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以同向啮合双螺杆挤出机为反应器,采用苯乙烯和异戊二烯为聚合单体,以正丁基锂为引发剂,采用三次加料法合成苯乙烯/异戊二烯/苯乙烯(SIS)三嵌段热塑性弹性体.氢核磁共振(1H NMR)谱分析结果表明,共聚物中聚异戊二烯嵌段以1,4-结构为主.采用四氧化锇催化双氧水氧化降解聚合物分子链,利用凝胶渗透色谱对氧化降解后的聚苯乙烯碎片进行分析,证明共聚物分子为(聚苯乙烯-聚异戊二烯-聚苯乙烯)(PS-PI-PS)三嵌段结构.动态力学分析(DMA)及透射电子显微镜(TEM)分析结果表明,SIS具有两相分离结构.拉伸试验结果表明,共聚物拉伸强度与苯乙烯含量有关. 相似文献
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研究了由温敏的聚(2-乙基-2-噁唑啉)和pH值敏感的聚(L-谷氨酸)组成的三嵌段共聚物,聚(2-乙基-2-噁唑啉)-b-聚(ε-己内酯)-b-聚(L-谷氨酸)的合成方法,(1)以对甲苯磺酸甲酯为引发剂引发2-乙基-2-噁唑啉进行正离子开环聚合反应,得到了羟基封端的聚(2-乙基-2-噁唑啉)(PEOz-OH);(2)以PEOz-OH为引发剂,以辛酸亚锡为催化剂,在氯苯中合成了PEOz-b-聚(ε-己内酯)两嵌段共聚物(PEOz-b-PCL-OH);(3)将PEOz-b-PCL-OH末端的羟基转换为氨基,得到氨基封端的两嵌段共聚物(PEOz-b-PCL-NH2);(4)以PEOz-b-PCL-NH2为引发剂引发γ-苄基-L-谷氨酸-N-羧酸酐(BLG-NCA)开环聚合,得到了PEOz-b-PCL-b-聚(γ-苄基-L-谷氨酸)(PEOz-b-PCL-b-PBLG)三嵌段共聚物;(5)以HBr的醋酸溶液为脱保护剂脱去苄基保护基,得到PEOz-b-PCL-b-聚(L-谷氨酸)(PEOz-b-PCL-b-PLGlu)三嵌段共聚物.采用1H-NMR、GPC和FT-IR表征了各步聚合物的结构、分子量和分子量分布. 相似文献
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研究了由温敏的聚(2-乙基-2-噁唑啉)和pH值敏感的聚(L-谷氨酸)组成的三嵌段共聚物,聚(2-乙基-2-噁唑啉)-b-聚(ε-己内酯)-b-聚(L-谷氨酸)的合成方法,(1)以对甲苯磺酸甲酯为引发剂引发2-乙基-2-噁唑啉进行正离子开环聚合反应,得到了羟基封端的聚(2-乙基-2-噁唑啉)(PEOz-OH);(2)以PEOz-OH为引发剂,以辛酸亚锡为催化剂,在氯苯中合成了PEOz-b-聚(ε-己内酯)两嵌段共聚物(PEOz-b-PCL-OH);(3)将PEOz-b-PCL-OH末端的羟基转换为氨基,得到氨基封端的两嵌段共聚物(PEOz-b-PCL-NH2);(4)以PEOz-b-PCL-NH2为引发剂引发γ-苄基-L-谷氨酸-N-羧酸酐(BLG-NCA)开环聚合,得到了PEOz-b-PCL-b-聚(γ-苄基-L-谷氨酸)(PEOz-b-PCL-b-PBLG)三嵌段共聚物;(5)以HBr的醋酸溶液为脱保护剂脱去苄基保护基,得到PEOz-b-PCL-b-聚(L-谷氨酸)(PEOz-b-PCL-b-PLGlu)三嵌段共聚物.采用1H-NMR、GPC和FT-IR表征了各步聚合物的结构、分子量和分子量分布. 相似文献
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本文研究了苯乙烯-异戊二烯两嵌段共聚物在CHCl_3中的折光指数浓度增量(dn/dc)和紫外吸收光谱。嵌段共聚物dn/dc具有很好的加和性,可以测定嵌段共聚物的组成。紫外吸收光谱的结果表明,除低苯乙烯含量的样品外,其它嵌段共聚物都显示明显的紫外增色性(UV hyperchromism)。因此UV和UV-RI双检测GPC不会得到可靠的嵌段共聚物组成数据。这种增色现象与其特征的紫外吸收谱图紧密关联 相似文献
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在四氢呋喃(THF)与环己烷的混合溶剂中,以正丁基锂(n-BuLi)为引发剂,采用具有较大空间位阻和特定电荷环境的P配合物为添加剂,实现了异戊二烯(Ip)和甲基丙烯酸甲酯(MMA)的阴离子嵌段共聚。分别采用GPC、^1H—NMR对聚合物的结构进行了分析表征。结果表明:随着THF与环己烷体积比的增大,单体的转化率呈现下降的趋势;同时空间位阻较大的P配合物的加入,堵塞了正、负离子对之间的部分通道,有效地抑制了MMA段聚合副反应的发生,在易于工业化的0℃之下成功合成了分子量分布窄(1.21)的聚异戊二烯一聚甲基丙烯酸甲酯嵌段共聚物(PI—b—PMMA),并且共聚物中PI嵌段以3,4结构链节为主。 相似文献
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α-甲基苯乙烯-异戊二烯)二嵌段共聚物的溶液性质 《功能高分子学报》2001,14(4):422-426
采用体积排斥色谱法(SEC)/示差折光指数(RI)/
-聚(α-甲基苯乙烯-异戊二烯)二嵌段共聚物的溶液性质直角激光光散射(RALLS)/示差粘度(DV)三检测联用技术,在THF为溶剂、25℃的条件下表征了聚(α-甲基苯乙烯-异戊二烯)(PαMS-PI)二嵌段共聚物;计算得到了PαMS-PI分子的无扰尺寸A为0.0778nm.mol 相似文献
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利用热重法研究了聚苯乙烯-聚异戊二烯/丁二烯-聚苯乙烯三嵌段共聚物S(IB)S在N2气氛以不同速率β升温时的热降解过程及动力学。结果表明,S(IB)S的热降解过程随着升温速率的增大由三步变为两步进行,热降解温度随着升温速率的增大而升高;分别采用Kissinger方程、Doyle方程计算热降解过程的表观活化能,并与用Coats-Redfen方法计算结果比较,分析鉴别出热降解过程的动力学表达式,从而确定了S(IB)S的热降解机理。 相似文献
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嵌段共聚物的微相分离和形态 总被引:1,自引:0,他引:1
嵌段共聚物的微相分离行为和形态的研究是当前多相高聚物研究中众所瞩目的研究内容,无论从基础理论和应用实际都有其极为重要的意义,因此在这方面的研究已有不少报道,并日趋深入。 以最简单的嵌段共聚物A—B为例,如聚苯乙烯—聚异戊二烯二嵌段共聚物 相似文献
