四苯醚砜双炔聚合过程及其聚合物的动态力学行为研究

本文用扭辫分析(TBA)和红外光谱研究了双[4-(4-乙炔基苯氧基)苯基]砜(简称四苯醚砜双炔)及其聚合物的动态力学行为.TBA热谱的结果可以明显地表征四苯醚砜双炔的熔融及其低温区和高温区的化学反应特征,以及其聚合物的玻璃化转变和分解反应等物理-化学转变行为.实验表明四苯醚砜双炔聚合物的玻璃化温度T_g极大地取决于聚合条件.     

Anomalous solubility of polyacrylamide prepared by dispersion (precipitation) polymerization in aqueous tert‐butyl alcohol

Polyacrylamide prepared by dispersion (precipitation) polymerization in an aqueous t‐butyl alcohol (TBA) medium is only partially soluble when the TBA concentrations in the polymerization media are in the range 82 vol % < TBA < 95 vol %. Independent experiments with a soluble (linear) sample of polyacrylamide show that the polymer swells sufficiently in the aforementioned media to lower the glass‐transition temperature of the polymer below the polymerization temperature (50 °C). The anomalous solubility has been attributed to the crosslinking of polymer chains that occurs during the solid‐phase polymerization of acrylamide in the swollen polymer particles. It is postulated that some of the radical centers shift from the chain end to the chain backbone during solid‐phase polymerization by chain transfer to neighboring polymer molecules, and when pairs of such radicals come into close vicinity, crosslinking occurs. However, dispersion (precipitation) polymerization in other media such as aqueous methanol and aqueous acetone yields polymers that are soluble. This result has been attributed to the fact that the polymer radical undergoes a chain‐transfer reaction with these solvents at a much faster rate than with TBA, which overcomes the effect of the polymer‐transfer reaction. Even the addition of as little as 5% methanol to a TBA–water mixture (TBA:water = 85:10) gives rise to a soluble polymer. The chain‐transfer constants for acetone, methanol, and TBA have been determined to be 9.0 × 10^?6, 6.9 × 10^?6, and 1.48 × 10^?6, respectively, at 50 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3434–3442, 2001     

基于2,6-二甲基萘的杂环聚芳醚酮的合成

由1,5-二(4'-氟苯甲酰基)-2,6-二甲基萘(1)和类双酚单体(2a～2d)通过N—C偶联聚合反应合成了一系列基于2,6-二甲基萘的新型杂环聚芳醚酮(3a～3d).采用FTIR、1H-NMR、DSC、TGA、GPC等手段对聚合物进行结构表征和性能测试,并研究了其溶解性及特性黏数.结果表明,聚合物在室温下易溶于氯仿、DMAc、NMP、吡啶和间甲酚等非质子极性有机溶剂,其氯仿溶液能形成无色透明、韧性较好的膜,特性黏数(ηinh)在0.76～1.40 dL/g范围内.聚合物3b～3d的数均分子量(Mn)和分散指数(PDI)分别在78000～104000和1.66～2.21范围内.该类聚合物的玻璃化转变温度(Tg)均大于280℃,在氮气氛围和800℃时的残余量在53%～69%范围内.该类聚合物在氮气中5%和10%的热失重温度分别在423～440℃和434～467℃范围内.     

漆酶催化对苯基苯酚的聚合

漆酶(EC 1．10．3．2)是一种氧化还原酶,可应用于催化氧化还原反应和高分子合成领域．聚酚类物质由于具有丌电子共轭结构,通过掺杂可以表现出一定的导电性,而有机导电聚合物是一类有着广泛应用前景的功能材料．此外这类物质还具有较高的三阶非线性系数,是一类重要的有机非线性光学材料,是激光技术的重要物质基础之一．而取代苯酚类物质由于其结构的特殊性,一般很难用化学方法使其聚合．有报道用辣     

聚亚胺酮的合成与性能研究

聚酰胺(PA)、聚醚酮(PEK)和聚酰亚胺(PI)等作为高性能材料已被开发并得到应用.这些高性能材料可用于航空、航天、微电子等高新技术领域[1~5].与此同时,为了满足人们对新材料的需求,科学界对新型高性能材料的开发和应用始终没有停止,且备受关注.本文首先通过傅-克酰基化反应合成     

Synthesis and polymerization of 2,5‐Bis(4′‐alkoxy‐phenyl)styrene for mesogen‐jacketed liquid crystal polymers

A series of novel reactive liquid crystals, 2,5‐bis(4′‐alkoxy‐phenyl)styrene, was designed and synthesized to prepare stereoregular mesogen‐jacketed liquid crystal polymers (MJLCPs). These monomers are different from their analogous studied previously in that they do not contain polar linkages such as ester or/and amide group and therefore are expected to polymerize easily both by radical and ionic polymerization. The preliminary studies show that the resulting polymers have higher glass transition temperature (Tg) and much better thermal stability than their analogous.     

