分散共聚法制备特殊形态高分子微球的研究

以聚乙二醇 (PEG)大分子单体为反应性稳定剂 ,在丙烯腈的分散共聚反应中添加少量苯乙烯以形成疏水性核 ,制备得到了亚微米级高分子微球 .透射电子显微镜研究表明 ,该高分子微球具有特异的形态结构 .同时研究了分散共聚体系中各种反应因素对微球形态和直径的影响 ,结果表明 ,苯乙烯单体的添加量、PEG大分子单体的浓度及分子量、混合溶剂的组成对微球直径和形态均有明显的影响 .X 射线光电子能谱 (XPS)研究结果表明 ,微球表面聚集有亲水性PEG链 ,核为疏水的聚 (丙烯腈 苯乙烯 ) ,即形成的特异形态的PEG接枝高分子微球亦为复合型结构     

Facile and chemo-selective synthesis of tertiary alkyl isothiocyanates from alcohols

When tert-alcohols were treated with (COOH)₂ and NaSCN in the presence of iodine, tertiary alkyl isothiocyanates were obtained in good yield, whereas the corresponding thiocyanates were obtained in low yield in the absence of iodine.     

Structures of a CO adlayer on a Pt(100) electrode in HClO4 solution studied by in situ STM

We have obtained the first in situ STM atomic images of a CO adlayer on a Pt(100)-(1 x 1) electrode in 0.1 M HClO(4) solution, exhibiting a phase transition from c(6 x 2)-10CO to c(4 x 2)-6CO at E > 0.3 V vs. RHE.     

Dynamic coordination polymers with 4,4'-oxybis(benzoate): reversible transformations of nano- and nonporous coordination frameworks responding to present solvents

Reversible construction of a nanoporous framework from a nonporous framework has been found in the zinc(II) coordination polymer with 4,4'-oxybis(benzoate) (oba). [Zn(2)(oba)(2)(dmf)(2)].2DMF (1), which has 1 nm scale channels, transforms to the nonporous coordination polymer [Zn(oba)(H(2)O)] (2) with the loss of the open framework. Compound 2 on treatment with DMF reversibly yields nanoporous compound 1.     

Synthesis of poly (ether-sulfone-amide)s by palladium-catalyzed polycondensation of aromatic dibromides containing ether sulfone structure,aromatic diamines,and carbon monoxide

A general method for the preparation of aromatic poly (ether-sulfone-amide)s has been developed. Polymerization is based on the palladium-catalyzed polycondensation of aromatic dibromides containing ether sulfone structural units, aromatic diamines, and carbon monoxide. Reactions were carried out in N, N-dimethylacetamide (DMAc) in the presence of palladium catalyst, triphenylphosphine, and 1,8-diazabicyclo [5,4,0]–7–undecene (DBU), and gave a series of poly (ether-sulfone-amide)s with inherent viscosities up to 0.86 dL/g under mild conditions. The polymers were quite soluble in strong acids, dipolar aprotic solvents, and pyridine. Thermogravimetry of the polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 470°C in air. The glass transition temperatures of the polymers were around 230°C, which are higher than those of poly (ether-sulfone) analogues. These polymers also showed the good tensile strengths and tensile modulus. © 1994 John Wiley & Sons, Inc.     

Superconducting Properties in Metallic Phase of NbS3

Metallic phase of NbS₃ was synthesized by heating the crystal of semiconducting NbS₃. Metallic NbS₃ undergoes superconducting transition around 2 K. The analysis of the angular dependence of the upper critical magnetic field suggests that the effect of filmy or fibrous morphology plays an important role in the superconducting properties.     

Generation of ynolates via reductive lithiation using flow microreactors

A new method has been developed for the generation and subsequent reaction of ynolates in a micro flow reactor system. This new procedure allowed for ynolates to be prepared at 0 °C or ambient temperature within 1 min via a reductive lithiation reaction, whereas the corresponding batch processes generally require low temperature control and extended reaction times of up to 1 h. The resulting ynolates were applied to the olefination of carbonyl compounds, with the reactions reaching completion in a much shorter reaction time in the continuous flow reactor than the batch reactor. These results highlight the practical utility of the ynolate reaction, and represent the first reported example of the use of lithium naphthalenide in a flow microreactor, which would contribute to progress of the flash chemistry.     

Control of thermoresponsivity of biocompatible poly(trimethylene carbonate) with direct introduction of oligo(ethylene glycol) under various circumstances

Poly(trimethylene carbonate) (PTMC) is a well‐known biodegradable polymer with good biocompatible properties which make it suitable for biomedical applications. Poly(5‐[2‐{2‐(2‐methoxyethoxy)ethyoxy}‐ethoxymethyl]‐5‐methyl‐1,3‐dioxa‐2‐one) (PTMC‐MOE3OM) and copolymers, bearing oligo ethylene glycol (OEG) at the side chain of PTMC backbone, were selected to investigate the cloud point behavior by solvents such as PBS, water, 10% ethanol solution and various ionic strengths. A pH‐responsive copolymer, poly(TMCM‐MOE3OM‐co‐(5‐methyl‐5‐carboxylic‐1,3‐dioxane‐2‐one)) as carboxylic acid carbonate showed a decreased critical temperature at pH 2. Photo‐responsive copolymer, poly(TMCM‐MOE3OM‐co‐coumarin derivatives) bearing 1% and 10% of photo‐induced molecules (7‐[(5‐(5‐methyl‐1,3‐dioxa‐2‐one)methoxy)]‐methoxy coumarin (TMCM‐coumarin)) exhibited a low cloud point because of the hydrophobic moieties. Meanwhile, alternative coumarin polymer including 2% of 4‐methyl‐7‐[(5‐(5‐methyl‐1,3‐dioxa‐2‐one)methoxy)butoxy)]‐methoxy coumarin (TMCM‐4‐methyl‐coumarin) has been successfully synthesized and copolymerized as a novel molecule. The various combinations of monomers were studied and the significant properties were determined via external triggers after copolymerization. This study showed basically synthetic progress toward designs and trivial rationalization of thermoresponsive copolymers close to body temperature. At present, various pendant groups as side part affect to the lower critical solution temperature (LCST) and biodegradable polymer in order to utilize the actual external stimuli application. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3466–3474