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The deformation-induced microstructure evolution of self-associated polymer blends, i.e., long chain polyamide alloys (LCPAs), was investigated and correlated with their mechanical performance. A PA1012 (soft phase)/PA612 (hard phase) blend was selected for this study. It is interesting that both Young's modulus and yield stress exhibit a nearly linear dependence with composition, which follows a...
Strongly segregated polyethylene-b-polystyrene (PE-b-PS) diblock copolymers were infiltrated within anodic aluminum oxide nanoporous templates (AAO) (with 60 nm diameter). After carefully removing the nanofibers from the nanopores, TEM revealed their morphology. This is the first time that the morphology of semi-crystalline diblock copolymers infiltrated within AAO templates is observed. Regardless...
The vital role of chain ends in the crystallization of linear polymers can be understood by unraveling the mechanisms of crystallization of cyclic polymers. A commercial chip-calorimeter Flash DSC1 was employed to compare the nucleation and overall crystallization rates between linear and cyclic poly(epsilon-caprolactones) (PCL) with similar molar masses of around 2 kg/mol. In the high temperature...
Isotactic poly(1-butene) (i-PBu) is a polyolefin of industrial relevance which exhibits an interesting polymorphism. Upon cooling from the relaxed melt at atmospheric pressure, a tetragonal phase (Form II) develops. However, being metastable, this structure slowly evolves upon aging in the stable trigonal modification (Form I). Another trigonal modification, denoted Form I′, can also crystallize directly...
Cross-nucleation of crystalline phases, i.e., the nucleation of a polymorph on a previously existing one, has recently been recognized to play a role among the different crystallization pathways of polymorphic substances. While several examples exist for small organic molecules, cross-nucleation has mostly been overlooked in semi-crystalline polymers. One of the reasons resides in the self-nucleation...
We review previous works on polymer confined crystallization employing strategies that allow confinement to go from the micron to the nanometer scale: droplets, blends, block copolymers and infiltration into alumina nanopores. We also present novel results, reporting homogeneous nucleation and first order crystallization kinetics, for the first time, in a homopolymer and a diblock copolymer infiltrated...
Low polydispersity linear and cyclic poly(ε-caprolactone) with molecular weights of 2–7.5 kg/mol were synthesized. Differences in the morphology of cyclic and linear single crystals (obtained from solution at identical temperatures) indicate that cyclic PCL crystals were obtained at higher supercoolings than linear ones. Cyclic PCL crystals (both crystallized from solution and from the melt) exhibited...
The synthesis of novel poly(ester-urethane)s (PEUs) based on polylactide was carried out. It was performed by a catalysed two-step reaction process, i.e., ring-opening polymerization (ROP) and chain extension reaction in bulk. For this purpose, α,ω-dihydroxyl PLA macrodiols were synthesized by catalysed ROP and employed as precursors that reacted in the melt with 4,4′-diisophenylmethane diisocyanate...
In this work, the nucleation and crystallization behavior of melt mixed PCL/CNT nanocomposites has been studied. The mixtures of PCL and pristine MWNTs were prepared by extrusion with different nanofiller contents: 0.3, 0.5, 0.7, 1 and 3%. Standard DSC measurements demonstrated pronounced nucleation effects as well as increases in PCL crystallinity. The nucleation effect saturates at only 0.5% (a...
The morphology of solution grown single crystals of a series of double crystalline diblock copolymers derived from l-lactide and ɛ-caprolactone has been investigated by means of transmission electron microscopy. The copolymers had a variable composition with a poly(l-lactide) weight percentage that ranged between 81 and 10%. All samples had a low polydispersity index (1.4–1.1) and a similar number...
A series of poly(mono n-alkyl itaconate)s, poly(methyl n-alkyl itaconate)s and poly(di n-alkyl itaconate)s with n=12, 14, 16, 18 and 22 have been prepared by radical polymerization. NMR studies point out that poly(methyl n-alkyl itaconate)s and poly(di n-alkyl itaconate)s are mainly syndiotactic polymers whereas poly(mono n-alkyl itaconate)s are obtained as almost atactic polymers. The characterization...
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