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1.
丁二烯-甲基丙烯酸甲酯嵌段共聚物的阴离子聚合及表征   总被引:1,自引:0,他引:1  
讨论了用阴离子方法进行了二烯与甲基丙烯酸甲酯共聚合的过程,并用GPC、FTIR、NMR和动态粘弹谱对共聚物进行了表征.证明所得聚合物为具有较高分子量、窄分布的二嵌段共聚物.  相似文献   

2.
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   

3.
用含氯前聚物路线和Heck反应分别合成[对苯乙炔-2,5-二(十二烷氧基)对苯乙炔]无规共聚物及交替共聚物.由元素分析、凝胶渗透色谱、吸收光谱及DSC对其进行表征,研究了共聚物的组成与导电率、溶解性及发光性能的关系.比较了无规共聚物与交替共聚物在性能上的差别.  相似文献   

4.
以4,4′(α,ω辛二酰氧)二苯甲酰氯,2,5二(4十六烷氧基苯甲酰氧基)对苯二酚和4,4′二(β羟基乙氧基)联苯为单体,通过溶液缩聚反应合成了一系列新的含两种液晶基元的串型液晶共聚物.共聚物通过GPC、DSC、TG、WAXD和偏光显微镜等方法表征.发现所有的共聚物加热至各自的熔点以上都能形成液晶态,在液晶态可以观察到大理石或破碎焦锥织构.所有共聚物的熔点(Tm)和液晶态清亮点(Ti)随聚合物中2,5二(4十六烷氧基苯甲酰氧基)对苯二酚用量的改变呈规律性变化.  相似文献   

5.
高磺化度芳香聚醚醚酮的合成与表征   总被引:8,自引:0,他引:8  
用3,3'-二磺酸钠基-4,4-二氟二苯酮合成了具有高磺化度的荷电聚醚醚酮.用红外吸收光谱及DSC对其进行了表征.研究了共聚物的组成、热稳定性、溶解性、成膜性及磺化度对共聚物性能的影响.  相似文献   

6.
研究了高交联大孔苯乙烯-二乙烯本共聚物在有溶胀剂和无溶胀剂条件下,反应温度、 反应时间及共聚物合成时所用致孔剂对其磺化反应的影响.结果显示,当磺化反应在不同溶胀 剂介质中进行时,共聚物的交换容量随交联度变化可是现不同的关系.与低交联大孔共聚物(交 联度7%)比较,高文联大孔共聚物(交联度60%)磺化反应速度更快,反应能在低得多的温度下 进行,同时溶胀介质对磺化产物的交换容量的影响变得很小.60%交联的共聚物于35C反应3h, 可获得接近于表面磺化的产物.  相似文献   

7.
热可逆性共价交联热塑性弹性体的研究   总被引:4,自引:2,他引:4  
本文以丙烯酸环戊二烯基已酯(CPDEA)、烯丙基环成二烯(A-CP)与丙烯酸乙酯(EA)进行乳液共聚,制得了含环成二烯侧基的共聚物.研究了工艺条件对转化率的影响,测定了共聚物的溶解性能和热转化行为.  相似文献   

8.
嵌段结构对两亲嵌段共聚物水溶液行为的影响   总被引:2,自引:1,他引:2  
在合成了二种具有相同组成不同嵌段结构排布的共聚物基础上对它们溶液的物理化学行为用荧光探针的方法进行了研究,结果表明:由于结构排布的不同其物理化学行为有着较大的差异,三嵌段结构的共聚物较二嵌段者更易于形成胶束体系,而二嵌段共聚物则易于发生凝胶化,对上述结果进行讨论和解释.  相似文献   

9.
用自由基溶液聚合方法制备一系列苯乙烯-丙烯酸甲酯线型共聚物,用核磁共振仪测定了苯基在共聚物中的百分比.在该共聚物的四氢呋喃溶液中,用三氯乙酸汞在共聚物的苯环上进行亲电取代反应,得到可溶性汞化共聚物.由于这类汞化共聚物可溶于四氢呋喃、二氯甲烷等溶剂,用重沉淀法(Reprecipitation)多次提纯,得到了纯度很高、溶解性较好的含重金属二价录的共聚物.用红外光谱仪测定共聚物上的汞基因,用原子吸收仪定量测试共聚中的汞的百分取代率.结果表明在本文实验条件下,二价示可取代在苯环上,与丙烯酸甲酯基因没有作用.  相似文献   