Poly(4-nitrophenyl)quinoxalines

Via the reaction of 4,4-bis(4-nitrophenylglyoxalyl)diphenyl ether with different bis(o-phenylenediamine)s, new poly(4-nitrophenyl)quinoxalines were synthesized, which are of interest as precursors for polymers containing protogenic groups. Some properties of the obtained polymers were studied. It was shown that the solubility of poly(4-nitrophenyl)quinoxalines in organic solvents and their viscosity characteristics are comparable with the parameters of polyphenylquinoxalines that do not bear nitro groups. A study of the thermal properties of the polymers showed that the introduction of nitro groups into polyphenylquinoxalines is accompanied by some increase in the glass transition temperature and a decrease in the onset temperature of runaway thermal degradation.     

树枝状醚酰胺多官能团(甲基)丙烯酸酯低聚物的合成及其紫外光固化性能的研究

合成了树枝状(甲基)丙烯酸化醚酰胺低聚物,采用拉曼光谱、光-差热分析和动态力学热分析方法对其紫外光固化动力学和固化膜热机械性能进行了研究.结果表明,这种树枝状低聚物在紫外光照下双键转化率可达80%以上,且其最大反应速率、固化膜的软化温度和玻璃化转变温度随双键浓度的增大而提高.     

高聚物玻璃化转变温度和分子参数的关系 Ⅱ.分子量对玻璃化转变温度的影响

根据前文提出的理论模型,本文推导出下述表征高聚物数均分子量(M_n)与玻璃化转变温度T_8关系的理论公式: T_g=T_g~∞-K_g/M_n K_g=T_g~∞·σ~2(T_g)·M_u十几种高聚物的K_g理论计算位能较好地和实验值吻合。应用理论关系式具体计算了聚苯乙烯、聚氯乙烯、聚二甲基硅氧烷和聚α-甲基苯乙烯的T_g随分子量的变化,其结果是令人满意的。     

聚丙烯酸[2,5-双(对甲氧基苯甲酰氧基)苄酯]及聚甲基丙烯酸[2,5-双(对甲氧基苯甲酰氧基)苄酯]的合成

周其凤等曾报道聚丙烯酸［２,５－双（对甲氧基苯甲酰氧基）节酯］［１］和聚甲基丙烯酸［２,５－双（对甲氧基苯甲酰氧基）苄酯］［２］的合成．但后来的研究发现,在合成单体的条件下出现的一种未见报道的异常反应［３］使产物成分复杂化,因此当时报道的聚合物可能不是聚丙烯酸［２,５－双－（对甲氧基苯甲酰氧基）苄酯］或聚甲基丙烯酸［２,５－双（对甲氧基苯甲酰氧基）苄酯］,而可能是共聚物．针对这一问题,我们重新设计了合成路线以避免发生上述副反应,成功地合成了丙烯酸或ａ－甲基丙烯酸［２,５－双－（对甲氧基苯甲酰氧基…     

硝基环氧化合物的单体结构对其聚合活性和聚合物性能的影响

研究了一些环氧化合物:[R=H(Ⅰ),NO_2(Ⅱ),NO_3(Ⅲ),OCH_2CH_2NO_2(Ⅳ),OCH_2CH_2NO_3(Ⅴ)]的单体结构对其阳离子开环聚合活性及其聚合物性能的影响。在催化系统下,其聚合活性大小有如下顺序:(Ⅰ)>(Ⅳ)≥(Ⅴ)>(Ⅲ)>(Ⅱ)。着重研究了上述硝基环氧化合物与四氢呋喃的共聚物的热稳定性、化学稳定性、玻璃化温度以及其胶片的力学性能。     

聚(L-谷氨酸γ-苄酯)-聚四氢呋喃-聚(L-谷氨酸γ-苄酯)三嵌段共聚物的合成与表征

聚氨基酸是一类低毒性、生物相容性良好、易被机体吸收和代谢的可降解合成高分子材料，在药物控释载体、组织工程支架、生物材料表面改性方面得到了广泛应用．但其降解周期及降解速度通常难以控制，应用受到一定限制．通过共聚方法将生物相容和亲水性良好的聚乙二醇（PEG）引入聚氨基酸链段中形成两亲性嵌段共聚物旧，研究其自组装行为，及作为基因转染和药物控释载体等已成为高分子科学领域新的研究热点．     

Synthesis and thermal properties of disiloxane-arylene polymers by dehydrocoupling polymerization of bis(dimethylsilyl)arylene with water

Disiloxane-arylene polymers having phenylene, biphenylene, and fluorenylene groups as arylene units were synthesized by dehydrocoupling polymerization of corresponding bis(silane) derivatives with water. The reactivity of Si-H was not affected by the structure of aromatic groups in the reaction. The polymers containing biphenylene and fluorenylene units are amorphous and show higher glass transition temperatures than the polymer from 1,4-bis(dimethylsilyl)benzene.     

