ABSTRACTA 12‐membered cyclic diamide monomer for nylon 64 was successfully synthesized in fairly high yield (∼45%). The synthesis conditions were varied to see the effect of the diamine and succinyl chloride reactants on yield. Threefold excess of 1,6‐hexamethylenediamine (HDA) gave the highest yield, while further increasing the amount of HDA decreased the yield. Using N,N‐diisopropylethylamine as acid scavenger resulted in the formation of two different cyclic amides, which were fully analyzed by 1H and 13C solution nuclear magnetic resonance spectrometry and mass spectrometry. Copolymerization of cyclic amides with ε‐caprolactam via an anionic route gave a block copolyamide with a two distinct endotherms in the differential scanning calorimetry analysis. However, copolymerization by the hydrolytic route gave only nylon 6 with terminal 64 units. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 96–103

Surface modified nano-silica was synthesized through a condensation reaction of the silanol groups on the silica surface with 3-aminopropyltrimethoxysilane (APS). This primary amine offers a wide range of derivatization options and acts as a linker between a silica surface and many organic species. Quantitation of the results indicated the presence of 3-4 reactive APS groups per nm(2) of silica. This implies that the silanol groups present on the surface of the silica have reacted to a high extent. APS-treated silica was further treated with a series of acid anhydrides to yield more stable amidoalkyl and imidoalkyl silica. The modified surfaces were analysed by thermogravimetric analysis (TGA), Fourier-transform infra-red (FT-IR) and solid-state C-13 NMR spectroscopy techniques to study the organic content and functional composition. Results indicate that the silica particles functionalized with imidoalkylsiloxane (IASi) have much higher thermal stabilities compared to aminoalkyl functionalized silica. It was also observed that thermal stability of the IASi does not depend on the acid anhydride used for the derivatization of the APS treated silica. Furthermore we used this IASi for the synthesis of poly(ethylene terephthalate) (PET)-silica nanocomposites. Dynamic mechanical analysis revealed an enhancement of the storage modulus with increasing silica content at ambient temperature as well as above the glass-transition temperature.

AbstractPA‐12,T was synthesized by melt condensation of 1,12‐diaminododecane (DA) and terephthalic acid salt and by solution polymerization of biscaprolactam terephthalamide (BCT) and DA in molten caprolactam. Stoichiometry of both methods were varied from 10 mol‐% excess terephthalic acid (or BCT) and 10 mol‐% excess DA and the impact on intrinsic viscosity, end group concentration and end group functionality was examined. PA‐12,T salt was then copolymerized with PA‐6,T salt and melting behavior was determined to examine the effect of random comonomers. Block copolymers were synthesized by anionic polymerization of PA‐6 with PA‐12,T macro‐coinitiators formed from the solution step‐growth reaction. The melting and solubility properties of the block copolymers were then correlated with the PA‐12,T block size and compared to randomly formed copolymers.

Abstractα‐Aminocaprolactam is a “green” monomer in two ways: it is a fermentation product from sugars, and its derivatives are naturally biocompatible and biodegradable. In this overview, the synthesis of a variety of α‐amino‐ε‐caprolactam (ACL) derivatives through reaction with acid chlorides, anhydrides, and alkyl halides is described first. The product vinyl and divinyl derivatives were then polymerized using free radical initiators, and the obtained polymers characterized by solution NMR spectroscopy, differential scanning calorimetry, and thermal gravimetric analysis. The homopolymers of these monomers displayed surprisingly high glass transition temperature (Tg) values plus unexpectedly large sub‐Tg transitions that are believed due to relaxation of hydrogen bonding of pendent ACL units that allows group rotation. Finally, bis‐ and tetra‐caprolactams of various diacid chlorides and diisocyantes were synthesized and shown to form self‐assembled polymers and networks with excellent physical and thermal properties.

The melting behaviors and crystal structures of a long alkyl chain polyamide and nylon 18 18, were investigated under annealing and isothermal crystallization conditions. Nylon 18 18 showed multiple melting peaks in differential scanning calorimetry (DSC) thermograms depending on thermal history of the samples. The origin of the multiple melting peaks may be a result of a melting and recrystallization mechanism during DSC scans. Wide-angle X-ray diffraction patterns showed two new diffraction peaks, which appeared at 0.44 and 0.37 nm, and are characteristic peaks of alpha-form (triclinic structure) of even-even nylons with increasing annealing temperature. The intensities of these peaks increased, and they split further apart, with elevated annealing temperatures. The solid-state (15)N CP/MAS NMR spectra of the nylon 18 18 samples that had been quenched and annealed also confirmed the alpha-crystalline form. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 92-98, 2012

A series of imidazolium salts having various substituents and functional groups were synthesized and characterized by FTIR and NMR spectroscopy. Organic modification of natural and synthetic layered silicates involving montmorillonite (MMT), laponite (lap), and synthetic mica (mica) was carried out by ion-exchange reaction. The obtained organo-clays were characterized by FTIR and powder X-ray diffraction techniques. Results indicate that these organically modified clays have much higher thermal stabilities compared to their corresponding imidazolium halides. It was also observed from TGA analysis that thermal stability does not depend on the functional group present at the 3-position of the imidazolium salts. These studies strongly supports premise that the removal of halide is necessary to improve the thermal stability of the organo-clay produced.

