Showing papers in "Macromolecular Chemistry and Physics in 1982"
TL;DR: In this paper, the synthesis and phase behaviour of a series of polymers having liquid crystalline sidechains and a poly(acrylic acid) backbone are described, and a comparison of the phase transitions of the different polyacrylates, with those of liquid-crystalline polymethacryls and polysiloxanes, establishes that the spacer group achieves partial "decoupling" of liquid crystal and polymer properties.
Abstract: The synthesis and phase behaviour of a series of polymers having liquid crystalline sidechains and a poly(acrylic acid) backbone are described. These polymers show a dependence of the phase transition temperatures on molecular weight. In copolymers of two liquid crystalline acrylic esters, induced smectic phases occur. A comparison of the phase transitions of the different polyacrylates, with those of liquid crystalline polymethacrylates and polysiloxanes, published elsewhere, establishes that the spacer group achieves partial “decoupling” of liquid crystalline and polymer properties.
250 citations
TL;DR: In this article, the authors examined mesophasic polymers of the general formula and where and are prepared and their solid and liquid crystalline behaviour examined and compared to that of the corresponding homologues with n even.
Abstract: Semiflexible mesophasic polymers of the general formula and where and are prepared and their solid and liquid crystalline behaviour examined and compared to that of the corresponding homologues with n even. Evidence is given of relevant odd-even effects in the thermodynamic parameters of the clearing transition. The conclusion is drawn in favour of an anisotropic structuration also of the flexible parts of the polymer chain in the liquid crystal phase.
116 citations
TL;DR: In this paper, the main kinetic behavior of the slurry polymerization of propene with a MgCl2-supported TiCl4/C6H5COOC2H5 catalyst, activated by Al(C 2H5)3, was studied.
Abstract: The main kinetic behavior of the slurry polymerization of propene with a MgCl2-supported TiCl4/C6H5COOC2H5 catalyst, activated by Al(C2H5)3, was studied, Examination of the dependence of the polymerization rate on temperature and concentrations of Al(C2H5)3 and of propene resulted in a Langmuir-Hinshelwood rate law with the number of polymerization centers dependent on time. The Polymerization rate as function of the polymerization temperature shows a maximum, which is compatible with the rate law. The analysis of the phenomenon of an optimum temperature gave 15 KJ. mol−1 and 36 KJ. Mol −1 for the activation energy of the rate determining step and the adsorption energy of Al(C2H5)3, respectively. Examination of the rapid decay of the polymerization rate showed that the main part of the decay is represented by a second order decay independent of the amount of polymer produced, which can be understood by a second order decay of surface sites by Al(C2H5)3. The number of active centers of the catalyst in gas phase polymerization was estimated applying the inhibition method with carbon monoxide. The results show a constant value for the propagation rate constant, Kp, during the second order rate decay. The observed polymerization kinetics strongly suggest the existence of two kinds of polymerization centers (isotactic and atactic).
107 citations
TL;DR: In this paper, the ionic conductivity of polyoxyethylene- and polyoxypropylene-polyurethane networks containing sodium tetraphenylborate was studied as a function of temperature and salt concentration.
Abstract: The ionic conductivity of polyoxyethylene- and polyoxypropylene-polyurethane networks containing sodium tetraphenylborate was studied as a function of temperature and salt concentration. The results can be rationalised in terms of free volume considerations. The fact that the WLF equation applies to the conductivity of these materials demonstrates that there exists a direct relationship between the ion conduction process and the viscoelastic properties of the networks.
99 citations
TL;DR: In this paper, the electro-optical properties of liquid crystalline polymers with polar mesogenic units in the side chain were investigated, and it was shown that in an electric field, they show all effects known from low molecular weight liquid crystals, e.g. the Freedericksz transition, the DAP-effect, the formation of William's domain, and dynamic scattering.
Abstract: The electro-optical properties of liquid crystalline polymers with polar mesogenic units in the side chain were investigated. It could be shown, that in an electric field, they show all effects known from low molecular weight liquid crystals, e.g. the Freedericksz-transition, the DAP-effect, the formation of William's domain, and the dynamic scattering. The optical response times are slightly longer than for low molecular weight liquid crystals, but in some cases at higher temperatures as short as 200 ms. By comparison of different polymers and some corresponding liquid crystalline monomers, it is found that: (1) the difference between the measuring temperature and the glass transition temperature mainly determines the optical response times, (2) the fixation of mesogenic groups to a polymer main chain via spacers influences the threshold voltage. Low values are found for long spacers. These results allow a discussion of the influence of polymer fixation of the mesogenic groups on their liquid crystalline properties, pointing to a partial decoupling of the motions of main chains and side chains.
