Ferrocene-containing polyesters and polyamides

A series of ferrocene-containing polyesters and polyamides were prepared by refluxing 1,1′-dichlorocarbonylferrocene with various diols and primary diamines in xylene–pyridine solvent. The polyamides were all solids, but some of the polyesters were liquids. Reported are the infrared spectra and solubility characteristics of all the polymers and, where possible, the molecular weight and molecular weight distributions. In general, these polyamides and polyesters were of relatively low molecular weight (below 4000), but the polyesters were readily chain extended and crosslinked by di- and triisocyanates. Elemental analyses are reported for all the polymers prepared.     

Phenothiaphosphine-containing polyamides and polyesters

Phosphorus-containing polyamides and polyesters, which had tricyclic fused rings (phenothia-phosphine rings) in the main chain, were prepared and the properties of the resulting polymers were examined. These polymers were obtained at highly reduced viscosities in satisfactory yields by the polycondensation of 2,8-dichloroformyl-10-phenylphenothiaphosphine 5,5,10-trioxide with aromatic diamines or bisphenols. The polyamides and polyesters were soluble in polar aprotic solvents such as dimethylacetamide and N-methyl-2-pyrrolidone; the polyesters were also soluble in chloroform. The polymers exhibited good heat resistance. The phenothiaphosphine-containing polyamides and polyesters self-extinguished immediately when flame was removed and were highly flame-resistant. The polyester obtained from bisphenol A showed a limiting oxygen index value of 43.5.     

Phenazasiline-containing polyamides and polyesters

A Phenazasiline ring was incorporated into a polymer backbone by polycondensation of 2,8-dichloroformyl-5,10-dihydro-5-methyl-10,10-diphenylphenazasiline (V) with aromatic diamines or bisphenols, and phenazasiline-containing polyamides and polyesters were obtained. The polyamides were prepared by low-temperature solution polycondensation in N-methyl-2-pyrrolidone (NMP) in the presence of lithium chloride. The polyesters were synthesized by interfacial polycondensation in a mixture of 1,2-dichloroethane and aqueous alkali in the presence of tetrabutylammonium chloride as an accelerator. These reaction conditions gave the corresponding polymers with high viscosities. The phenazasiline-containing polyamides exhibited good solubilities in polar aprotic solvents such as dimethylformamide, dimethylacetamide, and NMP, and also in m-cresol, although the polyesters showed limited solubilities in organic solvents. Under nitrogen, the phenazasiline-containing polyamides and polyesters showed little degradation below 400°C and had good heat resistance.     

Cyclizations in hyperbranched aliphatic polyesters and polyamides

Hyperbranched aliphatic polyesters of 2,2′-bis-(hydroxymethyl) propanoic acid and hyperbranched aliphatic polyamides obtained from new carboxy- and amino-functionalized caprolactams were studied by NMR spectroscopy and MALDI-TOF mass spectrometry. Ring-chain equilibria taking place through intramolecular hydroxy-ester, carboxy-amide or amine-amide interchanges and leading to the formation of cyclic branches or end-groups were found to exert a predominant influence on the molar mass of these hyperbranched polymers. A number of intra- or intermolecular side reactions, such as the formation of ethers in polyesters and the formation of anhydrides, imides, amidines and secondary amines in polyamides were also detected and resulted in polymer crosslinking on prolonged heating. The existence of such ring-chain equilibria and side-reactions make the control of hyperbranched polymer structure much more difficult than generally accepted.     

Synthesis and properties of polyamides and polyesters from neocarboranedicarboxylic dichloride

Polyamides and polyesters based on neocarboranedicarboxylie dichloride and previously not described have been prepared by low-temperature polycondensation in solution and characterized. In preparing the polyamides, the following diamines were used: benzidine, hexamethylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, and hydroquinone diaminodiphenyl ester. Polyesters were obtained by using the following diols: phenolthalein, hydroquinone, 4,4′-dihydroxydiphenylpropane, 9,9-dihydroxydiphenylfluorene, 1,6-hexanediol, and ethylene glycol. The resulting neocarborane polyesters melt and are easily soluble in tetrahydrofuran, amide solvents, and chloroform. The neocarborane polyamides described do not melt, are readily soluble in tetrahydrofuran and dimethylformamide, and form transparent films; they are thermostable in an inert at mosphere at high temperatures.     

