End-group Analysis Research Articles

ROMP Synthesis of Cobalticenium–Enamine Polyelectrolytes

The synthesis of redox-robust polyelectrolyte polymers has long been investigated. Two simple methods of synthesis of well-defined cobalticenium-containing polymers are presented using both the norbornene ring-opening-metathesis polymerization (ROMP) method initiated by a third-generation Grubbs catalyst and the mild uncatalyzed hydroamination of the easily available ethynyl cobalticenium hexafluorophosphate salt. In the first strategy, a norbornene monomer functionalized with an enamine-cobalticenium group is polymerized by ROMP, whereas in the second one a norbornene derivative functionalized with a secondary amine group is polymerized by ROMP using the same catalyst followed by hydroamination of ethynyl cobalticenium. The structures of the polymers have been established by 1H, 13C NMR, and DOSY NMR, IR, UV–vis spectroscopy, mass spectrometry, elemental analysis, and cyclic voltammetry. The number of units in the polymers have been determined for various polymer lengths using end-group analysis by 1H NMR using the diffusion coefficient determined by DOSY NMR and by cyclic voltammetry upon comparing the relative intensities of a monomer reference and the cobalticenium polymers.

Fatty acids based transparent polyurethane films and coatings

• Synthesis of polyesteramide from palmitic acid and dimer fatty acid. • Biobased transparent PU films and coatings. • Eco-friendly PU coatings. • Dimer fatty acid as a substitute to conventional dicarboxylic acids or anhydrides. Renewable resources used in the preparation of polymers are falling in the class of biomaterials which are rich in hydrocarbons and most of the times obtained from parts of profusely available agriculture feedstock. Use of non-edible vegetable oils and their fatty acids are currently the raw materials focused in synthesizing polymeric materials as renewable sources due to increasing economic and environmental concerns of petroleums. The current oil based polymers are prepared by consuming petroleum based anhydrides and dicarboxylic acids. With this investigation, we tried to substitute almost all components of petroleum feed stock by renewable sources in preparation of polyol. Initially palmitic acid was used as a renewable source to prepare palmitamide by amidation reaction. Further amide was converted into the polyesteramide resin (PEPAD) by reacting it with another renewable resource, i.e. dimer fatty acid which is the dimerized product of unsaturated fatty acids of vegetable oils. Structure of the prepared resin was confirmed by spectroscopic techniques and resin was also characterized by end group analysis like hydroxyl and acid values. The molecular weight of PEPAD was ranged between 2590 and 2760 g mol −1 . Palmitic acid based polyesteramide was used to prepare polyurethanes by varying amount of diisocyanate. The transparent polyurethane films and coatings were obtained and examined for water absorption, contact angle, hardness, coating properties, solvent, acid and alkali resistances. The thermal properties of the polyurethane films were estimated by TGA and discussed. It was found that change in NCO content affected on transparency as well flexibility of the prepared films. It also noticed that thermal stability was shifted toward higher range by increasing mole (NCO/OH) ratios due to formation of urea linkages.

13C NMR spectroscopy for the quantitative determination of compound ratios and polymer end groups.

13C NMR spectroscopic integration employing short relaxation delays was evaluated as a quantitative tool to obtain ratios of diastereomers, regioisomers, constitutional isomers, mixtures of unrelated compounds, peptoids, and sugars. The results were compared to established quantitative methods such as 1H NMR spectroscopic integration, gas chromatography, and high-performance liquid chromatography and were found to be within <3.4% of 1H NMR spectroscopic values (most examples give results within <2%). Acquisition of the spectra took 2–30 min on as little as 10 mg of sample, proving the general utility of the technique. The simple protocol was extended to include end group analysis of low molecular weight polymers, which afforded results in accordance with 1H NMR spectroscopy and matrix-assisted laser desorption-ionization time-of-flight spectrometry.