4,4’-二氯二苯酮合成二氮杂萘联苯酮结构聚醚砜酮的研究

以4-(4-羟基苯基)*2,3-二氮杂萘-1-酮(DHPZ)、4,4’-二氯二苯砜(DCS)和4,4’-二氯二苯酮(DCK)为原料,采用分步加料的方法,合成了系列高分子量的聚芳醚砜酮共聚物(PPESKs),其特性黏度在0.40 ～0.61dL/g之间,解决了由于DCK活性低不适合用于聚芳醚合成的问题.采用FTIR、示差...     

Properties of block (co)polymers of methyl methacrylate and perfluorinated polyphenylenegermane

Hybrid (co)polymers of linear-dendritic structure were prepared by radical polymerization of methyl methacrylate in the presence of superbranched perfluorinated polyphenylenegermane to high conversions. The molecular-weight characteristics and the sorption capacity of the products were examined. The glass transition point, elastic modulus, mechanical loss factor, and tensile strength of the copolymers obtained were determined.     

STUDY ON LIQUID CRYSTALLINITY OF POLY(N-VINYLCARBAZOLE)

The liquid crystallinity of poly(N-vinylcarbazole) was studied by using powder X-ray diffraction, polarized opticalmicroscopy, and differential scanning calorimetry. The results show that the lower molecular weight fractions of this polymerdo not form a liquid crystalline phase, while the samples of sufficiently high molecular weight do form a mesophase attemperatures above the glass transition. The lowest value of the degree of polymerization for PVK to form a stable liquidcrystalline phase was found to be in the range of 150 to 200, significantly higher than the value of 50 for most conventionalside chain liquid crystaline polymers.     

Side‐chain ferrocene‐containing (meth)acrylate polymers: Synthesis and properties

A comprehensive investigation on the synthesis and properties of a series of ferrocene‐containing (meth)acrylate monomers and their polymers that differ in the linkers between the ferrocene unit and the backbone was carried out. The side‐chain ferrocene‐containing polymers were prepared via atom transfer radical polymerization. The kinetic studies indicated that polymerization of most monomers followed a “controlled”/living manner. The polymerization rates were affected by the vinyl monomer structures and decreased with an increase of the linker length. Methacrylate polymerization was much faster than acrylate polymerization. The optical absorption of monomers and polymers was affected by the linkers. Thermal properties of these polymers can be tuned by controlling the length of the linker between the ferrocene unit and the backbone. By increasing the length of the linker, the glass transition temperature ranged from over 100 to ?20 °C. Electrochemical properties of both monomers and polymers were characterized. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of 4-cyanobiphenyl-4′-yloxy-functionalized poly(7-oxanorbornene-5,6-exo-dicarboximide)s via ring opening metathesis polymerization (ROMP)

N-[n-(4-cyanobiphenyl-4′-yloxy)alkyl]-7-oxanorbornene-5,6-exo-dicarboximide ( CBON ₂– CBON ₈) with increasing number of methylene groups in the alkyl part (n = 2–8) were synthesized by Mitsunobu condensation between the appropriate alcohols ( CBA ₂– CBA ₈) and 7-oxanorbornene-5,6-exo-dicarboximide ( ON ). The conditions for the ring opening metathesis polymerization of CBON _n giving acceptable molecular weights and molecular distributions were established. Characterization of the resulting polymers ( P ₂– P ₈) by ¹H- and ¹³C-NMR has shown a high trans content. Differential scanning calorimetry and optical microscopy analysis have shown that the alcohols CBA _n are thermotropic with some variations between the first and second heating-cooling cycles, the monomers CBON _n melt with no evidence of any mesomorphic state, the polymers P _n show only the glass transition, and the glass transition temperature (T_g) decreases with increases in the spacer length. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2807–2821, 1998     

Liquid-crystalline behaviour of 4-(ω-aminoalkyloxy)-4'-cyanobiphenyls and their side chain epoxy polymers

Liquid-crystalline side chain polymers were obtained from the ring-opening reaction of epoxy resin with mesogenic amines, 4-(ω-aminoalkyloxy)-4'-cyanobiphenyl. The amines with the alkyl group ranging from five to nine methylene units were synthesized, and were found to exhibit an enantiotropic nematic phase. Polymerization of these amines with ethylene glycol diglycidyl ether at 100°C yielded the polymers of low glass transition and melting temperatures. The mesomorphic properties of the amines and the resulting epoxy polymers are reported.     

烷基取代聚对亚苯基亚乙烯基衍生物的合成和性质研究

设计了一种合成烷基取代聚对苯撑乙烯 (PPV)衍生物的新方法 ,合成了一种新的烷基取代PPV 聚(2 甲基 5 十二烷基对苯撑乙烯 ) ,并用NMR、IR、GPC、元素分析等方法对化合物进行了表征与鉴定 .同时 ,测试了化合物的热学性质、紫外可见吸收和光致荧光性质 .发现化合物的玻璃化温度和第一分解温度随着共轭程度的增加而升高 ;化合物的THF稀溶液的光致荧光相对量子产率随共轭程度的降低而增加