共查询到19条相似文献,搜索用时 109 毫秒
1.
液体色谱,凝胶色谱分析低聚芳砜及其双烯大分子单体 总被引:2,自引:0,他引:2
本文用液相色谱和凝胶色谱对双酚A、双酚S型低聚芳砜及α,ω-双甲基丙烯酸聚芳砜酯大分子单体进行了组分分析,通过改合成条件、测定数均分子量等辅助手段确定液相色谱各峰的归属,计算其分子量及分子量分布指数,并对两种方法测定的结果进行了比较。用液相色谱观察低聚体每个组分的含量及其反应过程中的消长情况比凝胶色谱清晰。 相似文献
2.
本文用粘度和小角光散射法确定了聚苯醚砜(PPES)25℃时θ溶剂的组成(DMF与C_2H_5OH的体积比为81.5:18.5)。表征了PPES链的柔性参数A=(r_0~2/M)~(12)=0.0864 nm,C_∞=r_0~2/nl~2=2.5。订定PPES在DMF中25℃的MHS方程为[η]=0.0499 M~(0.63),与Allen的结果不同。得到了第二维利系数A_2与重均分子量的关系为A_2=0.0375 M~(-0.36),还测定了PPESDMF体系的Huggins参数X_1。 相似文献
3.
4.
5.
以氟苯和氯化亚砜反应合成了4,4’-二氟二苯亚砜,并将其与4,4’二羟基二苯硫醚在N-甲基吡咯烷酮溶剂中进行亲核取代反应合成了聚苯醚硫醚醚亚砜,用乙二酰氯/四丁基碘化铵还原该亚砜聚合物制备了聚苯醚硫醚。用红外光谱和核磁共振谱对合成单体的结构进行了确认,同时对聚合物进行了红外光谱、核磁共振、元素分析、X射线光电子能谱、X射线衍射、DSC分析、TG/DTG以及溶解性测试。结果表明聚苯醚硫醚样品具有氧醚和硫醚交替的线性结构,特性粘度为0.55 dL/g的PPSE熔点达236℃,在氮气条件下,样品起始分解温度和最大分解速率处温度分别为359℃和514℃,在700℃时的重量保留率为43.3%,且在加热条件下能溶解于N-甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)等极性有机溶剂中。 相似文献
6.
测定含甲基丙烯酰氧端基大分子单体分子量的新方法 总被引:1,自引:0,他引:1
建立了用紫外分光光度法测定含甲基丙烯酰氧端基大分子单体数均分子量的新方法 .在本实验条件下 ,以 95%乙醇∶THF( 7∶3 )为溶剂 ,在最大吸收波长 2 1 3nm处对含甲基丙烯酰氧端基的聚四氢呋喃大分子单体进行定量分析 ,所得结果与端基滴定分析法所得结果最大相对误差小于± 5% ,用t检验法对两法测定结果差别进行显著性检验 ,两法所得结果差别无显著意义 .紫外分光光度法可成为一种表征含甲基丙烯酰氧端基大分子单体数均分子量的方便方法 . 相似文献
7.
本文用广角及准弹性光散射法测定了聚苯醚砜各级分在DMF中和在θ溶剂中25℃时的均才半径R_G,第二维利系数A_2,流体力学半经R_H,扩散系数D_O,扩散系数的浓度依赖性k_F以及这些参数与分子量M的关系。它们的结果如下R_G=0.031MO~(0.55) D_O(θ)=0.906×10~(-4)M~(0.5) D_0=1.445×10~(-4)M~(0.55)A_2=0.033M~(-0.35) k_D(θ)=0.5M~(0.34) k_D=2.3×10~(-6)M~(1.36)α_H=R_H/R_H(θ)=0.63M~(0.05)R_H(θ)=0.0299M~(0.5)R_H=0.0188M~(0.55) 作者讨论了静态与动态两种高分子尺寸之间的关系;三种溶胀因子α_η和、α_H、α_G之间的关系;以及摩擦系数的浓度系数k_F与流体力学体积V_H之间的关系。它们的结果满足下面各关系式: R_H/R_G=[π(v+1)(2v+1)/3]~(1/2)(2-v)(1-v)/2, α_η~3=α_(G)~2α_H, k_F=1.2A_2M+N_AV_H/M,K_F(θ)=N_AV_H/M 相似文献
8.
9.
建立了用紫外分光光度法测定含甲基丙烯酰氧端基大分子单体数均分子量的新方法 .在本实验条件下 ,以 95%乙醇∶THF( 7∶3 )为溶剂 ,在最大吸收波长 2 1 3nm处对含甲基丙烯酰氧端基的聚四氢呋喃大分子单体进行定量分析 ,所得结果与端基滴定分析法所得结果最大相对误差小于± 5% ,用t检验法对两法测定结果差别进行显著性检验 ,两法所得结果差别无显著意义 .紫外分光光度法可成为一种表征含甲基丙烯酰氧端基大分子单体数均分子量的方便方法 . 相似文献
10.
