Etude cinétique de la dégradation du poly(oxytétraméthylèneoxytéréphtaloyle)

The kinetics of thermal degradation of poly(oxytetramethyleneoxyterephthaloyl) was studied. This polyester undergoes a pyrolysis reaction in the temperature range of processing via a statistical mechanism proceeding by a random scission of the carbon-oxygen bondings. This phenomenon is characterized by an energy of activation of 189,2kJ/mol (45,2kcal·mol^?1) and by a negative entropy of activation [?20,3J·mol^?1·K^?1 (?4,84cal·mol^?1·K^?1)]. Like most of the esters with a hydrogen atom in β position, this polyester undergoes degradation by an intramolecular mechanism involving the formation of a cyclic transition state. The very high value of the degradation constant of this polycondensate is probably a result of the presence, in this chain, of the very flexible tetramethylene segment.     

Kinetic studies of the anionic polymerization of methyl methacrylate in tetrahydrofuran with Na+ as counter ion,using monofunctional initiators

A newly designed automatically controlled stirred reactor suitable for kinetic measurements of reactions with half lives ≥2s has been applied to follow the anionic polymerization of methyl methacrylate in THF with Na⁺ as a counter ion in the presence of an excess of NaB(C₆H₅)₄. As initiators were used: benzylsodium reacted with α-methylstyrene (I), fluorenylsodium (II), and 9-methylfluorenylsodium (III). With I the initiation is fast as compared with the polymerization reaction which is first order in monomer concentration. Within the range of ?50°C to ?100°C an almost unperturbed “living” polymerization is observed. The Arrhenius plot of the rate constants results in a straight line with activation energy E_a = 4,4kcal·mol^?1 (= 18kJ·mol^?1) and frequency exponent A = 7,0.II and III are slow initiators, II giving rise to side reactions because of the “acidic” proton in 9-position after initiation, III exhibiting a rate constant of initiation k_i = 1l·mol^?1·s^?1 at ?72°C. The termination reaction is becoming increasingly important with increasing temperature and seems to be a unimolecular reaction with E_a,t = 11,5kcal·mol^?1 (= 48 kJ·mol^?1) and A_t = 10. Since the basic feature of the reactor is the possibility of drawing samples, polymers from each state of the reaction were available to be investigated also with respect to their tacticity. The monomer addition was shown to follow Bernoullian statistics. A structure of the “living” end being in harmony with the results observed is discussed.     

Thermodynamics of copolymerization of 1,3-dioxolane with 1,3-dioxepane and 1,3-dioxane

The equilibrium copolymerization of 1,3-dioxolane with 1,3-dioxepane in CH₂Cl₂ solution and with 1,3-dioxane without solvent is analyzed, and the equilibrium constants of homo- and cross-propagations are estimated and discussed. The corresponding thermodynamic parameters are calculated. The reported thermodynamic parameters of homopolymerization of 1,3-dioxane (ΔH_ss = ?3,1 kJ · mol^?1, ΔS_ss = ?35,5 J · mol^?1 · K^?1), were determined on the basis of the copolymerization data. Predictions of comonomer concentrations and microstructure of copolymers in the equilibrium copolymerization system are presented for any initial composition, on the basis of the determined equilibrium constants.     

Kinetics of the anionic polymerization of ϵ-caprolactone with K+ · (dibenzo-18-crown-6 ether) counterion. Propagation via macroions and macroion pairs

Following our earlier work on the polymerization of lactones involving crowned cations, kinetics of the anionic polymerization of ?-caprolactone (?CL) with K⁺ · (dibenzo-18-crown-6 ether) (K⁺DB18C6) counterion was studied calorimetrically in THF solution in the temperature range from 0 to 20°C. Dissociation constants of CH₃(CH₂)₅O^?K⁺DB18C6, modelling the active centers, were determined conductometrically: K_D (20°C) = 7,7 · 10^?5 mol · dm^?3, ΔH = 9,3 ± 0,2 kJ · mol^?1, ΔS = ?47 ± 2J · mol^?1 · K^?1. From kinetic measurements and from measurements of the dissociation constant of CH₃(CH₂)₅O^? K⁺DB18C6, rate constants of propagation via macroions and via macroion pairs were determined. Activation parameters for propagation via these species are equal to: ΔH = 39,2 ± 0,2 kJ · mol^?1, ΔS = ?63 ± 1 J · mol^?1 · K^?1, ΔH = 13,7 ± 0,1 kJ · mol^?1, ΔS = ?185 ± 2 J · mol^?1 · K^?1. At 20°C, k = 3,50 · 10² dm³ · mol^?1 · s^?1 and k = 5,2 dm³ · mol^?1 · s^?1. Due to the large difference of ΔH^≠ for propagation via macroions and macroion pairs (vide supra), the isokinetic point (k = k) would appear at ?65°C.     

