multiple melting behavior of poly(L-lactic acid) (PLLA) with an optical purity of 92 % were investigated after isothermally crystallized from the melt state by wide-angle X-ray diffraction and differential scanning calorimetry. Owing to the low optical purity, it was found that the disordered (a 0 ) and ordered (a) crystalline phases of PLLA were formed in the samples crystallized at lower (\95°C) and higher (C95°C) temperatures, respectively. The melting behavior of PLLA is different in three regions of crystallization temperature (T c ) divided into Region I (T c \ 95°C), Region II (95°C B T c \ 120°C), and Region III (T c C 120°C). In Region I, an exothermic peak was observed between the low-temperature and high-temperature endothermic peaks, which results from the solid-solid phase transition of a 0 -form crystal to a one. In Region II, the double-melting peaks can be mainly ascribed to the melting-recrystallization-remelting of less stable a crystals. In Region III, the single endotherm shows that the a crystals formed at higher temperatures are stable enough and melt directly without the recrystallization process during heating.

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Multiple melting behaviour of annealed crystalline polymers

Cited by 50 publications

References 28 publications

Information support for cancer survivors

Information support for cancer survivors

Morphology and crystallization kinetics of polyethylene/long alkyl-chain substituted Polyhedral Oligomeric Silsesquioxanes (POSS) nanocomposite blends: A SAXS/WAXS study

Calorimetric analysis of the multiple melting behavior of melt-crystallized poly(l-lactic acid) with a low optical purity

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