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1.
The random copolycondensation of isophthalic acid/terephthalic acid with various combinations of bisphenols (M1 and M2) with a tosyl chloride/dimethylformamide/pyridine condensing agent was carried out to investigate the effects of the monomer reactivity ratios, r1′ and r2′, on the reaction, like r1 and r2 in radical copolymerization. The ratios were calculated from the probabilities of finding an M2 unit next to an M1 unit and of finding an M1 unit next to an M2 unit, which were determined by an NMR analysis of the resultant copolymers. They were discussed with respect to the inherent viscosities (molecular weights) of the resultant copolymers. There was a fairly good relationship between r1′ and r2′ and the inherent viscosity values of the copolymers, indicating that copolycondensation could be facilitated by a combination of bisphenols; the lowering of r1′ and r2′ was indicative of random distributions in the copolymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3908–3915, 2003  相似文献   

2.
The polycondensation of isophthalic acid (IPA)/terephthalic acid (TPA) with aromatic diols by tosyl chloride/dimethylformamide/pyridine in solution was examined through changes in the IPA/TPA compositions, the kinds of dihydroxyl components, the periods of their addition, and the reaction temperatures. The reaction proceeded favorably at IPA/TPA ratios of 70/30 to 50/50, similarly to an earlier report on the interfacial reaction. The effects of the compositions were significant in the reactions with monosubstituted hydroquinones. The results were examined from distributions of the resulting oligomers prepared at a reaction extent of 0.7, determined by gel permeation chromatography. The reaction producing better results exhibited distributions closer to the theoretical ones. The period of addition also favorably affected the distributions as well as the results of the polycondensation. These results were attributed to the change in the reaction method, in which the diols reacted with the aggregates that formed from the activated IPA and TPA. The change was likely caused by the degree of association of IPA and TPA in the aggregates, on the basis of melting points and IR spectra of mixtures of dimethyl esters of IPA and TPA prepared by the quenching of the aggregates with methanol. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2321–2328, 2004  相似文献   

3.
In copolycondensation with 2,2‐bis(4‐hydroxyphenyl)propane (BPP) and bisphenols (BPs) containing various alkylidene linkages, the associative interactions between BP moieties in the resulting oligomers most likely affected the reaction. To modify the interactions to favorably control the reaction, several additives were examined in a two‐stage polycondensation of an equimolar mixture of isophthalic acid and terephthalic acid, first with BPP (50 mol %) and next with additional BPP. Of additives used, diphenylmethane of an equivalent to BPP in the preformed oligomers was most effective. The results are discussed in terms of the distributions of resulting oligomers prepared at 70% extent of reaction. Better results were obtained when the distributions showed profiles similar to the theoretical one calculated on the basis that the reactivity of the oligomers is the same independent of their chain lengths. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 970–975, 2003  相似文献   

4.
The copolycondensations of a mixture of equal parts of isophthalic acid and terephthalic acid with tetrachlorobisphenol A (TC‐BPA) and various aromatic diol comonomers were performed with a tosyl chloride/dimethylformamide/pyridine condensing agent. The reaction with bisphenols containing nonpolar substituents yielded better results than the reaction with polar groups did. Dihydroxybenzenes smaller in size than bisphenols of two benzene rings, especially chlorohydroquinone and chlororesorcinol, were satisfactorily incorporated and yielded copolymers of high inherent viscosities and weight‐average molecular weights (by gel permeation chromatography). The results of the copolycondensations were examined with sequence distributions in the resultant copolymers by NMR and were well evaluated by the ratio of the length of comonomer unit segments to TC‐BPA unit segments. Homopolycondensation with TC‐BPA in the presence of dichlorobenzenes as additives was also promoted to some extent. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 821–830, 2003  相似文献   

5.
The solution polyesterification of dicarboxylic acids in pyridine, the activated intermediates of which were difficult to dissolve in tosyl chloride/dimethylformamide/pyridine, was investigated in the presence of lithium chloride. The solubility of the activated dicarboxylic acids was largely improved by the presence of the salt, and the polycondensation with bisphenols was greatly facilitated. The salt was more effectively added to a pyridine solution of dicarboxylic acids than to the activated dicarboxylic acids in pyridine. The favorable additive effect on the improved solubility was attributed to a lowered degree of association of the activated dicarboxylic acids, which led to distributions of the resulting oligomers from bisphenols at an earlier stage closer to the theoretical ones and yielded better polycondensation results. The reaction, which proceeded through favorable distributions of the co‐oligomers, produced copolymers of higher inherent viscosities and slightly block sequence distributions determined by NMR. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2725–2733, 2004  相似文献   

