Preparation and properties of optically active polyurethane/TiO2 nanocomposites derived from optically pure 1,1′-binaphthyl

Zeraatpisheh²,

Sabzalian³

et al. 2011

Express Polym. Lett.

Abstract. A new chiral poly(ester-imide) (PEI) was prepared via direct polyesterification of N,N!-(pyromellitoyl)-bis-(L-tyrosine dimethyl ester) and N-trimellitylimido-L-methionine using tosyl chloride/pyridine/N,N!-dimethylformamide system as a condensing agent. The resulting new chiral polymer was obtained in good yield and had good thermal stability as well as good solubility in common organic solvents. After that, PEI/titanium bionanocomposites (PEI/TiO 2 BNCs) were prepared using the modified nanosized TiO 2 via sonochemical reaction that can accelerate hydrolysis, increase collision chance for the reactive system and improve the dispersion of the nanoparticles in polymer matrix. The scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results indicated that there is no aggregation of a large quantity of particles. Thermogravimetric analysis (TGA) confirmed that the heat stability of the BNC polymers in the temperature range of 400-800ºC was enhanced by addition of TiO 2 nanoparticles. Furthermore, in vitro toxicity test was employed for assessing the sensitivity of these compounds to microbial degradation. To this purpose, polymer and PEI/TiO 2 BNCs were investigated under soil burial conditions. The results of this study revealed that polymer and its BNCs are biologically active and non-toxic in the natural environment although some antimicrobial properties were found for BNCs.

Section: Thermal Propertiesmentioning

confidence: 99%

Section: Preparation Of Pei/tio 2 Bncs Throughmentioning

confidence: 99%

Sonochemical-assisted fabrication of biologically active chiral poly(ester-imide)/TiO2 bionanocomposites derived from L-methionine and L-tyrosine amino acids

Zeraatpisheh²,

Sabzalian³

et al. 2011

Express Polym. Lett.

“…The resulting PUs had specific head-to-tail structures and some regulated, higher order structures such as helical conformation because of its asymmetric carbon. A series of optically active PUs were prepared by Chen et al [233] from stepgrowth polymerization of chiral 1,1!-binaphthyl and TDI and the high-intensity ultrasonic was applied to the preparation of PU/TiO 2 nanocomposites. TGA studies indicated that thermal stability of the nanocomposites has improved with increasing nanoparticles content.…”

Section: Polyurethanesmentioning

confidence: 99%

Advances in synthetic optically active condensation polymers - A review

Zadehnazari²,

Iran³

2011

Express Polym. Lett.

Abstract. The study of optically active polymers is a very active research field, and these materials have exhibited a number of interesting properties. Much of the attention in chiral polymers results from the potential of these materials for several specialized utilizations that are chiral matrices for asymmetric synthesis, chiral stationary phases for the separation of racemic mixtures, synthetic molecular receptors and chiral liquid crystals for ferroelectric and nonlinear optical applications. Recently, highly efficient methodologies and catalysts have been developed to synthesize various kinds of optically active compounds. Some of them can be applied to chiral polymer synthesis. In a few synthetic approaches for optically active polymers, chiral monomer polymerization has essential advantages in applicability of monomer, apart from both asymmetric polymerization of achiral or prochiral monomers and enantioselective polymerization of a racemic monomer mixture. The following are the up to date successful approaches to the chiral synthetic polymers by condensation polymerization reaction of chiral monomers.

“…A technique for producing high refractive index nanocomposites and transparency in the fields of clear coatings, optical waveguides, and anti-reflection coatings for optical components was developed by incorporating premade inorganic colloidal particles into a polymer matrix. This method provides full synthetic control over the particle size, size distribution, and the surface properties of NPs [29][30][31]. Due to the high surface-area/particle-size ratio, there is a strong tendency for NPs to aggregate, therefore decreasing the resultant mechanical properties of the nanocomposite materials [32].…”

Section: Introductionmentioning

confidence: 99%

“…In order to improve homogeneous dispersion of NPs and better compatibility between the NPs and polymer matrix, many researches were focused upon the surface modification of NPs and the use of different coupling agents such as trialkoxy silanes was suggested. [29,30,37,42,43] The objective of this study is the efficient preparation of PUI/TiO 2 BNC using TiO 2 NPs modified by KH550 (with high refractive index, 2.5, in the crystal form of anatase and some small amount of rutile form), via ultrasonic irradiation process. The influence of interface structure on the thermal and the UV-vis absorber properties of the BNC are also discussed with the aid of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and UV-vis spectrometric instrument.…”

Section: Introductionmentioning

confidence: 99%

Exploration on structural morphology and properties of novel poly(urethane-imide)/TiO₂ bionanocomposites derived from L-tyrosine based diol

Designed Monomers and Polymers

2012

In this study, an optically active biodegradable poly(urethane-imide) (PUI) derived from Ltyrosine was synthesized. Since biopolyurethanes cannot be fully competitive with conventional thermoplastics and are sometimes too weak for practical use, these biopolymers have been formulated and associated with nano-sized fillers. For the preparation of PUI/titanium dioxide (TiO 2 ) bionanocomposites (BNC)s, the high-intensity ultrasound was applied. The PUI/TiO 2 BNCs were characterized by Fourier transform infrared spectroscopy, powder Xray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and UV-vis spectroscopy. The TEM and SEM results specified that the nanoparticles were dispersed homogeneously in PUI matrix on nanoscale. TGA/DSC confirmed that the heat stability of the novel BNCs was improved. UV-vis studies indicated that the resulting BNCs had high absorbance value than those values of pure PUI.