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Size control of the poly (1,4-phenylene-5-hydroxyisophthalamide) hollow spheres was examined by tuning the polymerization condition, focusing on concentration, temperature and solvent. Higher concentration lowered the diameter owing to the higher degree of super-saturation for nucleation. Temperature drop during the polymerization just before the nucleation was so effective to make the diameter smaller...
Disulfonated poly(arylene ether) and polyimide copolymers can phase separate to form nanoscale hydrophilic and hydrophobic domain morphology. Water in these domains has been assigned to three different states, tightly bound, loosely bound and free water. The states of water were characterized using DSC, NMR relaxation and TGA. The chemical structures of the proton exchange membranes were varied in...
Nascent powder particles of Ultra High Molecular Weight Polyethylene have been covered by multi-walled carbon nanotubes and then processed by means of sintering. The prelocalization of carbon nanotubes in the interfacial region between powder particles of UHMWPE allowed reaching an electrical percolation threshold as low as 0.04 wt%. It is also a possible way to reinforce specifically the interfacial...
A series of azo polyurethanes bearing push-pull type azo chromophores was synthesized by post-polymerization azo-coupling reactions between a polyurethane precursor and diazonium salts of different aniline derivatives, respectively. Colloidal spheres with narrow size distributions were obtained by aggregation of these azo polyurethanes in DMF-H2O mixed solvents, which were induced by slowly increasing...
Transition state analogue-built-polymer catalysts containing l-histidine, l-aspartic acid and l-serine moieties were synthesized using a racemic transition state analogue ‘phenyl-1-(N-benzyloxycarbonylamino)-2-(phenyl)ethyl phosphonate’ for the amidolysis of p-nitroanilide of N-(benzyloxycarbonyl)-phenylalanine, Z-L-Phe-PNA. The transition state analogue imprinted and non-imprinted polymer catalysts...
We present an approach to quantify different contributions to dissipation in elastomer nanoparticle composites based on strain sweeps. A modified Kraus equation is successfully used to approximate the loss modulus depending on strain amplitude G″γ measured at different temperatures. For natural rubber composites containing >10 vol% carbon black or >3 vol% carbon nanotubes two different contributions...
Facile preparation of tough hydrogels with excellent processability is of great practical importance, but it remains a great challenge. A novel type of hydrogen-bonded supramolecular PVA-glycerol gels is prepared with a very simple physical mixing method, in which glycerol molecules connect PVA chains into bundles by forming many H-bonds. The PVA-glycerol gels show much higher transparency than common...
We have investigated the wavelength dependence of the birefringence (Δn) for cellulose acetate propionate (CAP) films stretched at various draw ratios (DRs) and strain rates (SRs) by comparing with the result of cellulose triacetate (CTA). CAP exhibits extraordinary wavelength dispersion of Δn although CTA shows ordinary dispersion, indicating that Δn of CAP is determined by the acetyl and propionyl...
The full thermodynamic consistency claimed by Guenza and co-workers in their recent papers (J. McCarty et al., Macromolecules 45 (2012) 8482; A. J. Clark et al., Phys. Rev. Lett. 109 (2012) 168301; and A. J. Clark et al., J. Chem. Phys. 139 (2013) 124906), where they performed structure-based coarse graining of homopolymer melts using the polymer reference interaction site model theory, directly contradicts...
In contemporary research, there has been a surge in the efforts to design novel porous materials as adsorbents for CO2 capture. Polyamides are a class of robust polymers that are easy to synthesize from readily available starting materials. These have CO2-philic amide functional groups and hence are being considered as materials for CO2 adsorption and storage. Herein, we report facile and efficient...
Poly (l-lactide) (PLLA) is one of the most attractive polymers for use in biomedical applications. In such applications it is necessary to reduce the use of toxic chemicals and catalysts used in PLLA synthesis, to minimize any adverse effects. In view of this, we have performed ring opening polymerization (ROP) of l-lactide (LA) using biocompatible initiator, namely, Zinc l-Proline (ZnP) in bulk....
Poly(β-amino esters) and poly(amido amine) are important class of biodegradable polymers useful for biomedical applications. Synthesis of amphiphilic conetwork (APCN) gels and hydrogels of these polymers with controlled composition, degradation, and release behaviour is desirable. Herein, we report a strategy for the synthesis of multi-responsive APCN gels of poly(caprolactone) (PCL) and poly(β-amino...
A novel compound diethyl acetylphosphonate has been explored as efficient additive in iron based catalyst for stereo-polymerization of 1,3-butadiene to afford high crystalline 1,2-syndiotactic polybutadiene. Excellent 1,2 selectivity in range of 91.0–98.4% with controllable crystallinity has been achieved at high catalytic efficiency in wide ranges of cocatalyst and additive feeding as well as at...
Dynamic shear rheology study is conducted on the polyacrylonitirile (PAN) solution and composite solutions of PAN with up to 37.5 wt% annual plant lignin (APL) to address current barriers of PAN/lignin blend development as carbon fiber precursor. PAN/APL blends exhibit lower yield stresses, lower relaxation times, and lower viscosities than to PAN solution according to the dynamic frequency sweep...
The efficient formulation of layered gels that encompass both hydrophilic and hydrophobic domains could lead to novel materials with a range of vital functionalities. To facilitate the fabrication of these materials, we perform dissipative particle dynamics (DPD) simulations to model the formation of two-layered stackable gels where the gels are incompatible and their respective solvents are immiscible...
Unexpected tremendous effect of poly(acrylic acid) (PAA) as polydonor on the thermoresponsive behaviour of the comb-like poly(poly(ethylene glycol) methacrylate) (PPEGMA500) with short poly(ethylene glycol) (PEG) side chains as H-bond acceptor, both synthesized by atom transfer radical polymerization (ATRP), has been found indicating the formation of a unique class of interpolymer complexes between...
The relaxation behavior of a series of solvent free polyurethane model networks with variable cross-link density prepared based on different commercial diols and a diisocyanate containing component are studied by differential scanning calorimetry (DSC), dynamic-mechanical analysis (DMA) and dielectric relaxation spectroscopy (DRS). A systematic decrease of the calorimetric glass temperature Tg as...
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