Heterochain polyamides Communication 6. Preparation of polyamides and amide-ester copolymers by the aminolysis of polyesters

Summary The aminolysis of polyethylene sebacate with 1,6-hexanediamine was investigated and it was found that exchange of ethylene glycol and 1,6-hexanediamine residues occurs with formation of amide-ester copolymers or polyamides, depending on the relative amounts of reactants.     

Oxazoline functionalization of polyethylenes and their blends with polyamides and polyesters

The compatibilization of blends of polyamide‐6 (PA6) with linear low density polyethylene (LLDPE) and of poly(ethylene terephthalate) (PET) with high density polyethylene (HDPE), by functionalization of the polyethylenes with oxazoline groups was investigated. Chemical modification of LLDPE and HDPE was carried out by melt free radical grafting with ricinoloxazoline maleinate. Blends preparation was made either with a two‐steps procedure comprising functionalization and blending, and in a single step in which the chemical modification of polyethylene with the oxazoline monomer was realized in situ, during blending. The characterization of the products was carried out by FTIR spectroscopy and scanning electron microscopy (SEM). The rheological and mechanical properties of the blends were also investigated. The results show that functionalization of the polyethylenes can be achieved by melt blending with ricinoloxazoline maleinate even in the absence of free radical initiators. The compatibilization of the blends enhances the dispersion of the minor phase significantly, increases the melt viscosity, and improves the mechanical properties. The one‐step preparation of the compatibilized blends was also found to be effective, and is thought to be even more promising in view of commercial application.     

Synthesis and characterization of thermoplastic polyesters and polyamides from sebacyl bisketene

Sebacyl bisketene was generated in solution at ?78°C. Copolymerization in solution at 0°C with the secondary diamines, piperazine and N,N′dimethyl-1,6-hexamethylenediamine, yielded the polyamides poly(1,4-piperazylsebacyl) and poly[(methylimino)hexamethylene(methylimino)sebacyl], respectively. The polyamides were obtained in yields of 50–90%. The former had a glass transition temperature (T_g) at 30°C and a melting temperature at 165°C, whereas the latter had only a T_g at ?15°C. The polymers were insoluble in the usual polyamide solvents. Copolymerization with the diol bisphenol A yielded poly(oxy-1,4-phenyleneisopropylidene-1,4-phenyleneoxysebacyl). The polyester was obtained in yields up to 99%. Gel permeation chromatography (GPC) determinations showed molecular weights up to 50,000 when acetone was the reaction solvent but only 12,000 when tetrahydrofuran (THF) was the reaction solvent; the T_g for the polyester varied with the molecular weight with a maximum at 15°C. Tensile properties were obtained for the polyesters with molecular weights greater than 35,000.     

Investigations of the phase behavior of rod-like polyesters and polyamides substituted by flexible side chains

The phase behavior of a number of rigid-chain polyesters and polyamides is reviewed and compared to the result obtained from low-molecular-weight model systems. The dilution of the steric forces by flexible side chains appended to the rigid main chains is discussed. It is shown that even stiff-chain polyamides may be transformed to a thermotropic mesophase and an isotropic melt if the number and length of side chains per repeating unit is high enough.     

Sanidics: A new class of mesophases, displayed by highly substituted rigid-rod polyesters and polyamides

The structure of rigid-chain polyesters and polyamides which possess flexible side chains consisting of methylene or 1,4,7-trioxaoctyl oxide units have been investigated by means of X-ray scattering. The X-ray studies were performed on fibres and monodomains. Additional information was gained from calorimetric, dilatometric and microscopic studies. The investigations revealed that these polymers display mesophases and that the structures of the mesophases differ from those observed for discotic and calamitic phases. They are characterized by the fact that in the ordered and disordered phases board-like molecules are stacked parallel on top of each other and that these stacks of molecules are oriented parallel to each other. In the least ordered phase the molecules are only oriented parallel to each other. The various modifications of the mesophases observed so far differ with respect to each other in terms of the order within the stacks as well as in terms of the spatial arrangements of the stacks. A characteristic feature is the frequent absence of any correlation between the long range order which exists along different principal axes of the structure. We have coined the term sanidic for this new type of mesophase.     

Unsaturated polyamides and polyesters prepared from 1,4-bis(2-carboxyvinyl)benzene and 4-hydroxycinnamic acid

Various unsaturated polyamides and polyesters were prepared from the reactions of 1,4-bis(2-carboxyvinyl)benzene acid chloride with aromatic diamines and bisphenols, respectively. In addition, various unsaturated homo- and copolyesters were synthesized from 4-hydroxycinnamic acid and 4-hydroxybenzoic acid. They were heat-cured to thermally stable resins. The polymers were characterized by inherent viscosity measurements, FT-IR, x-ray, DTA, TMA, TGA, and isothermal gravimetric analysis. The water absorption as well as the solubility behavior of the polymers was also investigated. © 1996 John Wiley & Sons, Inc.     

