New soluble cyano‐containing poly(arylene ether) copolymers bearing pendant xanthene groups

Homopolymers and copolymers of poly(arylene ether nitrile) (PAEN)‐bearing pendant xanthene groups were prepared by the nucleophilic substitution reaction of 2,6‐difluorobenzonitrile with 9,9‐bis(4‐hydroxyphenyl)xanthene (BHPX) and with various molar proportions of BHPX to hydroquinone (100/0 to 40/60) with N‐methyl‐2‐pyrrolidone (NMP) as a solvent in the presence of anhydrous potassium carbonate. These polymers had inherent viscosities between 0.61 and 1.08 dL/g, and their weight‐average molecular weights and number‐average molecular weights were in the ranges 34,200–40,800 and 17,800–20,200, respectively. All of the PAENs were amorphous and were soluble in dipolar aprotic solvents, including NMP, N,N‐dimethylformamide, and N,N‐dimethylacetamide and even in tetrahydrofuran and chloroform at room temperature. The resulting polymers showed glass‐transition temperatures (T_g's) between 220 and 257°C, and the T_g values of the copolymers were found to increase with increasing BHPX unit content in the polymer. Thermogravimetric studies showed that all of the polymers were stable up to 422°C with 10% weight loss temperatures ranging from 467 to 483°C and char yields of 54–64% at 700°C in nitrogen. All of the new PAENs could be cast into transparent, strong, and flexible films with tensile strengths of 106–123 MPa, elongations at break of 13–17%, and tensile moduli of 3.2–3.7 GPa. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novolac resin–poly(ethyl methacrylate) interpenetrating polymer networks: Morphology and mechanical and thermal properties

Full interpenetrating networks (IPNs) and semi‐IPNs of Novolac (phenolic) resin and poly(ethyl methacrylate) (PEMA) were prepared by the sequential mode of synthesis. These were characterized with respect to their mechanical properties, that is, ultimate tensile strength (UTS), percentage elongation at break, modulus, and toughness. Thermal properties were studied by DSC and thermogravimetric analysis (TGA). The morphological features were studied through polarizing light microscopy (PLM). The effects of variation of the blend ratios on the above‐mentioned properties were examined. There was a gradual decrease of modulus and UTS with consequent increases in elongation at break and toughness for both types of IPNs with increasing proportions of PEMA. An inward shift and lowering (with respect to pure phenolic resin) of the glass‐transition temperatures of the IPNs with increasing proportions of PEMA were observed, thus indicating a plasticizing influence of PEMA on the rigid and brittle matrix of crosslinked phenolic resin. The TGA thermograms exhibit two‐step degradation patterns. Although there was an apparent increase in thermal stability at the initial stages, particularly at lower temperatures, a substantial decrease in thermal stability was observed in the regions of higher temperatures. The surface morphology as revealed by PLM clearly indicates two‐phase structures in all the full and semi‐IPNs, irrespective of PEMA content. The matrix–PEMA domain interfaces are quite sharp at higher concentrations of PEMA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 412–420, 2003     

The phase behavior and thermal stability of blends of poly(styrene‐co‐methacrylic acid)/poly(styrene‐co‐ 4‐vinylpyridine)