88 citations
TL;DR: In this paper, the carbonation reactions of polymeric organolithium compounds with high purity, gaseous carbon dioxide have been investigated in benzene and benzene/tetrahydrofuran (75/25) solutions.
Abstract: The carbonation reactions of polymeric organolithium compounds with high purity, gaseous carbon dioxide have been investigated in benzene and benzene/tetrahydrofuran (75/25) solutions. The polymers investigated were poly(styryl)lithium, poly(isoprenyl)lithium, and poly(styrene-b-isoprenyl)lithium. In Benzene solution the products are a mixture of the carboxylic acid and the ketone (dimer). No tertiary alcohol product (trimer) was observed. In benzene/tetrahydrofuran solution, the quantitative carboxylation of chain ends was observed.
85 citations
TL;DR: The cyclic ketene acetal, 2-methylene-4-phenyl-1,3-dioxolane (3), was shown to undergo free radical ring-opening polymerization to produce the polyester, poly[γ-(β-phenYL)butyrolactone] as mentioned in this paper.
Abstract: The cyclic ketene acetal, 2-methylene-4-phenyl-1,3-dioxolane (3), was shown to undergo free radical ring-opening polymerization to produce the polyester, poly[γ-(β-phenyl)butyrolactone]. The monomer 3 was synthesized by an acetal exchange reaction of chloroacetaldehyde dimethyl acetal with styrene glycol in an 87% yield followed by dehydrochlorination of the resulting cis and trans-2-chloromethyl-4-phenyl-1,3-dioxolane (2) with potassium tert-butoxide in tert-butyl alcohol in a 70% yield. 3 was shown to undergo essentially quantitative free radical ring-opening at all temperatures from 60–150°C and also nearly complete regioselective ring-opening with cleavage to give the more highly stable secondary benzyl free radical. Even in free radical copolymerization with styrene, methyl methacrylate, vinyl acetate, or 4-vinylpyridine, 3 gives essentially complete ring opening to introduce an ester groups into the backbone of the addition copolymer. The structures of the polymers were established by elemental analysis and 1H and 13C NMR spectroscopy.
84 citations
TL;DR: A series of polysters based on a triad aromatic ester mesogenic unit but containing different poly(alkylene oxide) flexible spacers in the main chain was prepared and its properties examined.
Abstract: A series of polysters based on a triad aromatic ester mesogenic unit but containing different poly(alkylene oxide) flexible spacers in the main chain was prepared and its properties examined. The flexible spacers consisted of poly(alkylene oxide)s of varying lengths based on either oligomers of ethylene oxide or propylene oxide. The spacer types, lengths and distributions were found to strongly affect the mesophase and melting behaviors of the polymers. Polymers with spacers having more than 10 units were not liquid crystalline, whereas those of shorter length exhibited mesophase properties. The polymers containing spacers with two, three, or four oxyethylene units showed two mesophases, and the textures of their mesophases suggested that both smectic and nematic phases were formed.
72 citations
TL;DR: The photodecomposition of α-methoxydeoxybenzoin and α,α-dimethoxybenzyl radicals was investigated both in the absence and in the presence of 1,1-diphenylethylene as mentioned in this paper.
Abstract: The photodecomposition of α-methoxydeoxybenzoin (1) and α,α-dimethoxydeoxybenzoin (2) was investigated both in the absence and in the presence of 1,1-diphenylethylene. The resulting products indicate that benzoyl radicals add to the olefinic double bond (initiation of polymerization), whereas the α-methoxybenzyl radicals generated from 1 do not add to the olefinic double bond (no initiation), but preferentially combine with other radicals (termination of polymerization). This reaction is largely suppressed in the case of α,α-dimethoxybenzyl radicals generated from 2 owing to sequential fragmentation into inactive methylbenzoate and highly reactive methyl radicals which add to the olefinic double bond and thus contribute to the initiation.
55 citations
TL;DR: In this article, a shift parameter scheme for the 13C shifts of the furan ring was devised and used for the assignment of the shifts, and an analysis of the chemical composition of several furfuryl alcohol resings with different catalysts was performed with the aid of the assignments.