Renewable Source Based Non‐biodegradable Polyurethane Coatings from Polyesteramide Prepared in One‐Pot Using Oleic Acid

AbstractThe highlight of the work was the preparation of polyesteramide in a one‐pot reaction which avoids isolation of diethanol amide as it is normally required in polyesteramide preparation. In the present work, oleic acid was reacted with diethanol amine resulting in diethanol amide which further reacted with phthalic anhydride in the same reaction vessel without isolation and purification. Therefore the reaction is a one‐pot, time‐saving and cost‐effective method as it requires minimum solvent and processing steps. In addition to this, the fatty acid used was a single fatty acid (oleic acid) that provides selective physico‐ chemical and anticorrosive properties for the resin. FT‐IR and 1H‐NMR spectroscopic studies confirmed the structure of the polyesteramide. End group analysis and molecular weight were used to calculate the stoichiometric balance of the NCO/OH ratio in the preparation of polyurethane. The prepared resin was converted to polyurethane coatings by reacting with toluene diisocyanate and methylene diphenyl diisocyanate. Thermal stability, physico‐chemical and coating properties of the polyurethane coatings were investigated. The polyurethane prepared showed a non‐biodegradable nature so that it is of commercial interest and value for applications in various fields. Study of coatings was also carried out for properties like adhesion, impact resistance, pencil hardness and the bending test.

Oligomeric Cationic Polymethacrylates: A Comparison of Methods for Determining Molecular Weight

This study compares three common laboratory methods, size-exclusion chromatography (SEC), (1)H nuclear magnetic resonance (NMR), and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), to determine the molecular weight of oligomeric cationic copolymers. The potential bias for each method was examined across a series of polymers that varied in molecular weight and cationic character (both choice of cation (amine versus guanidine) and relative proportion present). SEC was found to be the least accurate, overestimating Mn by an average of 140%, owing to the lack of appropriate cationic standards available, and the complexity involved in estimating the hydrodynamic volume of copolymers. MALDI-TOF approximated Mn well for the highly monodisperse (Đ < 1.1), low molecular weight (degree of polymerization (DP) <50) species but appeared unsuitable for the largest polymers in the series due to the mass bias associated with the technique. (1)H NMR was found to most accurately estimate Mn in this study, differing to theoretical values by only 5.2%. (1)H NMR end-group analysis is therefore an inexpensive and facile, primary quantitative method to estimate the molecular weight of oliogomeric cationic polymethacrylates if suitably distinct end-groups signals are present in the spectrum.

Synthesis and Characterization of Functionalized Polystyrene Using ATRP with Strong Base Technique

This paper deals with a simple method for the synthesis of functionalised polystyrene using ATRP and strong base chemistry. The α, Ω- dihydroxy terminated polystyrene (OH-PSt-OH) and α, Ω- diamine terminated polystyrene (NH2-PSt-NH2) were prepared by reacting α, Ω- Dibromo terminated polystyrene (Br- PSt-Br) with Potassiumhydroxide and Sodamide respectively. The synthesized polymers are characterized by different techniques. The Infrared (IR) spectrum confirms the formation of -OH and -NH2 as end group. The weight average molecular weight (Mw) of the synthesized polymer is determined by 1 H NMR end group analysis, gel permeation chromatography (GPC) and mass spectrometric technique and found to be around 2000 g/mol. Thermogravimetric analysis (TGA) showed single stage decomposition cantered at 400 o C. The Tg value of the polymers is determined using Differential Scanning Colorimetric (DSC) method and found to be in the range from 58 to 60°.

Substituent effects and activation mechanism of norbornene polymerization catalyzed by three-dimensional geometry α-diimine palladium complexes

A series of three-dimensional geometry 9,10-dihydro-9,10-ethanoanthracene-11,12-diimine methyl palladium chloride complexes were synthesized and characterized. These three-dimensional geometry α-diimine palladium complexes exhibited high activities toward the homopolymerization of norbornene and copolymerization of norbornene with 5-norbornene-2-carboxylic acid methyl ester in the presence of B(C6F5)3. It was observed that the palladium–halogen bond of the complexes could be effectively activated by B(C6F5)3. The activation mechanism was clarified by the end group analysis of the polymer, which provided a new pathway for the activation of palladium complexes. Meanwhile, the palladium catalysts with a three-dimensional geometry on the backbone were found to show a good thermal stability and afford a high incorporation of the polar monomer in norbornene polymerization. Moreover, the α-diimine palladium complexes with a large steric hindrance or strongly electron-donating group on the aryl ring of ligands could achieve a higher reactivity.

