Copolymerization of 2‐Acrylamido‐2‐methyl‐1‐propanesulfonic Acid and 1‐Vinylimidazole in Ethanol

Polymerization rate and copolymerization parameters of the free‐radical copolymerization of AMPS with 1‐VIm was studied as a function of the monomer feed and the pH value in ethanol. It was found that neutral and basic monomer mixtures containing the sodium salt of AMPS polymerized faster and led to polymers with a higher proportion of NaAMPS incorporated than those monomer mixtures containing the free acid. Additionally, based on the experimental data, copolymerization parameters of r_AMPS = 0.3 and r_1‐VIm = 0.13 were calculated for polymerization in acidic solution and r_AMPS = 4.1 and r_1‐VIm = 0.1 for polymerization in basic and neutral solutions. Finally, the thermal stability, rheological behavior, and intrinsic viscosity were determined for the polymers.

     

Segmented Block Copolymers with Monodisperse Hard Segments: The Influence of H‐Bonding on Various Properties

The properties of segmented‐copolymer‐based H‐bonding and non‐H‐bonding crystallisable segments and poly(tetramethylene oxide) segments were studied. The crystallisable segments were monodisperse in length and the non‐hydrogen‐bonding segments were made of tetraamidepiperazineterephthalamide (TPTPT). The polymers were characterised by DSC, FT‐IR, SAXS and DMTA. The mechanical properties were studied by tensile, compression set and tensile set measurements. The TPTPT segmented copolymers displayed low glass transition temperatures (T_g, ?70 °C), good low‐temperature properties, moderate moduli (G′ ≈ 10–33 MPa) and high melting temperatures (185–220 °C). However, as compared to H‐bonded segments, both the modulus and the yield stress were relatively low.

     

Elaboration of Poly(ε‐caprolactone)‐g‐TiNbO5 Nanocomposites via in situ Metal Complex Initiated Intercalative Polymerization

Summary: The preparation of poly(ε‐caprolactone)‐g‐TiNbO₅ nanocomposites via in situ intercalative polymerization of ε‐caprolactone initiated by an aluminium complex is described. These nanocomposites were obtained in the presence of HTiNbO₅ mineral pre‐treated by AlMe₃, but non‐modified by tetraalkylammonium cations. These hybrid materials obtained have been characterized by Fourier transform infrared absorption spectroscopy, wide‐angle X‐ray scattering, scanning electron microscopy, and dynamic mechanical analysis. Layered structure delamination and homogeneous distribution of mineral lamellae in the poly(ε‐caprolactone) (PCL) is figured out and strong improvement of the mechanical properties achieved. The storage modulus of the nanocomposites is enhanced as compared to pure PCL and increases monotonously with the amount of the filler in the range 3 to 10 wt.‐%.

SEM image of the fractured surface of a PCL‐TiNbO₅ nanocomposite film.     

Gas‐Phase Assisted Surface Polymerization Behavior of β‐Propiolactone on Inorganic and Organic Substrates and Consequent Composite Production

Summary: Gas‐phase assisted surface polymerization (GASP) of β‐propiolactone (βPL) was investigated using substrate‐supported anionic initiators to produce a strongly bonded poly(β‐propiolactone) (PPL)/CaO composite and a novel PPL crystalline deposit with a high melting point value on Al plates. The polymerization of βPL smoothly proceeded in the gas phase to give high‐molecular‐weight PPLs having high PDI values. An almost linear relationship between value and incremental increase in the deposit suggested the living nature of the GASP of βPL. The obtained polymer‐coated substrates, especially PPL/CaO composite, showed strong interaction at the organic/inorganic interface. Moreover, the thermal and structural analyses of deposits revealed that some specific conformations were formed on CaO powder and Al plate surfaces to give highly crystallized deposits. These results demonstrate that the GASP is an effective method for coating any substrate that has a complex shape and a surface morphology.

Accumulation process of poly(β‐propiolactone) on CaO as substrate‐supported initiator during GASP.     

Co(acac)2‐Mediated Radical Polymerization of Acrylonitrile: Control Over Molecular Weights and Copolymerization With Methyl Methacrylate

The cobalt‐mediated radical polymerization of acrylonitrile in DMSO using cobalt (II) acetylacetonate [Co(acac)₂] as mediator is studied. Both the evolution of molecular weight and conversion over time under various conditions are monitored. Molecular weights increase sharply at the beginning of the reaction and subsequently grow linearly with conversion. No branching of the polymer is observed by ¹³C NMR. By a careful design of the reaction parameters, number‐average molecular weights >1.2 · 10⁵ g · mol^?1 with a PDI around 2.4 together with conversions of up to 90% within 24 h are achieved. The copolymerization parameters of acrylonitrile with methyl methacrylate in DMSO at 30 °C are determined using the Kelen‐Tüdõs approach giving r_AN = 0.33, r_MMA = 0.71.