Abstract: The characterisation of the oligomers of furfuryl alcohol was performed using 13C NMR spectroscopy and high resolution 1H NMR spectroscopy. A shift parameter scheme for the 13C shifts of the furan ring was devised and utilised for the assignment of the shifts of the oligomers. An analysis of the chemical composition of several furfuryl alcohol resings produced with different catalysts was performed with the aid of the assignments.
52 citations
TL;DR: In this paper, a scheme for the interaction between the catalyst and the reactants to give the (R)-product was proposed, where the reaction time was increased with reaction time, because of the racemization of the product.
Abstract: In the asymmetric addition of hydrogen cyanide to benzaldehyde to give mandelonitrile, a cyanohydrin, the highest enantiomeric excess (e.e.) ever reported (90%) was obtained with (2d) whereas the corresponding linear dipeptide gave a very low e. e. This high e. e. decreased with the reaction time, because of the racemization of the product. All cyclic dipeptides used containing an (S)-histidine residue preferred the (R)-product. A scheme for the interaction between the catalyst and the reactants to give the (R)-product is proposed.
TL;DR: In this paper, the apparent Young's modulus shows a linear relationship with junction density of chitosan films and the linear relationship depends on the acid used in the casting solution.
Abstract: The apparent Young's modulus shows a linear relationship with junction density of chitosan films. The linear relationship of apparent Young's modulus with chitosan concentration is also observed. The linear relationship depends of the acid used in the casting solution. Relaxation times were of the order of 104 seconds, indicating a slow physical process. Stress-relaxation behavior of swollen chitosan films, prepared by solvent casting from dilute acetic or propionic acid solutions, can be represented by a one-component Maxwell model.
TL;DR: In this paper, a 7-step synthesis of 2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole (9) was described.
Abstract: 2-(2-Hydroxy-5-vinylphenyl)-2H-benzotriazole (9) was prepared by a seven step synthesis in about a 25% overall yield starting from o-nitroaniline. Diazotization in aqueous HCl gave a diazonium salt which was coupled with p-ethylphenol to an azo-dye which was reduced with zinc powder in sodium hydroxide solution to 2-(2-hydroxy-5-ethylphenyl)-2H-benzotriazole (4). This compound was acetylated and then brominated with N-bromosuccinimide to 2-[2-acetoxy-5-(1-bromoethyl)phenyl]-2H-benzotriazole (6) which was dehydrobrominated with triethylamine in acetonitrile or tributylamine in dimethylacetamide to the vinyl compound which was hydrolyzed to 9. This monomer was readily homopolymerized and copolymerized with styrene and methyl methacrylate using 2,2′-azobis(2-methylpropionitrile) as initiator.
TL;DR: In this article, partially deacetylated chitin with aromatic cyclic carboxylic acid anhydrides was successfully carried out under almost homogeneous conditions in organic aprotic solvents.
Abstract: Reaction of partially deacetylated chitin with aromatic cyclic carboxylic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyromellitic dianhydride was successfully carried out under almost homogeneous conditions in organic aprotic solvents using highly swollen precipitates of water-soluble chitin with about 50% deacetylation. The resulting amic acid-chitins were converted into the corresponding imide-chitins by heating. In addition to imidization, this heat treatment also promotes removal of acid anhydrides reacted at the hydroxyl group giving rise to the formation of selectively N-substituted derivatives. These novel chitin derivatives exhibit a much improved solubility in organic solvents and aqueous alkaline solutions. As anticipated, the imide-chitins, derived from trimellitic anhydride and pyromellitic dianhydride, showed reactivity toward amine under heterogeneous conditions, and the reaction capacities toward p-chloroaniline were determined to be 4,2 · 10−4 and 4,6 · 10−4 mol · g−1, respectively.
TL;DR: In this article, a series of dinuclear to nonanuclear all-ortho methylene-bridged oligophenols 2−9 has been synthesized according to a repetitive reaction sequence involving the C-orthoe regiospecific condensation of appropriate phenoxymagnesium precursors with salicyl alcohol or paraformaldehyde.
Abstract: The series of dinuclear to nonanuclear all-ortho methylene-bridged oligophenols 2–9 has been synthesized according to a repetitive reaction sequence involving the C-ortho regiospecific condensation of appropriate phenoxymagnesium precursors with salicyl alcohol or paraformaldehyde. IR, UV, mass, 1H and 13C NMR characteristics of these oligomers are discussed. X-ray crystal structures of 2, 3, and 4 are also reported.
