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Importance of the ‘mixing scale’ of reagents is shown through deformation experiments under shear flow on a reactive crosslinked dispersed phase. The EVA dispersed phase in a PDMS matrix can be crosslinked by ester–ester exchange reaction. Tetrapropoxyorthosilicate (TPOS) is used as the crosslinking agent and dibutyltin oxide (DBTO) is used as the precursor. Notion of ‘droplet-reactors’ is defined...
The thermal, optical and electrochemical properties of trans-poly(1-ethynylpyrene) (trans-PEP) and cis-poly(1-ethynylpyrene) (cis-PEP) have been studied as a function of polymer backbone configuration and internal stacking. Absorption spectra of the polymers showed that trans-PEP possesses a higher degree of conjugation than its homologue, cis-PEP. Intramolecular interactions occur between adjacent...
Polyelectrolyte multilayer films were prepared via the layer-by-layer self-assembly using poly(diallydimethylammonium chloride) (PDADMAC) and pyrene labeled polyanions of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and N,N-dimethylacrylamide copolymers with different charge densities (AMPS mole fraction) F AMPS =0.20–0.999. Multilayer growth with alternating deposition from salt-free...
The formation of polymer-cyclodextrin inclusion compounds of polycarbonate (PC), poly(methylmethacrylate) (PMMA) and poly(vinylacetate) (PVAc) guests with host γ-cyclodextrin (γ-CD) have been successfully achieved. Coalesced bulk polymer samples were obtained by removal of γ-CD from their inclusion compounds (ICs). The chemical and crystalline structures of ICs and coalesced PC, PMMA and PVAc were...
Poly(l-lactic acid) (PLLA) has poor heat stability above its glass transition temperature (T g ∼60°C). To improve its softing above T g , PLLA was mixed with small amount of crosslinking agents and irradiated with various irradiation doses to introduce crosslinking between polymer chains. The most effective agent for radiation crosslinking was triallyl isocyanurate (TAIC). For melt-quenched...
Low molecular weight polyesters containing fluorescein units in their backbones were successfully synthesized. These fluorescent polymers showed a high solubility in most of the common organic solvents. The onset degradation temperatures of the polymers were greater than that of fluorescein. The glass transition temperatures were in the range 126–194°C. The bathochromic fluorescence emissions in organic...
The structure of polymeric gel membranes to be used as electrolytes in the recording of bioelectrical signals has been investigated by means of ATR–FTIR and 7 Li and 13 C MAS NMR spectroscopies. The membranes, based on PMMA, 1,2-diethoxyethane and lithium perchlorate, showed different ionic conductivity as a function of their composition. Such differences have been analyzed on the...
This is a second paper in the series concerning the synthesis and characterization of composite polymeric particles with encapsulated magnetic iron oxide and bearing reactive β-diketone groups on the surface. Composite particles have been prepared by two-step method in which first step requires preparation of the iron oxide nano-particles and during second step iron oxide was encapsulated into formed...
Glass-transition temperatures for three soft-contact-lens (SCL) materials are measured by modulated differential scanning calorimetry as a function of SCL hydration, as determined by thermogravimetric analysis. The SCL materials are: a conventional hydrogel (SofLens ® 38, polymacon) with a low water content at saturation; a conventional hydrogel (SofLens™ One Day, hilafilcon A) with a high...
We investigate the miscibility of acrylic polyhedral oligomeric silsesquioxanes (POSS) [characteristic size d≈2nm] and poly(methyl methacrylate)(PMMA) in order to determine the effect of well-dispersed POSS nanoparticles on the thermomechanical properties of PMMA. Two different acrylic POSS species (unmodified and hydrogenated) were blended separately with PMMA at volume fractions up to ϕ=0.30. Both...
Poly(methyl methacrylate) (PMMA) sheets were surface grafted with acrylamide under reduced pressure in a solvent free vapour of acrylamide and benzophenone. The grafting was initiated with UV irradiation and no pre-treatment of PMMA by impregnation or sorption of reactants was required. Characterization of grafted samples by ESCA and contact angles showed that the nitrogen content increased with grafting...
The photo-oxidative stability of polyamide 6,6 (PA 6,6) doped with a hindered amine light stabilizer (HALS) and a mixture of cupric chloride and potassium iodide was examined.Several analytical techniques were employed, in order to evaluate the correlation between chemical modifications, morphology and mechanical properties of PA 6,6 films irradiated at λ>300nm, 90°C, and 50% relative humidity...
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