Photopolymerization of enzymatically synthesized methacrylated poly(caprolactone) with poly(ethylene glycol) macromonomer

Polycaprolactone (PCL) based α,ω-methacrylated macromonomer (DMPCL) was synthesized via enzymatic ring-opening polymerization (eROP) by using Novozyme 435 as the enzyme immobilized catalyst. DMPCL was further photopolymerized with monofunctional poly(ethylene glycol) methyl ether methacrylate (PEGMA-950) macromonomer and trimethylolpropane triacrylate (TMPTA) as tri-functionalized crosslinking agent in glass vials when CHCl₃ was the solvent and Irgacure 819 was the photoinitiator. Ultraviolet (UV) Light Emitting Diode (LED) bulbs enabled photoinduced reactions at room temperature with low heat generation and high reaction efficiency. The obtained gels were characterized with Fourier Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). DMPCL participated as an effective crosslinking agent in the photopolymerization of PEGMA-950. Combined usage of DMPCL and PEGMA-950 resulted in significantly more effective polymerization than the separate photopolymerizations of these macromonomers.     

Synthesis and Liquid Crystalline Behavior of Random Copolymer of Poly(ethylene oxide) Macromonomer and Liquid Crystalline Monomer by the Photon Transmission Technique

Random copolymers of poly(ethylene oxide) macromonomer with p‐vinylbenzyl end‐functional group (PEOVB) and liquid crystalline monomer, namely 6‐(4‐cyanobiphenyl‐4′‐oxy)hexyl acrylate (COA), were prepared by conventional free radical polymerization. A living anionic polymerization technique was employed for the synthesis of PEO macromonomers bearing p‐vinylbenzyl moiety at one end. The photon transmission method was also applied to study the phase transitions of COA monomer and its random copolymer with PEO. It was found that, for both samples, the nematic‐smectic A transition is continuous, but the critical fluctuation regions do not allow to obtain 3D XY values. Instead, we have obtained the values close to mean field regime. Scaling of thermal hystersis for random copolymer sample near the nematic‐isotropic transition was studied as well. Thermal hysteresis loops were produced under linearly varying temperature. It was shown that the areas of the hysteresis loops scale with the temperature scanning rate with an exponent being equal to 0.614 which is in good agreement with the field‐theoretical value.     

长链超支化聚合物的合成研究进展

长链超支化聚合物(HyperMacs)凭借其含有大量的功能端基和可调控的链结构等优点已经引起国内外科研人员越来越广泛的关注。HyperMcs除了拥有超支化聚合物固有的低粘度、溶解性好、含有大量的功能性端基的特点外,同时拥有高剪切敏感性、熔体弹性、冲击强度和零剪切粘度,因而在药物载体、能量存储及传递和纳米催化剂等方面可能拥有更为广泛的应用。本文根据HyperMacs合成方法的不同,分别从迭代法和ABx线型大分子单体法两个主要方面对其研究进展进行了总结和评述,并在此基础上展望了该类聚合物的研究方向和发展趋势。     

PVA-g-PS复合微球的制备与粒径控制研究

由链转移自由基聚合与端基置换反应法,合成了苯乙稀基单封端的聚醋酸乙烯酯(PVAc)大分子单体,使其与苯乙烯在乙醇/水的混合介质中进行自由基分散共聚,得到了表面以PVAc为接枝链的聚苯乙烯(PVAc-g-PSt)微球。将所得微球在碱性条件下醇解,形成了以亲水性聚乙烯醇(PVA)为壳、聚苯乙烯为核的复合微球(PVAc-g-PSt)。用核磁共振对聚合物的结构进行表征,定出了PVAc末端双键的含量;并用激光光散射、扫描电子显微镜对微球的粒径与形态进行了表征。研究结果表明,在共聚反应体系中大分子单体的分子量与浓度、苯乙烯浓度、引发剂浓度及溶剂的组成对微球的形态和粒径大小有明显影响。     

Synthesis and characterization of hyperbranched polystyrene via click reaction of AB2 macromonomer

Well‐defined hyperbranched polystyrenes have been successfully prepared by polymerization of AB₂ macromonomer, polystyrene containing an azide group at its one end and two terminal propargyl groups at the other end via click reaction. For preparation of AB₂ macromonomers, an ATRP initiator, bispropargyl 2‐bromosuccinate (BPBS) with two propargyl groups and one bromine group was synthesized by the successive bromination and esterification reaction of L ‐aspartic acid. The resulting BPBS initiated the ATRP of St, and subsequently, the terminal bromine groups of (CH≡C)₂‐PS‐Brs were substituted by N₃ via the reaction with sodium azide resulting the AB₂ macromonomer, (CH≡C)₂‐PS‐N₃ with various molecular weights. All intermediates and the resultant polymers were characterized by GPC, ¹H NMR, FTIR, and MALLS methods. The polymerization kinetics study showed fast increase of DP at the initial stage of polymerization and then slow increase of their DP. The final “HyperMacs” have high‐molecular weight up to M_w,MALLS = 340,000 g/mol, their molecular weight distributions were moderately narrow (M_w/M_n = 1.47–1.65). The ratios of [η]_H/[η]_L of the HyperMacs formed in the polymerization system increased with evolution of polymerization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 454–462, 2010     