TL;DR: In this paper, the reaction of a diisocyanate and an asymmetric aliphatic-aromatic diacid containing a preformed imide group was studied in order to obtain polyamide-imides.
Abstract: The reaction of a diisocyanate and an asymmetric aliphatic-aromatic diacid containing a preformed imide group was studied in order to obtain polyamide-imides. It is shown in this paper that combined 1H and 13C NMR spectrometry will permit the quantitative evaluation of the proportions of head-tail, head-head, tail-tail additions, provided the content of urea in the polymer is low. In order to obtain unequivocal assignments and to thoroughly characterize the NMR spectra of the polymer, several model compounds resembling the polymer backbone were synthesized. A model polymer was synthesized with the same purpose, and its 1H and 13C NMR spectra fully assigned. Unexpected chemical functions in the polymer, like urea and carboxylic acid, can also be easily detected and quantified by NMR.
TL;DR: In this article, the active species and living character of polymers were established by applying the ion-trapping technique, and they were obtained with CF3SO3H (trifilic acid-tfac) and (CF3SO2)2O(triflic anhydride-tfan), respectively.
Abstract: Mono- and dicationically living poly(1,3-dioxolane) (pdxn) and poly (1,3-dioxepane) (pdxp) were obtained with CF3SO3H (trifilic acid-tfac) and (CF3SO2)2O (triflic anhydride-tfan), respectively. Concentration of the active species and living character of polymers were established by applying the ion-trapping technique. Addition of a second cyclic acetal to the living bifunctional polyacetal (e. g. addition of dxn to pdxp) leads to the formation of a block copolymer (according to 13C NMR), but before the second monomer polymerizes completely, the transacetalization process leads to the conversion of the internal homoblock to a more or less (depending on time) statictical copolymer. Thus, competition of the homopropagation and transacetalization is not in favor of formation of the block copolymers with pure homoblocks, at least when the second block, built on the already existing homoblock, is formed slower than the homoblock is reshuffled by transacetalization.
TL;DR: In this paper, the excimer formation between pyrenes attached to the ends of a poly(ethyleneoxide) sample of nominal molecular weight 9600 has been examined in twelve solvents.
Abstract: Intramolecular excimer formation between pyrenes attached to the ends of a poly(ethyleneoxide) sample of nominal molecular weight 9600 has been examined in twelve solvents. In ten non-protic solvents the excimer to pyrene locally excited fluorescene intensity ratio IE/IM is inversely proportional to solvent viscosity, as expected for a diffusion-controlled process. Similar results were obtained for 〈k1〉 values obtained from flash-photolysis studies, where 〈k1〉 is the average rate constant for end-to-end cyclization in the polymer. In water and methanol, the extent of excimer emission and the rate of intramolecular excimer emission and the rate of intramolecular excimer formation were substantially greater than one would infer on the basis of solvent viscosity alone.
TL;DR: In this article, practical hints for the application of the indirect Fourier transformation method are given, including the problems of stabilization of the least squares routine, the estimation of the maximum dimension of the particles, the choice of an appropriate number of the spline functions, the combination of scattering functions measured with different primary beam geometry, standard deviation and error propagation of the solution functions, influence of the interparticle interference effect and background scattering on the results, determination of the radius of gyration and the scattering intensity at zero angle and finally the possibility of simulation of measuring curves starting with model
Abstract: Practical hints for the application of the indirect Fourier transformation method are given. In detail there are discussed the problems of stabilization of the least squares routine, the estimation of the maximum dimension of the particles, the choice of an appropriate number of the spline functions, the combination of scattering functions measured with different primary beam geometry, standard deviation and error propagation of the solution functions, influence of the interparticle interference effect and background scattering on the results, determination of the radius of gyration and the scattering intensity at zero angle and finally the possibility of simulation of measuring curves starting with model bodies is described. It is attempted to demonstrate the advantages of indirect Fourier transformation on hand of several practical examples.
TL;DR: In this paper, the 13C NMR spectra of chitin in lithium thiocyanate and in LiCl/dimethylacetamide solutions were used to characterize regular polymers.
Abstract: The 13C NMR spectra of N-acetyl-D-glucosamine (1) and chitobiose (2), monomer and dimer of chitin, were assigned and used to assign the 13C NMR spectra of chitin in lithium thiocyanate and in LiCl/dimethylacetamide solutions. The dissolution of chitin in formic acid was studied. IR, 13C and 1H NMR spectra show that dissolution occurs by a reaction of formic acid with chitin with the formation of formyl chitin as a statistical derivative of chitin. 13C NMR spectra of diformyl- and diacetylchitin were also assigned to characterize these regular polymers.