Hydrogen-bonded supramolecular polymers were prepared from the derivatives of alpha-amino-epsilon-caprolactam (ACL), obtained from a renewable resource. Several self-complimentary bis- or tetra-caprolactam monomers were synthesized by varying the number of carbons of the spacer between the hydrogen-bonding end groups. Physical properties of these hydrogen-bonded polymers were clearly demonstrated by differential scanning colorimetry, solid-state NMR, and X-ray powder diffraction analyses. The supramolecular behavior was also supported by fiber formation from the melt for several of these compounds, and stable glassy materials were prepared from the physical mixtures of two different biscaprolactams. The self-association ability of ACL was also used by incorporating ACL at the chain ends of low-molecular weight Jeffamine (M-n = 900 g/mol) using urea and amide linkages. The transformation of this liquid oligomer at room temperature into a self-standing, transparent film clearly showed the improvement in mechanical properties obtained by the introduction of terminal hydrogen-bonding groups. Finally, the use of monomers with a functionality of four gave rise to network formation either alone or combination with bifunctional monomers. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2451-2460, 2011

Polyamide 12, T-polyamide-6 (PA-12, T-PA-6) block copolymers were synthesized by anionic polymerization of caprolactam using a PA-12, T macrocoinitiator (McI). PA-12, T McI and its precursors are soluble in molten caprolactam allowing for both the McI step-growth polymerization and anionic polymerization to be performed in one-pot. It was found that the competing reaction rates of caprolactam ring-opening polymerization and McI transamidation are both deterred by a common ion effect using CaCl2 and soluble materials were obtained using > 1 mol % CaCl2. Without CaCl2, the reaction mixture solidifies in less than 30 s and produces crosslinked materials. To understand this effect, PA-12, T McI reactions with caprolactam were performed with 1-10 mol % CaCl2, and polymer structures were characterized using C-13 NMR and dilute solution viscometry. These data were then correlated with unique thermal properties and swelling behavior of the block copolymers. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2271-2280, 2011

However, one of the challenges for application driven research in the area of supramolecular polymers is to design and synthesize monomeric units that are inexpensive and commercially available or that can be easily synthesized on a large scale in one or two steps. The present work involves i) synthesis of novel self complementary monomers derived from a renewable resource, -amino-- caprolactam, by a one-step, high yielding procedure, ii) clear demonstration of macroscopic properties of hydrogen-bonded supramolecular polymers formed from the melts of these monomers and iii) initial exploration of practical application areas for these materials. Experimental Materials. L--amino--caprolactam hydrochloride, succinoyl chloride, adipoyl chloride, azeloyl chloride, acryloyl chloride, thionyl chloride, hexanoyl chloride, hexylisocyanate, 1,6-hexamethylene diisocyanate and triethyl amine were purchased from Aldrich. 1,6-Hexamethylene diamine was purchased from Fluka. Octadecanedioic acid chloride was synthesized from the reaction of octadecanedioic acid (Cognis) with thionyl chloride. Jeffamine, or poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether), with Mn= 900 g/mol was purchased from Aldrich. All solvents were purchased from Fischer Scientific.

New ether dimer (ED-Eh) and diester (EHDE) derivatives of alpha-(hydroxymethyl)acrylate, each having two 2-ethylhexyl side chains, and an amine-linked di(2-ethylhexyl)acrylate (AL-Eh), having three 2-ethylhexyl side chains, were synthesized and (co)polymerized to evaluate the effects of differences in the structures of the monomers on final (co)polymer properties, particularly glass transition temperature, T-g. The free radical polymerizations of these monomers yielded high-molecular-weight polymers. Cyclopolymer formation of ED-Eh and AL-Eh was confirmed by C-13 NMR analysis and the cyclization efficiencies were found to be very high (similar to 100%). Copolymers of ED-Eh, EHDE, and AL-Eh with methyl methacrylate (MMA) showed significant T-g decreases over poly(methyl methacrylate) (PMMA) due to 2-ethylhexyl side groups causing "internal" plasticization. Comparison of the T-g's of the copolymers of 2-ethylhexyl methacrylate, ED-Eh, EHDE, and AL-Eh with MMA revealed that the impacts of these monomers on depression of T-g's are identical with respect to the total concentration of the pendent groups. This is consistent with an earlier study involving copolymers of monomers comprising one and two octadecyl side groups with MMA. That is, the magnitude of decrease in T-g's was quantitatively related to the number of the 2-ethylhexyl pendent groups in the copolymers rather than their placement on the same or randomly incorporated repeat units. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2302-2310, 2010

A functional derivative of epsilon-caprolactam, 5-azepane-2-one ethylene ketal or gamma-ethylene ketal epsilon-caprolactam, has been synthesized by a very straightforward and highly efficient Beckmann rearrangement reaction. Homopolymers of this new monomer and its copolymers with epsilon-caprolactam have been synthesized by anionic ring-opening polymerization using N-acetyl-epsilon-caprolactam and NaH. The ketone groups can be easily released by deacetalyzation, and subsequent reaction leads to complete reduction to hydroxyl pendant groups. The ketone-containing (co)polymers respond sensitively to both thermal and photo-cross-linking in this novel class of materials. These new aliphatic polyamides bearing either ketone or hydroxyl pendant groups provide entries into it large number of application areas.

