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In this article, multiwalled carbon nanotubes (MWCNTs) with polymer shells based on cross-linked divinylbenzene (DVB) were controllably synthesized via direct in situ free-radical polymerization, thereby producing a hybrid composed of a core-shell microstructure and MWCNT center. The coated MWCNT hybrids (DVB@MWCNTs) were ultimately compounded with polystyrene (PS) to prepare nanodielectric composites...
We employed commercially available chip-calorimeter Flash DSC1 to investigate the low-temperature crystallization behaviors of random copolymer P(VDF-TrFE-CFE) (poly(vinylidenefluoride-trifluoroethylene-chlorofluoroethylene)), and compared them to the parallel results of P(VDF-TrFE). The resulted ferroelectric crystalline phases were identified by WAXD and FTIR. We found that, although our P(VDF-TrFE-CFE)...
Both silk fibroin (SF) and cellulose are considered as potential substitutes of synthetic polymers because of the problems for the exhaustion of fossil resources and the pollution of environment. In order to obtain a material that exhibits both the advantages of SF and cellulose, ionic liquid (IL) was introduced to prepare blend films of SF and cellulose in the present work. We found that by our new...
Dynamic mechanical analysis (DMA) was applied to investigate the correlation between dynamic mechanical behaviors of regenerated silk fibroin (RSF) and its structural transition which was characterized by near-infrared (NIR) spectroscopy. The tanδ peak split of DMA demonstrated that the apparent glass transition of amorphous RSF film (at around 177°C) was the contribution of both uncrystallizable...
An all-silk composite, in which uniaxially-aligned and continuous-typed Bombyx mori silk fibers were embedded in a matrix of silk protein (fibroin), was successfully prepared via a solution casting process. The structure, morphology, mechanical and thermal properties of such silk fiber/fibroin composites were investigated with X-ray diffraction, scanning electron microscopy, tensile and compression...
The thermally-induced conformational transitions of soybean protein films were studied as the films were heated under isothermal conditions in the range 40–100 °C. By comparing the kinetics of protein–water interactions as a function of temperature using time-resolved Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DTMA) measurements...
We present a novel method for calculating degradation kinetics in polymers. Our calculations directly use the dissociation energy of chemical bonds in a polymer chain to predict weight loss as a function of time and temperature in an Arrhenius-type activation function. The novelty lies in quantifying the thermal energy term for skeletal bonds in the chain backbone in the activation function that initiates...
A macroporous amphoteric membrane was successfully prepared by solution blending of a natural polymer chitosan (CS) and its derivative carboxymethylchitosan (CMCS). The adsorption of two model proteins (ovalbumin and lysozyme) with very different pI values on this CS/CMCS blend membrane was investigated in batch systems. The results showed that both proteins could be effectively adsorbed on the membrane,...
A natural amphoteric polyelectrolyte hydrogel film was prepared by solution blending of chitosan and its derivative carboxymethylchitosan, and cross-linked with glutaraldehyde. Under electric stimulus such a hydrogel quickly bends toward one electrode, showing an electrical sensitive behavior. Because of its amphoteric nature, the hydrogel bends either toward anode (pH≤7) or cathode (pH>7), depending...
Multiwalled carbon nanotubes (MWNTs) were functionalized with polyhedral oligomeric silsesquioxane (POSS) via amide linkages. The oxidized MWNT (MWNT–COOH) was converted to the acyl chloride-functionalized MWNT (MWNT–COCl) by treating them with thionyl chloride (SOCl 2 ), and then MWNT–COCl was reacted with aminopropylisooctyl-POSS to prepare aminopropylisooctyl polyhedral oligomeric silsesquioxane...
In this work, we show that simple dialysis of a poly(dl-lactic acid) (PLA) solution against water resulted in the spontaneous formation of PLA spheres. We observed initial formation of particles with irregular shape and large size, which then were disrupted into uniform and smooth nanospheres. Further, the formation process of PLA spheres was also investigated by dynamic light scattering technique...
Multiwalled carbon nanotubes (MWNT) were functionalized with amine groups using a ‘grafting to’ technique. The oxidized MWNT (MWNT–COOH) were converted to the acyl chloride functionalized MWNT (MWNT–COCl) by treating them with thionyl chloride (SOCl 2 ), and then MWNT–COCl was reacted with hexamethylenediamine to prepare MWNT–NH 2 . The formation of MWNT–NH 2 was confirmed...
The morphology of an incompatible polymer blend composed of poly(l-lactide) (PLLA) and poly(butylene succinate) (PBS) was examined by scanning and transmission electron microscopy, X-ray scattering, and X-ray photoelectron spectroscopy before and after the incorporation of an organoclay containing reactive functional groups, namely twice functionalized organoclay (TFC). TFC was prepared by treating...
A series of blend films of silk fibroin (SF) with nylon 66 were prepared by the common solution cast method. DSC analysis of every blend sample showed a large and broad endothermic peak around 150°C. For SF/nylon 66 samples containing 10 and 30wt% SF, large spherulites were observed and their melting processes were recorded using a polarizing microscope with hot-stage. Furthermore, a detailed study...
Monodisperse cross-linked polymer microspheres with carboxyl groups on their surface were prepared by means of emulsifier-free emulsion copolymerization. The characterizations by X-ray photoelectron spectroscopy and conductometric titration indicate that most carboxyl groups are located on the surface of microspheres. Their swelling degree or cross-linking degree has been investigated by an in situ...
Several different solvent systems are commonly used to dissolve Bombyx mori silk fibroin to prepare regenerated silk membranes and fibers though differences in the behavior of these solvents have not been fully investigated. Here we compare the effects of four of these on the rheology of silk fibroin solutions and on protein secondary structure as revealed by FTIR spectroscopy of cast membranes. The...
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