Rate coefficients of the free-radical polymerization of 1,3-butadiene

Rate coefficients of termination and transfer in the free-radical polymerization of 1,3-butadiene in chlorobenzene were determined in the temperature range 318 K < T < 333 K. On the basis of an earlier published temperature dependence of the rate coefficient of propagation, for the termination reaction the Arrhenius equation K_t = 1,13 · 10¹⁰ · exp(? 711 K/T) L · mol^?1 · s^?1 was obtained. For the transfer to monomer the experiments yielded the Arrhenius equation K_tr,M = 4,22 · 10⁶ · exp(? 5140 K/T) L · mol^?1 · S^?1 and for the transfer to the solvent K_tr,S = 2,25 · 10⁸ · exp(? 7050 K/T) L · mol^?1 · S^?1.     

Anionic polymerization of one-ended “living” strontium-polystyrene in tetrahydropyran in the presence of tetraglyme and in benzene

The anionic polymerization of the strontium salt of one-ended living polystyrene (SrS₂) was investigated at 20°C in tetrahydropyran (THP) in the presence of two different concentrations of added tetraglyme. Similarly to BaS₂ in tetrahydrofuran (THF) and to SrS₂ in THF and in pure THP, the observed pseudo-first-order rate constant of propagation, k_obs, was nearly independent of the total concentration of salt, their values being 7,5.10^?3 s^?1 and 9 · 10^?3 s^?1, respectively, i. e. about 100 to 120 times higher than in pure THP. This indicates that the propagation occurs mainly via an increased but constant amount of free S^? anions resulting from the two already known equilibria SrS₂ ? (SrS)⁺ + S^?(K₁) and 2 SrS₂ ? (SrS)⁺ + (SrS₃)^? (K₂) and the equilibrium of glymation (SrS⁺) + G ? G, (SrS)⁺ (K_i). A small not exactly determinable contribution of glymated ion-pairs and/or triple ions, whose rate constants would then probably be of the order of 18 l · mol^?1 · s^?1 and 80 l · mol^?1 · s^?1, respectively, could not be excluded. The glymation constant K_i was found to be about 3 · 10⁶ 1 · mol^?1, i.e., approximately 17 times greater than for the Na⁺ cation. Finally, a kinetic experiment with SrS₂ at 20°C in pure benzene (contaminated, however, with some remaining THP from the preparation of SrS₂) indicated that propagation by ion-pairs is possible with a bimolecular apparent rate constant K_app = 1,1 · 10^?1 l · mol^?1 · s^?1.     

Polymerization of 2-diethylamino-1,3,2-dioxaphosphorinane, 2. Kinetics

Kinetic studies of the anionic polymerization of 2-diethylamino-1,3,2-dioxaphosphorinane were performed in THF solution with (CH₃)₃SiO^?K⁺ as initiator at temperatures close to r.t. Initiation involves nucleophilic attack of the anion on P atom in the monomer molecule. Breaking of the P? O bond leads to an alcoholate anion as the growing species. Polymerization was shown to proceed via macroion-pairs and to be nearly living; e.g. at r.t. for every 250 propagations there is one termination. Rate constant of propagation k = 3,4 ± 0,31·mol^?1·s^?1 at 25°C, ΔH = 13,3 kcal·mol^?1 and ΔS = ?32,2 cal·mol^?1·K^?1. The ratio k/k was determined by solving a kinetic scheme involving propagation and termination. It was shown that termination consists in the alcoholate anion attack on P in either polymer or monomer molecule with expulsion of (C₂H₅)₂N^? anion and formation of a P? O bond. The dialkylamide anions cannot reinitiate polymerization. In solving the kinetic scheme it was assumed that termination involving both polymer and monomer proceeds with rate constants equal to each other.     