Soluble and stable alternating main-chain merocyanine copolymers through quantitative spiropyran–merocyanine conversion

A combined experimental and theoretical study on the synthesis and solution isomerization behavior of main chain copolymers with multiple spiropyran incorporation is presented. A series of alternating copolymers P(SP-alt-Cx) of spiropyran (SP) and flexible linkers (Cx, x = 6,8,10) is synthesized by Suzuki polycondensation (SPC). Careful 1H NMR polymer end group analysis is carried out to reveal termination reactions that limit molecular weight. Although methylene indoline and salicyl aldehyde end groups are found arising from SP cleavage during polymerization, acceptable Mn,SEC up to 34 kg mol−1 is achieved. P(SP-alt-Cx) can be transformed into the corresponding protonated form of the red alternating merocyanine (MC) polymer, P(MCH+-alt-Cx), in quantitative yield by direct acidification or pulsed ultrasound. The origin of the latter method lies in the sonochemical degradation of chloroform, which provides a continuous source of hydrochloric acid. Deprotonation of P(MCH+-alt-Cx) occurs upon the addition of a base resulting in the blue form P(MC-alt-Cx), as characterized by UV-vis spectroscopy and confirmed by density functional theory (DFT) calculations of model compounds. DFT further reveals P(MCH+-alt-Cx) to be the thermodynamically most stable form. It is proposed that the para-linkage to the phenyl-based comonomer Cx decreases acidity of protonated merocyanine and hence increases stability of P(MCH+-alt-Cx), which poses a marked difference compared to the commonly employed 6-nitro-substituted analogs.

Ring-opening polymerisation of ɛ-caprolactone catalysed by Brønsted acids

AbstractTwo new Brønsted acids [2,2′-ethylidene-bis (4,6-di-tert-butylphenol)] phosphoric acid (EDBPPOOH) and (3,3′,5,5′-tetra-tert-butylbiphenyl-2,2′-diol) phosphoric acid (TBPO-POOH) were synthesised and fully characterised by 1H NMR and 13C NMR spectra and mass spectra. The ringopening polymerisation (ROP) of ɛ-caprolactone (ɛ-CL) catalysed by the two Brønsted acids proceeded at 110°C without a solvent or at ambient temperature in toluene. Experimental results indicated that the two Brønsted acids were efficient catalysts for the ROP of ɛ-CL with moderate number-average molar mass (Mn) and narrow polydispersity indices (PDI). The catalytic activity of TBPO-POOH is higher than EDBP-POOH in the ROP of ɛ-CL. After benzyl alcohol was added, it was able to accelerate the polymerisation process. The polymerisation can also occur with the addition of water with a monomer/catalyst/initiator mole ratio of 100: 1: 1. The living polymerisation was ascertained by the linear relationships of the Mn vs. monomer conversion, then it was further confirmed by a second-feed experiment of a double monomer producing double Mn. A kinetic study of the relationships between monomer concentration and time revealed a first-order dependence on monomer concentration in the polymerisation. End-group analysis of 1H NMR spectra and electrospray-ionisation mass spectra suggests that the two Brønsted acids are capable of catalysing and initiating the ROP of ɛ-CL.

An investigation on synthesis of alkyd resin with sorbitol

• Three kinds of alkyd resins were synthesized using sorbitol. • The initial and later stage of the reaction followed a second-order rate law. • The average molecular weight were measured and theoretically calculated. • The film properties of the synthesized resins were determined. Sorbitol, as an abundant, cheap and renewable resource, is considered as a potential raw material for the manufacture of alkyd resin. In this study, the kinetics on preparation of alkyd resin using phthalic anhydride, sorbitol and soya bean fatty acid as raw materials is investigated. Three kinds of sorbitol based alkyd resins (SAR) samples having fatty acid content (OL f ) of 42% (SAR1), 52% (SAR2) and 62% (SAR3) were prepared with phthalic anhydride, sorbitol aqueous solution and soya bean fatty acid using fatty acid method. Kinetic studies showed that the initial and latter stages of the reaction follow a second-order rate law. The second-order rate constants were found to be of the order of 10 −5 g/mg KOH/min. Molecular weight and polydispersity index were determined by GPC and end-group analysis. The number average molecular weight of the alkyd resins ranged from 1435 to 1626 and the weight average molecular weight ranged from 3041 to 3648. A large polydispersity index was found in a range from 2.12 to 2.24. The varnish of alkyd resin SAR1 containing 50% 200# solvent gasoline and 1.25% cobalt naphthenate (drying agent) by weight dried faster than the others. The physical and chemical film properties of the sorbitol based alkyd resins were determined and compared with standard alkyd resins. The results showed that the performance of alkyd resin having fatty acid contents (OL f ) of 42% (SAR1) was almost the same as the standard alkyd resins. It could be a choice binder for alkyd resin paint and helpful to reduce production cost.