     

Synthesis of Block Copolymers containing Chain‐Controlled Aramid and Fluoroethylene Segments

Summary: Novel block copolymers containing aromatic polyamide (aramid) and fluoroethylene segments were synthesized by a two‐step solution polycondensation. This synthetic method could control the chain‐length of aramid segments and these copolymers could have high structural regularity. The number‐average molecular weight ( ) of one of these polymers is over 2.0 × 10⁴. Incorporating fluoroethylene segments improves the solubility of the resulting polymer compared with conventional aramids.

The synthesis of the fluoroethylene‐aramid block copolymers.     

Synthesis and Characterization of New Aromatic Polyamides with N,N′‐Di(4‐n‐alkylphenyl)benzodiimide Unit on the Main Chain

Summary: New aromatic polyamides containing two n‐alkylphenylimide units fused to the main chain were prepared by the activated polyamidation of 3,6‐di(4‐carboxyphenyl)‐N,N′‐di(4‐n‐alkylphenyl)pyromellitimides ( C _m DA , m = 0, 8, 12, 16) with oxy‐4,4′‐dianiline in a mixture of N‐methylpyrrolidone and pyridine (Py) in the presence of triphenyl phosphite and CaCl₂. The imide‐containing dicarboxylic acid monomers were synthesized by the imidization of 3,6‐di(4‐carboxyphenyl)pyromellitic dianhydride with 4‐n‐alkylanilines. The polymers showed both enhanced thermal stability and excellent solubility due to the presence of thermally stable pendent imido groups and internally plasticizing n‐alkyl chains. Their glass transition temperatures were between 225 and 285 °C and decreased with increasing side chain length. Wide‐angle X‐ray diffraction investigations revealed that all the polymers are amorphous and have typical layered structures formed by n‐alkyl side chains.

     

Colloidal Crystalline Arrays of β‐Polymorphic Poly(vinylidene fluoride)

Stable layers of nearly monodisperse spheres of β‐polymorphic poly(vinylidene fluoride) with iridescent properties are prepared. The colloidal crystalline arrays (CCAs) were characterized by optical microscopy, differential scanning calorimetry (DSC), and FT‐IR spectroscopy. FT‐IR spectroscopic and wide‐angle X‐ray scattering (WAXS) studies revealed a β‐polymorphic PVF₂ structure, the DSC study showed that the level of crystallinity in the CCA was much higher than that in the melt‐crystallized sample, and UV‐visible spectroscopy showed extinction peaks at 323 and 510 nm in the CCAs. The β‐polymorphic PVF₂ structure, along with the optical extinction properties of these CCAs, raises the prospect of their application in optical filters and/or piezoelectric sensors.

Optical micrograph of PVF₂ CCA films cast on glass substrates.     

Long‐Aliphatic‐Segment Polyamides: Salt Preparation and Subsequent Anhydrous Polymerization

Long‐aliphatic‐segment polyamides were prepared based on hexamethylenediamine and α,ω‐(CH₂)_x biosynthetic diacids (x = 10, 11, 12). The pertinent monomers (salts) were isolated as solids, thoroughly characterized for the first time, and then submitted to an anhydrous melt prepolymerization technique. The obtained prepolymers exhibited in the range of 5 100–11 800 g · mol^?1, and the molecular weight was further increased by up to 55% through solid‐state finishing. The suggested overall polyamidation cycle was conducted at short melt‐reaction times, so as to avoid any thermal degradation, and was proved efficient, indicating similar reactants polymerizability independently of the methylene content.

     

Synthesis and Characterization of Hyperbranched Poly(β‐ketoester) by the Michael Addition

Summary: A novel hyperbranched poly(β‐ketoester) was synthesized from 2‐(acetoacetoxy)ethyl acrylate by the Michael addition in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as catalyst. ¹H NMR integration experiments revealed that the degree of branching in the poly(β‐ketoester) was remarkably high at a level of 82.9%. The number‐average molecular weight of the polymer was between 2 100 and 12 000 and increased with reaction temperature and conversion.

Synthesis of hyperbranched polymer by Michael addition of AAEA.     

Preparation of Nano‐Polyethylene Fibers and Floccules by Extrusion Polymerization Under Atmospheric Pressure Using the SBA‐15‐Supported Cp2ZrCl2 Catalytic System

Summary: Nano‐polyethylene fibers and floccules were prepared under atmospheric pressure via ethylene extrusion polymerization in suit, using the SBA‐15‐supported Cp₂ZrCl₂ catalytic system. The major morphology units in the samples were fibers and floccules. The diameter of the single nano‐fibers was 120–200 nm. The single nano‐fibers could aggregate to form fiber aggregates and bundles. The number of PE floccules increased with extension of polymerization time, while the melting point of PE with nano‐fibers was little higher than that of common polyethylene.