Cationic polymerization of 1-azabicyclo[4.2.0]octane, 2. Reactivities of ions and ion-pairs

The cationic ring-opening polymerization of 1-azabicyclo[4.2.0]octane ( 1 ) was studied with initiators providing small and large anions, namely F^?, Br^?, I^?, picryl(Pic^?), CF₃SO₃^?. In nitrobenzene as solvent the macroions and macroion-pairs, independently of the anion size, propagate with the same rate constant k_p⁺ = k_p^± = 7,0 · 10^?3 mol^?1 · l · S^?1 at 35°C ( Δ H_P^≠ = 55 ± 5kj· mol^?1, Δ S_P^≠ = 105 ± 11 j · mol^?1 · K^?1). This result strongly indicates that it is not the large size of anoins which is exclusively responsible for the equality k_P⁺ = k_P^±. The structure of the onium ions, their strong solvation, and the resulting weak interactions with anions are primarily responsible for the observed equalities. In methanol as solvent polymerization proceeds 30 times slowlier than in nitrobenzene and ion-pairs are more reactive by 40% than ions, in agreement with Enikolopyan's findings.     

Elementary reactions in the cationic polymerization of oxepane. Comparison with the polymerization of tetrahydromfuran

In the polymerization of oxepane (OXP), initiated with derivatives of trifluoromethanesulfonic acid, covalent and ionic active centers were simultaneously observed by ¹H and ¹⁹F NMR spectroscopy. A higher proportion of secondary oxonium ions (these species detected by ¹⁹F NMR were independently observed by proton trapping with R₃P in the ³¹P NMR spectrum). The proportion of ionic species decreases with monomer conversion, indicating a substantial contribution of bimolecular ionization of the monomer. The effective molarity in oxepane polymerization [OXP]_eff ? 1 mol ·I^-1 was found to be lower by a factor of 10² than [THF]_eff in the polymerization of THF. The rate constant of the covalent propagation in the polymerization of OXP is similar to that measured for THF, however, due to the reduced reactivity of the oxepanium cation, the relative reactivity of the covalent active centers becomes higher than that of the ions. Thus, for OXP, in CH₃NO₂ at 25°C, K_pc = 3 · 10^?4 mol^?1 · 1 · s^?1, k_pi = 2 · 10^?4 mol^?1 · 1 · s^?1 whereas for THF k_pc = 5 · 10^?4 mol^?1 · 1 · s^?1 and k_pi = 2 · 10^?2 mol^?1 · 1 · s^?1 under similar conditions. The rates of ionization and temporary termination, measured by the “temperature jump” technique, allow to determine the contributions of inter-and intramolecular ionizations. These rates becomes equal at [OXP] = 1 mol · 1^-1 (= [OXP]_eff).     

Preparation of surface-modified polystyrene microspheres by an azo-initiator having analogous structure to the head group of phosphatidylcholine

A novel azo-initiator, 2-[(2-ethylphosphatoethyl)dimethylammonio]ethyl 4,4′-azobis-(4-cyanovalerate) (EAP-501), was prepared. EAP-501 [m. p. 97°C (dec.), λ_max 346 nm in H₂O] was found to be amphiphilic, with a Krafft point of 11,5°C and a critical micelle concentration of 47,2 mmol·dm^?3 at 30°C and 48,6 mmol·dm^?3 at 70°C. The rate and activation parameters for the thermal decomposition of EAP-501 at 70°C were estimated to be k_d = 2,35·10^?5 s^?1, ΔH^≠ = 118,4 kJ·mol^?1 and ΔS^≠ = 10,5 J·mol^?1·K^?1. Emulsion polymerization of styrene initiated with EAP-501 gave polymer microspheres in high yield. The resulting polystyrene microspheres were characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The polystyrene microspheres have diameters from 321 to 649 nm by varying the EAP-501 concentration. The ammonium phosphate groups, which are comparable to the polar head group of phospholipids, are concentrated on the surface of the particles. The particles were found to reduce the adsorption of bovine serum albumin (BSA) compared with particles prepared by the emulsion polymerization of styrene initiated with potassium persulfate as an initiator.     

Solvent effects on free-radical polymerization, 2. IR and NMR spectroscopic analysis of monomer mixtures of methyl methacrylate and N-vinyl-2-pyrrolidone in bulk and in model solvents

Binary systems of methyl methacrylate (MMA)/N-vinyl-2-pyrrolidone (NVP) and MMA/N-methyl-2-pyrrolidone (NMP) with NMP as saturated model of NVP and of NVP/methyl isobutyrate (MiB) with MiB as saturated model of MMA were investigated by means of IR and NMR spectroscopy. Investigations were carried out at room temperature or at 60°C in CHCl₃ (IR) or CDCl₃ and C₆H₁₂/C₆D₁₂ (NMR). It can be concluded from IR and NMR spectra that the polarity of MMA increases in the presence of NVP and the polarity of NVP decreases in the presence of MMA. Equilibrium constants K of complex formation were determined to: K = 0,169 ± 0,037 L · mol^?1 for MMA/NVP at 30°C, 0,112 ± 0,024 L · mol^?1 for NVP/MiB at 60°C and 0,125 ± 0,030 L · mol^?1 for MMA/NMP at 60°C.     