10.
用二苯甲烷钾为引发剂,阴离子聚合法合成了苯乙烯(St)-环氧乙烷(EO)嵌段共聚物,并用FTIR,^1H-NMR,SEC,WAXD和动态粘弹谱对共聚物进行了表征。结果表明所得聚合物为分子量可控,窄分布的两嵌段共聚物。  相似文献   

11.
This paper describes the synthesis and characterization of poly(butadiene)m-poly(L-lysine)n (m-n = 107-200, 107-100, and 60-50) block copolymers. The polymers are prepared in a two-step process whereby amine-terminated polybutadiene is used to initiate the ring-opening polymerization of the epsilon-benzyloxycarbonyl L-lysine N-carboxyanhydride. After deprotection, the self-assembly of the block copolymers in aqueous media were studied using dynamic light scattering, transmission electron microscopy, and circular dichroism spectroscopy. These block copolymers were found to form either spherical micelles or rod-like micelles at high pH depending on the composition of the block copolymer. As the pH is decreased, the micelles swell due to charge-charge repulsions between corona chains and from the helix-coil transition of the polypeptide block. The two systems that form rod-like micelles at high pH also exhibit a pH-induced rod-sphere transition at low pH. This transition was verified from Kratky analysis of the static light scattering data and via CONTIN analysis of the dynamic light scattering data, which shows a bimodal distribution in particle sizes.  相似文献   

12.
用CpTi(OBz)3/MAO催化体系合成的苯乙烯/丁二烯嵌段共聚合产物经丁酮、甲苯、四氢呋喃、氯仿连续抽提,并用已烷对丁酮的可溶级分进行再抽提;不同级分分别用GPC、^13C -NMR、DSC和WAXD等手段进行分析和表征。发现嵌段共聚物主要存在于氯仿可溶级分中,丁酮可溶级分基本上是无规聚苯乙烯和聚丁二烯组成的混合物(己烷可溶级分为聚丁二烯,不溶级分为无规模聚乙烯)。GPS谱图表明该嵌段共聚反应具有单催化活性中心的聚合特征,^13C-NMR谱图显示该嵌段共聚物分子链由间规聚苯乙链段和聚丁二烯链段组成,WAXD图谱显示嵌段共聚物有较高的结晶度。  相似文献   

13.
将活性负离子聚合与原子转移自由基聚合(ATRP)技术相结合,运用机理转移法制备了一种两亲性材料聚丁二烯-b-聚(甲基丙烯酸N,N-二甲氨基乙酯)(PB-b-PDMAEMA)嵌段共聚物.首先通过负离子聚合方法设计合成聚丁二烯,用环氧丙烷封端,2-溴异丁酰溴作酯化剂,合成具有活性端基溴的聚丁二烯大分子引发剂(PB-B r),再用其引发亲水性单体DMAEMA进行原子转移自由基聚合,聚合动力学证实了该聚合反应具有典型的活性/可控自由基聚合的特征.通过差示扫描量热法(DSC)研究嵌段共聚物的微相分离行为.制备的大分子引发剂及两亲性嵌段共聚物经凝胶色谱、红外和核磁表征证实了预定的结构.  相似文献   

14.
New poly(ether sulfone)-polyimide block copolymers were synthesized from α,ω-diamineterminated poly(ether sulfone) oligomer, aromatic diamines, and aromatic tetracarboxylic dianhydrides by low-temperature solution polymerization and subsequent thermal imidization. The block copolymers were insoluble in organic solvents. The multiblock copolymers obtained by the two-pot method showed microphase separation, while the random block copolymers by the one-pot method had single phase morphology. The mechanical properties of the block copolymers were greatly improved by the introduction of polyimide into the poly(ether sulfone). © 1993 John Wiley & Sons, Inc.  相似文献   

15.
The binary random in-chain silyl-hydride multi-functionalized poly(styrene/butadiene/isoprene and dimethyl[4-(1-phenylvinyl) phenyl]silane)(PS-DPESiH,PB-DPESiH,PI-DPESiH) copolymers were successfully synthesized.These functionalized copolymers were prepared in hexane with n-BuLi as the initiator at 50℃for 4 h.The silyl-hydride groups were introduced into polymer backbones quantitatively by living anionic polymerization.The copolymers were determined through ’H NMR,size exclusion chromatography(SEC) and differential scanning calorimetry(DSC) techniques,while the number of silyl-hydride groups was calculated and discussed.  相似文献   