Epitaxial crystallization of polymers onto benzoic acid: Polyethylene and paraffins,aliphatic polyesters,and polyamides

Epitaxial crystallization of polyethylene, n-paraffins, aliphatic polyesters, and various polyamides has been achieved on benzoic acid crystal substrates, specifically on their (001) crystals faces, which are made up of the aromatic rings. The epitaxial relationship is very similar for all polymers investigated: it is characterized by a unique chain orientation (parallel to the b axis of the substrate) and a plane of contact which is either the b-c, plane of polyethylene, or crystallographically similar ones for polyesters, or the plane of the hydrogen-bonded sheet for polyamides. Since benzoic acid is structurally similar to its alkali-metal salts, it is inferred that the nucleating efficiency of the latter toward chemically different but structurally similar polymers may well rest on an epitaxial relationship. Finally, the highly oriented morphology made it possible, for some polyesters with a monoclinic cell, to determine the angle between the chain axis and the Z axis of the optical indicatrix, a quantity not measured so far in polymers.     

Blends of different linear polyamides with hyperbranched aromatic AB2 and A2 + B3 polyesters

To explore the possible applications of hyperbranched polymers for modifying linear polyamides, two hyperbranched aromatic polyesters characterized as high T_g polymers possessing phenolic end groups were used in melt mixing with partly aromatic polyamide and commercially available aliphatic polyamide‐6, respectively. Different amounts of both hyperbranched polyesters (from 1 wt % up to 20 wt %) were added to the polyamides, and the influence of these hyperbranched polyesters on the properties of the polyamides was investigated. The hyperbranched polyester based on an AB₂ approach was found to be the most effective modifier. A significant increase of the glass transition temperature of the final blend was detected. However, a remarkable reduction of crystallinity as well as complex melt viscosity of those blends was also observed. The use of an A₂+B₃ hyperbranched polyester as melt modifier for the polyamides was less effective for changing the thermal properties, and the complex melt viscosity of the final material increased since heterogeneous blends were formed. In contrast to that, generally, the addition of the AB₂ hyperbranched polyester to the polyamides resulted in homogeneous blends with improved T_g and processability. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3558–3572, 2009     

Synthesis of aromatic polyesters and polyamides by alternating copolymerizations of 1,4-dicarbonyl-1,4-dihydronaphthalene with bezoquinones and benzoquinone diimines

1,4-Dicarbonyl-1,4-dihydronaphthalene ( 1 ) was synthesized by the dehydrochlorination reaction of 1,4-dihydronaphthalene-1,4-dicarbonyl chloride with triethylamine and obtained as its very dilute solution, but it easily polymerized in the concentration as high as 0.1 mol/L to give its polymer. 1 generated in situ by the dehydrochlorination reaction of 1,4-dihydronaphthalene-1,4-dicarbonyl chloride in a deoxygenated toluene polymerized alternatingly with benzoquinones such as 2-dodecylthio-p-benzoquinone, 2,5-di(tert-butyl)-p-benzoquinone, p-benzoquinone, and 2,3-dichloro-5,6-dicyano-p-benzoquinone, and with benzoquinone diimines such as N,N′-diethoxycarbonyl-p-benzoquinone diimine, N,N′-dibenzoyl-p-benzoquinone diimine, and N,N′-diphenyl-p-benzoquinone diimine to give aromatic polyesters and polyamides, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1929–1936, 1998     

Aromatic polyamides

Kinetics of the initial degradation of poly(1,3-phenylene isophthalamide) and of poly(chloro-2, 4-phenylene isophthalamide) has been studied by TG in inert as well as oxidative atmospheres. The information derived from the kinetic data is in agreement with our earlier reported studies on the degradation mechanism of these polyamides. The difference-differential method of Freeman-Carroll is shown to have problems when applied to high-char forming polymeric materials. The isoconversion method of Ozawa involving simple computations based on a particular reaction extent, is considered suitable for studying the complex degradation behavior of high-temperature and high-char forming polymer systems. Using this procedure, an activation energy of 215–230 kJ/mole is obtained for the initial degradation of the studied aromatic polyamides in inert and oxidative environments.