6.
A mixture of isophthalic acid (IPA) and terephthalic acid (TPA) was activated by a tosyl chloride/dimethylformamide/pyridine (Py) condensing agent in two steps via the treatment of a mixture of the initially activated IPA/TPA with additional TPA followed by the activation of TPA with the agent. The resulting mixture showed a solubility in Py different from that obtained by the activation of them all at once; the difference might be due to different structures of the aggregates of the activated IPA and TPA at the same composition of the diacids. The structures of the aggregates were evaluated on the basis of melting points and the IR spectra of a mixture of dimethyl esters of IPA and TPA produced by the quenching of the reaction mixtures with methanol. The mixture obtained by two‐step activation showed lower melting points and spectral changes due to enhanced associations of the esters with respect to the mixture prepared by the activation of them all at once. The aggregates were also examined in terms of the distributions of IPA and TPA in thermotropic copolyesters prepared from methylhydroquinone and chlorohydroquinone by their transition temperatures and 13C NMR. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3884–3892, 2001  相似文献   

7.
A two‐stage co‐oligomerization of the oligomers initially formed from an equimolar mixture of isophthalic acid (IPA) and terephthalic acid (TPA) and 2,2‐bis(4‐hydroxyphenyl)propane (BPA, 50 mol %) with bisphenols (BPs, 20 mol %) was carried out using a tosyl chloride/dimethylformamide/pyridine condensing agent. The distributions of the resulting oligomers (nx‐mers), which were quenched with methanol, were determined by a combination of gel permeation chromatography (GPC) and NMR. These distributions (presented by molar percentage) were conveniently calculated with the equation nx (mol %) = nx (% mol by GPC) × n0 (mol % by NMR)/n0 (% mol by GPC), where nx (% mol) = nx (wt % by GPC)/its molecular weight. The results showed the distributions of the preformed IPA/TPA‐BPA oligomers to be in fairly good accord with those obtained directly from GPC and to be supported by the NMR results. The calculation was applied to the co‐oligomers prepared up to a reaction of 0.7, at which there was an increase in the number of higher oligomers indivisible by GPC and the distributions could no longer be determined by molar percentage. The calculated distributions are discussed in relation to the results of copolycondensation. The sequence distributions in the resulting co‐oligomers, which were also examined by NMR, are compared with those in the copolymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 44–51, 2004  相似文献   

8.
Two‐stage copolycondensations of isophthalic acid/terephthalic acid (50/50) and a bisphenol (BP) first and then a comonomer BP were carried at 80 and 120 °C. BPs were divided into two groups: those with polar substituents and those without polar substituents. The copolycondensation with any combination of BPs proceeded nearly equally well at 80 °C. However, the reaction at 120 °C was retarded differently by the groups of comonomers. For the preformed oligomers from BPs without polar substituents, the temperature did not affect the reaction very much, but the reaction was significantly retarded with BPs containing polar groups. All of the reactions of the oligomers from BPs having polar groups with comonomer BPs, regardless of their substituents, were greatly disturbed by the temperature rising. The results were attributed to the temperature effect on the way in which the oligomers reacted with comonomers due to the interactions between them, and they were examined in terms of the distributions of comonomers determined by 1H NMR. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4556–4562, 2002  相似文献   

9.
A two‐stage copolycondensation of a mixture of equal parts of isophthalic acid and terephthalic acid was conducted using a tosyl chloride/dimethylformamide/pyridine condensing agent. In the initial stage x,y‐dihydroxytoluenes (x,y‐DHTs) or 2,4‐dihydroxyethylbenzene (2,4‐DHEB) was used and in the next stage isomeric DHTs or the DHEB was used. The results were examined in terms of how the reaction of the resulting oligomers with the next monomers proceeded, which was evaluated from distributions of the next monomers in the resultant copolymers as determined by 1H NMR. A structurally selective reaction was observed. The preformed oligomers from symmetrically substituted 3,5‐DHT reacted randomly with similarly substituted 2,6‐DHT or asymmetric 2,4‐DHEB, but those from 2,4‐DHEB reacted selectively with both of 3,5‐ and 2,6‐DHT. In the reactions of the oligomers from 2,6‐DHT, they reacted randomly with 2,6‐DHT but selectively with 2,4‐DHEB. Such selective reactions were also observed in the reaction of p‐isomeric 2,5‐DHT with the oligomers prepared from 3,5‐ or 2,6‐DHT. When the monomers were copolymerized simultaneously instead of stepwise, they distributed randomly in the resultant copolymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5687–5694, 2004  相似文献   

