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We present the synthesis and characterization of zwitterionic homopolymers and copolymers based on poly(2-vinyl pyridine) (P2VP). Different molar masses as well as copolymer compositions of poly(styrene-co-2-vinyl pyridine) (P(2VP-co-S) were synthesized using RAFT (reversible addition fragmentation chain transfer) polymerization, followed by quaternization of the nitrogen atom by either 1,3-propanesultone...
Monodisperse linear and 3-arm star polyisoprene (PI) melts were investigated under dynamic oscillatory shear flow. Master curves of linear rheological properties, G′ (ω) and G″ (ω), obtained by small amplitude oscillatory shear (SAOS) testing and nonlinear rheological properties, Q0 (ω), obtained by medium amplitude oscillatory shear (MAOS) testing, were created using the same shift factors by applying...
The paper is concerned with the experimental investigations of soft solids rheology at the onset of the fluid behavior. The aim of the work is to find the correlation between the dynamics moduli measured in MAOS and LAOS oscillatory regime and the data obtained in simple shear experiments. The tested samples are represented by colloidal systems and suspensions (impression material and a cosmetic cream),...
Using Fourier transform rheology the Giesekus, exponential Phan-Tien and Tanner, and modified eXtended Pom-Pom constitutive models were examined in the non-linear regime represented by large amplitude oscillatory shear (LAOS) measurements. For the experiments a 5 wt% solution of poly(ethylene oxide) (molecular weight 1000 kg/mol) solved in dimethyl sulfoxide was used. The minimal number of harmonics...
The properties of polymer nanocomposites depend strongly on how well nanoparticles are dispersed. However, the hydrophobic nature and low polarity of PE have made effective dispersion of nano-filler difficult without compatibilization. We have found improved dispersion of chemically functionalized graphene oxide (FGO) in PE. The hydroxyl and epoxide groups on graphene oxide (GO) are sites for grafting...
Poly(ε-caprolactone) (PCL) and poly (vinyl chloride) (PVC) are miscible with each other, and their glass transition temperatures differ a lot. With this feature, we tried to design a triple-shape memory material by simply blending them together. After carefully examining the glass transition broadness and the tensile behavior of various PCL/PVC blends, PCL-30% (the weight fraction of PCL was 30%)...
We developed a novel Hierarchical Multi-mode Molecular Stress Function (HMMSF) model for polydisperse polymer melts, which implements the basic ideas of (i) hierarchical relaxation, (ii) dynamic dilution, and (iii) interchain tube pressure. Here, the capability of this approach is demonstrated by comparison of predictions of the HMMSF model with uniaxial extensional viscosity data of sixteen different...
Here two particular formulations [M.H. Wagner, S. Kheirandish, O. Hassager, Journal of Rheology 49 (6) (2005) 1317–1327; H.K. Rasmussen, Q. Huang, Rheologica Acta 53 (3) (2014) 199–208; G. Marrucci, G. Ianniruberto, Macromolecules 37 (10) (2004) 3934–3942] of the ‘interchain pressure’ [39], incorporated into the molecular stress function method [M.H. Wagner, S. Kheirandish, O. Hassager, Journal of...
An advanced analytic method, based mainly on thermorheological analysis of standard frequency sweeps at several temperatures, is introduced which can determine a host of rheological indicators for long-chain branched polyethylenes and other materials with an Arrhenius-type temperature dependence. The method can be used to classify and categorize unknown samples to material types (tubular and autoclave...
We develop an approach for quantifying cure that applies thermodynamic modelling to interpret DSC data that is consistent with solid state NMR. The effect of elements of monomer geometry, such as the angle between functional groups and the distance between them, on curing of epoxy-amine thermosets is explored experimentally using this new technique. The effect of the angle between functional groups...
The development of a high sensitivity polymer melt extrusion flow instability detection die capable of estimating the normal stress differences of polymer melts during capillary rheometry tests via the ’hole effect’ is presented here as proof-of-principle. Two polymer melts, a low density polyethylene (branched topology) and a high density polyethylene (linear topology), were tested in a variety of...
Epoxy resin nanocomposites containing graphite nanosheets (GNS) and unsaturated polyester resin (UPR) were prepared by incorporating GNS in semi interpenetrating network (semi-IPN) of epoxy resin and unsaturated polyester resin (E-UPR). GNS are prepared by thermal shock treatment of sulphuric acid-graphite intercalation compound (GIC) followed by ultra-sonication. The E-UPR-GNS semi-IPNs were further...
The bead to bead-free fibers transition for electrospun filaments was investigated for well-defined linear and comb homopolymers. A series of monodisperse model comb structures with well-defined backbone and side chains was synthesized using anionic polymerization of polystyrene (PS). All model combs had the same backbone and a similar total molecular weight. The length and number of branches was...
New polyampholyte linear polymers and hydrogels based on N-acryloyl-N′-ethyl piperazine (AcrNEP) and maleic acid (MaA) were prepared by free-radical solution polymerization. The microstructure of copolymers was statistically estimated by the terminal copolymerization model. A maximum tendency (80%) of alternating sequence of monomers units occurred at about 85 mol % of AcrNEP in the reaction feed...
Previously, we explored the dynamics of a dilute suspension of rigid dumbbells as a model for polymeric liquids in large-amplitude oscillatory shear (LAOS) flow. We derived the expression for the polymer orientation distribution, and then we decomposed this function into its first five harmonics (the zeroth, first, second, third and fourth harmonics). In this work, we separate each harmonic into its...
The macroscopic alignment of conjugated polymers with low grain boundary is essential to carrier transport. We investigated the formation mechanism of the aligned films of the donor−acceptor copolymer of 3,6-bis(thiophen-2-yl)-N,N′-bis(2-octyl-1-dodecyl)-1,4-dioxo-pyrrolo [3,4-c]pyrrole and thieno- [3,2-b]thiophene (PDBT-TT) by solvent vapor enhanced drop-casting (SVE DC). The dichroic ratio (DR)...
The synthesis of low surface energy polymer grafted silica nanoparticles is reported for the utilization as highly efficient cell nucleation agents to obtain nanocellular, CO2 blown polystyrene (PS) and poly(methyl methacrylate) (PMMA) films in a batch process. For nanoparticle surface functionalization hydroxyl-terminated perfluoropolyether and poly(dimethylsiloxane) (PDMS) were used. Their successful...
Two solution reactors in series are utilized to synthesize poly(ethylene-cb-propylene) comb block copolymers, P(E-cb-P), where the first reactor prepares vinyl terminated atactic polypropylene (aPP) macromers from propylene using an organometallic catalyst favoring beta methyl elimination and the second reactor copolymerizes aPP macromers with ethylene using a different organometallic catalyst capable...
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