A Simple Route to Rod‐Coil Block Copolymers of Oligo‐ and Polythiophenes with PMMA and Polystyrene

A simple and efficient approach for the preparation of rod‐coil block copolymers comprising oligo‐ and polythiophenes blocks together with PMMA or PS blocks is described. The block copolymers were prepared using a two‐step procedure. α,ω‐dicarboxy‐terminated oligothiophenes and carboxy terminated poly(3‐hexylthiophene) were first prepared. These were then reacted with P₄S₁₀ in a second step to generate the α,ω‐thioester terminated oligothiophenes and poly(3‐hexylthiophene)s which were subsequently used in a one‐pot reaction as RAFT polymerization agents with methylmethacrylate and styrene. The di‐ and tri‐block copolymers hence obtained were fully characterized, both in solution and as thin films.

     

A Novel Bifunctional Trithiocarbonate for Styrene and Methacrylate RAFT Polymerization

The synthesis of butane‐1,4‐bis(phenylacetonitrile trithiocarbonate) and its application as a new chain transfer agent for controlled radical polymerization is reported. It is a bifunctional trithiocarbonate for the polymerization of methacrylates, and styrenic monomers and therefore a novel type of RAFT agent. Linear growth of molar masses with conversion and narrow molecular weight distributions are obtained. ABA triblock copolymers are successfully synthesized in two steps. MALDI‐TOF MS and SEC prove the living character of the polymers and uniform growth of both functionalities. The pre‐equilibrium kinetics are analyzed by SEC to determine transfer coefficients. The P(GMA) blocks are used as precursor for polymer‐analogous reactions.

     

Base Catalyzed Thiol–Ene Click Chemistry toward Inner CHCF Bonds for Controlled Functionalization of Poly(vinylidene fluoride)

A facile and controlled base catalyzed thiol–ene click chemistry toward electron‐deficient ?CH?CF? double bonds in poly(vinylidene fluoride) PVDF (P(VDF‐DB)) is reported in present contribution for the first time. The addition reaction is carefully conducted under varied conditions including at the elevated temperature, in the different solvents, and with the altered catalysts and thiols. The addition reaction is well confirmed to follow the base catalyzed route and exhibits close dependence onto the reaction conditions. Besides the addition reaction, the other two side reactions catalyzed by alkylamines, including the further main chain degradation of P(VDF‐DB) substrates together with the nucleophilic substitution of thiols to ?CH?CF? units, can be completely avoided by choosing a catalyst with a proper pK_a value. With respect to the universality and well controlled feature of the reaction, the low cost and readily prepared P(VDF‐DB) substrate and the mild reaction conditions, this strategy may offer a robust tool for attaching various functional groups into PVDF side chain.     

Base Catalyzed Thiol–Ene Click Chemistry toward Inner ?CHCF? Bonds for Controlled Functionalization of Poly(vinylidene fluoride)

A facile and controlled base catalyzed thiol–ene click chemistry toward electron‐deficient ? CH?CF? double bonds in poly(vinylidene fluoride) PVDF (P(VDF‐DB)) is reported in present contribution for the first time. The addition reaction is carefully conducted under varied conditions including at the elevated temperature, in the different solvents, and with the altered catalysts and thiols. The addition reaction is well confirmed to follow the base catalyzed route and exhibits close dependence onto the reaction conditions. Besides the addition reaction, the other two side reactions catalyzed by alkylamines, including the further main chain degradation of P(VDF‐DB) substrates together with the nucleophilic substitution of thiols to ? CH?CF? units, can be completely avoided by choosing a catalyst with a proper pK_a value. With respect to the universality and well controlled feature of the reaction, the low cost and readily prepared P(VDF‐DB) substrate and the mild reaction conditions, this strategy may offer a robust tool for attaching various functional groups into PVDF side chain.     

RAFT Dispersion Polymerization of Styrene in Water/Alcohol: The Solvent Effect on Polymer Particle Growth during Polymer Chain Propagation

The RAFT polymerization of styrene in a solvent consisting of a water/alcohol mixture with different water contents is performed and the solvent effects on polymerization kinetics, polymer chain propagation, and polymer particle growth are evaluated. It is found that the solvent affects the RAFT polymerization kinetics greatly, and the apparent polymerization rate constant (K_p ^app) increases with an increase in the water content of the water/alcohol mixture. In addition, RAFT polymerization in a water/alcohol mixture with a higher water content affords better control of the polydispersity index (PDI) of the synthesized polymers. Furthermore, the solvent also exerts a great influence on the growth of the polymer particles. Hollow particles are formed either at the initial polymerization with low monomer conversion or in the solvent with a low water content, whereas solid polymer particles are produced either at high monomer conversion or in the solvent with a high water content.