TL;DR: In this article, the detrimental yellowing of aromatic polyurethanes by irradiation may be accounted for by two mechanisms based on the formation of different photo-products, one at short wave lengths and proceeds through a photo-Fries type reaction; the second mechanism is observed at longer wave length and involves quinoidic structures derived from primary hydroperoxides.
Abstract: The detrimental yellowing of aromatic polyurethanes by irradiation may be accounted for by two mechanisms based on the formation of different photo-products. The first is observed at short wave lengths and proceeds through a photo-Fries type reaction; the second mechanism is observed at longer wave lengths and involves quinoidic structures derived from primary hydroperoxides. These two paths may be differentiated by incorporation of well-known additives into the polymer or by selection of various irradiation wave lengths.
TL;DR: In this article, the addition of hydroxyl groups on double bonds during the synthesis of unsaturated polyesters is studied with the help of model molecules, and a mechanism is discussed.
Abstract: The addition of hydroxyl groups on double bonds during the synthesis of unsaturated polyesters is studied with the help of model molecules. These are diesters of unsaturated diacids (maleic and fumaric acids) or monoesters of unsaturated monoacids (crotonic, cinnamic and p-cyanocinnamic acids) with 1,2-propanediol. The addition reaction take place to appreciable extents only with bis(hydroxypropyl) maleate and fumarate. The reaction is catalyzed by strong acids such as p-toluenesulfonic acid; it is reversible and favoured by high temperatures. A mechanism is discussed.
TL;DR: In this article, a copolymerization of carbon dioxide and epoxides containing a carbonate substituent using the diethylzinc/water system as catalyst is described.
Abstract: Polycarbonates with pendant carbonate groups were synthesized by copolymerization of carbon dioxide and epoxides containing a carbonate substituent using the diethylzinc/water system as catalyst. The polycarbonates underwent acidic and basic hydrolysis to release slowly the compound attached as the pendant group via the carbonate linkage. Other hydrolysis products were glycerol and CO2, but no oligomeric products were formed.
TL;DR: In this article, a thermal condensation of polychlorophosphinoyliminotrichlorophosphorane under atmospheric pressure at 240-290°C, pure POCl3 being eliminated, was studied by chemical analysis, 31P NMR, IR spectroscopy and thin layer chromatography.
Abstract: Polychlorophosphazenes 2 can easily be obtained by thermal condensation of dichlorophosphinoyliminotrichlorophosphorane (1) under atmospheric pressure at 240–290°C, pure POCl3 being eliminated. The different stages of the reaction were studied by chemical analysis, 31P NMR, IR spectroscopy, and thin layer chromatography. The procedure enables one to obtain polymers of low and high molecular weights. The samples do not contain any cyclic or reticular polymers. Species of low molecular weights can be separated from those with high molecular weights by treatment with heptane. The total yield of phosphorus is 100% with regard to the starting material. Substitution products (Cl by OCH2CF3) are obtained which are identical with those obtained with the polychlorophosphazenes prepared via classical methods.
TL;DR: The anionic polymerization of 1,3 and 1,4-diisopropenylbenzene (DIB) was found to be characterized by a rather low ceiling temperature and by rather strong differences in reactivity between the two double bonds as discussed by the authors.
Abstract: The anionic polymerization of 1,3 and 1,4-diisopropenylbenzene (DIB) was found to be characterized by a rather low ceiling temperature and by rather strong differences in reactivity between the two double bonds. At low degrees of conversion the polymers formed are essentially linear and carry one pendant double bond per monomeric unit. Branching and crosslinking can occur only at higher conversion. 1,3-DIB can be copolymerized anionically with α-methylstyrene. Grafting reactions were carried out on polymer backbones with pendant unsaturated groups, using two different pathways. The occurence of coupling reaction can be avoided by a proper choice of experimental conditions.
TL;DR: In this article, an equation derived from the Flory-Huggins relation with the concentration-dependent interaction parameters gij and the ternary parameter gT was used in the correlation of reported data on the preferential sorption in macromolecular coils.