Controlled radical copolymerization of vinyl acetate and dibutyl maleate by iodine transfer radical polymerization

Iodine transfer radical homo- and copolymerization of vinyl acetate (VAc) with dibutyl maleate (DBM) were carried out in the presence of ethyl iodoacetate (EtIAc) and 2,2′-azobis(isobutyronitrile) (AIBN) as chain transfer agent and initiator, respectively, at 60 °C. Molecular weight and its distribution and (co)polymer structure (i.e. copolymer composition and chain end groups) were analysed using gel permeation chromatography and 1H NMR spectroscopy, respectively. Homo- and copolymerization reactions proceed via a controlled characteristic with predetermined molecular weight and relatively narrow molecular weight distribution. The presence of DBM in the reaction mixture decreases the consumption rate of EtIAc as well as the polymerization rate. This is attributed to the effect of DBM on the transfer constant to the EtIAc and probably on the iodine exchange rate constant between the growing chains. The effect of the concentration of AIBN, EtIAc and overall monomers on the conversion, molecular weight and its distribution was studied. Simultaneously high conversion and molecular weight with a relatively narrow molecular weight distribution can be achieved only when equimolar and intermediate concentration of EtIAc and AIBN is used in the reaction mixture. End-group analysis by 1H NMR reveals that iodinated VAc end groups in the (co)polymer chains are unstable, resulting in aldehyde end groups. Thermogravimetric analysis shows that the thermal stability of the VAc-based polymer increases on incorporating DBM units into the copolymer chains. © 2013 Society of Chemical Industry

MALDI of synthetic polymers with labile end‐groups

Mass spectrometry is increasingly used in the field of synthetic polymers as a fast and accurate technique for end-group analysis. More particularly, matrix-assisted laser desorption/ionization (MALDI) has gained much popularity because it allows quite simple mass spectra to be obtained, displaying a single distribution for each polymeric species present in the sample, in contrast to electrospray ionization (ESI) which readily promotes multiple charging for most polymers. A soft ionization process, ensuring the integrity of the species upon transfer into gas phase ions, is however mandatory for polymer end-group analysis since information about the chain terminations mainly rely on the m/z values measured for polymer adducts. As compared to ESI, MALDI is sometimes suspected to be a quite "hard" ionization technique, leading to spontaneous dissociation of ionized species either in the source or during their flight time. This issue is of particular concern for polymers carrying so-called fragile end-groups arising from their mode of synthesis. In particular, controlled radical polymerization (CRP) processes, one of the most important advances in the field of polymer science during the last 20 years, allow the production of polymers with well-defined molecular distribution and low polydispersities, but they are all based on the low dissociation energy of the chemical bond between the last monomer and the terminating group. As a result, if macromolecules are activated while being ionized, this end-group is prone to fragmentation and ions measured in the mass spectra do no longer reflect the original chain composition. However, different results are reported in the literature about the ability of MALDI to generate intact ions from CRP synthetic polymers. This article reviews MALDI MS data reported for synthetic polymers produced by atom transfer radical polymerization (ATRP), reversible addition-fragmentation transfer polymerization (RAFT), and nitroxide-mediated polymerization (NMP), the three most studied CRP techniques. The general principle of each polymerization process, which defines the structure of the end-groups in both targeted macromolecules and species arising from eventual side-reactions, is first briefly presented. An overview of MALDI data reported for samples obtained upon polymerization of different monomers are then commented for each polymerization techniques with regards to the success of the ionization method to generate intact cationic adducts and its propensity to distinguish in-source fragments from polymerization side-products.

Ring-opening polymerization of ε-caprolactone initiated by samarium acetate

Poly(e-caprolactone) (PCL) was prepared by ring- opening polymerization initiated with samarium acetate. The effects of reaction temperature, molar ratio of monomer/ initiator and reaction time on the conversion of e-CL to PCL and the molecular weight were investigated. The temperature was varied between 80 and 150 °C and the molar ratio of monomer to initiator between 107 and 1000 mol/mol. The results indicatethatthe samariumacetate (SmAc3) induces the polymerization of e-CL to high conversion and polyesters with number-average molecular weights of 3.43×10 3 to 12.60×10 3 were obtained. The polymers were characterized by Nuclear Magnetic Resonance ( 1 H-NMR), size exclusion chromatography (SEC). Based on the 1 H-NMR end-group analysis of low-molecular-weight PCL, it was proposed a coordination-insertion mechanism for the polymerization. Kinetics study indicated that the polymerization rate is first- order with respect to monomer concentration.

