Monodisperse comb polystyrenes (comb-PS) with loosely to densely grafted architectures up bottlebrush structures were synthesized via anionic polymerization. This comb-PS series, named PS290-Nbr-44, had the same entangled backbone, Mw,bb = 290 kg/mol, corresponding a number of entanglements along backbone Zbb ≅ 20, and similar branch length, Mw,br 44 kg/mol or Zbr 3, but varied in branches per molecule, Nbr, from 3 190 branches. Consequently, average between two consecutive points (branch...

Linear mono- and polydisperse homopolymer melts have been investigated with Fourier transformation rheology (FT rheology) to quantify their nonlinear behavior under oscillatory shear via mechanical higher harmonics, i.e., I3/1(ω,γ0). Master curves of the zero-strain nonlinearity, 3Q0(ω) ≡ limγ0→0 I3/1/γ02, created for these linear melts, applying time–temperature superposition (TTS) principle. The quantity is examined its dependence on molecular weight, weight distribution, monomer. master...

The polymerization shrinkage of methacrylate-based composites is among the most important causes failure composite restorations. manufacturers claim that bulk-fill have a lower than conventional composites. This study aimed to assess five in comparison with composite.In this in-vitro experimental study, discs (n=30) were fabricated using everX Posterior (EXP), Filtek Bulk-Fill (FBP), SonicFill 2 (SF2), Tetric N-Ceram (TNB), X-tra fil (XF), and Z250 at center metal ring bonded microscope...

Due to their unique rheological and mechanical properties, bottlebrush polymers are inimitable components of biological synthetic systems such as cartilage ultrasoft elastomers. However, while properties can be precisely controlled through macromolecular structures, the current chemical spectrum available is limited a handful with aliphatic carbon backbones. Herein we design synthesize series inorganic based on combination polydimethylsiloxane (PDMS) polyphosphazene (PPz) chemistry. This...

The linear and nonlinear oscillatory shear, extensional combined rheology-dielectric spectroscopy of hybrid polymer nanocomposites for semiconductive applications were investigated in this study. main focus was the influence processing conditions on percolated poly(ethylene-butyl acrylate) (EBA) nanocomposite hybrids containing graphite nanoplatelets (GnP) carbon black (CB). rheological response samples interpreted terms dispersion properties, filler distortion from processing, percolation,...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Mahdi Abbasi, Nadereh Golshan Ebrahimi, Manfred Wilhelm; Investigation of the rheological behavior industrial tubular autoclave LDPEs under SAOS, LAOS, transient shear, elongational flows compared with predictions from MSF theory. J. Rheol. 1 November 2013; 57 (6): 1693–1714. https://doi.org/10.1122/1.4824364...

The foaming structure and rheological properties of four different isotactic homo-polypropylenes with various molecular weights an long chain branched polypropylene were investigated to find a suitable fingerprint for PP foams. weight distribution thermal measured using GPC-MALLS differential scanning calorimetry, respectively. Small amplitude oscillatory shear data uniaxial extensional experiments analyzed the frameworks van Gurp-Palmen plot (δ vs. | G*|) stress function model, These...

Strain hardening of long-chain branched polymers in elongational flow occurs due to the stretch backbone chain between branch points. With an increasing number side arms, length segment two points a comb decreases. Of particular interest is case when Nb arms per entanglement polymer larger than one. This leads not only strain but also hyperstretching, i.e., stress growth shows enhanced increase with strain. We consider data reported by Abbasi et al. [Macromolecules 50(15), 5964–5977 (2017)]...

Well-defined three-arm and four-arm star polymers designed via a Z-group approach carrying trithiocarbonate functionalities at the core are prepared reversible addition-fragmentation chain transfer (RAFT) polymerization featuring molecular weights of Mn,SEC = 156 kDa, Đ 1.16 (3-arm) 162 1.15 (4-arm) based on multi-angle laser light scattering (MALLS) detection, respectively. The star-shaped polystyrenes subjected (in bulk) to thermal stress in temperature range between 140 200 °C from 10...

Functional modular ATRP polymers suffer from accelerated ester cleavage due to HBr release as well the formation of triazolium salts <italic>via</italic> reaction triazole units with bromine terminal chain ends under thermal and thermomechanical insult.

Abstract The influence of topology on the strain hardening in uniaxial elongation is investigated using monodisperse comb and dendrigraft model polystyrenes (PS) synthesized via living anionic polymerization. A backbone with a molecular weight M w,bb = 310 kg mol −1 used for all materials, while number 100 short (SCB, w,scb 15 ) or long chain branches (LCB, w,lcb 40 are grafted onto backbone. LCB serves as precursor dendrigraft‐type branch‐on‐branch (bob) structures to add second generation...

SummaryThe activity of some essential oils against the common citrus moulds, Penicillium digitatum and P. italicum, was evaluated through in vitro vivo experiments. Direct contact vapour phase methods were used to test anti-fungal activities four oils. Thyme clove inhibited growth italicum completely when added culture medium at 600 µl l−1, or by using their volatiles 24 per 8 cm-diameter Petri dish. Sage fennel did not show any inhibitory either fungus. In experiments, direct thyme oil 200,...

The transient shear and extensional properties of ethylene vinyl acetate nanocomposites containing two geometrically different nanoparticles (spheres CaCO3 platelet clay) were investigated experimentally the data compared to rheological predictions modified molecular stress function (MSF) theory as recently proposed by Abbasi et al. [Rheol. Acta 51, 163–177 (2012)]. While good agreement was obtained for spherical particles, deviations observed particles at concentrations higher than 2.5 wt....

Different carbon-based fillers such as carbon nanotubes (CNTs), graphite, and thermally reduced graphene oxide (TrGO) are melt mixed with an isotactic poly(propylene) (iPP) the mechanical properties of resulting composites in solid state analyzed. The Young's modulus is increased around 25% relative to neat iPP at concentrations above 10 wt% CNTs or graphite whereas TrGO 40% similar concentrations. These results compared theoretical models showing that filler agglomeration surface area key...

Medium amplitude oscillatory shear (MAOS) in combination with Fourier Transformation of the mechanical stress signal (FT rheology) was utilized to investigate influence molecular weight, weight distribution and monomer on intrinsic nonlinearity 3Q0(ω). Nonlinear master curves 3Q0(ω) have been created, applying time-temperature superposition (TTS) principle. These showed a characteristic shape an increasing slope at small frequencies, maximum 3Q0,max decreasing high frequencies. 3Q0(De)...

The study investigates the thermal stability of ligation points resulting from photochemically induced Diels–Alder reactions within soft matter materials on molecular level.