The hydrogen bonding and miscibility behaviors of poly(styrene‐co‐methacrylic acid) (PSMA20) containing 20% of methacrylic acid with copolymers of poly(styrene‐co‐4‐vinylpyridine) (PS4VP) containing 5, 15, 30, 40, and 50%, respectively, of 4‐vinylpyridine were investigated by differential scanning calorimetry, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). It was shown that all the blends have a single glass transition over the entire composition range. The obtained T_gs of PSMA20/PS4VP blends containing an excess amount of PS4VP, above 15% of 4VP in the copolymer, were found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are able to form interpolymer complexes. The FTIR study reveals presence of intermolecular hydrogen‐bonding interaction between vinylpyridine nitrogen atom and the hydroxyl of MMA group and intensifies when the amount of 4VP is increased in PS4VP copolymers. A new band characterizing these interactions at 1724 cm⁻¹ was observed. In addition, the quantitative FTIR study carried out for PSMA20/PS4VP blends was also performed for the methacrylic acid and 4‐vinylpyridine functional groups. The TGA study confirmed that the thermal stability of these blends was clearly improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Phase behavior of binary and ternary blends of poly(styrene‐co‐methacrylic acid), poly(styrene‐co‐4‐vinylpyridine), and poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(styrene‐co‐methacrylic acid) (PSMA) and poly(styrene‐co‐4‐vinylpyridine) (PS4VP) of different compositions were prepared and characterized. The phase behavior of these copolymers as binary PSMA/PS4VP mixtures or with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as PPO/PSMA or PPO/PS4VP and PPO/PSMA/PS4VP ternary blends was investigated by differential scanning calorimetry (DSC). This study showed that PPO was miscible with PS4VP containing up to 15 mol % 4‐vinylpyridine (4VP) but immiscible with PS4VP‐30 (where the number following the hyphen refers to the percentage 4VP in the polymer) and PSMA‐20 (where the number following the hyphen refers to the percentage methacrylic acid in the polymer) over the entire composition range. To examine the morphology of the immiscible blends, scanning electron microscopy was used. Because of the hydrogen‐bonding specific interactions that occurred between the carboxylic groups of PSMA and the pyridine groups of PS4VP, chloroform solutions of PSMA‐20 and PS4VP‐15 formed interpolymer complexes. The obtained glass‐transition temperatures (T_g's) of the PSMA‐20/PS4VP‐15 complexes were found to be higher than those calculated from the additivity rule. Although, depending on the content of 4VP, the shape of the T_g of the PPO/PS4VP blends changed from concave to S‐shaped in the case of the miscible blends, two T_g were observed with each PPO/PS4VP‐30 and PPO/PS4VP‐40 blend. The thermal stability of the PSMA‐20/PS4VP‐15 interpolymer complexes was studied by thermogravimetry. On the basis of the obtained results, the phase behavior of the ternary PPO/PSMA‐20/PS4VP‐15 blends was investigated by DSC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Surface selectivity competition of newly synthesized polyarylidene(keto amine) polymers toward different metal ions

A new series of polyarylidene(keto amine)s (PAKAs) 3_a?3_e based on thiophene moieties in polymer main chains were synthesized with the solution polycondensation technique. The polymers were synthesized by the reaction of the new monomer 1,1′‐(1E,1′E)‐(2‐oxocyclohexane‐1,3‐diylidene)bis(methanylylidene)bis(thiophene‐5,2‐diyl)bis(2‐chloroethanone) ( 2 ) with different diamines. The new monomer was first synthesized under the normal conditions of the Friedel–Crafts reaction. The results obtained from both elemental and spectral analyses were consistent with the chemical structure of the new monomers and the polymers. Moreover, the identification of the polymers was carried out with different characterization techniques. The analytical competition of the newly synthesized PAKA polymers as selected examples ( 3_d and 3_e ) was also evaluated for a selective extraction of metal ions, including Cd(II), Co(II), Cu(II), Cr(III), Fe(III), Ni(II), and Zn(II), before their determination by inductively coupled plasma–optical emission spectrometry. The results of the selectivity study demonstrated that the 3_d and 3_e polymers was the most selective toward Co(II) and Fe(III), respectively. However, the adsorption capacity of 3_d for Co(II) was improved by 10.10% in comparison to that of 3_e for Fe(III) after only 1 h of contact time. Moreover, the adsorption isotherm data also showed that the adsorption process was mainly monolayer on the homogeneous adsorbent surfaces of both polymers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40873.     

Synthesis of poly(urethane)s based on diphenyl‐silane/germane and oxyphenyl units: Structure–properties relationship

A series of poly(urethane)s (PUs) based on diphenyl‐silane or ‐germane and oxyphenyl units were synthesized by polycondesation of 4‐[4‐[9‐[4‐(4‐aminophenoxy)‐3‐methyl‐phenyl]fluoren‐9‐yl]‐2‐methyl‐phenoxy]aniline (3) and four bis(chloroformate)s ( I–IV ). These monomers were prepared and characterized in previous works. The best conditions for the polymerization reactions were investigated by a kinetic study. Also, a selection of the best solvent for the reaction was developed. Polymers were characterized by IR and ¹H, ¹³C, and ²⁹Si‐NMR spectroscopy and the results were in agreement with the proposed structures. Poly(urethane)s showed inherent viscosity values between 0.12 and 0.31 dL/g, indicative of low molecular weight species, probably of oligomeric nature. The glass transition temperature (T_g) values were observed in the 127–168°C range by DSC analysis. Thermal decomposition temperature (TDT_10%) values were above 300°C. All PUs showed good transparency in the visible region (>80% at 350 nm) due to the incorporation of the bulky monomer (fluorene) and oxyether linkages. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal behavior of aliphatic–aromatic poly(ether-amide)s