聚醚砜单烯大分子单体的合成与表征及其共聚物的光学特性 总被引:1,自引:0,他引:1
本文采用溶液法以单酚(4-氯-4’-羟基二苯砜)为原料合成了不同聚合度的单酚低聚体,得到了控制聚合度的最佳聚合条件;用相转移催化剂法成功地将单酚转化为单烯大分子单体,并用IR、1H—NMR对其结构进行了表征;测定了双键官能度均在1.90以上.单烯大分子单体与苯乙烯的共聚研究表明,聚合度为2左右的单烯大单体在苯乙烯中溶解度最大,可达80%以上;共聚物有优异的光学特性,对折射率的提高比相应的双烯大分子单体有利;在可见及近红外区透光率达89%以上. 相似文献
11.
Hans R. Kricheldorf Majdi Al Masri 《Journal of polymer science. Part A, Polymer chemistry》1995,33(15):2667-2671
Attempts were made to synthesize poly(ether-sulfone)s from aliphatic diols or bissilylated diols on the one hand, and 4,4′-dichlorodiphenylsulfone or 4,4′-difluorodiphenylsulfone on the other hand. The reaction conditions and the catalyst were varied. Polycondensations of silylated diols with 4,4′-difluorodiphenylsulfone and powdered K2 CO3 in N-methylpyr-rolidone proved to give the best results. Using silylated isosorbide and isomannide as mono-mers chiral poly(ether-sulfone)s were prepared. GPC measurements indicate weight-average molecular weights in the range of 27×103–200×103. © 1995 John Wiley & Sons, Inc. 相似文献
12.
In this work, the condition for the analysis of title compounds by HPLC was chosen.The componentcontent and average molecular weight of some kinds of poly(ether-sulfone)s oligomers were determined suc-cessfully. The optimum condition for the partial hydrolysis reaction from 4,4'-dichlorodiphenylsulfone to 4-chloro-4'-hydroxyldiphenylsulfone was obtained.In addition,the constituent changes of the oligomer can beobserved and determined by this method in the polymerization process. 相似文献
13.
Jin Chul Jung Sang-Bong Park 《Journal of polymer science. Part A, Polymer chemistry》1993,31(13):3351-3359
To obtain an understanding of the low molecular weight character of wholly aromatic poly(1,4-arylene acyldiamide oxime)s (PAAs) having n-alkyloxymethyl side braches and the additional decrease in molecular weight during their cyclodehydration reaction leading to the corresponding poly(1,4-arylene-1,2,4-oxadiazole)s (PAOs), tautomeric structures of poly[1,4-phenylene-2,5-bis(n-octyloxymethyl)terephthaldiamide oxime] (C8-PAA) were 1H-NMR-spectroscopically investigated by using two model compounds: O,O'-dibenzoyl terephthaldiamide oxime (H-PAA-M, 4) and O,O'-dibenzoyl-2,5-bis(n-octyloxymethyl) terephthaldiamide oxime (C8-PAA-M, 5). In solution H-PAA-M existed exclusively as oximino isomer, while C8-PAA-M consisted only of imino tautomer and C8-PAA contained both the oximino and imino form, the former being dominant in composition. It was found that the presence of imino tautomer caused serious effects both on the low molecular weight character of C8-PAA and on the additional decrease in molecular weight during thermal cyclodehydration to C8-PAO, whereas the presence of oximino tautomer showed practically little effect. A discussion on the results is provided from mechanistic viewpoint. © 1993 John Wiley & Sons, Inc. 相似文献
14.
S. J. Wang Y. Z. Meng S. C. Tjong A. R. Hlil A. S. Hay 《Journal of polymer science. Part A, Polymer chemistry》2003,41(16):2481-2490
High‐molecular‐weight poly(phthalazinone)s with very high glass‐transition temperatures (Tg's) were synthesized via a novel N–C coupling reaction. New bisphthalazinone monomers ( 7a–e ) were synthesized from 2‐(4‐chlorobenzoyl) phthalic acid in two steps. Poly(phthalazinone)s, having inherent viscosities in the range of 0.34–0.91 dL/g, were prepared by the reaction of the bis(phthalazinone) monomers with an activated aryl halide in a dipolar aprotic solvent in the presence of potassium carbonate. The poly(phthalazinone)s exhibited Tg's greater than 230 °C. polymer 8b synthesized from diphenyl biphenol and bis(4‐flurophenyl) sulfone demonstrated the highest Tg of 297 °C. Thermal stabilities of the poly(phthalazinone)s were determined by thermogravimetric analysis. All the poly(phthalazinone)s showed a similar pattern of decomposition with no weight loss below 450 °C in nitrogen. The temperatures of 5% weight loss were observed to be about 500 °C. The poly(phthalazinone)s containing 4,4′‐isopropylidenediphenol and 4,4′‐(hexafluoroisopropylidene) diphenol and diphenyl ether linkage were soluble in chlorinated solvents such as chloroform. Other poly‐(phthalazinone)s were soluble in dipolar aprotic solvents such as N,N′‐dimethylacetamide. The soluble poly(phthalazinone)s can be cast as flexible films from solution. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2481–2490, 2003 相似文献
15.
