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When designing polymeric capacitors, it is important to understand the structure–property relationship between chemical functionalities and dielectric properties to tailor materials for specific applications in terms of dielectric constant, dielectric loss, band gap, breakdown strength, etc. Herein, we report a clear structure–property relationship with dielectric constant and dielectric loss in a...
The properties of composites prepared by melt compounding from graphite nanoplatelets (GNP) and pyromellitic anhydride modified poly(propylene carbonate) (PPC) were investigated. GNPs of different morphologies and acid residue levels were selected. Acid residues in GNP grades were detrimental for PPC in terms of thermal stability, stiffness and conservation of the molecular weight. The exfoliation...
Several polypropylene-g-polystyrene (PP-g-PS) and polypropylene-g-poly(n-butyl acrylate) (PP-g-PnBA) graft copolymers with well-defined molecular structures, basing on the same PP-Br precursor, were synthesized via a combination of metallocene-catalyzed polymerization and ATRP. The structure–property relationships of the resultant graft copolymers were systematically investigated. The crystallization...
The design of ω-amino-α-alkoxy-acetate as monomer enables to dramatically speed up the formation of polyamides catalyzed by the supported lipase B of Candida antarctica. Only 30 min are needed to reach 93% conversion whereas 240 h are necessary to observe the same level of conversion with a monomer devoided of an oxygen atom in position β relative to the electrophilic carbonyl group. Yields, Mn, Mw,...
Impact-resistance polypropylene copolymer (IPC) has been known as multiphase material in which ethylene–propylene rubber (EPR) is dispersed in homo-PP matrix (hPP). Although, the IPC has been commercially produced for several decades, the knowledge of its microstructural change under tensile stretch has not been well established. The present work, for the first time, shows the crystallite evolution...
Hierarchically ordered microstructures, self-assembled from copolymers, have drawn considerable attentions in the last decades. Study of hierarchical microstructure impacts many realms such as material engineering and biology science. In this article, notable recent advances in the fields of hierarchical polymeric microstructures generated in either bulk or selective solvents are highlighted, from...
Comprehensive dissipative particle dynamics simulations are performed to investigate the effect of A-block polydispersity on the phase behavior of AB-diblock copolymers. The experimental results of Lynd and Hillmyer on polydispersity induced domain spacing expansion at different segregations (Macromolecules 2005, 38, 8803) are well reproduced and explained in terms of interfacial free energy and molecular...
Liquid chromatography at the critical condition (LCCC) method has been proposed as an attractive method to characterize individual blocks in block copolymers because it can make one block chromatographically “invisible” at the critical condition of its corresponding homopolymer. However, observable dependence of retention time on the “invisible” block length was reported in LCCC experimental studies...
This study mainly aims at showing that the compatibilizing effect of organically modified nanoclay particles in 80/20 polyethylene (PE)/polyamide (PA) immiscible blends with nodular morphology, is strongly influenced by the rheological behavior and molecular characteristics of both polymers. Four PE/PA blend couples, based on two polyethylenes and two polyamides with different molecular characteristics...
Alkyl imidazolium-functionalized poly(ether ketone)s (Im-PEKs) were prepared as novel polymer membranes for O 2 /N 2 and CO 2 /N 2 separations. The Im-PEK polymers were synthesized by polycondensation between difluoro- and dihydroxy-monomers, followed by benzylic bromination and alkyl imidazolium-functionalization. The polymers with pendant imidazolium-based ionic salts...
Molecular dynamics simulations have been used to prepare semicrystalline samples of linear polyethylene (PE) using the anisotropic united atom (AUA4) model. The initial configurations of the simulations were obtained by controlled melting of the pure crystalline system and a unique re-connection method between chain segments in the intercrystalline regions. Systems containing two crystalline slabs...
We report the design and synthesis of a thermally-responsive dumbbell-shaped polymer based on one β-cyclodextrin (β-CD)-terminated polyethylene glycol (PEG) segment and several poly(N-isopropylacrylamide) (PNIPAM) segments through combining click reaction with atom transfer radical polymerization. Thermally-triggered self-assembly and molecular inclusion behaviors of the polymer were investigated...
The continuous epitaxial growth of vertically standing nanowalls of aromatic poly(azomethine), which consisted of hydroxyl-substituted aromatic dialdehydes and several aromatic diamines as building blocks, was achieved on a graphite substrate, using chemical liquid deposition in aqueous media. The vertical growth of poly(azomethine) nanowalls (ANWs) occurred on a graphite sheet, and they were arranged...
A series of binary copolymers, poly{2,5-bis[(4-octadecyloxyphenyl)oxycarbonyl]-styrene-co-2,5-bis[(4′-octadecyloxybiphenyl)oxycarbonyl]-styrene} (poly(M-OC18-co-M-C18)), were synthesized via free radical polymerization. The random nature of the copolymers was expected on the basis of the assumed similar reactivities because of the analogous monomers. A combination of differential scanning calorimetry...
A polymer sensor (P1) containing benzodiazaborole moieties for recognition of cyanide anion and sulfonate groups for water-solubility was synthesized by Suzuki cross-coupling polymerization, which enables cyanide detection in aqueous solution. The polymer showed visible fluorescence quenching upon exposure to cyanide anion concentrations as low as ∼2 μM. Selective detection of cyanide anions can be...
We demonstrate how the wear response of a polymer surface can be efficiently characterized by atomic force microscopy (AFM) using a spiral scan with a thermal tip. If the spiral is scanned at constant angular speed in the vicinity of the glass transition of the polymer, the corrugation of the modified surface is found to decay exponentially with the linear velocity v. This is attested by profiles...
The endothermic heat just above glass transition for the drawn poly(lactic acid)s (PLAs) films with four different d-isomer contents (1, 4, 10, and 20 mol%: named as PLA1, PLA4, PLA10, and PLA20) was observed on differential scanning calorimetry (DSC) heating scan. The amount of endothermic heat increases with increasing the draw ratio, which means that the endotherm is undoubtedly caused by stretching...
We report a procedure to fabricate antibacterial core/shell polymer nanoobjects with sheetlike, cylindrical, and spherical shapes. These shaped nanoobjects with chemically cross-linked polysiloxane cores and densely grafted polyammoniums shells were prepared by dispersing cross-linked microphase-separated materials of diblock copolymers, poly(2-(dimethylamino)ethyl methacrylate)-block-poly(3-(triethoxysilyl)propyl...
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