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It is shown that the glass transition temperature T g of molecular (non-polymeric) glass formers correlates with molecular mass M as T g (M) ∝ M α , α = 0.51 ± 0.02. The subclasses of molecular glasses with homologous chemical structure but different M exhibit a similar universal correlation with significantly lower scatter. A possible explanation of T g vs M correlation...
Novel biobased trisphenols were obtained by palladium- and cobalt-catalyzed [2 + 2 + 2] cycloaddition of dehydroanethole isomers which were readily prepared from the natural product trans-anethole. The trisphenols were transformed into their corresponding tricyanate esters and thermally cured to give polycyanurate networks. Comparison of the thermal properties, from differential scanning calorimetry,...
The kinetics of formation of the Form II mesophase from the melt has been investigated as a function of the concentration of ethylene chain defects in isotactic random butene-1/ethylene copolymers, using standard and fast scanning chip calorimetry. Presence of ethylene co-units in the butene-1 chain leads to a distinct reduction of the melt – Form II phase transformation rate which has been quantified...
Segmented polyurethanes based on polytetramethylene glycol (PTMG) of 1000 g/mol were synthesized using a two-step polymerization procedure. Various hard segments were obtained using hexamethylene diisocyanate (HDI) or 4,4′-methylenebis(phenyl isocyanate) (MDI) as the diisocyanates and hydroquinone bis(2-hydroxyethyl)ether (HQEE) or triptycene-1,4-hydroquinone bis(2-hydroxyethyl)ether (TD) as the chain...
Piezoresistive properties of polydimethylsiloxane (PDMS) filled with copper particles in volume fraction above the electrical percolation threshold (25.3–50.7 vol%) were investigated. Piezoresistive behavior of the PDMS-copper composites under compressive pressure showed not only a change in resistance by approximately six orders of magnitude (∼1.5 MPa), but also a change in the critical pressure...
In previous work we successfully used a stable Dominican amber to investigate the sub-glass transition dynamics of an organic glass with extremely low fictive temperature. The results provided an incentive to seek other stable ambers with lower values of fictive temperature. In the present work, a series of fossil resins from different locations, and ages ranging from approximately 100 years–230 million...
The use of vibrational spectroscopy to investigate complex structural changes in polymers yields chemically rich data, but interpretation can be challenging and subtle but meaningful spectral changes may be missed through visual inspection alone. Multivariate analysis is an efficient approach to gain an oversight of small but systematic spectral differences anywhere within the spectra, providing further...
We show that the equilibrium Poisson ratio of electrically neutral gels depends on their shear modulus. When immersed in a good solvent, gels increase their volume on imposed external deformation, but stiffer gels swell less and exhibit a larger Poisson ratio, closer to 0.5, while the gels with a higher solvent content (and correspondingly lower shear modulus) approach a Poisson ratio of 0.25. We...
Silica nanoparticles possessing three different diameters (23, 74 and 170 nm) were used to modify a piperidine-cured epoxy polymer. Fracture tests were performed and values of the toughness increased steadily as the concentration of silica nanoparticles was increased. However, no significant effects of particle size were found on the measured value of toughness. The toughening mechanisms were identified...
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 solution behavior and morphology of the nanostructures formed by novel block copolymers based on 1-cetyl[2-(acryloyloxy)ethyl]dimethylammonium bromide (ADHA) and 2-hydroxyethylacrylate (HEA) or N-isopropylacrylamide (NIPAM) have been studied using small angle X-ray scattering (SAXS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). In these block copolymers the pADHA...
In the present work, the development of morphology and selective wetting of nanoclay and carbon nanotubes (CNTs) in rubber nanocomposites were characterized qualitatively by means of the optical microscopy, TEM and AFM and quantitatively by means of the wetting concept. Carboxylated hydrogenated nitrile butadiene rubber (XHNBR), ionic liquid and ethanol were used as dispersing agent and they show...
We prepared a side-chain phenol-functionalized poly(ether sulfone) (P1) from a one-pot reaction of a 4,4′-dihydroxybenzophenone (DHBP)-based poly(ether sulfone), poly(oxy-1,4-phenylenecarbonyl-1,4-phenyleneoxy-1,4-phenylene-sulfonyl-1,4-phenylene (DHBP-PES)), with 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and phenol in the presence of sulphuric acid. The phenol linkages of P1 act as...
Molecular dynamics simulations were used to study the high strain rate mechanical properties of a cross-linked epoxy system comprised of diglycidyl ether of bisphenol A (DGEBA) that is cross-linked by a poly(oxypropylene) diamine with three propylene oxide moieties per diamine. Atomistic network structures were characterized using volume-temperature behavior and their response to mechanical deformation...
Poly(l-lactic acid) (PLLA) and metal organic framework (MOF) composites were prepared by melt extrusion of PLLA with 5, 10 and 20% w/w of activated Cu 3 (BTC) 2 MOF. The morphology and stability of injection-molded samples were evaluated using thermogravimetric analysis, differential scanning calorimetry (DSC), gel permeation chromatography, X-ray diffraction, and scanning electron...
The development of the first star-structured poly(l-lactides) (s-PLLAs) with dual functionality as both nucleating agent and plasticizer in polylactide (PLA) blends is described. Mechanisms controlling this functionality are deduced. Blends of PLA containing s-PLLAs show significant improvements in thermal and mechanical properties. The s-PLLAs are made by using appropriate saccharides, e.g., methyl-α-d-glucopyranoside...
A series of phenolphthalein-based cardo poly(arylene ether sulfone) (PES) block copolymers containing pendant imidazolium group (PI-PESs) were synthesized as novel anion exchange membranes for direct methanol alkaline fuel cells. These PI-PESs combine the advantages of pendant anion conductors on the polymer side chains with the thermochemical stabilities of the imidazolium group, showing high hydroxide...
A supramolecular polymer gel formed between triptycene-based bis(crown ether) and copolymer containing dibenzylammonium (DBA) moieties by host–guest interactions was described. We demonstrated the formation of the supramolecular polymer networks between the bis(crown ether) and the copolymer by the 1 H NMR spectroscopy and solution viscometry, and we also obtained a colorless and transparent...
The kinetics of crystal nucleation of poly(L-lactic acid) (PLLA) has been analyzed by fast scanning chip calorimetry in a wide temperature range between 313 and 383 K, that is, between temperatures about 30 K below and 40 K above the glass transition temperature. The relaxed melt was rapidly cooled to the analysis temperature and subsequently aged between 10 −1 and 10 4 s, to permit...
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