Biobased dimer fatty acid containing two pack polyurethane for wood finished coatings

Novel two pack polyurethane wood finished coatings are prepared from renewable sources, such as vegetable oil based fatty acid and dimer fatty acid. In actual experimental part oleic acid was reacted with diethanolamine to obtain amide which was on condensation polymerization with dimer fatty acid converted into the polyesteramide polyol. These are all being used to prepare polyurethanes. The functional and structural elucidation of dimer fatty acid based polyesteramide and diethanolamide were carried out by end group analysis, spectral studies such as FTIR and 1H NMR. Average molar masses of the polyesteramide were estimated by gel permeation chromatography (GPC). The polyesteramide was used in the preparation of wood finished polyurethane coatings by reacting it with aromatic diisocyanates. Thermogravimetric analysis (TGA) was used to study the thermal behavior of coatings. Physico-chemical and coating properties of the coatings were investigated by using standard methods. The results indicated that the bio-based wood finished PU coatings provided good mechanical, weather resistance as well possessed adequate coating properties for wood surface protections.

Branching Defects in Dendritic Molecules: Coupling Efficiency and Congestion Effects

An analytical model supplemented by Monte Carlo simulations specifies the statistics of branching defects in dendritic molecules as a function of the generation g as well as the maximal g for which defect-free synthesis is possible, gmax. The defects arise because of (i) imperfect coupling efficiency characterized by a constant fraction P ≤ 1 of successful add-on reactions in the absence of excluded volume effects and (ii) packing constraints associated with steric congestion at high g when the maximal density is approached. The model specifies ng, the number of junctions, and the number of defects for both g ≤ gmax and g > gmax, as well as gmax and its dependence on P. The branching polydispersity is characterized by the average number of junction–junction bonds, Xgeff. For g < gmax and efficient synthesis Xgeff is weakly reduced with respect to X, its value in defect-free molecules, and ng ∼ (Xeff – 1)g increases exponentially. In the congested regime, at g > gmax, branching is strongly reduced, and Xgeff slowly approaches 2 as Xgeff – 2 ∼ 1/g while ng eventually exhibits power law growth: ng ∼ g3 for dendrimers and ng ∼ g2 for dendronized polymers. The branching defects can be interrogated by different forms of end-group analysis utilizing the theory framework proposed.

Comparison of Selected Zirconium and Hafnium Amine Bis(phenolate) Catalysts for 1-Hexene Polymerization

The kinetics of 1-hexene polymerization using a family of three zirconium and hafnium amine bis-phenolate catalysts, M[t-Bu-ONXO]Bn2 (where M = Zr (a) or Hf (b), and X = THF (1), pyridine (2), or NMe2 (3)), have been investigated to uncover the mechanistic effect of varying the metal center M. A model-based approach using a diverse set of data including monomer consumption, evolution of molecular weight, and end-group analysis was employed to determine each of the reaction-specific rate constants involved in a given polymerization process. This study builds upon the mechanism of polymerization for 1a–3a, which has been previously reported by applying the same methodology to the hafnium containing analogues, 1b–3b. It has been observed that each elementary step-specific rate constant that involves the insertion of a monomer is reduced by an order of magnitude. As previously reported for catalysts 1a–3a, a quantitative structure–activity relationship was uncovered between the logarithm of the monomer-independent chain transfer rate constants and the Hf–X bond distance for catalysts 1b–3b. However, this dependence on the pendant ligand is 2.7 times weaker for the Hf-containing analogues versus those containing Zr. These findings underscore the importance of comprehensive kinetic modeling using a diverse set of multiresponse data, enabling the determination of robust kinetic constants and reaction mechanisms of catalytic olefin polymerization as part of the development of structure–activity relationships.