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两亲嵌段共聚物溶液内胶束形成的温度效应 总被引:2,自引:0,他引:2
合成了一系列具有两亲嵌段结构的聚(乙二醇)(PEO)一聚(丙二醇)(PPO)共聚物.利用荧光探针及示差量热法测定了共聚物水溶液的临界胶束形成温度(CMT)值.发现二嵌段共聚物(PEO-PPO)和三嵌段共聚物(PEO-PPO-PEO)有着类似的变化规律,即随共聚物分子中疏水链(PPO)长度的增大,其CMT值降低.但三嵌段共聚(PPO-PEO-PPO)则因疏水链段处于共聚物分子的两端,因而在溶液中有可能形成立体网状交联结构.此外,利用探针分子在不同极性溶剂中荧光峰值波长发生位移的现象可以对形成胶束内核的组织程度、极性大小进行估测. 相似文献
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Ningjing Wu Anna Zheng Yongmin Huang Wenbin Yao Honglai Liu 《Journal of Polymer Science.Polymer Physics》2006,44(13):1835-1845
The morphologies of AB diblock copolymer film between the substrate and surface were investigated via Monte Carlo simulations on simple cubic lattices. The morphological dependence of the diblock copolymer thin film on the thickness, as well as the composition and interactive intensity has been mainly studied. With the increase of A‐segments fraction, various microdomain morphologies including regular parallel stripe‐like, mesh‐like, and normal lamella near the region of the surface were generated in this work. The morphology of thin films of asymmetric diblock copolymer was found to form cylinders in a bulk system when Lz was equal to 30. The morphologies of PS‐b‐PDMS diblock copolymer films have been studied via atomic force microscopy (AFM) and transition electron microscopy (TEM) measurements. The surface morphology of the PS‐b‐PDMS copolymer thin film shows a mesh‐like microphase separated structure, and PDMS continuous phase protruded on the PS dispersed phase. The surface composition of PS‐b‐PDMS copolymer thin films was measured by means of X‐ray photoelectron spectroscopy (XPS) and ATR‐IR. The comparison results show that the experimental observations are in good agreement with the simulation results. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1835–1845, 2006 相似文献
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Wen‐Fu Lin Ting‐Jui Hsiao Jing‐Cherng Tsai Tsai‐Ming Chung Rong‐Ming Ho 《Journal of polymer science. Part A, Polymer chemistry》2008,46(14):4843-4856
The preparation of polyolefin‐based stereoregular diblock copolymers by postpolymerization of ethenyl‐capped syndiotactic polypropylene‐based propylene/norbornene copolymer (sPP‐based P‐N copolymer) led to the successful generation of a structurally uniform stereoregular diblock copolymer for self‐assembly studies. The ethenyl‐capped prepolymer was prepared by conducting propylene/norbornene copolymerization in the presence of Me2C(Cp)(Flu)ZrCl2/MAO. Ozonolysis of ethenyl‐capped sPP‐based P‐N copolymer provided the formyl group end‐capped, end‐functionalized prepolymer with a quantitative functional group conversion ratio. Subsequently, connecting the formyl end‐group of the stereoregular prepolymer by coupling with living anionic polystyrene resulted in the high yield production of stereoregular diblock copolymer (sPP‐based P‐N‐block‐polystyrene), which is difficult to prepare by other methods. The resulting stereoregular diblock copolymer possesses precise chemical architecture to self‐organize into consistent nanostructures as evidenced by transmission electron microscopy and small angle X‐ray scattering. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4843–4856, 2008 相似文献