Polymer reactions, 8. Oxidative pyrolysis of poly(propylene)

Poly(propylene) has been oxidized at temperatures between 240 and 289°C. The products were GC separated and on-line identified by an interfaced GC peak identification system. The major products are CO₂, H₂O, acetaldehyde, acetone, butanal, formaldehyde, methanol and other ketones and aldehydes. Most of the products can be accounted for by well-known reactions of alkoxyl and peroxyl radicals; the major products are derived from the secondary alkoxy and peroxy species. Oxygen starvation is manifested in diffusion limited products of olefins and dienes, and the increase of CO₂ and H₂O formation in pure oxygen atmosphere. The first order rate constant at 240°C is 2,4·10^?3 S^?1 with an overall activation energy of ca. 16 kcal·mol^?1 (67 kJ·mol^?1). If one assumes the oxidative pyrolysis to share the same reaction pathways as autoxidation at lower temperatures, then the observed rate constants and activation energy may be calculated from kinetic parameters measured earlier for autoxidation of poly(propylene) from 71 to 140°C. Good agreement was obtained implying a similarity of oxidative degradation of the polymers spanning a large temperature range.     

Enthalpy of polymerisation of 2-oxabicyclo[2.2.2]octan-3-one

The enthalpies of combustion of crystalline 2-oxabicyclo[2.2.2]octan-3-one ( 1 ), and five different crystalline poly(oxycarbonyl-1,4-cyclohexylene) samples formed from 1 were measured at 298, 15 K by high-precision bomb calorimetry. For 1 , the enthalpies of combustion and of formation were, ?ΔH(c) = 3717,5 ± 1,3 kJ·mol^?1 and ?ΔH(c) = ? 466,2 ± 1,6 kJ·mol^?1. After correction for the presence of n-butyl- or tert-butoxy-end groups in the polyester samples, a consistent enthalpy of polymerisation of 1 was obtained, ΔH(c → c) = ? 20,9 ± 2,3 kJ·mol^?1. The enthalpy of sublimation of 1 was measured, ΔH (1) = 69,6 ± 2,1 kJ·mol^?1; the value for the polyester unit was derived as 49 kJ·mol^?1.     

Configurational double bond selectivity in the epoxidation of hydroxy-terminated polybutadiene with m-chloroperbenzoic acid

The selectivity of the three different double bonds (CIS, TRANS and VINYL) of hydroxyterminated polybutadiene regarding epoxidation was evaluated, using m-chloroperbenzoic acid in toluene below room temperature (?10°C, ?5°C, 0°C and 5°C). To determine the kinetic constants for the three configuratons (k_1,cis = (2,59–0,6) × 10^?2 L · mol^?1 · min^?1; k_{2, trans} = (5,35–0,82) × 10^?2 L · mol^?1 · min^?1; k_{3, vinyl} = (0,97–0,01) × 10^?2 L · mol^?1 min^?1), ¹H and ¹³C NMR was used along with a system of three parallel equations. The activation energy values were also evaluated (E_{a, cis} = 53,9 kJ · mol^?1; E_{a, trans} = 70,7 kJ · mol^?1 and E_a, vinyl = 261,1 kJ · mol^?1) for the three double bond types.     

