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Saeb M.R.,Iran Institute for Color Science and Technology | Khorasani M.M.,Iran National Petrochemical Company | Ahmadi M.,Amirkabir University of Technology | Mohammadi Y.,Iran National Petrochemical Company | And 4 more authors.
Polymer (United Kingdom) | Year: 2015

It is the dual nature of chain shuttling polymerization (CSP) that makes control of olefin block copolymer (OBC) composition difficult and difficult, but at the same time, stimulating. Although recent investigations on OBCs brought some insights to the kinetics and microstructure of block copolymers differentiating from ethylene and α-olefins, some crucial features of these systems are not uncovered because of experimental difficulties. Thus, attention is still placed upon theoretical concepts that enable deeper understanding of behavior of end-of-batch OBCs. Extending the predictability of a well-developed Monte Carlo algorithm, we present for the first time an explicit image of hard-soft segmental growth at the course of CSP process. The stochastically tailored ethylene/1-octene copolymers with diverse architectural characteristics were simulated and characterized in terms of mole fraction of soft and hard segments, block length distribution, sequence length distribution, longest ethylene sequence distribution, and the distribution of the number of blocks per growing copolymer chain to be used as unique signatures of this reaction mechanism. © 2015 Elsevier Ltd. All rights reserved.

Ghavaminejad A.,Chonbuk National University | Sasikala A.R.K.,Chonbuk National University | Unnithan A.R.,Chonbuk National University | Thomas R.G.,Chonnam National University | And 7 more authors.
Advanced Functional Materials | Year: 2015

A method for the versatile synthesis of novel, mussel-inspired, electrospun nanofibers with catechol moieties is reported. These mussel-inspired nanofibers are used to bind iron oxide nanoparticles (IONPs) and the borate-containing anticancer drug Bortezomib (BTZ) through a catechol metal binding mechanism adapted from nature. These smart nanofibers exhibit a unique conjugation of Bortezomib to their 1, 2-benzenediol (catechol) moieties for enabling a pH-dependent drug delivery towards the cancer cells and the IONPs via strong coordination bonds for exploiting the repeated application of hyperthermia. Thus the synergistic anticancer effect of these mussel-inspired magnetic nanofibers were tested in vitro for the repeated application of hyperthermia along with the chemotherapy and found that the drug-bound catecholic magnetic nanofibers exhibited excellent therapeutic efficacy for potential anticancer treatment. Drug-loaded magnetic nanofibers are designed for a synergistic anticancer treatment that combines hyperthermia treatment and chemotherapy. A mussel-inspired binding is used to incorporate iron oxide nanoparticles (IONPs) and the drug onto the nanofibers. The smart nanofibers are capable of pH-dependent drug delivery to cancer cells, and their IONPs enable multiple cycles of hyperthermia therapy with the application of an alternating magnetic field (AMF). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Saeb M.R.,Iran Institute for Color Science and Technology | Mohammadi Y.,Iran National Petrochemical Company | Ahmadi M.,Amirkabir University of Technology | Khorasani M.M.,Iran National Petrochemical Company | And 4 more authors.
Chemical Engineering Journal | Year: 2015

A standard Monte Carlo-based program with innovative data storage structure was developed and put into practice to tailor ethylene/1-hexene copolymers through semibatch single site metallocene catalyzed copolymerization. The distribution of copolymer composition, ethylene sequence length, longest ethylene sequence length, as well as the number-average degree of polymerization, and sequential placement of 1-hexene comonomer segments along copolymer chains were monitored and evaluated applying a computerized feeding to metallocene catalyzed ethylene/1-hexene copolymerization. In particular, bivariate copolymer composition-chain length (CC-CL) distribution was compared for two feeding recipes with uncontrolled and well-controlled comonomer insertion. The advantages of controlled feeding in comparison to uncontrolled feeding were discussed in view of aforementioned architectural features. To obtain macromolecules with tailored comonomer distributions, special feeding strategies were developed by training and examining the developed model to capture crystallization analysis fractionation (CRYSTAF) of ethylene/1-hexene chains, as a unique signature of tailored copolymers with rather narrow bivariate CC-CL distribution. The simulation results appropriately highlight the critical importance of computerized feeding with respect to uncontrolled feeding. © 2015 Elsevier B.V.

Hashmi S.,Shenzhen University | Hashmi S.,Chonbuk National University | Hashmi S.,NED University of Engineering and Technology | GhavamiNejad A.,Chonbuk National University | And 6 more authors.
Soft Matter | Year: 2015

In a material consisting of graphene oxide or reduced graphene oxide and poly-N-isopropylamide (PNIPAM) in an aqueous solution, a new type of rheological behaviour is found. When subjecting the material to a short and relatively small deformation pulse, the modulus, which is observed by small deformations in the linear-viscoelastic or very slightly nonlinear range, oscillates with periodicities between 100 and several 1000 seconds; however, in many cases, it also increases systematically. The periodicity depends on the filler content and the sample preparation method (in situ polymerisation vs. blending). When subjecting the material to high nonlinear deformations (γ0 = 100-300%), the resulting linear viscoelastic behaviour changes from a periodic oscillation to a quick recovery of the original data, followed by a decrease and a subsequent increase beyond the value of the modulus of the material prior to the deformation pulse. © The Royal Society of Chemistry 2015.

Vatankhah-Varnoosfaderani M.,Shenzhen University | Vatankhah-Varnoosfaderani M.,Chonbuk National University | Vatankhah-Varnoosfaderani M.,Islamic Azad University | Vatankhah-Varnoosfaderani M.,University of North Carolina at Chapel Hill | And 8 more authors.
Macromolecular Rapid Communications | Year: 2015

Copolymers of N-isopropylacrylamide (NIPAM) and dopamine methacrylate can establish a reversible, self-healing 3D network in aprotic solvents based on hydrogen bonding. The reactivity and hydrogen bonding formation of catechol groups in copolymer chains are studied by UV-vis and 1H NMR spectroscopy, while reversibility from sol to gel and inverse as well as self-healing properties are tested rheologically. The produced reversible organogel can self-encapsulate physically interacting or chemically bonded solutes such as drugs due to thermosensitivity of the used copolymer. This system offers dual-targeted and controlled drug delivery and release - by slowing down release kinetics by supramolecular bonding of the drug and by reducing diffusion rates due to modulus increase. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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