Poly(dodecamethylene terephthalamide) (PA-12,T) was synthesized by melt condensation polymerization of 12,T salt with 0, 1, 3, 5, or 10% molar excess of 1,12-diaminododecane (DA), terephthalic acid (TA), or benzoic acid (BA). Intrinsic viscosities (IV) (0.5 g/dL in 96% H2SO4 at 25 degrees C) were measured to determine relative molecular weight differences. IV was highest for reactions containing 1 and 3 mol % excess DA (1.36 and 1.31 dL/g, respectively), followed by the product of pure 1 : 1 salt (1.25 dL/g). For all concentrations of excess TA and BA, IV was decreased. C-13-NMR chemical shifts for DA, TA, and BA end groups were identified and their concentrations determined by comparison with the intensity of main chain polymer peaks. A log-log plot of IV versus number average molecular weight calculated from 13C-NMR data shows a linear trend with Mark-Houwink constants of K = 55.8 x 10(-5) dL/g and alpha = 0.81. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3388-3395, 2010

Semi-aromatic polyterephthalamides 10,T and 12,T were synthesized with 0–60wt-% PA-6,T comonomer by a melt polycondensation process. Molecular weights of the copolymers ranged from 12,000 to 27,000g/mol and all produced tough melt-pressed films. The substituted aromatic carbon of the 13C NMR spectra revealed that comonomer sequences are statistical; e.g., 50:50wt-% PA-12,T-co-6,T copolymer had 12,T-12,T:12,T-6,T:6,T-6,T sequence ratios of approximately 1:2:1. Copolymers of both PA-10,T and 12,T exhibited a eutectic melting point at 30wt-% PA-6,T, with melting points decreasing linearly from 315 and 292°C to minima of 280 and 272°C, respectively. Melting enthalpies showed similar minima at ca. 35wt-% PA-6,T. WAXD and DMA were used to further characterize the eutectic behavior, and a comprehensive analysis of PA-6,T copolymer melting behavior is given.

New supramolecular assemblies based on cyclodextrin and adamantane were prepared. Two methacrylate monomers bearing cyclodextrin and adamantane were synthesized, and copolymerized with poly(ethylene glycol) methyl ether methacrylate, (PEGMA, 300 g/mol), by free radical polymerization. Copolymers bearing pendent cyclodextrin and adamantane were characterized by NMR, FTIR, TGA, SEC, Differential scanning calorimetry (DSC), and UV-visible spectrophotometer. All copolymers showed two distinct glass transitions. The specific interaction between pendent adamantyl and cyclodextrin was examined by H-1-NMR. The viscoelastic properties of supramolecular assemblies were investigated with frequency and temperature sweep experiments. The specific host-guest interaction between pendent adamantyl and cyclodextrin lead to large increases of the viscosity; and depending on the concentration of these groups, also to gel formation. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 581-592, 2010

Methacrylate monomers have been widely used in medical and dental applications such as bone cements, dental fillings, bioadhesives, and hydrogels. One major problem of these monomers resides in their low rates of polymerization leading to leaching problems that cause irritation of the surrounding tissues and even cell death. Here we describe the synthesis and polymerization of new mono-methacrylates containing multifunctional pyrrolidinone moieties. Such monomers possess stronger inherent hydrogen bonding potential susceptible to increase their reactivity and polymerization rates. These monomers were shown to homopolymerize rapidly leading to crosslinked polymers. The corresponding rates of polymerization were found to be comparable to difunctional methacrylates such as hexanediol dimethacrylate. Intermolecular hydrogen bonding interactions involving the pyrrolidinone unit leads these monomers to behave as “pseudo” difunctional monomers upon homopolymerization.

Nylon 18 18 and nylon 18 1,3-adamantanedicarboxylic acid (ADA) have been synthesized via melt polycondensation and characterized by thermal and Spectroscopic techniques. Good film forming behavior combined with film toughness and flexibility indicate reasonable molecular weights for both. The higher aliphatic content of nylon 18 18 leads to increased resistance to common organic solvents over commercial nylons. Crystallization of nylon 18 18 combines hydrogen bonding of the amide units with a more significant contribution from van der Waals forces than possible for lower aliphatic content nylons due to the greater aliphatic chain lengths. Solid state N-15 CP/MAS NMR indicates a mostly amorphous polymer, with crystalline regions comprised of the thermodynamically stable a-form generally adopted by even-even nylons. Nylon 18 ADA as-produced is completely amorphous as determined by differential scanning calorimetry. However, solution cast samples of nylon 18 ADA shows some ordered structures that can grow into more stable crystals with annealing. These crystals, once melted, do not recrystallize possibly due to chain rearrangement inhibited by bulky adamantly-groups. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4409-4419, 2009