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11.
《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1081-1093
Abstract Synthesis and characterization of a flexible polymer produced from silane coupling agent (SCA) and hydroxyl terminated polybutadiene (HTPB) were performed. Mechanical properties of chemically and electrochemically prepared conducting composites synthesized from this polymer were investigated. Conductivities of the composites were also measured. Polypyrrole enhanced the mechanical properties of the chemically prepared conducting composite. Doping with iodine greatly changed the conductivity of the composite. However, the change in mechanical properties and the conductivities of the electrochemically prepared composite were not as significant when compared with the electrochemically prepared polypyrrole. Among the composites, a chemically prepared composite was highly flexible like rubber. However, the electrochemically produced composite possesses two orders of magnitude higher conductivity. Also, this composite revealed higher tensile strength and elasticity with respect to pristine polypyrrole. 相似文献
12.
Abstract Macroazoinitiator (MAI) was prepared from hydroxyl‐terminated polybutadiene (HTPB) and 4,4′‐azobis‐4‐cyanopentanoic acid by direct polycondensation in the presence of 1‐methyl‐2‐chloropyridinium iodide at room temperature. This MAI used for block copolymerization of AAm at 60°C gave the best results in chloroform but the formation of a crosslinked product could not be ruled out in dioxane. It was inferred that for production of a linear block copolymer, homogeneous reaction mixture was required. The resulting products were characterized by spectral studies IR and NMR, viscosity measurements. Distinct phase segregation of hydrophobic and hydrophilic blocks was evident through DSC analysis. 相似文献
13.
A method is described for the preparation of functional polybutadiene (PB) with hydroxyl groups along the polymer chain. This material can be used directly or as the starting substrate for further polymerization in both academic and industrial processes. We have developed a convenient method to obtain a polymer with a narrow molecular weight distribution and with a known content of hydroxyl groups along the backbone. By controlling the hydroxylation reaction conditions, the appropriate molar ratios of THF, water and acid with the epoxide are 30, 15 and 1.5, respectively. By minimizing the crosslinking reaction, the desired PB was prepared and subsequently characterized. 相似文献
14.
Yasuo Horikawa Takeshi Takeda Toshiki Takizawa Taro Akazawa Ryota Fujio Tatsuo Fujimaki 《Journal of polymer science. Part A, Polymer chemistry》1996,34(7):1183-1188
The anionic polymerization of 1,3-butadiene using a novel metalloidal anion initiator, triallylstannyllithium (TALi)-allyllithium (ALi), was studied. The TALi-ALi initiated anionic polymerization of 1,3-butadiene gave the star polymer along with the linear polybutadiene (PBD). The star polymer consisted of three PBD branches and a central tin atom. What is striking is a fact that the number-average molecular weights (Mn) and molecular weight distribution of three PBD branches and linear PBD were almost identical. A reversible chain transfer polymerization mechanism, which includes the equilibrium between tri(macroallyl)-stannyllithium and macroallylic anion, is proposed. © 1996 John Wiley & Sons, Inc. 相似文献
15.
16.
HTPB/TDI,HDI聚合反应动力学研究 总被引:4,自引:0,他引:4
对端羟基聚丁二烯/甲苯二异氰酸酯,端羟基聚丁二烯/己二异氰酸酯甲苯溶液体系进行了反应动力学研究,用基团分析方法计算了相应体系的活化能,并对无催化剂和有催化剂的体系作了比较。结果表明,二丁基二月桂酸象对上述体系有强的催化作用,使体系的活化能降低,反应速度加快。对于对端差基聚丁二烯/甲苯二异氰酸酯体系,无催化剂时前后期反应活化能分别为29.1kJ/mol、37.4kJ/mol,有催化剂时前后期反应活化 相似文献
17.
18.
