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transition of alanine-rich A-block which is similar to the “crystalline module,” glycine rich B-block which is similar to the “elastic module” and their block copolymer BA using temperature-modulated differential scanning calorimetry (TMDSC). In the present

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Introduction Amphiphilic block copolymers are characterized by a hydrophobic block linked to a hydrophilic block by a covalent bond. These materials are interesting if applied as incompatible or heterogeneous blend in itself

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Abstract  

Polyamide-6-block-polybutadiene copolymers have been prepared by the anionic polymerization of ɛ-caprolactam in presence of α,ω-dihydroxy terminated polybutadiene. TG, Hi-Res™ TGA, DSC, TMDSC and DMA techniques have been applied. The suitability of the methods used to determine the content, thermal stabilities and glass transition temperatures of the components constituting the block copolymer is discussed.

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Journal of Flow Chemistry
Authors: Aiichiro Nagaki, Kana Akahori, Yusuke Takahashi, and Jun-ichi Yoshida

Living anionic polymerization of perfluoroalkyl methacrylates initiated by 1,1-diphenylhexyllithium was conducted without adding lithium chloride in an integrated flow microreactor system. The high degree of polydispersity index (PID) control was achieved at 0 °C (2-(nonafluorobutyl)ethyl and 2-(tridecafluorohexyl)ethyl methacrylates) or −40 °C (2,2,2-trifluoroethyl methacrylate). The subsequent reaction of a reactive polymer chain end with alkyl methacrylates or tert-butyl acrylate led to the formation of fluorine-containing block copolymers with narrow PDI.

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Abstract  

Monolayers of amphiphilic di-block copolymer, PEO40-b-PMA(Az)19 on water surface and solid surfaces, such as silicon wafer and quartz glass, were analyzed by surface pressure — molecular area (π-A) isotherm, UV-Vis spectroscopy, atomic force microscopy (AFM) and total X-ray reflectivity (TXR). The monolayer prepared at 22 mN m-1 consisted of H aggregated azobezene (Az) moieties, which orientated perpendicular to the solid surface. The monolayer structure, including H aggregated Az and orientation of Az, was stable after annealing at 98�C, at which temperature the hydrophilic PEO domain was the liquid phase and the hydrophobic PMA(Az) was in the smectic A phase.

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Abstract  

Using temperature-modulated differential scanning calorimetry, the melting behaviour of poly(oxytetramethylene)-alt-(aromatic oligoamide) (POTM-alt-AOA) has been studied in comparison with that of polyoxytetramethylene glycohols (POTMGs). The apparent melting temperature of the block copolymers is found to be less than that of the corresponding POTMGs by approximately 30°C. The relaxation time of melting of a POTM segment has been estimated and compared with that of POTMG. The relaxation time of POTM-alt-AOA is slightly shorter than that of POTMG when the molar mass of the POTM segment is 2900; however, it is longer when the molar mass is 1400.

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Summary The mixing state of amphiphilic di-block copolymers consisted of poly(ethylene oxide) and poly(methacrylate) having azobenzene moieties in the side chains p(EO)114pMA(Az)24 and poly(ethylene oxide) p(EO)114 was investigated from the viewpoints of isothermal crystallization and nano-scale ordered structure. The chemical potential, which required establishing the constant crystal growth rate, decreased with the p(EO) content up to 60%. The hexagonal packed cylinder structure was observed for the blends with the p(EO) content up to 60% and the lattice spacing of (100) and (110) planes increased with the p(EO) content up to 60%. The blends of amphiphilic p(EO)114pMA(Az)24 and p(EO)114 were miscible without in the p(EO) content below 60%.

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Journal of Thermal Analysis and Calorimetry
Authors: R. De Lisi, G. Lazzara, S. Milioto, and N. Muratore

Abstract  

Macromolecule/laponite nanomaterials were studied by DSC and X-ray diffraction techniques. The matrices are poly(ethylene) glycols at various molecular masses and poly(ethylene oxides)-poly(propylene oxides)-poly(ethylene oxides) tri-block copolymers. The latter were tuned by modulating the molecular masses, at constant hydrophilic/hydrophobic ratio, and the hydrophilicity. For all the investigated systems, the enthalpy of melting (ΔH m) is nearly constant up to a given composition thereafter it increases monotonically reaching the value of the pure macromolecule. We proposed a model to interpret the DSC data. Briefly, it was invoked a mechanism of interaction following which some segments of the adsorbed macromolecule are anchored to the laponite (RD) particles and the remaining segments are radiating away from the surface. The portion of the macromolecule in contact with RD does not contribute to ΔH m whereas that radiating away from the clay does. Once that the RD surface is saturated, the excess of the macromolecule behaves like the pure one. The proposed model allowed to compute successfully the ΔH m values. The X-ray diffraction experiments ruled out the polymer intercalation between the silicate sheets.

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Abstract  

The phase transition and nano-scale ordered structure of four types of blends prepared from four di-block copolymers, consisting of hydrophilic poly(ethylenoxide) and hydrophobic poly(methacrylate) derivative, PEOm-b-PMA(Az)n having different PEO molecular length and same degree of polymerization of PMA(Az) were investigated. All blend systems formed hexagonal packed PEO cylinder structure, which was same with the nano-scale structure of these parent block copolymers. The SAXS and AFM observation suggested that the size of hexagonal structure of blend was larger than the average size of parent block copolymers. The melting enthalpy of PEO in blends was larger than the average value of parent block copolymers. DSC, SAXS and AFM observations indicated the miscible blend systems.

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