Amphiphilic Copolymers of Polyfluorene Methacrylates Exhibiting Tunable Emissions for Ink‐Jet Printing

Functionalized polyfluorene receives more and more attention due to its wide applications. Here, the syntheses of three novel polyfluorene‐based methacrylate macromonomers exhibiting a vast flexibility for further applications are reported. Their emissions strongly depend on the end groups and thus the macromonomers provide blue, green, and red emissions simultaneously with the same excitation light of 365 nm. Their well‐defined copolymers with 2‐(dimethylamino) ethyl methacrylate via reversible addition‐fragmentation chain transfer polymerization are investigated in detail. These copolymers exhibit high quantum yields in solid film (up to 0.8), and self‐assemble into photoluminescent nanoparticles in aqueous solutions with pure blue, green, and red emissions. By simply mixing them, perfect white light emission with high quality is obtained. These aqueous nanoparticles solutions are ready for ink‐jet printing to produce exquisite bright and colorful fluorescent pictures.

     

基于HEA封端聚氨酯大孔树脂颗粒的合成、表征及水声声学性能

制备了丙烯酸-β-羟乙酯（HEA）封端的聚氨酯（PUA）大分子单体,采用正庚烷作致孔剂,用悬浮聚合法合成了聚氨酯-苯乙烯（PUA-St）及聚氨酯-苯乙烯-甲基丙烯酸乙酯-二乙烯基苯（PUA-St-EMA-DVB）AB-交联共聚物大孔树脂颗粒。SEM表明：合成的PUA-St-EMA-DVB颗粒含有规整的、孔径较大的孔洞,...     

Controlled synthesis of amphiphilic block copolymers based on poly(isobutylene) macromonomers

The synthesis of a monoacrylate functionalized poly(isobutylene) (PIB) macromonomer (PIBA) has been achieved by a two‐step reaction starting from a commercially available PIB. Firstly, terminal olefins (vinylidene and trisubstituted olefin) of PIB were transformed to a phenolic residue by Friedel‐Crafts alkylation followed by subsequent esterification of the phenol with acryloyl chloride, catalyzed by triethylamine. PIBA structure was confirmed by ¹H‐NMR, ¹³C‐NMR and GPC before utilizing in the RAFT copolymerization with N,N‐dimethylacrylamide (DMA) to obtain statistical copolymers (P[(DMA‐co‐(PIBA)]). Monomer conversions were consistently higher than 85% for both DMA and PIBA as monomer feed composition was varied. Chain extension of poly(N,N‐dimethylacrylamide) with PIBA to synthesize block copolymers (P[(DMA‐b‐(PIBA)]) was also achieved with near quantitative monomer conversions (>97%). Block formation efficiency was not quantitative but purification of block copolymers was possible by selective precipitation. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 634–643     

ATRP合成大分子单体法制备核壳结构微球

以α-溴代丙酸乙酯(EPN-Br)为引发剂, N,N, N′,N″,N″-五甲基二亚乙基三胺(PMDETA)为配体,使甲基丙烯酸叔丁酯进行原子转移自由基聚合,合成了端基带溴原子的聚甲基丙烯酸叔丁酯(PtBMA-Br)大分子中间体,通过其与甲基丙烯酸的亲核取代反应,得到了末端C=C双键含量高的大分子单体（MAA-PtBMA）,其相对分子质量可控制在5400-12000g/mol的范围内,分子量分布≤1.20。以偶氮二异丁腈为自由基引发剂,在乙醇中使MAA-PtBMA大分子单体与苯乙烯（St）进行分散共聚,制得了甲基丙烯酸叔丁酯接枝聚苯乙烯（PtBMA-g-PSt）微米级共聚微球,该微球具有核壳结构。     

Graft copolymers having hydrophobic backbone and hydrophilic branches. XXX. Preparation of polystyrene‐core nanospheres having a poly(2‐methacryloyloxyethyl phosphorylcholine) corona

Polystyrene core nanosphere particles possessing 2‐methacryloyloxyethyl phosphorylcholine (MPC) polymers on the corona were prepared by the free radical polymerization of hydrophilic polyMPC macromonomer and hydrophobic styrene with AIBN as a radical initiator in ethanol as a polar solvent. The morphology of the nanospheres was observed by transmission electron micrograph (TEM). The nanospheres were spherical in form and have a narrow size distribution. Their sizes could be controlled by varying the molecular weight of the macromonomer and the amount of it in feed. Electron spectroscopy for chemical analysis (ESCA) of the nanosphere surfaces suggested that polyMPC chains were located favorably on the surface of the nanosphere. The nanospheres having the polyMPC chains on their surfaces can be significant and useful materials in technological and medical fields. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3052–3058, 2000