Hydrolysis kinetics of terephthalic and 5-sulfonatoisophthalic acid esters

The saponification reaction of bis(2-hydroxyethyl) terephthalate ( 3 ) and sodium 3,5-bis(2-hydroxyethoxycarbonyl)benzenesulfonate ( 6 ) was followed under pH-stat conditions in the alkaline pH range (pH 8 to 10 at 50 to 80°C) to determine the consecutive reaction rate constants for the hydrolysis of the diesters and the intermediate monoesters. The observed overall reaction rate constants were split into the individual rate constants for the hydrolysis catalyzed by the solvent, the OH^? ions, the SO groups and the COO^? groups (k₀, k_OH?, k_SO, kCOO?, respectively). No intermolecular catalysis by either the sulfonato or the carboxylato groups and no “autocatalysis” by the solvent was found. The activation parameters for the hydrolysis of the corresponding esters of both acids are equal; for the diesters 3 and 6 : ΔH^? = 73,7 (72,0) kJ mol^?1 [17,6 (17,2) kcal mol^?1], ΔG^? = 103,8 (104,7) kJ mol^?1 [24,8 (25,0) kcal mol^?1], ΔS^? = ?89,6 (?97,6) J mol^?1 K^?1 [?21,4 (?23,3) cal mol^?1 K^?1]; for the monoesters [terephthalic acid mono(2-hydroxyethyl) ester and 5-sodiumsulfonatoisophthalic acid mono(2-hydroxyethyl) ester]: ΔH^? = 80,4 (78,7) kJ mol^?1 [19,2 (18,8) kcal mol^?1], ΔG^? = 109,3 (109,7) kJ mol^?1 [26,1 (26,2) kcal mol^?1], ΔS^? = ?86,3 (?93,0) J mol^?1 K^?1 [?20,6 (?22,2) cal mol^?1 K^?1]. It is concluded that disorders in the fine structure of polyester fibers modified with sulfonato group containing comonomers may primarily be responsable for their lower hydrolytic stability and not any catalytic effects of these groups.     

Dependence of the kerr constants of benzene,p-dioxane and poly(oxydiethylene terephthalate) on temperature

The Kerr constants of benzene, p-dioxane, and of poly(oxydiethylene terephthalate) (PDET) in p-dioxane solution were measured at several temperatures. As in the case of some other pure liquids reported in the literature, the values obtained for benzene and p-dioxane are fitted by equations of the type _mK = a + b · T^?1 with a = (0,3 ± 0,6) · 10^?26 m⁵ · V^?2 · mol^?1 and b = (16,0 ± 1,8) · 10^?24 m⁵ · V^?2 · mol^?1 · K for benzene and a = (3,9 ± 0,9) · 10^?26, b = ?(8,2 ± 2,6) · 10^?24, in the same units, for p-dioxane. The values of the mean molar Kerr constant per repeating unit 〈_mK〉/x extrapolated to infinite dilution in the case of PDET yield a values of d(〈_mK〉/x)/dT = (13,5 ± 0,9) · 10^?27 m⁵ · V^?2 · mol^?1 · K^?1, in excellent agreement with the calculated result of 13,2 · 10^?27 (in the same units) reported in the literature.     

The polymerization of acenaphthylene by carbocation salts in nitrobenzene

Acenaphthylene was polymerized in nitrobenzene at 25°C by NO₂SbF₆, C₂H₅COSbF₆, C₆H₅COPF₆, and (C₆H₅)₂CHSbF₆. With monomer so rigorously purified that it contained only ca. 0,01 mol-% of inhibiting impurities the reaction pattern indicated propagation by unpaired cations, and a k = 23,3 ± 2 dm³·mol^?1·s^?1 (the first for this monomer) was obtained. There are at least two chain-breaking reactions of which one is the proton transfer to monomer which has K = 2,3 dm³·mol^?1·s^?1. The kinetic irregularities and colours which develop at high conversions are probably due to the formation of non-propagating allylic cations from unsaturated end-groups.     

Free radicals in colloidal systems: Formation and decay of radicals in the tensides α-hexadecyl-ω-hydroxypoly(oxyethylene) and α-tetradecyl-ω-(sodium sulfonato)tri(oxyethylene)