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The target of the present investigation is synthesis and characterization of an amphiphilic diblock copolymer with antibacterial property. Ring opening polymerization (ROP) of ε-caprolactone (CL) and tetrahydrofuran (THF) was carried out under inert atmosphere by using L-cysteine as a bridging agent in the presence of stannous octoate (SO) as a catalyst. The nano silver end capped diblock copolymer was synthesized by in situ method. Thus obtained nano silver end capped L-cysteine bridged diblock copolymer was characterized by various analytical methods like Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, circular dichroism (CD), fluorescence spectroscopy, gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and zeta potential. The antimicrobial property of the nano silver end capped diblock copolymer against e-coli was tested. 相似文献
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Interesting self-assembly behavior and morphological change of a novel organotin-containing diblock copolymer were firstly reported. The organotin-containing diblock copolymer, poly(methyl methacrylate)-block-poly(acetoxydibutyltin methacrylate) (PMMA-b-PADBTMA), was prepared via RAFT polymerization of ADBTMA with PMMA as the macroCTA and AIBN as the initiator in toluene. Both the FT-IR and TG analysis revealed an incorporation of both co-monomers in the resulted polymer backbone. The ratio of two segments was determined indirectly by TG analysis, gravimetric method and derivative process. All results from the different methods were well matched. And it was found that the morphology of the diblock copolymer could be changed easily from vesicles to nano-particle or cross-linked nano-composite under the ultrasonication or additional Ph2SnCl2, respectively. All the morphologies were analyzed by SEM, TEM and DLS. The self-assembly and the morphological change attributed to the strong coordination action between tin atoms and the carbonyl groups among PADBTMA segments. 相似文献
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《先进技术聚合物》2018,29(7):2025-2035
