A functional derivative of ε-caprolactam, 5-azepane-2-one ethylene ketal or γ-ethylene ketal ε-caprolactam, has been synthesized by a very straightforward and highly efficient Beckmann rearrangement reaction. Homopolymers of this new monomer and its copolymers with ε-caprolactam have been synthesized by anionic ring-opening polymerization using N-acetyl-ε-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 a large number of application areas.

Poly(e-caprolactone)/organomodified montmorillonite nanocomposites were prepared by in situ polymerization with dibutyltin dimethoxide as an initiator/ catalyst. The montmorillonite was first modified with 1-decyl-2-methyl-3-(11-hydroxyundecyl)imidazolium cation. The hydroxyl functionality was used not only for initiating polymer chains from the surface of the clay platelets but also for grafting polymer chains to the surface by acting as a reversible chain-transfer agent. The molecular weights of the polymer chains were controlled by the ratio of monomer to hydroxyl content. X-ray diffraction and transmission electron microscopy studies confirmed that highly exfoliated nanostructures were formed. The amount of inorganic component did not affect the thermal behavior of the polymer matrix as shown by differential scanning calorimetry or thermogravimetric analysis. The highly exfoliated clay sheets acted as nucleating agents and increased the degree of crystallinity from 51 to 69% at 5 wt %. Dynamic mechanical analysis revealed an enhancement of the storage modulus with increasing clay content above the glass-transition temperature.

Hydrogen‐bonded supramolecular polymers were prepared from the derivatives of α‐amino‐ε‐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 (Mn = 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. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Summary: a-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 a-amino-e-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 (T g ) values plus unexpectedly large sub-T g 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.

A 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 1 H and 13 C solution nuclear magnetic resonance spectrometry and mass spectrometry. Copolymerization of cyclic amides with ecaprolactam 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. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52,[96][97][98][99][100][101][102][103]