A. Radulescu D. Schwahn J. Stellbrink M. Monkenbusch L. J. Fetters D. Richter 《Journal of Polymer Science.Polymer Physics》2011,49(2):144-158
Multiblock ethylene‐1‐butene copolymers (PEB‐n) with graded ethylene content (where n is the number of ethyl branches per 100 backbone carbons) represent efficient cold filter plugging point (CFPP) depressants for crude oils and middle distillates. The aggregation behavior and the interaction with wax molecules of a tetrablock PEB‐2.6/PEB‐6.0/PEB‐10.9/PEB‐13.2 and triblock PEB‐6.5/PEB‐8.9/PEB‐10.1 copolymers in decane solutions were investigated over a wide temperature range by combining different small‐angle neutron scattering techniques and optical microscopy. The experimental results revealed in the decrease of temperature formation and evolution of multisized structural levels showing a hierarchical organization on the length scale from 1 nm up to 10 μm. One‐dimensional polymer aggregates arising as initial structures associate and branch that lead to the occurrence of complex macroaggregates with diffusive interfaces and sizes of several microns. The one‐dimensional copolymer structure shows longitudinal density modulation and micellar‐like substructures in neat polymer solutions. When wax is added, this structure becomes more homogeneous in decrease of temperature as a consequence of the cocrystallization of wax and copolymer. The wax crystallization in board‐like objects of much smaller size than required by the CFPP criterion of oil and refinery industry (filter mesh size of 45 μm) is templated and controlled by the assembling features of the crystalline–amorphous PEB‐n multiblock copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
19.
New measurements of the pressure distribution generated by two Newtonian liquids in the Truncated Cone-and-Plate Apparatus are presented, in order to evaluate the exact form of the inertial contribution for a range of Reynolds numbers (Re) fromRe = 140 toRe = 36,000;Re = R
2 /, where and are the liquid density and viscosity respectively,R is the plate radius, and is the angular velocity of the cone. The Walters equation for lowRe, p
w
= 0.15
2 (r2 – R2), is shown to be in excellent agreement with the measurements up toRe = 1000, provided an appropriate correction for the Newtonian hole pressure is made. Up toRe = 1000, the measured slope is within 1% of the theoretical value of 0.15 given by the Walters equation; as the Reynolds number increases above 1000, the data become increasingly nonlinear inr
2. Other theoretical predictions made especially for largeRe begin to disagree with the data even belowRe = 1000. The application of the experimentally determined additive inertial contribution to measurements of pressure distribution in four dilute polymer solutions is found to reproduce adequately the expected form of the viscoelastic pressure distribution, even at highRe where the Walters equation is not valid. Measurements of a combination of normal-stress differencesN
1 + 2N
2 for polymer solutions involving specific polymer/solvent interaction sites show a difference of 45% with change of solvent, while no difference is observed in solutions of polymers without the interaction sites. The normal-stress ratio —N
2/N
1 for a 5% solution of cis-polybutadiene is 0.24 at a shear rate of 100 s–1, and it appears to approach the zero shear limit of 2/7 given by the Doi-Edwards theory. The Higashitani-Pritchard-Baird-Lodge equation relating the elastic hole pressure to the normal-stress differenceN
1 –N
2 gives a qualitative agreement betweenN
1 –N
2 from the TCP Apparatus and the hole pressure from the Stressmeter; the percent difference is 0 at shear stress < 25 Pa, 35% at = 45 Pa, and 18% at the highest = 63 Pa. 相似文献
20.
Philip Dimitrov Pradeep Iyer Marcel Van Beylen Thieo E. Hogen‐Esch 《Journal of polymer science. Part A, Polymer chemistry》2009,47(8):2198-2206
The anionic polymerization of butadiene initiated with 1,4‐dilithio‐1,1,4,4‐tetraphenylbutane (LiTPB) in diethyl ether (DEE) gives polybutadiene (PBD) with high 1,2 content (>70%), narrow polydispersities (1.04 < Mw/Mn < 1.20), and predicted molecular weights. In THF, this polymerization does not work very well. After removal of DEE and addition of THF, the PBD dianion is end capped quantitatively by addition of 1,1‐diphenylethylene (DPE) to give the diphenylalkyl end capped PBD dianion. Subsequent addition of methyl methacrylate at low temperatures results in the formation of well‐defined PMMA‐b‐PBD‐b‐PMMA triblock copolymers. The results are accounted for by taking into account the effects of Li ion solvation on the BD initiation and end capping of the PBD anion by DPE. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2198–2206, 2009 相似文献