The thermal properties of a set of experimental aliphatic–aromatic polyamides containing ether linkages were examined as a function of their chemical structure. Variations of the glass transition temperature (T_g) and melting temperature (T_m) could be correlated with the length of the aliphatic spacers and with the orientation of the phenylene rings. Polymers with a high concentration of p-oriented phenylene units showed a higher T_g than those containing mainly m-oriented ones; T_g values ranged from 110 to 155°C. Surprisingly, a negligible dependence of T_gs on the nature of flexible spacers was observed. For all of the polymers, the thermal stability was virtually the same, about 440°C, when tested by dynamic thermogravimetric analysis (TGA). However, quite different levels of thermal stability were found by isothermal TGA analysis for polyamides with different flexible spacers. Moreover, the poly(ether-amide)s described here compare fairly well with wholly aromatic polyamides when measured by dynamic TGA; but isothermal TGA measurements clearly demonstrated that they decompose faster than aromatic polyamides. Treatment of the TGA curves by the method of McCallum provided kinetic data that confirmed a better long-term stability for poly(ether-amide)s with a higher proportion of para-oriented phenylene rings. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:975–981, 1998     

Novel aliphatic–aromatic poly(amide urea)s: Synthesis, characterization and application to the elimination of environmentally toxic heavy metal ions

This work describes eight novel aromatic and aliphatic–aromatic poly(amide urea)s. These polyamides are semicrystalline and are soluble in polar aprotic solvents. They also demonstrate a film-forming capability, they exhibit moderate thermal resistance and the decomposition temperature is similar in oxidizing and inert atmosphere. The urea group imparts hydrophilicity to the polymers and is an efficient host unit for anions, which facilitates the preparation of solid polymer phases to be used as extractants for the extraction/elimination of environmentally toxic cations from aqueous environments. These systems give moderate but promising results in the extraction of different Pb^II and Hg^II salts from aqueous solution.     

Synthetic and spectroscopic studies of chelate polymers involving azelaoyl bis‐N‐phenyl hydroxamic acid with transition metal ions

Chelate polymers of azelaoyl bis‐N‐phenyl hydroxamic acid with Mn(II), Co(II), Ni(II), and Zn(II) were synthesized for the first time in a dimethylformamide (DMF) medium. These newly synthesized chelate polymers were characterized on the basis of several analytical techniques, namely, elemental analyses, infrared and reflectance spectral studies, magnetic moment, and thermal analyses. On the basis of data obtained with these techniques, the composition of the polymeric units, the structure, and the geometry were ascertained. It was found that the Mn(II) and Zn(II) chelate polymers had a tetrahedral geometry, whereas the Co(II) and Ni(II) chelate polymers were octahedral. Thermal analytical data clearly indicated that the Ni(II) chelate polymer was highly thermally stable relative to the Mn(II), Co(II), and Zn(II) chelate polymers. Since these chelate polymers are highly insoluble in almost all the organic solvents, including alcohol, acetone, chloroform, carbon tetrachloride, DMF, and DMSO, and have high thermal stability, they may be used as surface‐coating materials and as thermally stable materials. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 273–278, 2006     

Microwave‐assisted and classical heating polycondensation reaction of bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine with diisocyanates as a new method for preparation of optically active poly(amide imide)s