Abstract: An equation derived from the Flory-Huggins relation with the concentration-dependent interaction parameters gij and the ternary parameter gT was used in the correlation of reported data on the preferential sorption in macromolecular coils. A linear plot was suggested, assuming that the dependence of gT on the composition of the mixed solvent resembles that of g12, i.e. gT(u1) = agg12(u1). Linear correlation could be carried out in 19 ternary systems out of 22, and the correlation constants were used to calculate the difference of interaction parameters g13 − (V1/V2)g23 and the proportionality constant ag. For most systems, ag is positive and smaller than unity; for systems containing chloroform it approaches zero. The difference between the interaction parameters gij and the interaction parameters χij is discussed. A comparison between the difference g13−(V1/V2)g23 obtained by a linear correlation of data on preferential sorption with the values calculated using data on the respective binary systems was possible only for the system benzene/cyclohexane/polystyrene; the fit was very good. It is shown how the individual parameters of the Flory-Huggins equation affect the occurrence, position and type of inversion in preferential sorption.
TL;DR: In this article, micelles of a block copolymer poly(styrene/butadiene/styrene) with cores consisting of poly butadiene blocks were stabilized in dilute solutions by UV radiation in the presence of a photo-initiator and also by fast electrons.
Abstract: Micelles of a block copoymer poly(styrene/butadiene/styrene) with cores consisting of polybutadiene blocks were stabilized in dilute solutions by UV radiation in the presence of a photo-initiator and also by fast electrons, and micelles of a block copolymer poly(styrene/ethene-co-1-butene/styrene) with cores formed by the aliphatic blocks were stabilized by fast electrons, in dilute solutions. Stabilization of micelles, i. e., crosslinking of the chains in micellar cores as well as the properties of stabilized micelles were studied by conventional light scattering, by light scattering photon correlation spectroscopy and by gel permeation chromatography.
TL;DR: An X-ray structure analysis was performed on single crystals of the cycloalkane (CH2)36 as mentioned in this paper, where the lattice belongs to the space group Aa and is arranged in layers.
Abstract: An X-ray structure analysis was performed on single crystals of the cycloalkane (CH2)36. The lattice belongs to the space group Aa and is arranged in layers. The unit cell has the dimensions α = 1,033 nm, b = 0,824 nm, c = 4,22 nm, β = 107, 1° and contains four molecules. The molecules consist of two stretched stems which are linked by sharp folds at each end. The folds have the conformation …t(g g t g g) t… lying parallel to the b-axis. Raman measurements suggest that the stems are slightly twisted. A comparison of the homologous series (CH2)n, n = 36, 48, 60, and 72 using X-ray powder methods showed that the (CH2)36-structure, including the fold conformation, is also representative for the longer chain cycloalkanes.
TL;DR: In this article, a few unsaturated polysters prepared by melt polycondensation of maleic anhydride and aliphatic glycols in different proportions have been characterized and the salient features of the 1H and 13C NMR spectra of the polyesters and of model compounds are compared.
Abstract: A few unsaturated polysters prepared by melt polycondensation of maleic anhydride, phthalic anhydride, and aliphatic glycols in different proportions have been characterized. The salient features of the 1H and 13C NMR spectra of the polyesters and of model compounds are compared. It appears that from 15 to 20% of maleic acid residues have reacted with excess glycol to yield branching points while the remaining free olefinic double bonds have undergone cis trans isomerization almost quantitatively along the oligomeric chains.
TL;DR: In this paper, the polycondensation of 4,4′-methylenediphenylisocyanate and 6-(4-carboxyphthalimido)-hexanoic acid was studied under different conditions in order to establish the influence of factors such as temperature, catalyst, stoichiometric disbalance, and addition order of reactants on the molecular weight and the chemical composition of the final polyamide-imide.
Abstract: The polycondensation of 4,4′-methylenediphenylisocyanate and 6-(4-carboxyphthalimido)-hexanoic acid was studied under different conditions in order to establish the influence of factors such as temperature, catalyst, stoichiometric disbalance, and addition order of reactants on the molecular weight and the chemical composition of the final polyamide-imide. All these factors proved to influence the extent of possible side reactions that lead to undersirable functions, the main ones being urea functions that locate within the polymer backbone. Other side-reactions proposed to explain the formation of acylureas or biurets did not take place in appreciable extent since these functions could not be detected by NMR spectroscopy. Therefore, particular emphasis was made to prevent the formation of urea by changing the polycondensation conditions. A first attempt to clarify the regularity degree of the polymers (amounts of head to tail and head to head addition) by 1H NMR spectroscopy was also made.