16.
聚芳醚腈-聚硅氧烷嵌段共聚物的合成   总被引:4,自引:0,他引:4  
采用4-烯丙基-2-甲氧基苯酚(Eugenol)为端基的聚二甲基硅氧烷与氟代苯端基含杂萘联苯结构聚芳醚腈,以碳酸钾为催化剂,二甲基亚砜与邻二氯苯为溶剂的条件下进行芳香亲核取代反应(SNAr),合成了一种高分子量的聚芳醚腈-聚硅氧烷嵌段共聚物,并采用FTIR和1H-NMR对该产物的结构进行了表征.DSC测试结果表明该类嵌段共聚物具有两个玻璃化转变温度(Tg),分别为-98~-90℃和255~287℃,而且共聚物具有优良的耐热性,10%的热失重温度(Td)在450℃以上.采用原子力显微镜和透射电镜观测发现该共聚物存在明显的相分离特征.  相似文献   

17.
以α-甲基萘钾为引发剂,按顺序加入丁二烯、八甲基环四硅氧烷(D4)在THF中进行负离子嵌段共聚,制备了聚了二烯-聚二甲基硅氧烷嵌段共聚物.讨论了聚合条件对嵌段共聚合过程的影响.考察了聚了二烯活性链引发D4进行嵌段共聚的反应动力学,求得在THF中30℃时D4开环链增长的表观速率为10kg/mol.h、表观活化能为28.3kJ/mol.  相似文献   

18.
A novel linked‐half‐sandwich lutetium–bis(allyl) complex [(C5Me4? C5H4N)Lu(η3‐C3H5)2] ( 1 ) attached by a pyridyl‐functionalized cyclopentadienyl ligand was synthesized and fully characterized. Complex 1 in combination with [Ph3C][B(C6F5)4] exhibited unprecedented dual catalysis with outstanding activities in highly syndiotactic (rrrr>99 %) styrene polymerization and distinguished cis‐1,4‐selective (99 %) butadiene polymerization, respectively. Strikingly, this catalyst system exhibited remarkable activity (396 kg copolymer (molLu h)?1) for the copolymerization of butadiene and styrene. Irrespective of whether the monomers were fed in concurrent mode or sequential addition of butadiene followed by styrene, diblock copolymers were obtained exclusively, which was confirmed by a kinetics investigation of monomer conversion of copolymerization with time. In the copolymers, the styrene incorporation rate varied from 4.7 to 85.4 mol %, whereas the polybutadiene (PBD) block was highly cis‐1,4‐regulated (95 %) and the polystyrene segment remained purely syndiotactic (rrrr>99 %). Correspondingly, the copolymers exhibited glass transition temperatures (Tg) around ?107 °C and melting points (Tm) around 268 °C; typical values for diblock microstructures. Such copolymers cannot be accessed by any other methods known to date. X‐ray powder diffraction analysis of these diblock copolymers showed that the crystallizable syndiotactic polystyrene (syn‐PS) block was in the toluene δ clathrate form. The AFM micrographs of diblock copolymer showed a remarkable phase‐separation morphology of the cis‐1,4‐PBD block and syn‐PS block. This represents the first example of a lutetium‐based catalyst showing both high activity and selectivity for the (co)polymerization of styrene and butadiene.  相似文献   

19.
Two block copolymers of isotactic polypropylene and 1,4 polybutadiene were synthesized using techniques involving a transformation from anionic to Ziegler–Natta polymerization mechanisms. The yield of block copolymer was about fifteen percent (weight basis) in both polymerizations, the remainder being unreacted polybutadiene from the first block synthesis. Molecular characterization experiments and model reactions were consistent with a block-like structure for the copolymers; definitive evidence for the proposed molecular structure was obtained through transmission electron microscopy which clearly revealed microphase-separated morphologies characteristic of block copolymers.  相似文献   

20.
A new hydrocarbon-soluble (additive-free) dicarbanionic organolithium initiator, obtained by a simple halogen-lithium exchange reaction (Gilman's reaction) from a diarylhalide containing a side C15 alkyl chain, has been designed and used to initiate the anionic polymerization of butadiene and styrene. The dilithiated species formed afford well-defined poly(styrene-b-butadiene-b-styrene) (SBS) triblock copolymers with a high percentage of 1,4-microstructure polybutadiene (91%) and excellent mechanical properties, such as ultimate tensile strength higher than 30 MPa and elongation at a break of 1000%. This represents a breakthrough in the synthesis of SBS polymers, one of the most used thermoplastic elastomers.  相似文献   

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