A new class of optically active poly(amide imide)s were synthesized via direct polycondensation reaction of diisocyanates with a chiral diacid monomer. The step‐growth polymerization reactions of monomer bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L‐leucine (BPABTL) (5) as a diacid monomer with 4,4′‐methylene bis(4‐phenylisocyanate) (MDI) (6) was performed under microwave irradiation, solution polymerization under gradual heating and reflux condition in the presence of pyridine (Py), dibuthyltin dilurate (DBTDL), and triethylamine (TEA) as a catalyst and without a catalyst, respectively. The optimized polymerization conditions according to solvent and catalyst for each method were performed with tolylene‐2,4‐diisocyanate (TDI) (7), hexamethylene diisocyanate (HDI) (8), and isophorone diisocyanate (IPDI) (9) to produce optically active poly(amide imide)s by the diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.09–1.10 dL/g. These polymers are optically active, thermally stable, and soluble in amide type solvents. All of the above polymers were fully characterized by IR spectroscopy, ¹H NMR spectroscopy, elemental analyses, specific rotation, and thermal analyses methods. Some structural characterization and physical properties of this new optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1647–1659, 2004     

Investigating alternative routes for semi‐aromatic polyamide salt preparation: The case of tetramethylenediammonium terephthalate (4T salt)

In the current article, the effect of different techniques was investigated on the preparation of tetramethylenediammonium terephthalate (4T salt), which consists of an industrially important precursor of high‐performance polyamides. In particular, 4T salt was synthesized through solution, slurry, and solvent‐free techniques. In each case the salt was isolated as a solid, correlating for the first time the salt preparation/isolation method with attained properties and morphology. This correlation led to a generalized comparison between all synthesized 4T salt grades, aiming at understanding the preparation mechanism of 4T salt. Accordingly, highly pure 4T salt, free of any unreacted diacid traces, can be only obtained from a clear salt solution either by cooling or by nonsolvent addition. Furthermore, by altering the crystallization conditions of the salt, thermal and morphological properties can be significantly affected, which further result in a qualitative correlation with the rate of subsequent direct solid‐state polymerization (DSSP). The DSSP reactions were carried out in the microscale of a thermogravimetric chamber, where the different 4T salt grades were heated isothermally until full conversion. Polyamide grades of different thermal and analytical properties were received, underlining that the quality of the salt is a corner stone for subsequent DSSP. These findings can be further exploited also to the DSSP of other semi‐aromatic polyamides. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42987.     

Thermal degradation of poly(dimethylsilylene) and poly(tetramethyldisilylene‐co‐styrene)

Thermal degradation of poly(dimethylsilylene) homopolymer (PDMS) and poly(tetramethyldisilylene‐co‐styrene) copolymer (PTMDSS) was investigated by pyrolysis‐gas chromatography and thermogravimetry (TG). PDMS decomposes by depolymerization, producing linear and cyclic oligomeric products, whereas PTMDSS decomposes by random degradation along the chain resulting in each monomeric product and various other combination products. The homopolymer was found to be much less stable than the copolymer. The decomposition mechanisms leading to the formation of various products are shown. The kinetic parameters of thermal degradation were evaluated by different integral methods using TG data. The activation energies of decomposition (E) for the homopolymer and the copolymer are found to be 122 and 181 kJ/mol, respectively, and the corresponding values of order of reaction are 1 and 1.5. The observed difference in the thermal stability and the values of the kinetic parameters for decomposition of these polymers are explained in relation with the mechanism of decomposition. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Novel poly(amide‐hydrazide)s and copoly(amide‐hydrazide)s from bis‐(4‐aminobenzyl) hydrazide and aromatic diacid chlorides: Synthesis and characterization

