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The self-assembled microstructures of the bottlebrush polymers in aqueous solution are investigated by dissipative particle dynamic simulation. A series of structures, such as cylinder, sphere, lamella, perforated lamella, and network, are obtained from the solutions at various concentrations. These structures are arranged into several phase diagrams constructed by the main and side chains in various...
A series of poly(l-lactide) stereocopolymers with various optical purities (100%–88%) were synthesized by ring-opening copolymerization of the enantiomeric feedstock mixtures of l-lactide and D-lactide at 140 °C for 16 h under reduced pressure. The obtained relationship between microstructure and optical composition of poly(l-lactide) (PLLA) copolymers confirmed that the stannous octoate-catalyzed...
In this work, the combined effects of polydispersity and viscosity on microstructure that evolves with domain coarsening and crystallization are investigated in the blends of amorphous solution polymerized styrene-butadiene rubber (SSBR) and crystalline trans-1,4-polyisoprene (TPI). We find that the bicontinuous patterns in SSBR/TPI undergo a complicated coarsening process and evolve to microstructures...
Effect of degree of sulfonation on dynamic mechanical properties, dehydration rate, crystallinity, thermal stability and other fuel cell properties (e.g. proton conductivity, ion exchange capacity, water uptake capacity, etc.) of SPEEK membrane are studied and correlated with microstructure. With increasing degree of sulfonation (DS), α-relaxation peak shifts from 135 to 166 °C, while β-relaxation...
Polymer chain structural factors, like chain microstructure, comonomer content in copolymer, dyad sequence distribution, molecular weight (MW) and molecular weight distribution (MWD), etc. have a great influence on the properties and applications of polymer materials. In this paper, chain structural factors and thermal behaviors of novel trans-1,4-poly (isoprene-co-butadiene) copolymers (TBIR-15,...
The well-defined anionic polymerization of (E)-1,3-pentadiene (EP) using various RLi initiators in nonpolar solvent was studied. The results of the polymerization kinetics with n-BuLi initiator in cyclohexane confirmed the expected living nature of the anionic polymerization of EP. An apparent activation energy of 86.17 ± 2.93 kJ/mol has been achieved for the poorly reactive EP polymerization, while...
Poly(phenylsilsesquioxanes) of regular ladder like structure were synthesized by condensation of [PhSi(O)OH]4 obtained in situ from sodium cyclosiloxanolate {(Na+)4[PhSi(O)O−]4} nL (L = iPrOH, H2O). The composition of oligomers present in the reaction mixture was analysed with MALDI ToF during the course of polycondensation. Redistribution of siloxane bonds and cyclization of macromolecules were detected...
An ever-increasing demand for novel hydrogels for smarter applications necessitates careful investigation of their swelling–deswelling behavior. In the present work, poly(N-isopropylacrylamide) (PNIPA) hydrogels were prepared at different temperatures. Hydrogels prepared below 25 °C were transparent and homogeneous whereas those prepared above 25 °C were slightly hazy to opaque. Scanning electron...
It is the dual nature of chain shuttling polymerization (CSP) that makes control of olefin block copolymer (OBC) composition difficult and difficult, but at the same time, stimulating. Although recent investigations on OBCs brought some insights to the kinetics and microstructure of block copolymers differentiating from ethylene and α-olefins, some crucial features of these systems are not uncovered...
The modulatory effect of oligoguluronate (GB) on the gelation of macromolecular alginate (ALG) was investigated by means of dynamic oscillatory rheology, fluorescence and AFM measurements. An inhibitory effect in the range of 0.25 < R (Ca/G) < 0.60 and a promotive effect in the range of R > 0.60, were quantified. The two effects are thought to be associated with the different molecular events...
Chemical reactions occurring during reactive melt mixing of equimolar blend of poly(bisphenol-A carbonate) and poly(ethylene 2,6-naphthalate) at 280 °C in presence of a catalyst, were studied. Beside expected direct “inner–inner” ester-carbonate and outer–inner exchange reactions, consecutive reactions that lead to the elimination of CO2 and ethylene carbonate from backbone, were also detected. The...
The fluorinated polyimides with high fractional free volume were prepared from 6FDA and aromatic diamines with bulky triptycene and pendent phenyl moieties. These polymers showed excellent solubility, high thermal stabilities and outstanding mechanical properties. The correlation of gas separation performance with the microstructure of these polyimide membranes was investigated. The results indicated...
At present, polylactide (PLA) film with high toughness is on expectation, but in general, it is brittle with 45 MPa tensile strength and only 3% elongation at break. The present work clarifies that isotropically small crystalline lamellae is the key microstructure to obtain super-tough PLA (180 MPa tensile strength and 80% elongation at break). The systematic study on two parameters of biaxial-stretching...
Polyurethane (PU) exhibit very high electromechanical activity, and has a great interest for a wide range of transducer and actuator applications. It has been recently pointed out that this strong electrostriction may result from the phase separation. In the present work, a model taking account the PU nanostructure is presented. In order to validate this model, three PUs of similar compositions but...
A new strategy to generate nanofibrous composite constructs with a controlled internal 3D microstructure is proposed. The process exploits the cooperative effect of electric field and charges occurring when electrospinning and electrospraying are carried out alternately on a micropatterned collector. Experiments and numerical simulations show that the nanofibers form a perfect electrostatic template...
In-situ wide-angle X-ray scattering technique was used to investigate the microstructural changes of polyacrylonitrile (PAN) based fibers with the macroscopic fiber strain. Crystalline phase, transition layer, and amorphous matrix were found coexistence in the PANFs. Tensile deformation induced the PAN-chain transformation from amorphous matrix to crystalline region through the transition layer. After...
One of the most promising aspects of the anodic aluminium oxide (AAO) template is the ability to generate a variety of different hierarchical one-dimensional (1D) polymer morphologies with structural definition on the nanometric scale. In-situ polymerization of monomers in reduced space of porous AAO template nanocavities can give rise to the direct production of versatile polymer nanostructures....
The influences of free volume and temperature on the viscoelastic properties of polycarbonate (PC)/multi-walled carbon nanotube (MWNT) composites were investigated by positron annihilation lifetime spectroscopy (PALS) and dynamic mechanical analysis (DMA). Three methods, including PALS, DMA and differential scanning calorimetry were used to determine the glass transition temperature (T g )...
A predictive multiscale computational framework has been proposed to study the viscoelastic properties of polymeric materials. Using the Inverse Boltzmann Method, both the static structures and dynamic behavior of all-atomistic models of polymers can be reproduced by a simple coarse-grained model, which bridges the scale from nano to meso. On this coarse-grained level, the entangled network of polymer...
The dependence of the fluorescence quenching of electropolymerized poly(aniline-co-m-chloroaniline) with polymer composition has been investigated. Fluorescence emission in polyaniline is quenched when the polymer is oxidized (brought to emeraldine state); the copolymers exhibit decreasing quenching as chloroaniline contents increases. Quenching shows a strong decrease in the presence of 0.1% m-chloroaniline...
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