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This article reviews our understanding of ionization processes of weak polyelectrolytes. The emphasis is put on a general introduction to site binding models, which are able to account for many experimental features of linear and branched polyelectrolytes, including dendrimers. These models are fully compatible with the classical description of acid–base equilibria. The review further discusses the...
The miscibility of the dicyanate of bisphenol A, with three dicyanate monomers, with aryl/alkylene ether backbones is studied at different compositions of a binary blend. Solubility parameters are calculated for dicyanate monomers and selected oligomers using the methods of Small and Fedors to predict compatibility. The results are evaluated in terms of the accuracy of the model in reproducing observed...
Random side-chain functionalized copolymers were synthesized, utilizing a facile Yamamoto protocol by applying 2,7-dibromo-9,9-bis(6-bromohexyl)-9H-fluorene, (E)-1,2-bis(4-bromophenyl)ethene, 2,7-dibromo-9,9-dioctyl-9H-fluorene as comonomers. The precursor copolymers were post-functionalized utilizing di-n-propylamine and the resulting target copolymers were fully characterized. The optical classification...
New macromolecular self-assembling building blocks, star polypeptide-b-polyhedral oligomeric silsesquioxane (POSS) copolymers, were synthesized from octa-azido functionalized POSS (OVBN 3 -POSS) with alkyne-poly(γ-benzyl-l-glutamate) (alkyne-PBLG) via a click reaction. The incorporation of POSS units at the core of PBLG moieties plays an important role, allowing intramolecular hydrogen bonding...
The morphological structures of slowly cooled blends of deuterated metallocene-catalyzed octene linear low-density polyethylene (O-mLLDPE(D)), and hydrogenous low-density polyethylene (LDPE(H)) were studied by using small angle neutron scattering in combination with complementary small angle X-ray scattering and differential scanning calorimetry. The phase segregation, which is more nanoscale than...
Poly(methyl methacrylate) -functionalized graphene (MG) is prepared from graphene oxide (GO), using atom transfer radical polymerization (ATRP) and reducing with hydrazine hydrate. PMMA causes an increase of height of MG sheet for polymerization of MMA at side and basal planes. MG layers become thinner for exfoliation during composite formation. Graphene sheets enhance piezoelectric β-polymorph PVDF...
Water and salt transport properties were determined in a family of sulfonated pentablock copolymers to characterize their potential as chlorine-tolerant desalination membrane materials. The degree of sulfonation, block molecular weight, and casting conditions can be independently varied to tune the transport properties of these materials. Data for water uptake, water permeability, salt permeability,...
Morphology of undeformed polyethylene crystals obtained by high pressure crystallization was investigated by SEM. It was revealed by exposing the interior of the samples by microtoming followed by permanganic etching. The etching procedure was refined to reveal defected sites of lamellae in addition to differentiation of crystalline and amorphous phases. From 1 to 3 screw dislocations with large Burgers...
Pure gas permeability coefficients of a series of copolymers based on polar, hydrophilic poly(ethylene glycol) dimethacrylate, n = 14 (PEGDMA) and siloxane-based co-monomer, [methyl bis(trimethylsiloxy)silyl] propyl glycerol methacrylate (SiGMA) are reported. SiGMA is miscible with PEGDMA and able to form homogeneous films. SiGMA contains a bulky siloxane-based end group, which acts to increase permeability,...
A processing method using high speed mixing was developed for the generation of nanocomposites comprised of α,ω-dihydroxy-polydimethylsiloxane (PDMS) and untreated fumed silica nanoparticles (U-FSN). Conventional condensation cure with poly(diethoxysiloxane) (PDES) was employed so as to generate PDMS/FSN nanocomposites with increasing weight fractions of siliceous domain. This study focuses on the...
Brill transition and crystallization behaviour of nylon 56, a representative polymer of odd–even polyamides, were investigated by simultaneous WAXD and SAXS synchrotron radiation. Nylon 56 crystallized from solution into a peculiar structure where hydrogen bonds were established along the two directions. Nylon 56 experimented on heating a Brill transition that lead to a pseudohexagonal packing and...
Polyfluorene based precursor polymers were synthesized either by Yamamoto type or Suzuki polycondensation. These polymers were then converted to the corresponding conjugated polycations by treatment with trifluoroacetic acid. The formation of the conjugated polycations were followed by UV–vis and characterized by 1 H NMR. The absorption maxima of the polycations fall in the range of 580–690 nm...
A new approach has been developed to enhance the processability of main-chain benzoxazine polymers by synthesizing benzoxazine main-chain oligomers that are low in viscosity while maintaining the major part of the advantages of main-chain type polybenzoxazines. A series of main-chain benzoxazine oligomers have been synthesized using bisphenol-F isomers. The structure of the oligomers has been characterized...
This paper describes a convenient one-pot terpolymerization of CO 2 , cyclohexene oxide (CHO) and maleic anhydride (MAH) to afford a poly (ester-carbonate) with a low content of ether units (2.9–4.3 mol%) using a highly active Zn–Co(III) double metal cyanide complex (DMCC) catalyst. Terpolymerization was carried out in tetrahydrofuran (THF) at 75–90 °C and 1.0–4.0 MPa and no cyclic carbonate...
Polyimide-silica membranes are interesting hybrid architectures that possess excellent mechanical, thermal and chemical properties. However, the dispersion of inorganic domains in the polymer matrix and the compatibility between the organic and inorganic phases are critical factors in these hybrid systems, due to the lack of favorable interactions between the hydrophobic polymer and hydrophilic silica...
Randomly branched (arborescent) poly(sodium 2-acrylamido-2-methyl-N-propanesulfonates) (NaPAMPS) were synthesized via self-condensing vinyl polymerization using activators generated by electron transfer atom transfer radical polymerization (AGET ATRP). The controlled self-condensing AGET ATRP of NaAMPS was realized in the presence of 2-(2-bromopropionyloxy)ethyl acrylate (BPEA) as a branching monomer...
The effect of nanoscale surface morphology of pure-silica MFI zeolite on the interfacial, mechanical, and thermal properties of pure-silica MFI zeolite/poly(vinyl acetate) (PVAc) composites was investigated under different annealing conditions. Mg(OH) 2 inorganic whisker- or asperity-like nanostructures were achieved on MFI nano- and micro-particle surfaces via Grignard or solvothermal treatment...
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