A new aromatic diamine, viz., bis‐(4‐aminobenzyl) hydrazide (BABH), which contains preformed hydrazide and methylene linkage, was synthesized starting from α‐tolunitrile. The BABH and intermediates involved in its synthesis were characterized by spectroscopic methods. Novel poly(amide‐hydrazide)s were synthesized by low temperature solution polycondensation of BABH with isophthaloyl chloride (IPC) and terephthaloyl chloride (TPC). Furthermore, two series of copoly(amide‐hydrazide)s, based on different mol % of BABH and bis‐(4‐aminophenyl) ether (ODA) with IPC/TPC were also synthesized. Poly(amide‐hydrazide)s and copoly(amide‐hydrazide)s were characterized by inherent viscosity [η_inh], FTIR, solubility, X‐ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The polycondensation proceeded smoothly and afforded the polymers with inherent viscosities in the range of 0.18–0.93 dL/g in (NMP + 4% LiCl) at 30°C ± 0.1°C. These polymers dissolved in DMAc, NMP or DMSO containing LiCl. The solubility of copolymers was considerably improved in line with less crystalline nature due to random placement of constituent monomers during the copolymerization. XRD data indicated that poly(amide‐hydrazide)s from BABH alone and IPC/TPC had higher crystallinity than the corresponding copoly(amide‐hydrazide)s derived from a mixture of BABH and bis‐(4‐aminophenyl) ether (ODA). Polymers showed initial weight loss around 160°C which is attributed to the cyclodehydration leading to the formation of corresponding poly(amide‐oxadiazole)s. Copolyamide‐hydrazides showed T_max between 400 and 540°C which is essentially the decomposition of poly(amide‐oxadiazole)s. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of water‐soluble oligosalicylaldehyde‐sulfanilic acid and its Cu(II), Co(II), Pb(II) complexes

This work presents the synthesis and characterization of a new water‐soluble oligophenol derivative, 4‐(2‐hydroxybenzylideneamino)benzenesulfanilic acid (OSAL‐SA) and its metal complexes. The chemical structure of the water‐soluble polymer was characterized by nuclear magnetic resonance (¹H NMR) and Fourier transform infrared (FTIR) spectroscopies and thermogravimetric analyses (TGAs). Pb(II), Cu(II), Co(II) complexes of the polymer were also synthesized in methanol. Characterizations of water insoluble polymer‐metal complexes were performed by FTIR, flame atomic absorption spectroscopy, and TGA. The conductivity measurements of OSAL‐SA and polymer–metal complexes were carried out by the four‐probe technique. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Microwave‐promoted rapid synthesis of new optically active poly(amide imide)s derived from N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine diacid chloride and aromatic diamines

A pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) was reacted with L ‐isoleucine in acetic acid, and the resulting imide acid [N,N′‐(pyromellitoyl)‐bis‐L ‐isoleucine] (4) was obtained in a high yield. 4 was converted into N,N′‐(pyromellitoyl)‐bis‐L ‐isoleucine diacid chloride by a reaction with thionyl chloride. The polycondensation reaction of this diacid chloride with several aromatic diamines, including 1,4‐phenylenediamine, 4,4′‐diaminodiphenyl methane, 4,4′‐diaminodiphenylsulfone (4,4′‐sulfonyldianiline), 4,4′‐diaminodiphenylether, 2,4‐diaminotoluene, and 1,3‐phenylenediamine, was developed with two methods. The first method was polymerization under microwave irradiation, and the second method was low‐temperature solution polymerization, with trimethylsilyl chloride used as an activating agent for the diamines. The polymerization reactions proceeded quickly and produced a series of optically active poly(amide imide)s with good yields and moderate inherent viscosities of 0.17–0.25 dL/g. All of the aforementioned polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 951–959, 2004     

Multicarboxylic aromatic acid core initiator for the synthesis of star‐shaped poly(ϵ‐caprolactone) with carboxyl end groups

We successfully carried out the ring‐opening polymerization of ?‐caprolactone with 1,3,5‐benzenetricarboxylic acid and 1,2,4,5‐benzenetetracarboxylic acid as the core initiators at 225°C in bulk, and three‐armed and four‐armed star poly(?‐caprolactone)s [poly(?‐CL)s] with carboxyl end groups were obtained. No transesterification, which would have led to a decrease in the molecular weight of poly(?‐CL), was found. The effects of the polymerization conditions on the polymerization are discussed; the poly(?‐CL)s were characterized by ¹H‐NMR, gel permeation chromatography, and thermogravimetric analysis in detail. A mechanism of alkyl–oxygen bond scission by the nucleophilic attack of the carboxyl anions via hydrogen proton transfer is presented for this system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3713–3717, 2006     

Synthesis and characterization of conducting poly(aniline‐co‐diaminodiphenylsulfone) copolymers