10.
A two‐stage copolycondensation of an equimolar mixture of isophthalic acid and terephthalic acid first with a bisphenol (BP) and then with another BP was carried out with a tosyl chloride/dimethylformamide/pyridine condensing agent. When the preformed oligomers from a BP with no substituent or a methyl substituent were allowed to react with another BP comonomer containing polar SO2, CO, or Cl groups, the copolycondensation was significantly promoted. Such effects were absent with the unsubstituted BP and the methyl derivative. In addition, during the reaction of oligomers from BPs with polar groups, a similarly polar BP did not react so effectively, and the unsubstituted BP did not have any effect on the copolycondensation. On the basis of the sequence distributions for the resultant copolymers determined by 1H NMR, it was likely that the copolycondensation could be promoted when the second comonomers were randomly distributed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4024–4031, 2002  相似文献   

11.
When a mixture of terephthalic acid (TPA) and various dicarboxylic acids was activated by tosyl chloride (TsCl)/dimethyl‐ formamide (DMF)/pyridine (Py), the resulting mixture became dissolved in Py, although the activated TPA was insoluble even at 120 °C. The temperature at which the mixture became soluble was varied with their compositions and the structure of diacids. Mixing the separately activated TPA and isophthalic acid (IPA) also improved the solubility of the activated TPA to some extent. The interesting phenomena were attributed to associations of the activated diacids through the dipole–dipole interactions between the carbonyl groups. The structures of associates were estimated in terms of transition temperatures of the thermotropic IPA/TPA‐methylhydroquinone and IPA/TPA‐chlorohydroquinone copolymers. The transition temperatures were significantly affected by the temperature of polycondensation, the preparative procedures of a mixture of the activated diacids, and several additives. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 196–201, 2001  相似文献   

12.
A two‐stage copolycondensation of a mixture of equal parts of isophthalic acid and terephthalic acid first with a′,b′‐dihydroxyacetophenone (a′,b′‐DHAP) and then with isomeric c′,d′‐DHAP was examined at 60 and 80 °C. A structurally selective reaction was observed. At 80 °C, the preformed oligomers from symmetrically substituted 2′,6′‐DHAP reacted better with similarly substituted 2′,6′‐ or 3′,5′‐DHAP to give the copolymers of significantly higher inherent viscosity values than from the reaction with asymmetrically substituted 2′,4′‐DHAP, whereas at 60 °C they did almost equally well with any c′,d′‐DHAP. Similarly, the reaction of oligomers from 2′,4′‐DHAP with asymmetrically substituted 2′,4′‐DHAP or 2,4‐dihydroxybenzophenone yielded better results than those from the reaction with 2′,6′‐ or 3′,5′‐DHAP at both temperatures. The copolycondensations with comonomers of the structure independent of DHAPs were not affected by the preformed oligomers from DHAPs. The results are discussed in terms of the distributions of resulting oligomers determined by gel permeation chromatography. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 616–623, 2003  相似文献   

13.
14.
A new condensing agent comprised of tosyl chloride (TsCl) and triphenylphosphine oxide (TPPO) in pyridine was very effective for the preparation of polyesters of aromatic dicarboxylic acids and bisphenols with higher molecular weight than those obtained from TsCl/dimethylformamide in pyridine. Among the phosphorus compounds examined TPPO was most effective, and the reaction using half an equivalent with respect to the carboxyl groups yielded the most favorable results at temperatures of more than 100°C.  相似文献   

15.
Poly(p‐oxybenzoyl) (POB) crystals were prepared with the reaction‐induced crystallization of oligomers during the direct polycondensation of p‐hydroxybenzoic acid (HBA) with p‐toluenesulfonyl chloride (TsCl) and N,N‐dimethylformamide in pyridine. Sheaflike lozenge‐shaped POB crystals were obtained, of which the longer diagonal was 7.0–8.0 μm. The influence of the polymerization condition on the morphology was examined to optimize the preparative condition for the crystals exhibiting the clearest habit, and the favorable condition was determined as the molar ratio of TsCl to HBA of 1.3 and polymerization concentration of 3.0%. The crystals possessed extremely high crystallinity and outstanding thermal stability. The formation mechanism of the crystal was proposed as follows. When the number‐average degree of polymerization of the oligomers exceeded a critical value of about 4, they were precipitated to form the hexagonal lamellae. The crystals were grown very quickly to lozenge‐shaped crystal through screw dislocation with the continuous precipitation of oligomers from the solution. Finally, the further polymerization occurred in the precipitated crystal with developing polymer‐chain packing. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3275–3282, 2003  相似文献   