Z. Y. Ren W. Y. Liu Y. M. Hou Y. Zhu L. K. Chang D. Z. Ma 《Journal of Thermal Analysis and Calorimetry》2001,63(1):153-160
Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
16.
V. Percec M. Grigoras R. S. Clough J. Fanjul 《Journal of polymer science. Part A, Polymer chemistry》1995,33(2):331-344
The ability to achieve high molecular weight poly(ether ketone)s from the polycondensation of bis(aryl chloride)s with bis(phenolate)s has been consistently demonstrated. The polymerizations presented here help to delineate for specific bis(aryl chloride)/bisphenolate pairs the reaction conditions required to obtain high molecular weight polymers. Polycondensation of 1,3-bis(4-chlorobenzoyl)-5-tert-butylbenzene ( 6 ) and 2,2′-bis(4-chlorobenzoyl)-biphenyl ( 15 ) with various bisphenolates as well as of 2,2′-bis(4-hydroxyphenoxy)biphenyl ( 33 ) with 4,4′-dichlorobenzophenone ( 41 ) and 1,3-bis(4-chlorobenzoyl)benzene ( 43 ) were used as representative model systems to select reaction conditions that led to high molecular weight polymers. © 1995 John Wiley & Sons, Inc. 相似文献
17.
用大单体技术合成了带规整聚苯乙烯支链的聚丙烯酸接枝共聚物 .研究了各种聚合条件包括温度、时间、单体浓度、大单体分子量及大单体与小单体的投料比等对接枝效率、共聚物分子量的影响 .纯化的共聚物表现出良好的乳化性质及高吸水率 ,在稀溶液中的行为如同聚电解质 .此接枝共聚物与含规整聚氧乙烯支链的聚丙烯酸乙酯络合生成的大分子间络合物膜呈现化学阀的作用 ,水通过它的渗透速率能通过调节pH加以可逆地控制 . 相似文献
18.
Tomoyuki Ohishi Ryuji Sugi Akihiro Yokoyama Tsutomu Yokozawa 《Journal of polymer science. Part A, Polymer chemistry》2006,44(17):4990-5003
Chain-growth polycondensation of 3-(alkylamino)benzoic acid alkyl esters 1 was investigated for obtaining poly(m-benzamide)s with defined molecular weights and low polydispersities. Polymerization conditions were first studied to find that ethyl 3-(octylamino)benzoate ( 1b ) polymerized in a chain polymerization manner in the presence of lithium 1,1,1,3,3,3-hexamethyldisilazide (LiHMDS) as a base and phenyl 4-methylbenzoate ( 2b ) as an initiator in THF at 0 °C. The molecular weight of the polymer was controlled by the feed ratio of monomer to initiator. The polymerization of 1c – i with a variety of N-alkyl groups was then carried out under the established conditions to yield well-defined poly(m-benzamide)s, which showed higher solubility than those of the corresponding poly(p-benzamide)s. Furthermore, the 4-octyloxybenzyl group on the amide nitrogen in poly 1i was removed by treatment with trifluoroacetic acid (TFA) to give N-unsubstituted poly(m-benzamide) (poly 1j ) with a low polydispersity, which is soluble in DMAc and DMSO, contrary to the para-substituted counterpart. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4990–5003, 2006 相似文献
19.
Chin-Ping Yang Yung-Yu Yen 《Journal of polymer science. Part A, Polymer chemistry》1992,30(9):1855-1864
Novel aromatic poly(amide-imide)s with high inherent viscosities were prepared by direct polycondensation reaction of 2,5-bis(4-trimellitimidophenyl)-3,4-diphenylthiophene ( IV ) and aromatic diamines using triphenyl phosphite in the N-methyl–2-pyrrolidone (NMP)/pyridine solution containing dissolved CaCl2. The diimide-diacid IV was readily obtained by the condensation reaction of 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene ( III 1) with trimellitic anhydride. The obtained poly(amide-imide)s showed high thermostability. Their decomposition temperatures at 10% weight loss in nitrogen atmospheres were above 550°C and the anaerobic char yield at 800°C ranged from 48 to 68%. Almost all the poly(amide-imide)s showed high glass transition temperatures above 300°C by differential scanning calorimetry (DSC) measurements. These polymers were readily soluble in various organic solvents and could be cast into transparent, tough, and flexible films. Their casting films showed obvious yield points in the stress-strain curves and had strength at break up to 74.2 MPa, elongation to break up to 70.1%, and initial modulus up to 4.56 GPa. The factors affecting the reaction of diimide-diacid IV and 4,4′-oxydianiline in view of monomer concentration, reaction temperature, and amount of CaCl2 were also investigated. © 1992 John Wiley & Sons, Inc. 相似文献