SEM micrograph of the nano‐polyethylene fibers produced at a polymerization time of 60 min: micro‐fibers and floccule surface morphologies.     

Swelling and Adsorption Properties of Hydrophobic Poly[(N‐(3‐(dimethylamino)propyl)methacrylamide)‐co‐(lauryl acrylate)] Hydrogels in Aqueous Solutions of Surfactants

Summary: The swelling and adsorption behavior of a series of hydrophobic poly[(N‐(3‐(dimethylamino)propyl)methacrylamide)‐co‐(lauryl acrylate)] [P(DMAPMA‐co‐LA)] hydrogels was studied as a function of temperature in aqueous solutions of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant dodecyltrimethylammonium bromide (DTAB). Between 0 and 41.7 mol‐% of lauryl acrylate (LA) were used as a hydrophobic comonomer in the hydrogel synthesis. In SDS solutions, the equilibrium swelling ratio of the hydrogels decreased with increasing temperature. At SDS concentrations below 0.0083 M , the hydrogels exhibited an almost linear swelling behavior. However, for SDS concentrations above 0.0083 M , non‐linear swelling behavior was observed in the range 28–36 °C. In contrast to the SDS solutions, in all DTAB solutions the equilibrium swelling ratio of the hydrogels increased with increasing temperature and a positive temperature sensitive property was shown for all P(DMAPMA‐co‐LA) hydrogels. The adsorption capacities of the hydrogels in aqueous solutions of SDS and DTAB were determined via surface tension measurements. An increase in the LA content in the hydrogel caused an increase in the amount of adsorbed surfactant molecules in both media.

Effect of the DTAB concentration on the adsorption capacities of P(DMAPMA‐co‐LA) hydrogels.     

Poly[ethylene‐co‐(vinyl alcohol)]‐graft‐Poly(ε‐caprolactone) by Reactive Extrusion, 2 – Parameter Analysis

EVOH‐g‐PCL were prepared by a solvent‐free reactive extrusion process using a co‐rotating twin screw extruder. Kinetic simulations were made of selected reaction conditions at 185 °C. Changes in the screw rotation rate resulted in evolution of the residence time distribution and slightly changed the monomer conversion. An increase of the [OH]₀/[Cl]₀ ratio made the reactive system more viscous and decreased the overall pumping capacities of the extruder. Increase of the mean residence time, combined with a positive kinetic effect of [OH]₀ increase, leaded to an important increase in conversion. For all the conducted experiments, equivalent distribution dispersions and good agreements between calculated conversion and those measured were obtained. An increase in temperature from 185 to 200 °C resulted in total conversion.

     

Some Mechanical Properties of Poly[(acrylic acid)‐co‐(itaconic acid)] Hydrogels

Two series of hydrogels of poly[(acrylic acid)‐co‐(itaconic acid)] have been prepared by copolymerization in solution using tetrafunctional N,N′‐methylenebisacrylamide (NMBA) as cross‐linker. The resulting polymer was swollen in water at 298 K to yield homogenous transparent hydrogels. These hydrogels were characterized in terms of swelling and compression‐strain measurements. The influence of the comonomer composition and concentration of cross‐linking agent on volumetric swelling and the mechanical properties of these hydrogels were investigated. Inefficient cross‐linking is indicated by the small values of ν_e relative to the theoretical cross‐linking densities.

Dependence of measured affective cross‐linking density (ν_e) on the theoretical cross‐linking density (ν_t) for acrylic acid/itaconic acid hydrogels prepared at a fixed composition of AA80/AI20 wt.‐%, but at different concentrations of NMBA.     

Modeling of the Emulsion Terpolymerization of Styrene, α‐Methylstyrene and Methyl Methacrylate

Summary: This work deals with modeling the terpolymerization of styrene, α‐methylstyrene and methyl methacrylate in the presence of an inhibitor. The model used is a “tendency model” based on the kinetics of the complex elementary chemical reactions both in the aqueous phase and in the particles. It considers the reversible propagation of α‐methylstyrene and the main physical phenomena occurring during the process, i.e., (i) partitioning of monomers, surfactant and inhibitor between the aqueous phase, polymer particles, monomer droplets and micelles; (ii) homogeneous and micellar nucleation; (iii) radical absorption and desorption; (iv) gel and glass effects. The main kinetic parameters of the model are estimated on the basis of batch experimental data in order to be able to describe the complete picture of this complex process. The model can be used to predict (with good precision) the global monomer conversion, number and weight‐average molecular weight, the average diameter and number of polymer particles and the glass transition temperature, and consequently to study the effects of AMS on conversion and terpolymer and latex characteristics.