16.
The intermolecular interactions and miscibility behavior between poly(ether imide) (Ultem®1000) and a copolyester of bisphenol-A with a mixture of terephthalic and isophthalic acid (Ardel®D-100) in compositions of 100/0, 80/20, 60/40, 40/60, 20/80 and 0/100 have been investigated in dilute solutions in chloroform. An Ubbelohde-type home-made viscometer was used to determine the specific viscosities of the blends in a constant temperature bath. Several viscosity interaction parameters used as the criteria of miscibility were determined from viscosity measurements. The parameters suggested that Ultem®1000 and Ardel®D-100 were miscible. The miscibility of the polymers was confirmed by the results of differential scanning calorimetry measurements.  相似文献   

17.
4,4′‐hexafluoroisopropylidene‐2,2‐bis‐(phthalic acid anhydride) (1) was reacted with L ‐methionine (2) in acetic acid and the resulting N,N′–(4,4′‐hexafluoroisopropylidenediphthaloyl)‐bis‐L ‐methionine (4) was obtained in high yield. The direct polycondensation reaction of this diacid with several aromatic diols such as bisphenol A (5a), phenolphthalein (5b), 1,4‐dihydroxybenzene (5c), 4,4′‐dihydroxydiphenyl sulfide (5d), 4,6‐dihydroxypyrimidine (5e), 4,4′‐dihydroxydiphenyl sulfone (5f) and 2,4′‐dihydroxyacetophenone (5g) was carried out in a system of thionyl chloride and pyridine. Expecting that the reaction with thionyl chloride in pyridine might involve alternative intermediates different from an acyl chloride, the polycondensation at a higher temperature favorable for the reaction of the expected intermediate with nucleophiles was attempted, and a highly thermally stable poly(ester‐imide) was obtained by carrying out the reaction at 80°C. All of the above polymers were fully characterized by 1H‐NMR, 19F‐NMR FT‐IR spectroscopy, elemental analysis and specific rotation. Some structural characterization and physical properties of these optically active poly(ester‐ imide)s are reported. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

18.
刘胜生  于广谦 《应用化学》1996,13(4):110-112
茂锆载体催化剂下的乙烯/辛烯共聚及聚合物的~(13)CNMR研究刘胜生,于广谦,黄葆同(中国科学院长春应用化学研究所长春130022)关键词茂锆载体催化剂,共聚,序列分布,~(13)CNMR由于茂锆催化剂具有高活性,单一活性中心等特点[1,2],并且能...  相似文献   

19.
A novel synthetic method for the preparation of copolyesters comprised of diols and bisphenols using tosyl chloride (TsCl)/DMF/pyridine (Py) as a condensing agent has been developed. A variety of combinations of monomers could produce relatively high molecular weight copolymers, and better results were obtained by initial oligomerization of diols followed by bisphenols. In order to demonstrate usefulness of this method, copolymers comprised of IPA/TPA (50/50), bis(2‐hydroxyethyl)terephthalate (BHET),and several bisphenols were prepared and compared to the poly(ethylene terephthalate) (PET) modified by TPA and 2,2‐bis(4‐hydroxyphenyl)propane (BPA) diacetate in terms of their thermal properties. The length of mesogenic unit segments in the thermotropic IPA/TPA (50/50)‐BHET/ 4,4′‐dihydroxybenzophenone (4,4′‐DHBP) (50/50) copolymer was changed by initial reaction of BHET followed by dropwise addition of 4,4′‐DHBP in the two‐stage polycondensation and also by varying the amounts of BHET used at the initial and final stages in the three‐stage copolycondensation, and the results were studied by NMR and their thermal properties. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1270–1276, 2000  相似文献   

20.
This article describes the homopolymerization of methyl acrylate (MA) and its attempted copolymerization with ethylene using three single‐site catalysts. The primary catalyst under investigation is formed from a bis(imino)pyridine iron(II) chloride with methylaluminoxane ( 1 ), which is compared with bis(4,5,6,7‐tetrahydro‐1‐indenyl)zirconium dimethyl/tris(pentafluorenyl)borane) ( 2 ), and a P,O‐chelated nickel(II) enolate catalyst ( 3 ). Catalyst ( 1 ) leads to the highest activities exceeding those of catalyst ( 2 ) by a magnitude, whereas catalyst ( 3 ) results in formation of no polymer. The kinetics of the polymerizations and the effect of the Al/Fe‐ratio and temperature on the activity and molecular weight of the polymers have been determined. In the ethylene/MA copolymerization trials, catalyst ( 1 ) produces a blend of the two homopolymers, polymethyl acrylate (PMA) and polyethylene. Remarkably, using catalyst ( 1 ) it is possible to produce polymer blends with up to 52% PMA at relatively high activities. The polymerization kinetics has been determined based on the directly measured uptake of ethylene during the runs. NMR spectroscopy, DSC and GPC measurements have been used as efficient methods to prove that polymer blends instead of true copolymers were formed. Finally, some conclusions about the polymerization mechanism will be drawn. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5542–5558, 2008  相似文献   

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