Organic radicals were produced in the tensides C₁₆H₃₃(OCH₂CH₂)₂₁OH and C₁₄H₂₉(OCH₂CH₂)₃-SO₃Na in aqueous solutions using a short pulse of high energy electrons. The radicals were formed by OH attack on the (OCH₂CH₂)_x-parts of the tensides. The decay of the 250nm absorption of the radicals was recorded at different initial radical concentrations and tenside concentrations. Several radicals could be produced in one micelle. Radicals formed in the same micelle decay within microseconds or faster. The half life time τ₁ in a micelle carrying two radicals is 2,0·10^?6 s for C₁₆H₃₃(OCH₂CH₂)₂₁ OH and less than 6·10^?7 s for C₁₄H₂₉(OCH₂CH₂)₃SO₃Na. A model for intramicellar radical-radical reactions is proposed according to which the rate is faster in tensides of high critical micelle concentration. Single radicals in micelles of C₁₆H₃₃(OCH₂CH₂)₂₁OH can deactivate each other without leaving the micelles. This intermicellar reaction is discussed in terms of the rate of diffusion-controlled micelle-micelle encounters, an encounter time of 7·10^?8s, and the above time τ₁ for intramicellar reaction. The observed rate constant 2k of intermicellar reaction is 3,5·10⁶ mol^?1·l·s^?1. At low tenside concentrations, the bimolecular rate constant increases since more single tenside radicals are present in solution. They react rapidly (ca. 10⁸ mol^?1·l·s^?1) with radicals in micelles. Single radicals in C₁₄H₃₃(OCH₂CH₂)₃-SO₃Na micelles cannot directly react with each other because of the Coulombic repulsion between two anionic micelles. Reaction occurs after the exit of a tenside radical from its micelle, the rate of which depends on the micellar equilibrium M_n?M_n?1+M (M: tenside molecule; n: agglomeration number of micelle). A single radical in solution reacts with a single radical in a micelle with 2k = 1,0·10⁸ mol^?1·l·s^?1 and with another single radical in solution with 4,0·10⁷ mol^?1·l·s^?1.γ-Irradiation of both tensides in aqueous solution leads to slight increases in viscosity, followed by turbidity beyond the “gel dose” and phase separation. These effects are explained in terms of crosslinking of tenside molecules. Formation of a large network requires bridges between all participating tenside molecules (not only bridges between micelles).     

Radiation-induced radical formation and crosslinking in aqueous solutions of N-isopropylacrylamide

To investigate chain-initiating and crosslinking mechanisms, radical formation in dilute aqueous solutions of N-isopropylacrylamide (NIPAAm) and poly-NIPAAM was studied using electron pulse radiolysis with optical detection at room temperature. Several transients of NIPAAm generated by reactions with electrons, hydroxyl radicals and hydrogen atoms were observed. Electron attachment to the carboxyl group (k_e = 9.0 x 10⁹ dm³ · mol⁻¹ · s⁻¹) forms the radical anion, which undergoes fast and reversible protonation (pK_a = 7.8) at the carboxyl oxygen. At pH > pK_a, slow and irreversible protonation of the electron adduct at the vinyl group leads to the α-carboxyalkyl radical CH₃(^.CH)CONHCH(CH₃)₂, which is also formed by addition of H atoms to NIPAAm (k_H = 7.3 × 10⁹ dm³ · mol⁻¹ · s⁻¹). Addition of OH radicals (k_OH = 5.4 × 10⁹ dm³ · mol⁻¹ · s⁻¹) forms CH₂(OH)(^.CH)CONHCH(CH₃)₂. Hydrogen abstraction was not observed in the case of NIPAAm monomer, but it was found for the reaction of OH radicals with thermally polymerized NIPAAm. Semi-empirical quantum chemical calculations support the assignment of the observed spectra to the radicals. A reaction mechanism for the formation of crosslinks is discussed.     

Acidolytic polymerization of N-methyldodecanelactam

The polymerization rate of 1-methylazacyclotridecan-2-one (N-methyldodecanelactam) ( 1 ) initiated with dodecanoic acid ( 2 ) can be described within the whole range of conversions in terms of the simple relation In ([ 1 ]₀/[ 1 ]) = k[ 2 ]₀t, in spite of the complexity of the overall reaction scheme. The rate constants (k) determined for 240, 260, and 280°C are 0,32, 1,21, and 3,4 kg · mol^?1 h^?1, respectively, and the constants of the Arrhenius equation are A = 6,6 · 10¹³kg · mol^?1 h^?1, E = 140 kJ · mol^?1. The resulting poly(N-methyldodecaneamide) ( 3 ) is a semicrystalline polymer (m.p. 65°C), soluble in polar organic solvents. The following constants of the Mark-Houwink equation were determined for solutions of this polyamide: for 5000 < M?_w < 150 000 g · mol^?1 at 25°C in THF (2-propanol), K = 0,124 (0,161) cm³ · g^?1, a = 0,59 (0,56); for 5 000 < M?_w < 80 000 g · mol^?1 at ?-temperature = 30,5°C in 1,4-dioxane, K = 0,215 cm³ · g^?1, a = 0,50. Analyses of molar masses, both theoretical and experimental (light-scattering, GPC, osmometry, end groups), indicate that at the polymerization temperature of 280°C side reactions already take place, reflected in random cleavage and in branching of chains.