Comparison of experimental and simulated results of the weight‐average molecular weight versus conversion for the emulsion terpolymerization of styrene, alpha methylstyrene and methyl methacrylate at 60 °C.     

A Completely Biodegradable Poly[(L‐lactide)‐co‐(ε‐caprolactone)] Elastomer Reinforced by in situ Poly(glycolic acid) Fibrillation: Manufacturing and Shape‐Memory Effects

A new completely biodegradable shape‐memory elastomer consisting of PLLCA reinforced by in situ PGA fibrillation is described. The manufacturing processes and shape‐memory effects of the composites are discussed. DMA results reveal a strong interface interaction between in situ PGA fibrillation and PLLCA. Compared with the SMP‐based composites that are commonly used, the shape‐memory test shows that in situ PGA fibrillation can improve the recovery properties of PLLCA; in fact, the shape‐recovery rate increases from 80.5 to 93.2%.

     

Terpyridine‐Functionalized TentaGel Microbeads: Synthesis,Metal Chelation and First Sequential Complexation

The functionalization of polystyrene/poly(ethylene glycol) TentaGel® microbeads (d = 20 μm) with 2,2′:6′,2″‐terpyridine units is described resulting in a material with easily accessible ligands which possess an excellent affinity for transition metal ions. The subsequent loading with different metal ions via metal‐to‐ligand complexation yielded the corresponding Co^II, Ni^II, Fe^II, and Cu^II modified beads. The isolated materials were investigated in detail utilizing UV/vis spectroscopy, optical microscopy, atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Moreover, grafting of free terpyridine moieties via ruthenium(II )/ruthenium(III )‐chemistry onto the beads is demonstrated. This opens‐up new pathways for the selective modification of such microbeads and the preparation of functional materials.

Scheme of the formation of bis‐terpyridine‐metal complexes bound to polystyrene/poly(ethylene glycol) TentaGel® microbeads.     

1,8‐Naphthalimides as Blue Emitting Fluorophores for Polymer Materials

The copolymerization of 1,8‐naphthalimide derivatives (as fluorophore) with acrylonitrile has been investigated. The photophysical characteristics of monomeric and polymeric fluorophores in N,N‐dimethylformamide solution have been determined and discussed. During copolymerization, no changes in the chromophoric systems of the fluorophore occur. The influence of the studied monomeric 1,8‐naphthalimide fluorophores upon the structurally bleached polyacrylonitrile has been determined. Infrared absorption characteristics of the polymerizable 4‐alkoxy‐ and 4‐allyloxy‐N‐substituted‐1,8‐naphthalimides have been measured and discussed. The effect of the substituents upon the vibration frequencies of the carbonyl and allylic groups has been established.

Blue fluorescent polyacrylonitrile copolymers with 1,8‐naphthalimides side‐group.     

Palladium‐Catalyzed Carbonylative Synthesis of 2,3‐Disubstituted Chromones

An unexpected palladium‐catalyzed carbonylative synthesis of 2,3‐disubstituted chromones has been developed. Starting from 2‐bromofluorobenzenes and ketones, the corresponding chromones were produced in good yields. By control experiments, this transformation was found to proceed through a sequential carbonylation/Claisen–Hasse rearrangement/intramolecular nucleophilic aromatic substitution approach (S_NAr). More specifically, the reaction sequence started with a palladium‐catalyzed carbonylation of the ketone with o‐bromofluorobenzene to give the vinyl benzoates, which subsequently transformed into 1,3‐diketones via a Claisen–Hasse rearrangement. The final products were produced after an intramolecular S_NAr reaction of the in situ formed 1,3‐diketone.

     

Telomerization of Butyl Methacrylate and 1‐Octadecanethiol by Reactive Extrusion

Butyl methacrylate and 1‐octadecanethiol telomers were prepared by radical reactive extrusion. The main advantages of the use of this processing technique are that mass reactions can be conducted and continuous production is achieved within a reduced reaction time and a correct temperature control. Preliminary studies concerned the choice of the reactants for the telomerization reaction and the adaptation of the telomerization reaction to the reactive extrusion process. The transfer constant to C₁₈H₃₇SH was measured, and then experimental studies were conducted to verify that the hypothesis and approximations made for kinetic modeling are realistic. Particularly, it was shown that the use of relatively high chain‐transfer agent to monomer concentration ratio had no perceptible effect on the monomer conversion kinetic. These results allowed the choice of reactive extrusion conditions. Telomers were prepared using a laboratory co‐rotating twin‐screw extruder. The effect of reaction conditions (temperature, 1‐octadecanethiol to monomer concentration ratio) and of processing conditions (throughput, screw rotation speed) on the residence time distributions, molar mass and monomer conversions were examined. This study allowed the continuous synthesis of butyl methacrylate telomers having variable controlled molar masses and complete monomer conversion.

Screw profile used in reactive extrusion telomerization.