Mechanistic Studies on Initiation and Propagation of Rare Earth Metal-Mediated Group Transfer Polymerization of Vinylphosphonates

Initiation of rare earth metal-mediated vinylphosphonate polymerization with unbridged rare earth metallocenes (Cp2LnX) follows a complex reaction pathway. Depending on the nature of X, initiation can proceed either via abstraction of the acidic α-CH of the vinylphosphonate (e.g., for X = Me, CH2TMS), via nucleophilic transfer of X to a coordinated monomer (e.g., for X = Cp, SR) or via a monomer (i.e., donor)-induced ligand-exchange reaction forming Cp3Ln in equilibrium (e.g., for X = Cl, OR), which serves as the active initiating species. As determined by mass spectrometric end group analysis, different initiations may also occur simultaneously (e.g., for X = N(SiMe2H)2). A general differential approach for the kinetic analysis of living polymerizations with fast propagation and comparatively slow initiation is presented. Time-resolved analysis of monomer conversion and molecular weights of the formed polymers allow the determination of the initiator efficiency throughout the whole reaction. Using this normalization method, rare earth metal-mediated vinylphosphonate GTP is shown to follow a Yasuda-type monometallic propagation mechanism, with an SN2-type associative displacement of the polymer phosphonate ester by a monomer as the rate-determining step. The propagation rate of vinylphosphonate GTP is mainly determined by the activation entropy, i.e. the change of rotational and vibrational restrictions within the eight-membered metallacycle in the rate-determining step as a function of the steric demand of the metallacycle side chains and the steric crowding at the metal center.

PAMAM dendrimers on controlled pore glass: The effect of tethered dendrimer size and tethered affinity groups NTA and terpy on metal ion and indicator dye uptake

PAMAM dendrimer monolayers were covalently immobilized onto controlled pore glass (CPG) particles as platforms to graft the metal ion affinity groups nitrilotriacetic acid (NTA) and terpyridine (terpy). Functional end group analyses, metal ion loading capacities and indicator dye complexation to metal affinity sites were measured as a function of dendrimer size. Metal ions were efficiently extracted from 5ppm solutions flowing through a packed column of modified CPG and loading capacities increased linearly with immobilized dendrimer size at pH 7.2 as determined by atomic absorption spectroscopy. The dendrimer tethered terpy affinity group was surprisingly effective in aqueous solution for extraction of Zn, Cu and Pb ions, but not as effective for Ni ions when compared to tethered NTA. Metal ion indicator dyes bind to the immobilized metal affinity sites showing a generational dependence. Subsequent addition of pyrophosphate releases dye back into solution as a demonstration of an immobilized indicator displacement assay.

A Renewable Lignin–Lactide Copolymer and Application in Biobased Composites

The need for renewable alternatives to traditional petroleum-derived plastics has driven recent interest in biobased composite materials that are sourced from carbon-neutral feedstocks. Lignin, an abundant plant-derived feedstock, has been a candidate for renewable materials; however, it is often difficult to blend with other biopolymers. In order to improve the miscibility of lignin with other bioplastics, we developed a catalytic and solvent free method for synthesis of a lignin–PLA copolymer. Graft polymerization of lactide onto lignin catalyzed by triazabicyclodecene (TBD) resulted in a lignin-g-poly(lactic acid) copolymer; chain length of the PLA is controlled by varying of the lignin/lactide ratio and preacetylation treatment. End-group analysis reveals high grafting efficiency and preferential grafting on lignin aliphatic hydroxyls over phenolic hydroxyls. The lignin-g-PLA copolymers display a glass transition temperature range from 45 to 85 °C and multiphase melting behavior. The lignin-g-PLA copolymers are used as dispersion modifiers in PLA-based materials to enhance UV absorption and reduce brittleness without a sacrifice in the modulus of elasticity.

Thermo-mechanical behaviour of Polyamide 6 chain extended with 1,1′-Carbonyl-Bis-Caprolactam and 1,3-Phenylene-Bis-2-Oxazoline

A commercial Polyamide 6 (PA6) was melt compounded by using a twin screw extruder with a combination of 1,1′-Carbonyl-Bis-Caprolactam (CBC) and 1,3-Phenylene-Bis-2-Oxazoline (PBO), in order to evaluate their effect on the chain extension behaviour of the resulting materials. An increase of the viscosity values with the chain-extender amount was evidenced by rheological tests on the compounded pellets and relative viscosity measurements on solubilized samples, while the opposite trend was determined increasing the residence time at elevated temperatures. The increase of the molecular weight due to the presence of CBC and PBO was confirmed by the reduction of carboxylic and aminic functionalities evidenced in end group analysis. DSC tests showed a reduction of the melting temperature and of the crystallinity degree proportionally to the chain extender amount. Elastic modulus of the chain-extended materials was similar to that of the corresponding PA6 grades at different molecular weight, while crystallinity drop due to chain extension determined an increase of the strain at break values.