Distribution of lamella thicknesses in isothermally crystallized polypropylene and polyethylene by differential scanning calorimetry

Włochowicz, A.; Eder, M.

doi:10.1016/0032-3861(84)90374-4

Cited by 152 publications

(94 citation statements)

References 5 publications

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“…In the solid state, peaks at 66°C and 138°C are seen in pNdc 18 -b-pNte 18 due to the melting of pNte and pNdc crystals, respectively. These melting peaks are similar to those obtained from polyethylene oxide (PEO) and polyethylene (PE) homopolymers (33,34). It is evident that the thermal properties of peptoids are dominated by the properties of the side chains (21).…”

Section: Resultssupporting

confidence: 62%

Self-assembly of crystalline nanotubes from monodisperse amphiphilic diblock copolypeptoid tiles

Sun

Jiang

Lund

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

120

131

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The folding and assembly of sequence-defined polymers into precisely ordered nanostructures promises a class of well-defined biomimetic architectures with specific function. Amphiphilic diblock copolymers are known to self-assemble in water to form a variety of nanostructured morphologies including spheres, disks, cylinders, and vesicles. In all of these cases, the predominant driving force for assembly is the formation of a hydrophobic core that excludes water, whereas the hydrophilic blocks are solvated and extend into the aqueous phase. However, such polymer systems typically have broad molar mass distributions and lack the purity and sequence-defined structure often associated with biologically derived polymers. Here, we demonstrate that purified, monodisperse amphiphilic diblock copolypeptoids, with chemically distinct domains that are congruent in size and shape, can behave like molecular tile units that spontaneously assemble into hollow, crystalline nanotubes in water. The nanotubes consist of stacked, porous crystalline rings, and are held together primarily by side-chain van der Waals interactions. The peptoid nanotubes form without a central hydrophobic core, chirality, a hydrogen bond network, and electrostatic or π-π interactions. These results demonstrate the remarkable structure-directing influence of n-alkane and ethyleneoxy side chains in polymer self-assembly. More broadly, this work suggests that flexible, low-molecular-weight sequence-defined polymers can serve as molecular tile units that can assemble into precision supramolecular architectures.peptoid polymers | sequence-defined polymers | supramolecular assembly | polymer amphiphiles | peptoid nanostructures S elf-assembly of copolymers comprising hydrophilic and hydrophobic blocks in water is a subject of long-standing interest (1, 2). The hydrophilic blocks can be either charged (e.g., polyacrylic acid) or uncharged (e.g., polyethylene oxide) (3, 4), and the hydrophobic blocks are either amorphous (e.g., polybutadiene) or crystalline (e.g., polyethylene) (5, 6). A variety of morphologies such as spheres, disks, cylinders, and vesicles have been identified in these systems (1, 3, 7-10). These morphologies comprise solid cores of the hydrophobic blocks surrounded by solvated hydrophilic chains that extend into the aqueous phase. In all of these cases, the predominant driving force for assembly is the formation of a hydrophobic core that excludes water. In a few cases, it has been shown that the enthalpic gain from the crystallization of polymer blocks can drive micellar self-assembly in organic solvents (11) and can regulate the micellar morphology or stability in aqueous solutions (12).The recently developed ability to synthesize polymers of precisely controlled monomer sequence (13) opens up the possibility to study the fundamental relationship between polymer sequence and polymer function. Peptoids are one particularly promising class of bioinspired polymer, where the main chain length and monomer sequence can be precisely controlled (1...

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Section: Resultssupporting

confidence: 62%

Self-assembly of crystalline nanotubes from monodisperse amphiphilic diblock copolypeptoid tiles

Sun

Jiang

Lund

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

120

131

View full text Add to dashboard Cite

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“…The lamellar thickness and its distribution were calculated by applying the DSC experimental results to the Thomson equation. 22,23 The elastic recovery (ER) of HDPE films was determined from a stress-strain curve during cyclic loading of samples by using a Zwick 1100 tensile tester (Zwick, Germany), which can be used as an index for representing the structural arrangement and the hard elasticity of lamellar crystalline structure. The initial length of test samples was 50 mm, the strain rate was 100%/ min, and the maximum tensile strain was 100%.…”

Section: Discussionmentioning

confidence: 99%

Effects of melt‐extension and annealing on row‐nucleated lamellar crystalline structure of HDPE films

Lee¹,

Park²,

Song³

2006

J of Applied Polymer Sci

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The row-nucleated lamellar crystalline structure of high-density polyethylene (HDPE) films was prepared by applying elongation stress to HDPE melt during T-die cast film extrusion and subsequently annealing the extruded films. This unusual crystalline structure was analyzed in terms of lamellar crystalline orientation, long-period lamellar spacing, crystallite size, and degree of crystallinity. The contribution of melt-extension represented by draw-down-ratio (DDR) to the overall orientation was found to be most noticeable than other processing variables. Meanwhile, the long-period lamellar spacing, the crystallite size, and the degree of crystallinity were influenced predominantly by the annealing temperature. Finally, the processing (melt extension and annealing temperature) -structure (lamellar crystalline structure) -property (hard elasticity) relationship of HDPE films was investigated.

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“…The interface distribution function as for example used by Iijima et al gives the most probable value for the lamellar thickness, whereas the correlation function as for example used by Cheng et al gives the mean value. Finally the relation of T c versus l c can be determined with DSC as well, as demonstrated by for example Wlochowicz et al [62]. Another important note is that in case of extremely narrow molecular weight distributions trends will most likely be different, and only using s e to fit the relation is insufficient.…”

Section: The Relation Between Crystallization Temperature and Lamellamentioning

confidence: 99%

The prediction of mechanical performance of isotactic polypropylene on the basis of processing conditions

Caelers

Govaert

Peters

2016

Polymer

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Distribution of lamella thicknesses in isothermally crystallized polypropylene and polyethylene by differential scanning calorimetry

Cited by 152 publications

References 5 publications

Self-assembly of crystalline nanotubes from monodisperse amphiphilic diblock copolypeptoid tiles

Self-assembly of crystalline nanotubes from monodisperse amphiphilic diblock copolypeptoid tiles

Effects of melt‐extension and annealing on row‐nucleated lamellar crystalline structure of HDPE films

The prediction of mechanical performance of isotactic polypropylene on the basis of processing conditions

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