The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We report the synthesis and hydrogelation of star-shaped poly(l-lysine) modified with indole or phenyl group (s-PLL-g-Indo or s-PLL-g-Phenyl). The star-shaped graft copolypeptides were synthesized using readily available alcohols as the initiators to perform ring-opening polymerization (ROP) promoted by 1,1,3,3-tetramethylguanidine (TMG), followed by deprotection and side chain modification. The introduction...
Polypropylene has been oriented by solid-phase deformation processing to draw ratios up to ∼16, increasing tensile stiffness along the draw direction by factors up to 12. Nanoindentation of these materials showed that moduli obtained for indenter tip motion along the drawing direction (3) into to 1–2 plane (axial indentation) were up to 60% higher than for indenter tip motion along the 2 direction...
Functionalization of poly(vinylidene fluoride-co-hexafluoro propylene) (HFP) is made to prepared membrane for its application in fuel cell. The sulphonation of HFP membrane is carried out under control condition to maintain its stiffness and toughness of the membrane. The evidence of functionalization (sulphonation) is confirmed through different spectroscopic techniques such as NMR, FTIR, EDS mapping...
A major challenge in the gel science is to create mechanically strong hydrogels with anisotropic properties as observed in many biological tissues. Here, we report a simple one-step method of producing high-strength physical hydrogels exhibiting microstructural and mechanical anisotropy. As the precursor material, we use semicrystalline shape-memory hydrogels consisting of poly(N, N-dimethylacrylamide)...
Liquid crystalline physical gels (LCPGs) with stable mechanical properties and fast electro-optical response properties were prepared through the self-assembly of side chain liquid crystalline polymers (SCLCPs) with different spacer length poly [ω-4′-cyano-(1, 1′-biphenyl)] acrylate (PmACB, m is the spacer length of SCLCP, m = 0, 2, 4) as gelators in a nematic liquid crystal, 4-pentyl-4′-cyanobiphenyl...
To reveal the influence of graphene oxide (GO) on the mechanical properties of natural rubber (NR) crosslinked by different vulcanization systems, synchrotron radiation wide angle X-ray diffraction (WAXD) experiments were conducted to investigate the strain-induced crystallization (SIC) behaviors of the NR/GO nanocomposites. We found that the sulfur/accelerator (S/A) ratio in the vulcanization recipes...
In this paper, a time and resource efficient way of preparing porous carbon cathode for lithium-sulfur batteries with superior cycle stability has been demonstrated. In this simple work, we used commercially available polymer as carbon source and non-solvent mixture as porogen or pore former. The cathode has been fabricated by using polyacrylonitrile as base polymer via phase inversion route. By this...
Nanocomposites based on polypropylene have been prepared by in situ polymerization of propene in presence of mesoporous SBA-15 silica. Synthetic reactions were carried out with a zirconocene catalyst under either homogenous or supported conditions, the SBA-15 particles being used as carriers, and testing the immobilization of the catalytic system by several approaches. The existence of polypropylene...
Polyurethanes are known for their satisfactory mechanical strength, which is highly desired for various applications. Poly (ethyl formal disulfide)-based materials have excellent self-healing ability because of containing abundant exchangeable disulfide bonds, while their strength is relatively low (<0.8 MPa). Combining the advantages of the two materials, in this article, we synthesized self-healable...
Addition of a β-nucleating agent (β-NA) is the most effective method of preparing β-nucleated isotactic polypropylene (β-iPP); however, the poor dispersion and agglomeration of β-NAs limit nucleation efficiency. To solve this problem, a self-dispersing β-NA strategy was developed based on in situ preparation of β-NA (instead of pre-addition) during the processing of iPP. Zinc adipate (ZnAA), a typical...
To develop tissue engineering scaffolds that possess similar morphological structures to natural extracellular matrices (ECMs) is a major technological challenge. Herein, the feasibility of utilizing polycaprolactone (PCL) as biocompatible and biodegradable binding agent to fabricate electrospun three-dimensional (3D) scaffolds has been demonstrated. The obtained 3D scaffolds are soft while elastic,...
The glass transition temperature (Tg) breadth of gradient copolymers can be dramatically increased by covalent attachment of homopolymer (or random copolymer heavy in one comonomer) leading to block-gradient copolymers or by blending with oligomer. Styrene/n-butyl acrylate (S/nBA) and styrene/4-vinyl pyridine (S/4VP) gradient and block-gradient copolymers were synthesized by one-pot, semi-batch nitroxide-mediated...
In the present research, the complete dissolution of carrageenan was realized by using NaOH aqueous solution and the corresponding mechanism was successfully revealed. The properties of carrageenan solution prepared in NaOH aqueous solution were comprehensively studied by gel temperature, differential scanning calorimetry and dynamic light scattering. The intra- and intermolecular interactions of...
A more efficient route for the synthesis of phosphonated dimethyl isophthalate, disodium salt is shown to provide a significantly higher yield (42%), in contrast to a previously reported yield (15%). This higher yield enabled the synthesis of phosphonated poly(ethylene terephthalate) (PPET) ionomers using conventional melt polycondensation with ethylene glycol and dimethyl terephthalate. The physical...
To achieve high-performance thermosets from renewable resources, six acetovanillone-derived poly(aryl ether)s (two with the acetic moiety, two with the phenyl methacrylic moiety, and two with the vinyl benzyl ether moiety) were prepared. The poly(aryl ether)s with acetic- or phenyl methacrylic moiety were applied as epoxy curing agents to cure with a phenol-dicyclopentadiene epoxy resin (HP7200)....
Self-healing materials offer the ability to repair cracks within a polymeric material of molecular, micro- and macroscopic scale. The previously reported polyurethane urea (PUU) polymer with a high number of associative hydrogen bonding moieties was prepared containing 1-(2-aminoethyl) imidazolidone (UDETA). This chain terminating molecule defines the network density of the polymer and the affinity...
To develop membrane materials for gas separation, a series of semi-alicyclic polyimides was synthesized using one-step thermal solution imidization from an alicyclic dianhydride with non-planar twisted structure, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA). All synthesized polyimides exhibited amorphous structures and superior thermal stability, with high...
New polyclathrochelate derivatives were obtained using the mild one-step polycondensation reaction of an iron(II) center chelated to three polar furil dioxime side groups and doubly capped with various aryl diborate central spacers. Nitrogen adsorption measurements of the polychlathrochelates (PCL1-4) reveal a strong correlation between the intrinsic microporosity and the nature of aryl diborate spacer...
Herein we report a two-step tandem synthesis of hyper-cross-linking hollow microporous organic nanospheres (H-MONs) based on incorporation of reversible addition-fragmentation chain transfer (RAFT) polymerization and in-situ hyper-cross-linking self-assembly process in one-pot. The synthesized polylactide-b-polystyrene (PLA-b-PS) diblock copolymers and unreacted styrene (S) monomers, without further...
In this work, we have systematically studied the miscibility and phase structure of a hydrogen-bonded polymer blend composed of short rigid poly(N-acryloyl piperidine) (PAP) and long flexible poly(acrylic acid) (PAA). Ultrathin PAP/PAA blend films with various compositions were prepared by solution-casting method. It was found that the spin-coated blend films had distinct surface features with many...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.