Papers by Keyword: Polymer Blend

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Authors: Naznin Sultana, Min Wang
Abstract: Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) was used to make composite scaffolds for bone tissue engineering in our previous studies. To control the degradation rate and process of composite scaffolds, PHBV was blended with poly(L-lactic acid) (PLLA), which has a much higher degradation rate than PHBV, and PHBV/PLLA blends were used as polymer matrices for composite scaffolds. Composite scaffolds based on these blends and containing nano-sized hydroxyapatite (nHA) were fabricated using an emulsion freezing / freeze-drying technique. Non-porous films of PHBV/PLLA blends were prepared using the solvent casting method. In vitro degradation tests of non-porous PHBV/PLLA blends and porous composite scaffolds were conducted by immersing samples in phosphate buffered saline (PBS) for various periods of time. It was found that the composition of polymer blends affected water uptake of films and scaffolds. For PHBV/PLLA-based scaffolds, the incorporated nHA particles also significantly increased water uptake within the initial immersion time. Both PHBV/PLLA blends and composite scaffolds underwent rapid weight losses within the first few weeks. The degradation of composite scaffolds arose from the dissolution of nHA particles and degradation of the PLLA component of polymer blends. Composite scaffolds exhibited enhanced adsorption of bovine serum albumin (BSA), a model protein, in the current study.
Authors: A. Oya, Takashi Yokoyama, M. Yamamoto, D. Hulicova
Authors: Chang Lu, Xin Hui Huang, Jia Xi Wang, Xiao Ning Hu
Abstract: Selective localization of carbon nanotubes (CNTs) at the interface of immiscible polymer blend was achieved by the method that poly(styrene-co-maleic anhydride) (SMA) was first reacted with CNTs, and then blended with nylon6/polystyrene (PA6/PS). In the PA6/PS blends, CNTs was localized in PA6 phase and the percolation threshold was 2wt%. However, for the PA6/PS/(SMA- CNTs) composites, TEM results showed that most of CNTs were selectively localized in matrix, but some of tubes were induced by SMA to disperse at the interface. The localization of CNTs at the interface caused the percolation threshold of PA6/PS/(SMA- CNTs) was only 0.33 wt%, which is much lower than that of PA6/PS/ CNTs.
Authors: A. Takahara, X. Jiang, N. Satomi, Kenji Tanaka, T. Kajiyama
Authors: Nattapon Uthaipan, Banja Junhasavasdikul, Charoen Nakason, Anoma Thitithammawong
Abstract: The mixing efficiency of intermeshing rotor internal batch mixers for the preparation of rubber-rich thermoplastic vulcanizates (TPV) based on ethylene propylene diene terpolymer (EPDM) and polypropylene (PP) blends was investigated. Two laboratory scale mixers, namely intensive batch mixer (INS) and kneader batch mixer (KND), were used. The mixer choice at controlled mixing conditions was investigated to determine its effects on morphological and mechanical properties and crosslink density of the prepared EPDM/PP TPVs. Such effects were found on the degradation of the polymer, on the distribution of the EPDM phase in the blend morphology, particularly the size of EPDM inclusion, and on the crosslink density of the EPDM phase. In summary, the different mixing efficiencies of INS and KND type mixers affect the EPDM/PP TPVs and their properties. Also, the INS mixer has higher mixing efficiency than the KND mixer.
Authors: Mohd Farhan Bin Ab Aziz, Rahmah Mohamed
Abstract: Biodegradability of films made from sago starch blend with PVA and LLDPE has been investigated. Blend films with different starch concentration were buried in the soil for 30 days for degradation test. FTIR and SEM have been performed on the film before and after degradation test to evaluate the biodegradability of the films. It was found that degradation rate increases with addition of starch into the blends.
Authors: Ahmad Nazib Alias, T.I.T. Kudin, Z.M. Zabidi, M.K. Harun, A.M.M. Ali, Mohamad Faizul Yahya
Abstract: Polarized absorption and dielectric spectra of blended poly (N-vinlycarbazole) (PVK) with polyvinylpyrrolidone (PVP) in different composition ratiosare investigated. Polymer coating was carried out using doctor blade technique on a quartz substrate. The polarized optical source was produced by using the uv-vis sheet polarizer. The polarized absorption and dielectric spectrum for parallel and perpendicular reveal that there are different significant results obtained between PVK and PVP with various polymer compositions.The polarized optical properties such aspolarization, ρwere calculated.These spectra indicate that the anisotropic properties of each polymer blends is different from each other.
Authors: N.F.M. Sahapini, Ahmad Nazib Alias, Z.M. Zabidi, Mohd Ashmir Yahya
Abstract: A Polymer blends compose of Poly (3,4-ethylenedioxythiophene):Poly (styrene sulphonic acid)(PEDOT:PSS) and Polyaniline (PANi) have been prepared using drop casting technique. Optical parameters such as refractive index (n), extinction coefficient (k), reflectance, and optical dielectric were determined in this study. It is found that reflectance spectra increase as the PANi concentration decreases in the sample of small photon energy. The refractive index of the sample shows significant effect with the PEDOT:PSS concentration. As the concentration of PEDOT:PSS increases, the refractive index shows a normal dispersion behavior. Extinction coefficient decrease as the wavelength increase within the range of 300 nm to 350 nm that may contribute to the loss fraction of light due to scattering and the decreasing of absorbance at this range. However, the extinction coefficient increases from 350 nm to the maximum wavelength of 800 nm since the absorbance is also increasing. Both the real and imaginary part of the dielectric constant decreases when the photon energy increases. This revealed that the compositions of PEDOT:PSS influence the optical properties of hybrid PEDOT-PSS:PANi thin film.
Authors: Makoto Uchida, Naoya Tada
Abstract: To evaluate the effect of the size of the microstructure on the mechanical property of the cavitated rubber blended (voided) amorphous polymer, the FEM simulation based on the rate form second-order homogenization method, in which rates of the macroscopic strain and strain gradient are given to the microstructure, was performed. Computational simulations of micro-to macroscopic deformation behaviors of amorphous polymers including different sizes and volume fractions of the voids were performed. Non-affine molecular chain network theory was employed to represent the inelastic deformation behavior of the amorphous polymer matrix. With the increase in the volume fraction of the void, decrease and periodical fluctuation of stress and localized deformation in the macroscopic field were observed, and were more emphasized with the increase in the size of the void. These results were closely related to the non-uniform deformation and volume increase of the void in the microscopic field.
Authors: N.A. Zakaria, S.Y.S. Yahya, M.I.N. Isa, Mohamed Nor Sabirin, Ri Hanum Yahaya Subban
Abstract: The ionic conductivity and mechanical properties of poly (vinyl chloride) (PVC)/poly (ethyl methacrylate) (PEMA) polymer blends containing LiN(CF3SO3)2 as doping salt has been studied using electrical impedance spectroscopy (EIS) and Dynamic Modulus Analysis (DMA) as a function of polymer blend ratios and lithium salt concentration. The film with PVC/PEMA composition of 65:35 obtained the highest conductivity with good transparency. DMA showed that both the storage modulus (E') and the glass transition temperature (Tg) of the PVC/PEMA is increased with PEMA concentration. In the case of PVC/PEMA-LiN(CF3SO2)2 films, the conductivity was found to increase with concentration of salt added with a maximum in conductivity at 35 wt.% LiN(CF3SO2)2. The Tg values of the doped films was found to increase with concentration of salt such that the film with the highest conductivity value has the highest Tg.
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