Polyaniline, poly(aniline‐co‐4,4′‐diaminodiphenylsulfone), and poly(4,4′‐diaminodiphenylsulfone) were synthesized by ammonium peroxydisulfate oxidation and characterized by a number of techniques, including infrared spectroscopy, ultraviolet–visible absorption spectroscopy, ¹H‐NMR, thermogravimetric analysis, and differential scanning calorimetry. These copolymers had enhanced solubility in common organic solvents in comparison with polyaniline. The conductivities of the HCl‐doped polymers ranged from 1 S cm^?1 for polyaniline to 10^?8 S cm^?1 for poly(4,4′‐diaminodiphenylsulfone). The copolymer compositions showed that block copolymers of 4,4′‐diaminodiphenylsulfone (r₁ > 1) and aniline (r₂ < 1) formed and that the reactivity of 4,4′‐diaminodiphenylsulfone was greater than that of aniline. The results were explained by the effect of the ? SO₂? group present in the polymer structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2337–2347, 2003     

Thermal stability of poly(ethylene‐co‐trimethylene terephthalate)s

The thermal stability of poly(ethylene‐co‐trimethylene terephthalate) was first studied by thermogravimetry under nitrogen atmosphere at different heating rates. The results showed that the thermal behavior of the copolyester had a strong dependence on the chemical composition. The average activation energy from Ozawa technique increases with the concentration of EG units in the polyester, and a greater TG concentration in the copolyesters would decrease the onset degradation temperature. These phenomena may be attributed to the presence of one more methylene of TG unit than of EG in the copolymer. It is also noted that the yield of solid residue increases with the concentration of EG units in the polymer chain at any heating rate, which may be associated with the content of aromatic ring in the polymer chain. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3330–3335, 2006     

Preparation of segmented semifluorinated poly(aryl ether)s from aromatic trifluorovinyl ethers and oligo(ethylene glycol)s

A series of new segmented semifluorinated polyaryl ethers (PAEs) containing a biphenyl segmented by semifluorinated oligoethylene (SFE) units were prepared by nucleophilic addition of a commercial oligo(ethylene glycol)s to 4,4′‐bis(4‐trifluorovinyloxy)biphenyl. These new thermoplastics were characterized by ¹H and F¹⁹ nuclear magnetic resonance (NMR) and attenuated total reflectance Fourier transform infrared (ATR‐FTIR). Gel permeation chromatography (GPC) analysis displayed number average molecular weights (M_ns) from 9000 to 13,000. Thermal properties of the polymers were studied by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). DSC chromatograms displayed glass transition temperatures (T_gs) from 11 to 1°C. The onsets of degradations were observed by TGA analysis between 313 to 333°C in air and 326 to 363°C in nitrogen, respectively. A second onset of degradation was observed from 452 to 470°C for all polymers. In addition, crystalline morphologies were studied by tapping mode atomic force microscopy (TM‐AFM) and showed needle‐like crystallites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41798.     

Solid state polymerization in a micro‐reactor: The case of poly(tetramethylene terephthalamide)

The aim of this work was to develop and optimize a direct solid state polymerization (DSSP) process on a micro scale for alkyldiammonium‐terephthalate salts. This was successfully demonstrated for the first time by the case of tetramethylenediammonium‐terepththalate salt (4T salt). The derived polymer (PA4T) presents interesting properties, but the temperature‐favored acid catalyzed cyclization of tetramethylenediamine (TMD) to mono‐functional pyrrolidine and ammonia inhibits a high polymerization conversion. DSSP was performed in a thermogravimetrical analysis (TGA) chamber, and the continuously monitored weight loss was correlated to polymerization conversion via the release of water, excluding any mass and heat transfer limitations. It was found that the conditions under which the DSSP is performed and the morphology of the starting material affect both the reaction rate and the product quality. The effect of the critical process parameters, namely vent size, heating rate to reach SSP temperature, and reaction temperature were quantified by the observed mass loss and by ¹H NMR analysis. It was noticed that, besides the water formed by amidation, other volatile compounds were also released during the DSSP reaction, with main component, the TMD. In particular, it was observed that conditions favoring the evaporation of TMD also favored a higher reaction rate. The TMD loss was minimized by optimization of the aforementioned process conditions, leading to a more thermally stable and a higher molecular weight final product. The thermal stability of the PA4T was found to be inversely correlated to the concentration of carboxylic end groups present in the formed polymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43271.