A novel silver nanoparticle doped diblock copolymer was synthesized by a 3‐step process via bulk polymerization process under nitrogen atmosphere. The above prepared polymer is characterized by FTIR spectroscopy, fluorescence emission spectroscopy, circular dichroism (CD), HRTEM, and FESEM. The sulphamicacid end capped poly(ε‐caprolactone) (P1) system exhibited higher tensile strength than the sulphamicacid bridged diblock copolymer (P2) and nano Ag doped sulphamicacid bridged diblock copolymer (P3) systems. The splinting activity of the diblock copolymers was tested and confirmed the low temperature splinting activity of the diblock copolymer. The Ag nanoparticle catalyzed catalytic reduction of p‐nitrophenol (NiP) was tested, and the apparent rate constant (kapp) was determined as 7.36 × 10−3 sec−1. The thermal studies were carried out by DSC and TGA methods. The TGA study declared that the P1 system has higher degradation temperature than the P2 and P3 systems. The P1 system has higher melting temperature (Tm) (75.5°C) than the P2 and P3 systems. The CD study indicated that the conformation of sulphamicacid was not changed even after the formation of nano Ag doped sulphamicacid bridged diblock copolymer. 相似文献
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Summary: The morphologies of diblock copolymers confined in a cylindrical tube have been investigated by the dissipative particle dynamics (DPD) method. Results indicate that the morphology depends on the volume ratio of the immiscible blocks, the diameter of the cylindrical tube and the interactions between the blocks and between the confinement wall and blocks. For symmetric diblock copolymers, when the tube wall is uniform toward the two blocks, perpendicular lamellae or a stacked disk morphology are generally formed except when the diameter of the cylindrical tube is very small; in that case, a special bi‐helix morphology forms because of the entropy effect. When the tube wall is non‐uniform, as the diameter of the tube increases, perpendicular lamellae are first formed, then changing to parallel lamellae and, finally, back to perpendicular lamellae again. An intermediate morphology characterizing the transition between perpendicular and parallel lamellae is observed. If the non‐uniformity of the wall is further enhanced, only parallel lamellae can be found. In the case of asymmetric diblock copolymers, more complex morphologies can be obtained. Multi‐cylindrical micro‐domains and a multilayer helical phase as well as other complex pictures are observed. Generally, the morphologies obtained could find their counterparts from experiments or Monte Carlo simulations; however, differences do exist, especially in some cases of asymmetric diblock copolymers.
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本文采用原子转移自由基聚合方法合成了聚丙烯酸叔丁酯-聚丙烯腈嵌段共聚物(PtBA-b-PAN), 酸解得到聚丙烯酸-聚丙烯腈两亲嵌段共聚物(PAA-b-PAN). 随后, PAA-b-PAN嵌段共聚物在水溶液中自组装形成以PAA为壳, PAN为核的胶束. 用此胶束为模板, 加入FeCl3溶液后得到了壳层负载Fe3+的聚合物纳米粒子, 经230 ℃空气中预氧化, 600 ℃氮气氛煅烧, 得到了核壳结构的, 具有磁性的碳纳米粒子. 用1H NMR, IR, GPC, TGA, TEM, XRD, AGM等技术对嵌段共聚物及纳米粒子进行了表征, 结果表明纳米粒子的壳层含γ-Fe2O3, Fe2.5C混合物, 核含碳, 直径为35 ± 5 nm, 饱和磁化强度为2.16 emu/g. 在分离、吸波和传感器等方面具有潜在的应用前景. 相似文献