     

固冲汤加清热解毒药治疗脾肾亏虚型崩漏的止血疗效

目的 观察固冲汤加清热解毒药治疗脾肾亏虚型崩漏的止血疗效。方法 选取2018年1月~2019年2月我院收治的脾肾亏虚型功血患者50例,按照随机数字表法分为治疗组和对照组,每组25例。治疗组给予固冲汤加清热解毒药治疗,对照组给予妈富隆治疗,比较两组近期止血疗效、治疗前后症状积分、中医证候疗效、中医单项症状疗效及实验室检查指标[血红蛋白（HGB）、凝血酶原时间（PT）、部分凝血活酶时间（APTT）]。结果 治疗组近期止血总有效率为92.00%,高于对照组的80.00%,差异有统计学意义（P＜0.05）。治疗组中医证候总有效率为96.00%,高于对照组的60.00%,差异有统计学意义（P＜0.05）。两组阴道出血量、出血天数比较,差异无统计学意义（P＞0.05）;两组神疲乏力、心悸气短、腰膝酸软、头晕耳鸣比较,差异有统计学意义（P＜0.05）。治疗组HGB高于对照组[（99.24±12.39）g/L vs（92.08±17.47）g/L],PT、APTT低于对照组[（11.76±0.60）s vs（13.61±0.63）s]、[（33.43±1.60）s vs（37.72±1.80）s],差异有统计学意义（P＜0.05）。结论 固冲汤加清热解毒药治疗脾肾亏虚型崩漏患者止血疗效确切,可增加机体免疫力,提高HGB含量,缩短PT、APTT时间,达到标本兼治,在改善患者症状、提高患者生活质量方面效果优于妈富隆。     

Luminescent Copolymer‐Rhenium(I) Hybrid Materials via Picolylamine‐Modified Poly(pentafluorophenyl acrylate)

The synthesis and photophysical properties of well‐defined polymer‐rhenium(I) hybrid materials is described. Reversible addition‐fragmentation chain transfer polymerization of pentafluorophenyl acrylate yields a parent homopolymer that serves as a reactive scaffold for the preparation of a series of new statistical copolymers containing pendent pyridyl functional groups in conjunction with various other repeat unit species. Attachment of [Re(CO)₃(phen)]⁺ fragments via coordination through the pendent pyridyl groups yields the hybrid metal‐copolymer materials. Photophysical studies confirm successful rhenium coordination as judged from the absorption and emission profiles of the hybrid materials and further verify that the polymeric scaffold has no discernable effect on the luminescent properties of the coordinated rhenium species.     

A Novel Strategy to Synthesize Double Comb‐Shaped Water Soluble Copolymer by RAFT Polymerization

Summary: A double comb‐shaped water soluble copolymer, poly[poly(ethylene oxide) methyl ether methacrylate]‐block‐poly(N‐isopropylacrylamide)‐block‐poly[poly (ethylene oxide) methyl ether methacrylate], abbreviated as [P(MA‐MPEO)‐block‐PNIPAM‐block‐P(MA‐MPEO)], with a controlled molecular weight and narrow polydispersity was successively synthesized using a macromonomer technique. The ⁶⁰Co γ irradiation polymerization of MA‐MPEO in the presence of dibenzyl trithiocarbonate (DBTTC) at room temperature afforded a polymer, P(MA‐MPEO)‐SC(S)S‐P(MA‐MPEO), which was subsequently used as a macro RAFT agent in the RAFT polymerization of N‐isopropylacrylamide, and water soluble double comb‐shaped copolymers, P(MA‐MPEO)‐block‐PNIPAM‐block‐P(MA‐MPEO), were successfully obtained.

Structure of the double comb‐shaped copolymer.     

Synthesis of an Acid‐Labile Diacrylate Crosslinker for Cleavable Michael Addition Networks

A novel acid‐cleavable diacrylate crosslinker, DCDA, was used as a difunctional Michael acceptor in the synthesis of acid‐cleavable crosslinked networks via base‐catalyzed Michael addition of telechelic poly(ethylene glycol) bis(acetoacetate). Michael addition networks containing DCDA were degraded in the presence of catalytic quantities of acids to form soluble polymeric products. Michael addition networks of non‐degradable diacrylate crosslinkers were chemically unchanged under identical reaction conditions and remained insoluble. Thermal degradation of DCDA‐containing networks was also investigated using TGA, which confirmed the thermal reactivity and concentration of the acid‐labile crosslink points.

     

Characterization of New Amphiphilic Block Copolymers of N‐Vinyl Pyrrolidone and Vinyl Acetate, 1 – Analysis of Copolymer Composition,End Groups,Molar Masses and Molar Mass Distributions

New amphiphilic block copolymers consisting of N‐vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4‐dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. ¹³C NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, ¹³C NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non‐ideal RAFT mechanism.